22 October 2021

Walking Revisited

Stop the presses! Oh, Darn. Too late. The blog post said walking improved health and lowered the risk of death. But it didn’t say that moderate to vigorous exercise will do much more than walking for your fitness.

Welcome back. A month ago, I blogged about three studies that found walking was great with more steps generally associated with lower all-cause mortality (see Just Keep Walking). That seemed reasonable, but the studies also found no significant association between how fast one walks and mortality after adjusting for total steps per day.

All-cause mortality vs steps per day among U.S. adults age 40 or older (figure used in Just Keep Walking, from jamanetwork.com/journals/jama/fullarticle/2763292).

Though I expressed my surprise, I did find other studies that also reported any level of physical activity, regardless of intensity, was associated with a substantially lower risk of death.

Well, that was last month. In the meantime, news was released of another study that found moderate-vigorous physical activity boosts fitness three times more than walking.

Now that’s not surprising. Shall we look at that study?

Testing Physical Activity for Fitness
A team of investigators led by researchers with Boston and Harvard universities set out to better define the relationship between physical activity and physical fitness.

They enlisted 2,070 Framingham Heart Study participants (age 54 ± 9 years, split between men and women) to test how (1) moderate-vigorous physical activity (exercise), (2) low-moderate physical activity (steps/day walking) and (3) minimizing sedentary physical activity translate to cardiorespiratory fitness.

The participants wore accelerometers to measure the intensity and frequency of exercise, steps/day and sedentary times for two 8-day periods, 7.8 years apart. During the second period the participants’ cardiorespiratory fitness was assessed on a cycle ergometer with breath-by-breath gas exchange data obtained during four stages of exercise, initiation to recovery.

Activity levels and VO2 of 2,070 participants during second period; VO2 measured as milliliters of oxygen used in one minute per kilogram of body weight (from academic.oup.com/eurheartj/advance-article-abstract/doi/10.1093/eurheartj/ehab580/6357860).

Example of cycle ergometer measurement of VO2 (photo from www.endurancedave.com/post/whats-the-best-training-protocol-for-your-fastest-1-hour-cycling-effort).

The principal measure of cardiorespiratory fitness was peak oxygen uptake (VO2), which denotes the highest oxygen uptake reached during exercise to voluntary exhaustion.

Principal Findings
Here are the three study results that I found most interesting:

To achieve the equivalent change in cardiorespiratory fitness, each minute increase in moderate-vigorous physical activity (exercise) would require at least 3 minutes of intermediate cadence walking and at least 14 minutes less sedentary activity. 

Activity levels and VO2 of 2,070 participants during second period (from academic.oup.com/eurheartj/advance-article-abstract/doi/10.1093/eurheartj/ehab580/6357860).
As you would expect, participants with either higher moderate-vigorous physical activity or higher steps/day had higher fitness levels. But this was regardless of how much time they spent sedentary. It appears that much of the negative effect that being sedentary has on fitness may be offset by higher levels of exercise and walking.

Participants with high activity values at one period and low activity values at the other, 7.8 years apart, had equivalent levels of fitness. There may be a “memory effect” of previous physical activity on current levels of fitness.

Wrap Up
The earlier studies reported that increased steps/day was associated with lower rates of mortality, though it tended to reach a limit.

In the recent study, increased steps/day was associated with higher fitness levels. The lead researcher noted there was no evidence of a threshold beyond which higher levels of activity were no longer associated with greater fitness.

Fitness isn’t mortality, but they’re sure related. If you’d like to improve your fitness, try increasing the level of exertion through exercise or by picking up the pace. (The study categorized 60-99 steps/minute as low-level exertion, 100-129 steps/minute as moderate and greater than 130 steps/minute as vigorous.)

Be well and thanks again for stopping by.

Study of physical activity and fitness in European Heart Journal: academic.oup.com/eurheartj/advance-article-abstract/doi/10.1093/eurheartj/ehab580/6357860
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/929580
Cardiopulmonary exercise testing: www.massgeneral.org/medicine/pulmonary/treatments-and-services/cardiopulmonary-exercise-testing

15 October 2021

Dental Check-Up Revisited

Welcome back. About 11 years ago, I released a blog post that became one of the blog’s most popular. In those years, I wrote mainly about me, and that post chronicled my dental history. (Yes, of course it was humorous, see Dental Check-Up Time.)

Simulated reconstruction of Warren’s dentist at work
from Dental Check-Up Time and Amazon).

It began when I was young, when one visited the dentist only if something was wrong. The likelihood of there being something wrong was much higher in those pre-fluoride, pre-flossing, pre-periodic cleaning, pre-sugarless gum, pre-soft-toothbrush days. And while there was Novocain, which is no longer the anesthetic of choice, it was used sparingly for the big stuff, like extractions.

I ended that post, noting how dentistry had evolved; the only pain on visiting a dentist nowadays is the bill. I also mentioned my dental epiphany. On my first visit to a new dentist some 25 years ago, I was shown the evil decay-causing micro-creatures that were sloshing around in my mouth. That night, I rushed out to buy an antiseptic mouthwash, and I’ve rinsed twice a day ever since. Evil or good, the micro-critters don’t stand a chance.

I was thrilled to see that my mouthwash made the cut in a recent study as one of the best approaches for dental care.  

That study by researchers affiliated with the University of Buffalo (one is now with the University of Rochester) identified the best, worst and unproven approaches for dental care.

Assessing Dental Care Approaches
The researchers’ ratings followed their search and assessment of published systematic reviews of self-administered interventions to prevent periodontal disease.

Lest the terms be unfamiliar, periodontal disease is mainly the result of infections and inflammation of the gums and bone surrounding and supporting the teeth. In its early stage, called gingivitis, the gums can become swollen and red and may bleed. In its more advanced form, called periodontitis, the gums can pull away from the teeth, bone can be lost and the teeth may loosen and even fall out. 

Periodontal disease progression (from https://medlineplus.gov/ency/imagepages/19942.htm).
Periodontitis is common but largely preventable. It's normally the result of poor oral hygiene.

OK. To speed you on your way, I’ll get right to the researchers’ findings. Be forewarned that relatively few interventions have been proven effective.

What’s Recommended, What’s Not?

Best: toothbrush; interdental brush; water pick; mouthwash containing chlorhexidine gluconate (CHX), cetylpyridinium chloride (CPC) or essential oils (e.g., Listerine).

Regular brushing (with periodic dental hygienist cleaning) controls dental plaque, the sticky, colorless or pale-yellow film of bacteria that forms on and between teeth, both above and below the gum line. Interdental brushes and water picks are effective for reducing gingivitis, as are mouthwashes based on CHS, CPC and essential oils.

Toothpicks, though not effective for gingivitis, are useful for monitoring gum health. Gently prodding gums and monitoring for bleeding can detect signs of gum disease.

Unproven: electric toothbrush, dental floss, probiotics, dietary supplements and many mouthwashes.

They may be easier to use, but electric toothbrushes are no better than properly used manual brushes for reducing plaque and gingivitis. Similarly, while flossing is essential for interdental cleaning (including removal of interdental plaque between tightly spaced teeth), its overall value for reducing plaque and gingivitis has not been shown.

Probiotics are a promising yet unproven strategy to prevent gum disease; but there’s little evidence that dietary supplements improve gum health or that mouthwashes containing tea tree oil, green tea, anti-inflammatory agents, hydrogen peroxide, sodium benzoate, stannous fluoride, hexetidine or delmopinol reduce gingivitis. There’s also insufficient evidence that professional plaque removal with a scraper (scaling) prevents gum disease.

Worst: toothpastes containing triclosan.

I used Colgate Total toothpaste for many years before seeing reports that triclosan, its main ingredient for controlling plaque and gingivitis, was a suspected carcinogen. More years passed before Colgate replaced triclosan with sodium fluoride.

Wrap Up
As forewarned, there are surprisingly few self-administered interventions proven to prevent gingivitis and periodontitis, which makes the researchers’ umbrella review even more valuable. I look forward to future updates and hope you agree.

Warren’s dental visit freebies--toothbrush, floss, interdental brush.
Thanks for stopping by.

Umbrella review of periodontal prevention strategies in Journal of International Academy of Periodontology: www.perioiap.org/publications/57-october-2021/256-proven-primary-prevention-strategies-for-plaque-induced-periodontal-disease-an-umbrella-review
Article on review on EurekAlert! website: www.eurekalert.org/news-releases/930042
Periodontal disease:

08 October 2021

Medical Emoji

Welcome back. About two months ago, I devoted a blog post to the world of emoji (see Emoji). That post gives me a free card to jump right into today’s topic without passing Go or devoting space to emoji basics, like what are they.

Though it was all new to me before seeing a recent commentary in the Journal of the American Medical Association (JAMA), collaborators affiliated with the University of London, Emojination and Unicode Consortium, Massachusetts General Hospital and Harvard Medical School have been promoting the use of emoji in the field of medicine.

Emoji Usage
Medicine has used visual analog scales to gauge and communicate the intensity or frequency of symptoms for some time. Since 1983, for example, the Wong-Baker FACES Pain Rating Scale has helped children communicate their level pain by showing faces ranging from happy (0, no pain) to crying (10, worst pain imaginable).

The Wong-Baker FACES Pain Rating Scale (from wongbakerfaces.org/).

The authors of the commentary point out that these visual analog scales are trademarked and carry licensing fees. They opt for emoji that are open source and nonproprietary, especially if digitally accessible. The availability of a preloaded, curated, digital set of emoji would offer standardization, universality and familiarity, increasing usage. Appropriate emoji could facilitate communication of patient symptoms, concerns and other clinically relevant information; annotate patient instructions; and much more.

Emoji would also be a valuable tool for dealing with language or verbal challenges, whether treating children, non-native speakers or patients affected by disabilities that affect their ability to communicate.

Medical Emoji Status
As described in my earlier post, there are currently 3,521 approved emoji. Of these, the authors count about 30 other than generic body part images (e.g., ear, hand, leg, foot) that could be relevant to medicine. Those 30 are the result of efforts over the past five years.

For example, syringe and pill emoji were introduced in 2015; male and female health workers in 2016; individuals with disabilities (e.g., hearing aid, cane for the blind, mechanical arm and leg) in 2017; stethoscope, drop of blood, bone, tooth and microbe in 2019; and heart and lung in 2020.

Examples of current medical emoji (from jamanetwork.com/journals/jama/fullarticle/2783847).

The authors are actively organizing a more comprehensive and cohesive set of emoji. Two of the authors have already proposed 15 new medical emoji for the next release: intestines, leg cast, stomach, spine, liver, kidney, pill pack, blood bag, IV bag, CT scan, weight scale, pill box, ECG, crutches, and white blood cell.

Medical emoji proposed to Unicode Consortium, 2020 (from jamanetwork.com/journals/jama/fullarticle/2783847).

Wrap Up
The authors emphasize that emoji complement traditional modes of communication but carry their own constraints, such as communicating digitally, familiarity with human anatomy and simply adjusting to emoji. With medical emoji still in their infancy, however, there is a window of opportunity to shape the way this method of communication is incorporated into medical practice and research.

They recommend that the medical community begin work toward consensus on what iconography would best serve patients and the profession. Take the lead by formalizing a unified perspective on emoji relevant to the field.

Where there is currently no formal process for proposing and evaluating medical emoji, physician organization committees could be tasked with managing emoji submission and advocacy. Such a dedicated effort would enable diverse medical practitioners to participate and influence the evolution of a clinically and demographically representative set of images for widespread use.

What do you think? Would emoji work for you? Thanks for stopping by.

Commentary on medical emoji in JAMA Network: jamanetwork.com/journals/jama/fullarticle/2783847
Article on commentary on EurekAlert! website: www.eurekalert.org/news-releases/927717

01 October 2021

Coronavirus Variants

Welcome back. Do you remember the old days, when COVID-19 wasn’t a threat? Oh, wait, that was only a few months ago.

With vaccine hesitancy, vaccine politicization, the my-freedom-trumps-public-health crowd and loads of misinformation, it’s difficult to keep the coronavirus controlled, especially when new variants keep popping up and spreading among the unvaccinated, unmasked and un-socially distanced.

Vaccination protesters (photo by John Lamparski-NurPhoto-AP from www.theatlantic.com/ideas/archive/2021/08/vaccine-refusers-hesitancy-mandates-fda-delta/619918/).
You’re familiar with all that, of course, but to keep terms straight, COVID-19, the coronavirus disease 2019, is caused by SARS-CoV-2, the severe acute respiratory syndrome coronavirus 2, which is part of a large family of coronaviruses. Multiple variants of SARS-CoV-2 have been documented. Variants arise because viruses constantly change through mutation.

OK, now that you’ve got all that, there’s a recent article I found of interest and thought you might too. The American Chemical Society, a nonprofit organization chartered by the U.S. Congress, has a weekly newsmagazine, Chemical & Engineering News (C&EN). C&EN interviewed scientists on how coronavirus variants are studied and judgements made as to how well they can be managed with existing vaccines. I’ll review highlights from the article.

Lab Testing
Researchers test new variants by comparing them with the current variants. The tests typically mix the virus with antibodies from the plasma of people who either recovered from COVID-19 or are fully vaccinated. (Plasma is the major liquid component of blood, consisting of water and dissolved constituents, including proteins. Antibodies are proteins that our immune system produces to fight the infection after infection or vaccination.)

Testing the ability of antibodies to block SARS-CoV-2 in Duke University’s Regional Biocontainment Lab (photo by Thomas Oguin III from cen.acs.org/biological-chemistry/infectious-disease/How-to-interpret-new-studies-coronavirus-variants/99/i32).
The primary test questions are (1) will the antibodies prevent the new variants from infecting our cells, and (2) how readily the new variants spread compared with their predecessors?

Although what happens in the lab isn’t necessarily what will happen in our bodies, the testing provides rapid, effective assessments of the variants.

Variant Infectiousness
Mutations can give new variants a tighter grip on our cells, such that a smaller amount of virus can start an infection. Other mutations may help the virus reproduce more quickly or in greater quantities, increasing the chance that an infected person will spread the virus.

A more infectious virus may not make people sicker, but it will infect more people, making outbreaks harder to control. A case in point is the Delta variant, which spreads more easily than the Beta variant, even though the Beta variant is better at evading our neutralizing antibodies.

Epidemiologists and modelers use population-level data to estimate how many people each infected person will infect. The original coronavirus was calculated to spread to 2 or 3 unvaccinated people who made no change in their behavior to prevent transmission. The Delta variant is calculated to spread to 6 or 7.

Reviewing Research on New Variants
I rarely blog about studies that haven’t been peer reviewed, and I sympathize with those keeping abreast of coronavirus research. The flow of new information is a deluge. Apparently, much of that information is shared on preprint servers before peer review. And apparently claims about new variants--claims that might reach the public--don’t always match the data.

The interviewed scientists approach these studies with care, ignoring claims and focusing on the testing, source of antibodies, how data on vaccine efficacy were collected, how mild or severe disease are defined, and if multiple variants were compared head-to-head or from different labs, where anything might differ.

Wrap Up
When fully vaccinated individuals become infected (“breakthrough infections”), those who are unvaccinated may wonder why get vaccinated. Why? Because the principal goal of vaccines is to prevent severe disease and death. Thus far, the vaccines have done well with less than 5% of fully vaccinated people hospitalized. As more infectious variants evolve, infections might increase.

Summary percentages of data on COVID breakthrough hospitalizations and deaths, New York Times, August 2021 (www.nytimes.com/interactive/2021/08/10/us/covid-breakthrough-infections-vaccines.html).

For healthy, fully vaccinated people, a mild infection with a variant could boost immunity. For immunocompromised people and older adults who normally don’t produce a lot of antibodies, booster shots could be important for improved protection.

But with so many people worldwide lacking a first shot and being potential sources of new variants, we have to question whether boosters should be distributed broadly before addressing the unvaccinated. Thanks for stopping by.

Center for Countering Digital Hate report on vaccine disinformation: www.counterhate.com/disinformationdozen
SARS-CoV-2 variants: www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html
Article on understanding coronavirus variants in C&EN: cen.acs.org/biological-chemistry/infectious-disease/How-to-interpret-new-studies-coronavirus-variants/99/i32
Summary of C&EN article on EurekAlert! website: www.eurekalert.org/news-releases/927837
Earlier C&EN article on SARS-CoV-2 variants: cen.acs.org/sections/new-covid-19-variants-vaccines-effective.html

24 September 2021

Just Keep Walking

Welcome back. As important as it was, perhaps last week’s blog post endorsing exercise was too much for some, especially referencing the 2016 European Guideline of at least 150 minutes/week of moderate intensity or 75 minutes/week of vigorous activity, or some combination (Time to Get Active). By the way, that’s also the current guideline of the American Heart Association.

If it was too much, you could just take a walk.

How Many Steps?
If you were following this blog in 2015, you might recall a two-part, guest blog post on walking to stay fit by a then-recently retired elementary school principal in Ontario, Canada (Stepping into Fitness, Part 1, Stepping into Fitness, Part 2).

When her fitness began to ebb with retirement, and her entire wardrobe seemed to have mysteriously shrunk, she was ready for a change. For Christmas, her son gave her a wristband monitor to encourage her to walk regularly and record the number of steps on her computer or smartphone.

The newly retired school principal (in red) with members of a local walking club (from Stepping into Fitness, Part 1).

She adopted the goal of 10,000 steps per day, roughly 5 miles. In the 1960s, Japan’s pedometer companies and walking clubs were promoting 10,000 steps daily as a way to achieve fitness. At the time of her writing, the American Heart Association was also recommending 10,000 steps for improved health and decreased risk of heart disease. Should 10,000 steps be your goal?

Recent Findings on Steps and Intensity
To help you decide, I’ll summarize the findings of three studies.

National Cancer Institute researchers led a study published in 2020 that assessed the associations of daily step counts and intensity (cadence) with all-cause mortality.

A representative sample of 4840 U.S. adults (mean age 56.8; 54% female) wore accelerometers to count steps for a mean of 5.7 days. Over a mean follow-up of 10.1 years, there were 1165 all-cause mortality deaths. The rate of deaths fell with increased steps--64% of those who took fewer than 4000 steps/day, 28% of those who took 4000 to 7999 steps/day, 11% of those who took 8000 to 11,999 steps/day, and 9% of those who took at least 12,000 steps/day.

All-cause mortality vs steps per day among U.S. adults age 40 or older (from jamanetwork.com/journals/jama/fullarticle/2763292).
There was no significant association between step intensity and mortality after adjusting for total steps per day.

All-cause mortality vs steps per day among U.S. adults by age (from jamanetwork.com/journals/jama/fullarticle/2763292).
University of North Carolina investigators led a team that conducted a study presented at a 2021 American Heart Association Conference.

The researchers analyzed daily steps, walking patterns and all-cause mortality of 16,732 women (mean age 72; mostly white, non-Hispanic) who had worn a waist step counter for 4 to 7 days. Each participant’s steps were divided into: (1) bouts of walking 10 minutes or longer with few interruptions and (2) short spurts of walking during regular daily activities. Over a mean follow-up of 6 years, there were 804 deaths.

The researchers found:
- Each initial increase of 1000 steps/day over no daily steps had 28% fewer deaths.
- Exceeding 2000 steps/day in uninterrupted bouts had 32% fewer deaths.
- Participants who took more steps in short spurts lived longer regardless of how many steps they took in longer, uninterrupted bouts; however, the short-spurt benefits leveled off at about 4500 steps/day.

A University of Massachusetts investigator led a research team in the most recent assessment of steps/day and all-cause mortality.

Steps and intensity of 2110 participants (mean age 45.2, 57.1% female, 42.1% Black) were monitored with an accelerometer for 7 days; 72 participants died during the mean follow-up of 10.8 years.

Grouping steps/day as low (fewer than 7000), moderate (7000-9999) and high (10,000 or more), the team found the risk of all-cause mortality associated with low steps/day to be 28% greater than with moderate steps/day and 45% greater than with high steps/day. There was no association of step intensity with mortality.

Wrap Up
I was surprised that step intensity--how fast one walks--is not associated with mortality; but other studies have also found that any level of physical activity, regardless of intensity, is associated with a substantially lower risk of death.

How many steps should you walk? Do what you can, knowing that more steps per day, all at once or in shorter spurts, could improve your health and help you live longer. Be well and thanks for stopping by.

American Heart Assoc. fitness guidelines: www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults
National Cancer Institute led study in JAMA Network Open: jamanetwork.com/journals/jama/fullarticle/2763292
Univ. of North Carolina led study presented at American Heart Assoc. Conference: newsroom.heart.org/news/taking-more-steps-daily-may-lead-to-a-longer-life
Univ. of Massachusetts led study in Jama Network Open: jamanetwork.com/journals/jamanetworkopen/fullarticle/2783711