Month: October 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

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