Monday, September 27, 2021

Is the pandemic worsening childhood obesity rates?

 - Jennifer Middleton, MD, MPH

The COVID-19 pandemic is correlating with worsening health measures in adults (obesity and alcohol consumption, for starters), and new evidence demonstrates concern with increasing rates of childhood obesity as well. 

Centers for Disease Control and Prevention (CDC) researchers examined data from IQVIA's electronic records, including over 432,000 children and teens aged 2-19 years from across the United States (US). Among this relatively diverse cohort (34.3% non-white), they found that:

Between the prepandemic and pandemic periods, the rate of BMI increase approximately doubled, from 0.052 (95% confidence interval [CI] = 0.051–0.052) to 0.100 (95% CI = 0.098–0.101) kg/m2/month (ratio = 1.93 [95% CI = 1.90–1.96]). Persons aged 2–19 years with overweight or obesity during the prepandemic period experienced significantly higher rates of BMI increase during the pandemic period than did those with healthy weight. 

The rate change was most dramatic for children aged 5-11 years (0.09 kg/m2/month or 3 oz/m2/month which is 2.5 times higher than during the prepandemic time period.). The CDC authors posit that school interruptions are a likely contributor to these changes which makes sense given that school is, for many children, an essential source of nutritious meals and physical activity

A somewhat smaller study of 191,000 US children published last month using Kaiser Permanente data from Southern California had similar findings, with statistically significant differences in weight gain among children aged 5-11 years ("a mean gain among 5- through 11-year-olds of 2.30 kg (95% CI, 2.24-2.36 kg) more during the pandemic than during the reference period"). These researchers provided more information about the diversity of their cohort, with "10.4% Asian and Pacific Islander, 50.4% Hispanic, 7.0% non-Hispanic Black, and 25.3% non-Hispanic White."

Ensuring access to nutritious meals and physical activity are necessary components of a healthy school environment. A bill is currently pending in the US Congress to fund universal free meals in all US schools. Studies show that providing time for physical education does not harm children's educational gains. Additionally important is creating a healthy psychological environment, as weight-based bullying in school is very common, with both peers and educators as perpetrators. Family physicians can support children by letting their US congressperson know of their support for the Universal School Meals Act, by encouraging school leaders to allow time for physical activity during the school day, and by educating ourselves about our conscious or subconscious biases about overweight persons. We can then work with families to have nonjudgmental conversations about behavior modifications to limit or reverse weight gain. 

If you'd like to read more, check out this AFP article on "Evaluation and Treatment of Childhood Obesity" and this AFP Cochrane review on "Interventions for Reducing Childhood Obesity." These AFP patient education handouts on "Helping Your Child Keep a Healthy Weight" and "Helping Your Child Lose Weight" contain several practical tips to discuss with families as well.

Monday, September 20, 2021

The challenge of correctly diagnosing hypertension in adults

 - Kenny Lin, MD, MPH

Screening for high blood pressure in adults can be straightforward or quite complex. The U.S. Preventive Services Task Force (USPSTF) recently reaffirmed its longstanding recommendation to screen for hypertension with office blood pressure measurement but advises confirming the diagnosis with measurements outside of the clinical setting. The diagnostic standard for out-of-office measurement is 24-hour ambulatory blood pressure monitoring (ABPM), but ABPM is often unavailable, not covered by insurance, or inconvenient for patients.

A more accessible alternative, reviewed by Dr. Jeffrey Weinfeld and colleagues in the September issue of AFP, is home blood pressure monitoring (HBPM). In addition to confirming a hypertension diagnosis, HBPM can be used to identify white coat hypertension (elevated readings in the office but normal readings at home) and masked hypertension (elevated readings at home but normal readings in the office). Patients can purchase a clinically validated blood pressure monitor for $37 to $100 without insurance, and this expense may be reimbursed from a health care flexible spending account. The downside of HBPM is that patients sometimes forget to check their blood pressures at home or forget to record and bring in the readings. 

What is the role of automated oscillometric office blood pressure (AOBP) devices such as those used in the Systolic Blood Pressure Intervention Trial (SPRINT)? A systematic review and meta-analysis previously summarized in AFP found that AOBP systolic measurements were on average 14.5 mm Hg lower than manual blood pressures in patients with hypertension and better aligned with values obtained with ABPM. In a Letter to the Editor in the August issue, Dr. Lenard Lesser argued that the USPSTF "missed an opportunity to promote AOBP measurements as an easier-to-implement alternative to ambulatory blood pressure monitoring." Dr. Lesser pointed out that the only randomized trial of hypertension screening cited by the USPSTF that reported improvements in clinically meaningful outcomes actually used AOBP.

In the latest entry in JAMA's Rational Clinical Examination series, Dr. Anthony Viera and colleagues systematically reviewed studies that addressed the question, "Does This Adult Patient Have Hypertension?" Comparing AOBP with HBPM, they found that 

The thresholds for defining hypertension and the prevalence of hypertension were similar in office BP measurement and home BP measurement studies, and the estimated predictive values of office oscillometric BP measures and HBPM were numerically nearly identical. ... The combination of results from office BP measurement and HBPM has better diagnostic accuracy than the independent results alone, and when concordant, is likely sufficient for diagnosis. However, 24-hour ABPM should be considered when results are discordant, especially for patients with a higher pretest probability of hypertension.

Monday, September 13, 2021

Do salt substitutes improve mortality in persons at high risk of CVD?

 - Jennifer Middleton, MD, MPH

The current Dietary Guidelines for Americans recommend limiting daily sodium intake to 2,300 mg or less, but 90% of Americans aged 2 years and older consume more salt than this amount daily. The best evidence to date recommends lowering sodium intake to reduce the risk of cardiovascular disease (CVD), but given the pervasiveness of sodium in the American diet, lowering salt intake can be challenging. Replacing table salt with a lower-sodium product could be a more feasible change, and a large randomized controlled trial now suggests that doing so may decrease mortality from CVD in those persons at higher risk. 

The study researchers enrolled nearly 21,000 participants from 600 villages in rural China. The researchers randomized villages to either continued usual salt use or use of a provided salt substitute (75% sodium chloride and 25% potassium chloride). Participants either had a history of stroke or were at least 60 years of age with hypertension:

The mean duration of follow-up was 4.74 years. The rate of stroke was lower with the salt substitute than with regular salt (29.14 events vs. 33.65 events per 1000 person-years; rate ratio, 0.86; 95% confidence interval [CI], 0.77 to 0.96; P=0.006), as were the rates of major cardiovascular events (49.09 events vs. 56.29 events per 1000 person-years; rate ratio, 0.87; 95% CI, 0.80 to 0.94; P<0.001) and death (39.28 events vs. 44.61 events per 1000 person-years; rate ratio, 0.88; 95% CI, 0.82 to 0.95; P<0.001).  

The difference in adverse events due to hyperkalemia was not statistically significant between groups. 

Generalizing the results of this study may be risky; I would presume that most Americans, for example, consume more processed foods and foods prepared outside of the home than the rural Chinese participants in this study. Since "[m]ost sodium consumed in the United States comes from salt added during commercial food processing and preparation, including foods prepared at restaurants," simply decreasing sodium intake in foods prepared at home may not have as great of an effect among persons eating the standard American diet. Then again, even a small benefit could have a sizable effect on population outcomes, and salt substitutes are inexpensive and simple to incorporate into home cooking. Given the minimal harms associated with the salt substitute product in this study, recommending a salt substitute for home use still seems like a reasonable recommendation for our patients at higher risk of CVD.

Taking the time to discuss these recommendations with patients is worthwhile; the United States Preventive Services Task Force (USPSTF) gives a "B" grade to "Behavioral Counseling Interventions to Promote a Healthy Diet and Physical Activity for CVD Prevention in Adults with Cardiovascular Risk Factors." As with all behavior change, tailoring strategies to each patient's circumstances increases the likelihood of success. In addition to recommending salt substitutes, we can teach our patients to read food labels for sodium content, recommend low salt recipes, and discourage frequent restaurant meals. For patients having difficulty making changes, this 2018 AFP article on "Diets for Health: Goals and Guidelines" includes this table with suggestions for overcoming common barriers to eating a healthier diet.

Monday, September 6, 2021

Alliance of international health journals calls for emergency action to limit climate change

 - Kenny Lin, MD, MPH

Today, one week ahead of the 76th session of the United Nations General Assembly, more than 200 health journals worldwide have simultaneously published an editorial calling on health professionals, policy makers, and governments to support emergency actions to limit average global temperature increases to below 1.5 degrees Celsius. Asserting that increases above that level would "risk catastrophic harm to health that will be impossible to reverse," the editorial's authors advocate for "fundamental and equitable changes to societies" to alter the world's current catastrophic temperature trajectory:

Equity must be at the center of the global response. Contributing a fair share to the global effort means that reduction commitments must account for the cumulative, historical contribution each country has made to emissions, as well as its current emissions and capacity to respond. Wealthier countries will have to cut emissions more quickly, making reductions by 2030 beyond those currently proposed and reaching net-zero emissions before 2050.

Last month, a landmark report from the Intergovernmental Panel on Climate Change (IPCC) concluded that human activities since 1850, primarily burning of fossil fuels, have already warmed the planet by 1.1 degrees Celsius. At 1.5 degrees, the IPCC warned, extreme weather patterns would become more frequent, and rising sea levels, vector-borne diseases, life-threatening heat waves, and severe droughts would affect billions of people worldwide. Currently, the 10 countries with the greatest greenhouse gas emissions (China, the U.S., the European Union, India, Russia, Japan, Brazil, Indonesia, Iran, and Canada) account for more than two-thirds of global emissions.

American Family Physician strongly supports this global effort to prevent future environmental catastrophes. Our first full-length clinical review article about the health impacts of global warming appeared in 2011. An accompanying editorial highlighted the physician's role in efforts to slow global warming, including reducing the carbon footprints of hospitals and health care facilities. In 2016, Associate Deputy Editor Caroline Wellbery, MD, PhD observed that the 2015-2020 Dietary Guidelines for Americans' "heart-healthy recommendations align with ... environmental concerns," making eating less meat a healthy and environmentally responsible dietary choice.

A 2019 update on managing health impacts of climate change discussed ways that clinicians can mitigate "morbidity and mortality from worsening cardiopulmonary health, worsening allergies, and greater risk of infectious disease and mental illness, including anxiety, depression, and posttraumatic stress disorder from extreme weather events." Health professionals must recognize how their workplaces directly contribute to making climates less healthy: "The U.S. health care sector is responsible for 10% of all greenhouse gas emissions, 10% of smog formation, 12% of air pollution emissions, and smaller but significant amounts of ozone-depleting substances and other air toxicants." The article also suggested counseling patients on the personal and environmental benefits of utilizing active transport and a consuming plant-based diets.

Physicians' lack of training in climate science and global warming's negative impacts on health may be an obstacle to leveraging the collective authority of the medical profession to address the climate crisis. This gap is closing, though, as recent editorials in Academic Medicine have called for critical curricular reforms in medical school and residency education, and in some cases, medical students themselves have been leading these educational efforts.