Month: July 2022

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