Myhyperbola

When I took up running in college, a friend of mine scoffed at the idea. He hated running and was convinced runners were “wearing out” their joints. He liked to say he was saving his knees for his old age.

So, was he onto something? Does running really ruin your joints, as many people believe?

Runners can get arthritis, but is running the cause?

You may think the answer is obvious. Surely, years of running (pounding pavements, or even softer surfaces) could wear out your joints, much like tires wear out after you put enough miles on them. And osteoarthritis, the most common type of arthritis, usually affects older adults. In fact, it’s often described as age-related and degenerative. That sounds like a wear-and-tear sort of situation, right?

Maybe not. Sure, it’s easy to blame running when a person who runs regularly develops arthritis. But that blame may be misguided. The questions to ask are:

• Does running damage the joints and lead to arthritis?
• Does arthritis develop first and become more noticeable while running?
• Is the connection more complicated? Perhaps there’s no connection between running and arthritis for most people. But maybe those destined to develop arthritis (due to their genes, for example) get it sooner if they take up running.

Extensive research over the last several decades has investigated these questions. While the answers are still not entirely clear, we’re moving closer.

What is the relationship between running and arthritis?

Mounting evidence suggests that that running does not cause osteoarthritis, or any other joint disease.

• A study published in 2017 found that recreational runners had lower rates of hip and knee osteoarthritis (3.5%) compared with competitive runners (13.3%) and nonrunners (10.2%).
• According to a 2018 study, the rate of hip or knee arthritis among 675 marathon runners was half the rate expected within the US population.
• A 2022 analysis of 24 studies found no evidence of significant harm to the cartilage lining the knee joints on MRIs taken just after running.

These are just a few of the published medical studies on the subject. Overall, research suggests that running is an unlikely cause of arthritis — and might even be protective.

Why is it hard to study running and arthritis?

• Osteoarthritis takes many years to develop. Convincing research would require a long time, perhaps a decade or more.
• It’s impossible to perform an ideal study. The most powerful type of research study is a double-blind, randomized, controlled trial. Participants in these studies are assigned to a treatment group (perhaps taking a new drug) or a control group (often taking a placebo). Double-blind means neither researchers nor participants know which people are in the treatment group and which people are getting a placebo. When the treatment being studied is running, there’s no way to conduct this kind of trial.
• Beware the confounders. A confounder is a factor or variable you can’t account for in a study. There may be important differences between people who run and those who don’t that have nothing to do with running. For example, runners may follow a healthier diet, maintain a healthier weight, or smoke less than nonrunners. They may differ with respect to how their joints are aligned, the strength of their ligaments, or genes that direct development of the musculoskeletal system. These factors could affect the risk of arthritis and make study results hard to interpret clearly. In fact, they may explain why some studies find that running is protective.
• The effect of running may vary between people. For example, it’s possible, though not proven, that people with obesity who run regularly are at increased risk of arthritis due to the stress of excess weight on the joints.

The bottom line

Trends in recent research suggest that running does not wear out your joints. That should be reassuring for those of us who enjoy running. And if you don’t like to run, that’s fine: try to find forms of exercise that you enjoy more. Just don’t base your decision — or excuse — for not running on the idea that it will ruin your joints.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Loneliness is complicated. You can feel lonely when you lack friends and miss companionship, or when you’re surrounded by people — even friends and family.

Either way, loneliness can have devastating health effects. It boosts risk for coronary artery disease, stroke, depression, high blood pressure, declining thinking skills, inability to perform daily living tasks, and even an early death. The remedy? Below we offer three ways to ease loneliness and add happiness by helping you expand your social network.

Taking the first steps

Not all loneliness can be solved by seeking out people. Loneliness that occurs despite relationships may require talk therapy and a journey that looks inward.

Reducing loneliness caused by a lack of relationships is more of an outward journey to make new friends. “That’s a challenge as we get older, because people are often established in their social groups and aren’t as available as they might have been in a different phase of life. So you have to be more entrepreneurial and work harder to make friends than you once did,” says Dr. Jacqueline Olds, a psychiatrist at Harvard-affiliated McLean Hospital and the coauthor of two books on loneliness.

Trying these strategies can help.

1. Seek like-minded souls

Being around people who share your interests gives you a head start on making friends: you already have something in common.

Start by considering your interests. Are you a voracious reader, a history lover, a movie aficionado, a gardener, a foodie, a puppy parent, or an athlete? Are you passionate about a cause, your community, or your heritage? Do you collect things? Do you love classic cars? Do you enjoy sprucing up old furniture? Maybe you want to learn something new, like how to cook Chinese food or speak another language. Search for online groups, in-person clubs, volunteer opportunities, or classes that match any of your interests or things you’d like to try.

Once you join a group, you’ll need to take part in it regularly to build bonds. If you can gather in person, it’s even better. “The part of our brain involved in social connection is stimulated by all five senses. When you’re with someone in the same room, you get a much stronger set of stimuli than you do by watching them on an electronic screen,” Dr. Olds says.

2. Create opportunities

If joining someone else’s group is unappealing, start your own. Host gatherings at your place or elsewhere. “All it takes is three people. You can say, ‘Let’s read books or talk about a TV show or have a dinner group on a regular basis,'” Dr. Olds says.

Other ideas for gatherings — either weekly or monthly — include:

• game nights
• trivia nights
• hikes in interesting parks
• beach walks
• bird-watching expeditions
• running or cycling
• meditation
• museum visits
• cooking
• knitting, sewing, or crafting
• shopping
• day trips to nearby towns
• jewelry making
• collector show-and-tell (comic books, antique dolls, baseball cards).

The people you invite don’t have to be dear friends; they can just be people you’d like to get to know better — perhaps neighbors or work acquaintances.

If they’re interested in a regular gathering, pin down dates and times. Otherwise, the idea might stay stuck in the talking stages. “Don’t be timid. Say, ‘Let’s get our calendars out and get this scheduled,'” Dr. Olds says.

3. Brush up your social skills

Sometimes we’re rusty in surface social graces that help build deeper connections. “It makes a huge difference when you can be enthusiastic rather than just sitting there and hoping someone will realize how interesting you are,” Dr. Olds says.

Tips to practice:

• Smile more. Smiling is welcoming, inviting, and hospitable to others.
• Be engaging. Prepare a few topics to talk about or questions to ask — perhaps about the news or the reason you’ve gathered (if it’s a seminar, for example, ask how long someone has been interested in the subject). Or look for a conversation starter. “Maybe the person is wearing a pretty brooch. Ask if there’s a story behind it,” Dr. Olds suggests.
• Be a good listener. “Listen in a way that someone realizes you’re paying attention. Hold their gaze, nod your head or say ‘Mm hmm’ as they’re talking so you give feedback. Assume everyone in the world is just yearning for your feedback,” Dr. Olds says.
• Ask follow-up questions. Don’t ignore signals that someone has interesting stories to tell. “If they allude to something, your job is to look fascinated and ask if they can tell you more. They’re dropping crumbs on a path to a deeper exchange,” Dr. Olds notes.

Even chats that don’t lead to friendships can be enriching. A 2022 study found that people who had the most diverse portfolios of social interactions — exchanges with strangers, acquaintances, friends, or family members — were much happier than those with the least diverse social portfolios.

Ultimately, a wide variety of interactions contributes to well-being, whether you’re talking to the cashier at the supermarket, a neighbor, an old friend, or a new one. And all of these connections combined may go a long way toward helping you feel less lonely.

About the Author

Heidi Godman, Executive Editor, Harvard Health Letter

Heidi Godman is the executive editor of the Harvard Health Letter. Before coming to the Health Letter, she was an award-winning television news anchor and medical reporter for 25 years. Heidi was named a journalism fellow … See Full Bio View all posts by Heidi Godman

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Howard LeWine, M.D., is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Snuff is a smokeless tobacco similar to chewing tobacco. It rarely makes headlines. But it certainly did when the FDA authorized a brand of snuff to market its products as having a major health advantage over cigarettes. Could this be true? Is it safe to use snuff?

What did the FDA authorize as a health claim?

Here’s the approved language for Copenhagen Classic Snuff:

If you smoke, consider this: switching completely to this product from cigarettes reduces risk of lung cancer.

While the statement is true, this FDA action — and the marketing that’s likely to follow — might suggest snuff is a safe product. It’s not. Let’s talk about the rest of the story.

What is snuff, anyway?

Snuff is a form of tobacco that’s finely ground. There are two types:

• Moist snuff. Users place a pinch or a pouch of tobacco behind their upper or lower lips or between their cheek and gum. They must repeatedly spit out or swallow the tobacco juice that accumulates. After a few minutes, they remove or spit out the tobacco as well. This recent FDA action applies to a brand of moist snuff.
• Dry snuff. This type is snorted (inhaled through the nose) and is less common in the US.

Both types are available in an array of scents and flavors. Users absorb nicotine and other chemicals into the bloodstream through the lining of the mouth. Blood levels of nicotine are similar between smokers and snuff users. But nicotine stays in the blood for a longer time with snuff users.

Why is snuff popular?

According to CDC statistics, 5.7 million adults in the US regularly use smokeless tobacco products — that’s about 2% of the adult population. A similar percentage (1.6%) of high school students use it as well. That’s despite restrictions on youth marketing and sales.

What accounts for its popularity?

• Snuff may be allowed in places that prohibit smoking.
• It tends to cost less than cigarettes: $300 to $1,000 a year versus several thousand dollars a year paid by some smokers.
• It doesn’t require inhaling smoke into the lungs, or exposing others to secondhand smoke.
• Snuff is safer than cigarettes in at least one way — it is less likely to cause lung cancer.
• It may help some cigarette smokers quit.

The serious health risks of snuff

While the risk of lung cancer is lower compared with cigarettes, snuff has plenty of other health risks, including

• higher risk of cancers of the mouth (such as the tongue, gums, and cheek), esophagus, and pancreas
• higher risk of heart disease and stroke
• harm to the developing teenage brain
• dental problems, such as discoloration of teeth, gum disease, tooth damage, bone loss around the teeth, tooth loosening or loss
• higher risk of premature birth and stillbirth among pregnant users.

And because nicotine is addictive, using any tobacco product can quickly become a habit that’s hard to break.

There are also the “ick” factors: bad breath and having to repeatedly spit out tobacco juice.

Could this new marketing message about snuff save lives?

Perhaps, if many smokers switch to snuff and give up smoking. That could reduce the number of people who develop smoking-related lung cancer. It might even reduce harms related to secondhand smoke.

But it’s also possible the new marketing message will attract nonsmokers, including teens, who weren’t previously using snuff. A bigger market for snuff products might boost health risks for many people, rather than lowering them.

The new FDA action is approved for a five-year period, and the company must monitor its impact. Is snuff an effective way to help smokers quit? Is a lower rate of lung cancer canceled out by a rise in other health risks? We don’t know yet. If the new evidence shows more overall health risks than benefits for snuff users compared with smokers, this new marketing authorization may be reversed.

The bottom line

If you smoke, concerns you have about lung cancer or other smoking-related health problems are justified. But snuff should not be the first choice to help break the smoking habit. Commit to quit using safer options that don’t involve tobacco, such as nicotine gum or patches, counseling, and medications.

While the FDA’s decision generated news headlines that framed snuff as safer than smoking, it’s important to note that the FDA did not endorse the use of snuff — or even suggest that snuff is a safe product. Whether smoked or smokeless, tobacco creates enormous health burdens and suffering. Clearly, it’s best not to use any tobacco product.

Until we have a better understanding of its impact, I think any new marketing of this sort should also make clear that using snuff comes with other important health risks — even if lung cancer isn’t the biggest one.

Follow me on Twitter @RobShmerling

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

We all want our child to have friends. We want them to be happy, and to build the social skills and connections that will help them now and in the future.

Sometimes, and for some children, making friends isn’t easy. This is particularly true after the COVID-19 pandemic. Because of isolation and remote school, many children either didn’t learn the skills they need to make friends — or those skills got rusty.

Here are some ways parents can help.

Start at home: Learning relationship skills

Making and keeping friends involves skills that are best learned at home with your family. Some of them include:

• Empathy. Make sure that everyone in the family treats each other fairly and with kindness. Sometimes we turn a blind eye to sibling fights, or feel justified in snapping at our partner when we have had a long day. No matter what we say, our children pay attention to what we do.
• Curiosity about others. Make a family habit of asking each other about their day, their interests, their thoughts.
• Communication skills. These days, devices endanger the development of those skills. Shut off the devices. Have family dinners. Talk with each other.
• Cooperation. Do projects, play games, and do chores as a family. Work together. Help your child learn about taking turns and valuing the input of others.
• Regulating emotions. It’s normal to have strong feelings. When your child does, help them find ways to understand big emotions and manage them.
• Knowing when and how to apologize — and forgive. This really comes under empathy, but teach your child how to apologize for their mistakes, make amends, and forgive the mistakes of others.

All of these apply also to how you and your partner talk about — or with — other people in front of your children, too!

Be a good role model outside the home, too

When you are outside your home, be friendly! Strike up conversations, ask questions of people around you. Help your child learn confidence and strategies for talking to people they don’t know.

Make interactions easier

Conversations and interactions can be easier if they are organized around a common interest or activity. Here are some ways parents can help:

• Sign your child up for sports or other activities that involve their peers. Make sure it’s something they have at least some interest in doing.
• Get to know the parents of some of your child’s peers — and invite them all to an outing or meal. It could allow the children to get to know each other while taking some of the pressure off.
• When planning playdates, think about fun, cooperative activities — like baking cookies, or going to a park or museum.

Keep an eye on your child — but don’t hover

Ultimately, your child needs to learn to do this — and you don’t want to embarrass them, either. The two exceptions might be:

• If the children aren’t interacting at all, you might want to suggest some options for activities. Facilitate as necessary, and step back out again.
• If there is fighting or meanness on either side, you should step in and make it clear that such behavior isn’t okay.

Keep an open line of communication, and be supportive

Talk with your child regularly about their day, about their interactions, and how things made them feel. Listen more than you talk. Be positive and supportive. Remember that part of being supportive is understanding your child’s personality and seeing the world from their eyes. You can’t make your child someone they are not.

If your child keeps struggling with making friends, talk to your doctor

All parents need help sometimes — and sometimes there is more to the problem than meets the eye. This is particularly true if your child has ADHD or another diagnosis that could make interactions more challenging.

For information on supporting friendships at different ages, check out the advice from the American Academy of Pediatrics.

Follow me on Twitter @drClaire

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

The transgender population is steadily increasing. Last year, investigators reported that 1.3% of people between the ages of 18 and 24 in the United States identify as transgender, compared to 0.55% of the country’s older adults. This trend has implications for public health, and one issue in particular concerns the risk of prostate cancer in transgender women.

Because removing the prostate can lead to urinary incontinence and other complications, doctors leave the gland in place when initiating hormonal treatments to induce female sex characteristics in transitioning people. This process, which is called feminizing or gender-affirming hormonal therapy (GAHT), relies on medications and surgery to block testosterone, a male sex hormone. Prostate cancer is fueled by testosterone, and therefore GAHT lowers overall risks for the disease. But transgender women can still develop prostate cancer in ways that remain poorly understood, according to the authors of a new paper.

“More individuals are openly identifying as transgender, particularly as advances are made in reducing the discrimination and marginalization that this group has faced,” says Dr. Farnoosh Nik-Ahd, a urologist at the University of California, San Francisco, and the paper’s first author. “Thus, it’s important to understand their health outcomes and how best to care for this population.”

Dr. Nik-Ahd and her colleagues wanted better insights into prostate cancer incidence and screening rates among transgender women, so they performed a comprehensive review of the literature that generated some notable findings. One is that that the prevalence of GAHT in the transgender population is still unknown. Some studies put the figure at roughly one in every 12,000 to 13,000 people who identify as transgender. But this is likely an underestimate, the authors claim, and it’s not broken out by sex.

Questions over GAHT

Similarly, little is known about the impact of GAHT on the likelihood of developing prostate cancer, the team reported. Prostate cancer rates do appear to be lower among transgender women than they are among cisgender men (men whose gender identify matches their sex at birth). For instance, one study found just a single case of prostate cancer among 2,306 transgender women receiving routine health care at a clinic in Amsterdam, Holland, between 1975 and 2006. Another study, also from Holland, detected six cases of prostate cancer among 2,281 transgender women over 17 years, which again is less than the comparable rate among cisgender men.

But the interpretation of these rates is limited by the fact that transgender women often experience barriers to care. Nearly a third of them live in poverty, and many avoid the health system for fear of mistreatment. Some scientists suspect that estrogen given during GAHT may somehow contribute to prostate cancer development when given over long durations. However, more confirmatory evidence is needed. Worryingly, one study found that survival among transgender women with prostate cancer is worse than it is in cisgender men with the disease, yet that research lacked data on GAHT use.

Interpreting PSA values for specific populations

Dr. Nik-Ahd’s team was especially concerned about the lack of guideline recommendations for prostate-specific antigen (PSA) screening in the transgender population. None of the available guidelines worldwide mention transgender women, and the PSA cutoff of 4 nanograms per milliliter (ng/mL) of blood — which raises suspicions for prostate cancer — is specific to cisgender men. PSA levels ordinarily plummet in people taking GAHT, so the limit for what’s considered normal in transgender women should be capped at 1.0 ng/mL, the researchers propose. In the absence of more specific guidance, they also recommend that people meeting age criteria for PSA screening get tested before starting on GAHT, in order to obtain a baseline value.

Many doctors are already familiar with other common drugs that alter PSA values — in this case with screening implications for cisgender men, points out Dr. Heidi Rayala, a urologist affiliated with Beth Israel Deaconess Medical Center in Boston, and a member of the Harvard Medical School Annual Report on Prostate Diseases editorial board. For instance, PSA values drop by half in men taking finasteride or dutasteride for hair loss (or to shrink an enlarged prostate). “Doctors take extra care when interpreting PSA in cisgender men who take these drugs,” she says. “The same care needs to be taken in interpreting PSA values in transgender women. And there needs to be broader education on this topic for both primary care doctors as well as the transgender community.

Dr. Nik-Ahd agrees. “Future research should aim to understand baseline PSA values for those on gender-affirming hormones, and to understand how to navigate some of the psychosocial barriers around PSA screening so as to not stigmatize transgender patients,” she says.

About the Author

Charlie Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases

Charlie Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, Charlie has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio View all posts by Charlie Schmidt

About the Reviewer

Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Marc B. Garnick is an internationally renowned expert in medical oncology and urologic cancer. A clinical professor of medicine at Harvard Medical School, he also maintains an active clinical practice at Beth Israel Deaconess Medical … See Full Bio View all posts by Marc B. Garnick, MD

Be honest: just how much television are you watching? One study has estimated that half of American adults spend two to three hours each day watching television, with some watching as much as eight hours per day.

Is time spent on TV a good thing or a bad thing? Let's look at some of the data in relation to your risks for cognitive decline and dementia.

Physical activity does more to sharpen the mind than sitting

First, the more time you sit and watch television, the less time you have available for physical activity. Getting sufficient physical activity decreases your risk of cognitive impairment and dementia. Not surprisingly, if you spend a lot of time sitting and doing other sedentary behaviors, your risk of cognitive impairment and dementia will be higher than someone who spends less time sitting.

Is television actually bad for your brain?

Okay, so it's better to exercise than to sit in front of the television. You knew that already, right?

But if you're getting regular exercise, is watching television still bad for you? The first study suggesting that, yes, television is still bad for your brain was published in 2005. After controlling for year of birth, gender, income, and education, the researchers found that each additional hour of television viewing in middle age increased risk for developing Alzheimer's disease 1.3 times. Moreover, participating in intellectually stimulating activities and social activities reduced the risk of developing Alzheimer's.

Although this study had fewer than 500 participants, its findings had never been refuted. But would these results hold up when a larger sample was examined?

Television viewing and cognitive decline

In 2018, the UK Biobank study began to follow approximately 500,000 individuals in the United Kingdom who were 37 to 73 years old when first recruited between 2006 and 2010. The demographic information reported was somewhat sparse: 88% of the sample was described as white and 11% as other; 54% were women.

The researchers examined baseline participant performance on several different cognitive tests, including those measuring

• prospective memory (remembering to do an errand on your way home)
• visual-spatial memory (remembering a route that you took)
• fluid intelligence (important for problem solving)
• short-term numeric memory (keeping track of numbers in your head).

Five years later, many participants repeated certain tests. Depending on the test, the number of participants evaluated ranged from 12,091 to 114,373. The results of this study were clear. First, at baseline, more television viewing time was linked with worse cognitive function across all cognitive tests.

More importantly, television viewing time was also linked with a decline in cognitive function five years later for all cognitive tests. Although this type of study cannot prove that television viewing caused the cognitive decline, it suggests that it does.

Further, the type of sedentary activity chosen mattered. Both driving and television were linked to worse cognitive function. But computer use was actually associated with better cognitive function at baseline, and a lower likelihood of cognitive decline over the five-year study.

Television viewing and dementia

In 2022, researchers analyzed this same UK Biobank sample with another question in mind: Would time spent watching television versus using a computer result in different risks of developing dementia over time?

Their analyses included 146,651 people from the UK Biobank, ages 60 and older. At the start of the study, none had been diagnosed with dementia.

Over 12 years, on average, 3,507 participants (2.4%) were diagnosed with dementia. Importantly, after controlling for participant physical activity:

• time spent watching television increased the risk of dementia
• time spent using the computer decreased the risk of dementia.

These changes in risk were not small. Those who watched the most television daily — more than four hours — were 24% more likely to develop dementia. Those who used computers interactively (not passively streaming) more than one hour daily as a leisure activity were 15% less likely to develop dementia.

Studies like these can only note links between behaviors and outcomes. It's always possible that the causation works the other way around. In other words, it's possible that people who were beginning to develop dementia started to watch television more and use the computer less. The only way to know for sure would be to randomly assign people to watch specific numbers of hours of television each day while keeping the amount of exercise everyone did the same. That study is unlikely to happen.

The bottom line

If you watch more than one hour of TV daily, my recommendation is to turn it off and do activities that we know are good for your brain. Try physical exercise, using the computer, doing crossword puzzles, dancing and listening to music, and participating in social and other cognitively stimulating activities.

About the Author

Andrew E. Budson, MD, Contributor; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Andrew E. Budson is chief of cognitive & behavioral neurology at the Veterans Affairs Boston Healthcare System, lecturer in neurology at Harvard Medical School, and chair of the Science of Learning Innovation Group at the … See Full Bio View all posts by Andrew E. Budson, MD

Scientific advances have brought us scores of new drugs in recent years. In the US, one major agency — the FDA — is responsible for making sure that the drugs they approve are safe and effective. Yet there were more than 14,000 drug recalls in the last 10 years, according to FDA statistics. That averages out to nearly four drug recalls a day!

Why are drug recalls so common, and how can you maximize safety when taking the medicines you need?

Why do so many drug recalls occur?

The FDA approves prescription drugs if research shows a medicine is safe and effective. Usually the risks are well known by the time approval is granted. For over-the-counter drugs, the bar is lower: proof that they work is not required, but the FDA still maintains oversight for safety.

Drug recalls are common because:

• Rare side effects may be missed in clinical trials. Studies leading to drug approval might have hundreds or thousands of study subjects. But a rare problem may not be detected until tens of thousands of people have taken a drug.
• Study subjects tend to be healthier than the general population. When you’re trying to figure out if a drug works, the chances of success are higher and reliability of results is greater if study subjects are healthy. Once a drug is approved, people taking it may be older, less healthy, or taking multiple drugs for health issues.
• Problems during or after manufacturing can make a safe drug harmful. Examples include bacterial contamination, incorrect labeling, and improper storage.
• Bad behavior by drug makers may affect drug safety. For example, multiple over-the-counter supplements marketed for male sexual performance were recalled in recent years because they were laced with prescription drugs for erectile dysfunction.

Are most drug recalls high-risk?

Fewer than one in 10 poses a serious health risk. The FDA grades risk severity for recalls as follows:

• Class I is dangerous and poses a serious health risk (a hand sanitizer contaminated with methanol)
• Class II might cause a temporary or slight risk of serious harm (a diabetes medicine stored at the wrong temperature)
• Class III is unlikely to cause any harm to health, but there is a violation of FDA requirements (an ointment for dermatitis in damaged tubes).

Between 80% and 90% of drug recalls are Class II.

In 2022, 6% of recalls were Class 1, 86% were Class II, and 7% were Class III.

How do drug recalls happen?

The FDA inspects drug manufacturing facilities every two to three years. The agency also tests thousands of drugs each year.

Problems spotted during inspections, concerns identified by drug makers, or problems reported by patients or health care professionals can prompt a recall. The FDA then assigns a risk classification, supervises actions taken by the drug maker to remedy the problem, and monitors the product to make sure the problem is eliminated.

Drug recalls in the US are almost always voluntary. That means the drug maker acknowledges the problem and takes corrective action rather than waiting for a possible mandate from the FDA.

How can you stay informed about medicines you use?

Here are some practical measures to take:

• Sign up to receive texts or emails about recalls, market withdrawals, and safety alerts from the FDA.
• When filling prescriptions, take a good look at your medicine. Pills should not be discolored or crumbling, or have an unusual odor. If your prescription hasn’t changed, a refill should look similar to what you’ve taken in the past. If you suspect a problem, contact your pharmacist or the health care professional who prescribed it. And if you do confirm a problem, you can report it to the FDA.
• If you learn of a recall for a drug you take, check the lot number on the package to see if your medication is affected. If the risk is classified as high (Class I), contact your doctor right away for advice. For many recalled drugs, there are safe and effective alternatives.
• A recall notice will tell you if the medicine can be replaced or if you can be reimbursed. If you are instructed to dispose of medication, do so safely.

Another way to limit your potential exposure to recalled drugs is to take fewer drugs. Review your medication list with your doctor regularly and take only what you truly need.

The bottom line

News on drug recalls may not inspire confidence. It might make you wonder if the drugs you take are safe. In general, yes: the vast majority of medicines on the market have an excellent safety profile. But with more than 1,000 drug recalls every year, there’s plenty of room for improvement by drug makers and good reason to encourage better regulation of the industry.

Follow me on Twitter @RobShmerling

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Driving along the freeway recently, a billboard caught my eye. In bold letters it proclaimed:

Milk hydrates better than water.

Wait, could this be true? And if so, should I be rehydrating with milk after a workout? And should we all have milk, rather than water, in our water bottles?

What’s behind the claim?

Unsurprisingly, the ad is sponsored by the milk industry. And while I’d never heard this claim before, the studies behind the idea aren’t particularly new or compelling. The website supporting this ad cites three small studies dating back more than a decade:

• A 2007 study enrolled 11 volunteers (five men, six women) who exercised until they were markedly dehydrated on several occasions. Each time they rehydrated with a different drink, and their urine output was measured over the following five hours. After drinking milk, the study volunteers produced less urine (and therefore retained more fluid) than with water or a sports drink (Powerade). Therefore, milk was considered to provide better hydration.
• A study published in 2016 described seven men with marked dehydration following exercise who drank fat-free milk, water, or Powerade. The results were similar.
• A 2016 study enrolled 72 healthy, well-hydrated men who drank various fluids and then had their urine production measured over the next four hours. The drinks used in this study were water, whole milk, skim milk, beer, Dioralyte (an oral rehydration solution used after fluid loss from diarrhea), tea, coffee, diet cola, regular cola, orange juice, and Powerade. The researchers found that fluid retention was best after drinking either type of milk or the oral rehydration solution; results for the other drinks were similar to water.

Sounds like milk is a winner, right? Maybe. But there are other things to consider.

The study details matter

The findings of these studies aren’t definitive. As with all research, there are important limitations. For example:

• The small number of participants in these studies means that just a few people could have an outsized impact on the results.
• Two of the three studies involved significant dehydration by intensely exercising in a warm environment, leading to several pounds of fluid loss. Therefore, the results may not apply to people engaged in more typical daily activities or workouts. In addition, the studies equated better hydration with less urine production in the hours after drinking various fluids. This is only one way to define hydration, and not clearly the best one.
• The advantage of milk reported in these studies may be too small or too temporary to matter much. For example, in the study of 72 people, milk drinkers produced about 37 ounces of urine over four hours while water drinkers produced 47 ounces. Does the 10-ounce difference have a meaningful health impact? If the study participants had been monitored for a longer period, would this difference disappear?
• The amount of milk consumed in the study of seven men would contain more than 1,000 calories. That may be acceptable for an elite athlete after hours of intensive exercise in the heat, but counterproductive and costly for someone working out for 30 minutes to help maintain or lose weight. Tap water is free and has no calories!

Hyping hydration: Many claims, little evidence

The billboard promoting milk reflects our relatively recent focus on hydration for health. This is promoted — or perhaps created — by advertisers selling sports drinks, energy drinks and, yes, water bottles. But does drinking “plenty of water” translate to weight loss, athletic performance, and glowing appearance? Does monitoring urine color (darker could indicate dehydration) and downing the oft-recommended eight glasses of water daily make a difference in our health? On the strength of evidence offered so far, I’m not convinced.

But wait, there’s more! Emotional support water bottles, a trend popularized recently in Australia, offer one part public expression of your commitment to health and one part security blanket. (Yes, it’s a thing: #emotionalsupportwaterbottle has more than 80 million views on TikTok.) And then there’s intravenous hydration on demand for healthy (and often wealthy) people convinced that intravenous fluids will improve their looks, relieve their hangovers, help with jet lag, or remedy and prevent an assortment of other ailments.

Is this focus on hydration actually helpful?

Before water bottles were everywhere and monitoring fluid intake became commonplace, medically important dehydration wasn’t a problem for most healthy people who were not rapidly losing fluids due to heat, intense exercise, diarrhea, or the like.

The fact is, drinking when thirsty is a sound strategy for most of us. And while there are important exceptions noted below, you probably don’t need fluids at hand at all times or to closely monitor daily fluid intake to be healthy. There are far more important health concerns than whether you drink eight glasses of water each day.

When is dehydration a serious problem?

Weather, exercise, or illness can make dehydration a major problem. Particularly susceptible are people who work or exercise outside in hot and humid environments, those at the extremes of age, people experiencing significant fluid loss (as with a diarrheal illness), and those without reliable access to fluids. If significant dehydration occurs, replacing lost fluids is critically important, and may even require a medical setting where intravenous fluids can be provided quickly.

The bottom line

Despite the claims of milk ads and the iffy studies justifying them, the idea of replacing water with milk for rehydration may not convince everyone: the taste, consistency, and extra calories of milk may be hard to get past.

As for me, until there’s more convincing evidence of an actual health advantage of milk over water for routine hydration, I’ll stick with water. But I’ll forego the water bottle.

Follow me on Twitter @RobShmerling

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Turns out that when your mother told you to stop sitting near the TV or you might need glasses, she was onto something.

Myopia, or nearsightedness, is a growing problem worldwide. While a nearsighted child can see close objects clearly, more distant objects look blurry. Part of this growing problem, according to experts, is that children are spending too much time indoors looking at things close to them rather than going outside and looking at things that are far away.

What is nearsightedness?

Nearsightedness is very common, affecting about 5% of preschoolers, 9% of school-age children, and 30% of teens. But what worries experts is that over the last few decades its global prevalence has doubled — and during the pandemic, eye doctors have noticed an increase in myopia.

Nearsightedness happens when the eyeball is too large from front to back. Genes play a big role, but growing research shows that there are developmental factors. The stereotype of the nerd wearing glasses actually bears out; research shows that the more years one spends in school, the higher the risk of myopia. Studies also show, even more reliably, that spending time outdoors can decrease a child’s risk of developing myopia.

Why would outdoor time make a difference in nearsightedness?

While surprising, this actually makes some sense. As children grow and change, their lifestyles affect their bodies. A child who is undernourished, for example, may not grow as tall as they might have if they had better nourishment. A child who develops obesity during childhood is far more likely to have lifelong obesity. And the eyes of a child who is always looking at things close to him or her might adjust to this — and lose some ability to see far away.

Nearsightedness has real consequences. Not only can it cause problems with everyday tasks that require you to see more than a few feet away, such as school or driving, but people with myopia are at higher risk of blindness and retinal detachment. The problems can’t always be fixed with a pair of glasses.

What can parents do?

• Make sure your child spends time outdoors regularly — every day, if possible. That’s the best way to be sure that they look at things far away. It’s also a great way to get them to be more active, get enough Vitamin D, and learn some important life skills.
• Try to limit the amount of time your child spends close to a screen. These days, a lot of schoolwork is on screens, but children are also spending far too much of their playtime on devices rather than playing with toys, drawing, or other activities. Have some ground rules. The American Academy of Pediatrics recommends no more than two hours of entertainment media a day, and has a great Family Media Plan to help families make this happen.
• Have your child’s vision checked regularly. Most pediatricians do regular vision screening, but it is important to remember that basic screening can miss vision problems. It’s a good idea for your child to have a full vision examination from an ophthalmologist or an optometrist by kindergarten.
• Call your pediatrician or child’s eye doctor if you notice signs of a possible vision problem, such as
  • sitting close to the television or holding devices close to the face
  • squinting or complaining of any difficulty seeing
  • not being able to identify objects far away (when you go for walks, play I Spy and point to some far-away things!)
  • avoiding or disliking activities that involve looking close, like doing puzzles or looking at books, which can be a sign of hyperopia (farsightedness)
  • tilting their head to look at things
  • covering or rubbing an eye
  • one eye that turns inward or outward.

If you have any questions or concerns about your child’s vision, talk to your pediatrician.

Follow me on Twitter @drClaire

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

When you first learned the facts about pregnancy — from a parent, perhaps, or a friend — you probably didn’t learn that up to one in three ends in a miscarriage.

What causes miscarriage? How is it treated? And why is appropriate health care for miscarriage under scrutiny — and in some parts of the US, getting harder to find?

What is miscarriage?

Many people who come to us for care are excited and hopeful about building their families. It’s devastating when a hoped-for pregnancy ends early.

Miscarriage is a catch-all term for a pregnancy loss before 20 weeks, counting from the first day of the last menstrual period. Miscarriage happens in as many as one in three pregnancies, although the risk gradually decreases as pregnancy progresses. By 20 weeks, it occurs in fewer than one in 100 pregnancies.

What causes miscarriage?

Usually, there is no obvious or single cause for miscarriage. Some factors raise risk, such as:

• Pregnancy at older ages. Chromosome abnormalities are a common cause of pregnancy loss. As people age, this risk rises.
• Autoimmune disorders. While many pregnant people with autoimmune disorders like lupus or Sjogren’s syndrome have successful pregnancies, their risk for pregnancy loss is higher.
• Certain illnesses. Diabetes or thyroid disease, if poorly controlled, can raise risk.
• Certain conditions in the uterus. Uterine fibroids, polyps, or malformations may contribute to miscarriage.
• Previous miscarriages. Having a miscarriage slightly increases risk for miscarriage in the next pregnancy. For instance, if a pregnant person’s risk of miscarriage is one in 10, it may increase to 1.5 in 10 after their first miscarriage, and four in 10 after having three miscarriages.
• Certain medicines. A developing pregnancy may be harmed by certain medicines. It’s safest to plan pregnancy and receive pre-pregnancy counseling if you have a chronic illness or condition.

How is miscarriage diagnosed?

Before ultrasounds in early pregnancy became widely available, many miscarriages were diagnosed based on symptoms like bleeding and cramping. Now, people may be diagnosed with a miscarriage or early pregnancy loss on a routine ultrasound before they notice any symptoms.

How is miscarriage treated?

Being able to choose the next step in treatment may help emotionally. When there are no complications and the miscarriage occurs during the first trimester (up to 13 weeks of pregnancy), the options are:

Take no action. Passing blood and pregnancy tissue often occurs at home naturally, without need for medications or a procedure. Within a week, 25% to 50% will pass pregnancy tissue; more than 80% of those who experience bleeding as a sign of miscarriage will pass the pregnancy tissue within two weeks.

What to know: This can be a safe option for some people, but not all. For example, heavy bleeding would not be safe for a person who has anemia (lower than normal red blood cell counts).

Take medication. The most effective option uses two medicines: mifepristone is taken first, followed by misoprostol. Using only misoprostol is a less effective option. The two-step combination is 90% successful in helping the body pass pregnancy tissue; taking misoprostol alone is 70% to 80% successful in doing so.

What to know: Bleeding and cramping typically start a few hours after taking misoprostol. If bleeding does not start, or there is pregnancy tissue still left in the uterus, a surgical procedure may be necessary: this happens in about one in 10 people using both medicines and one in four people who use only misoprostol.

Use a procedure. During dilation and curettage (D&C), the cervix is dilated (widened) so that instruments can be inserted into the uterus to remove the pregnancy tissue. This procedure is nearly 99% successful.

What to know: If someone is having life-threatening bleeding or has signs of infection, this is the safest option. This procedure is typically done in an operating room or surgery center. In some instances, it is offered in a doctor’s office.

If you have a miscarriage during the second trimester of pregnancy (after 13 weeks), discuss the safest and best plan with your doctor. Generally, second trimester miscarriages will require a procedure and cannot be managed at home.

Red flags: When to ask for help during a miscarriage

During the first 13 weeks of pregnancy: Contact your health care provider or go to the emergency department immediately if you experience

• heavy bleeding combined with dizziness, lightheadedness, or feeling faint
• fever above 100.4° F
• severe abdominal pain not relieved by over-the-counter pain medicine, such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil). Please note: ibuprofen is not recommended during pregnancy, but is safe to take if a miscarriage has been diagnosed.

After 13 weeks of pregnancy: Contact your health care provider or go to the emergency department immediately if you experience

• any symptoms listed above
• leakage of fluid (possibly your water may have broken)
• severe abdominal or back pain (similar to contractions).

How is care for miscarriages changing?

Unfortunately, political interference has had significant impact on safe, effective miscarriage care:

• Some states have banned a procedure used to treat second trimester miscarriage. Called dilation and evacuation (D&E), this removes pregnancy tissue through the cervix without making any incisions. A D&E can be lifesaving in instances when heavy bleeding or infection is complicating a miscarriage.
• Federal and state lawsuits, or laws banning or seeking to ban mifepristone for abortion care, directly limit access to a safe, effective drug approved for miscarriage care. This could affect miscarriage care nationwide.
• Many laws and lawsuits that interfere with miscarriage care offer an exception to save the life of a pregnant patient. However, miscarriage complications may develop unexpectedly and worsen quickly, making it hard to ensure that people will receive prompt care in life-threatening situations.
• States that ban or restrict abortion are less likely to have doctors trained to perform a full range of miscarriage care procedures. What’s more, clinicians in training, such as resident physicians and medical students, may never learn how to perform a potentially lifesaving procedure.

Ultimately, legislation or court rulings that ban or restrict abortion care will decrease the ability of doctors and nurses to provide the highest quality miscarriage care. We can help by asking our lawmakers not to pass laws that prevent people from being able to get reproductive health care, such as restricting medications and procedures for abortion and miscarriage care.

About the Authors

Sara Neill, MD, MPH, Contributor

Dr. Sara Neill is a physician-researcher in the department of obstetrics & gynecology at Beth Israel Deaconess Medical Center and Harvard Medical School. She completed a fellowship in complex family planning at Brigham and Women's Hospital, and … See Full Bio View all posts by Sara Neill, MD, MPH

Scott Shainker, DO, MS, Contributor

Scott Shainker, D.O, M.S., is a maternal-fetal medicine specialist in the Department of Obstetrics and Gynecology at Beth Israel Deaconess Medical Center (BIDMC). He is also a member of the faculty in the Department of Obstetrics, … See Full Bio View all posts by Scott Shainker, DO, MS