Children and teenagers saw their body mass index (BMI) increase at almost double the rate during the pandemic, according to a Centers for Disease Control and Prevention (CDC) study that suggested some COVID-19 precautions may have contributed to higher weight gain.
The CDC’s Morbidity and Mortality Weekly Report released Thursday determined that the monthly rate of BMI increase among 2- to 19-year-olds accelerated during the pandemic to reach 0.1 kg/m² per month. Comparatively, during the pre-pandemic period, the rate of increase was 0.052 kg/m² per month.
The documented weight gain came as children were sent home from schools due to COVID-19, disrupting eating and exercise routines, boosting stress and sometimes impacting their food security.
All BMI categories except underweight saw “significant increases in their rate of BMI change during the pandemic.” Overall, researchers estimate that 22.4 percent of the age group classified as obese in August 2020, while a year prior they projected 19.3 percent had obesity.
Children and teenagers who were overweight or obese before the pandemic experienced “significantly” higher rates of BMI increases during COVID-19, compared to those considered to have healthier weights.
Those with obesity before the pandemic saw a BMI rate of change reach 5.3 times as high as before the pandemic. Children and teenagers with moderate or severe obesity gained on average 1 and 1.2 pounds per month, respectively. That rate would amount to 6.1 and 7.6 gained pounds in six months.
Among age groups, children ages 6 to 11 saw the highest increase in the rate of BMI change, reaching 2.5 times as high as the rate before the pandemic.
For the study, the researchers used 2.5 million BMI measurements from a group of more than 432,000 people ages 2 to 19 from before the pandemic, defined as between Jan. 1, 2018, to Feb. 29, 2020, to during COVID-19, specifically between March 1, 2020, and Nov. 30, 2020.
The report labeled the study as the “largest and first geographically diverse analysis” studying the pandemic’s effects on BMI.
The CDC suggests the results call for more efforts to address the BMI change rate among children and teenagers, including through screenings for BMI and food security, improved access to pediatric weight management programs and food assistance resources.
“Accelerated weight gain, especially among children with overweight or obesity, can cause long-lasting metabolic changes that put children at risk for serious and costly co-occurring conditions, such as type 2 diabetes, hypertension, and depression,” the report notes.
The CDC released an analysis on Wednesday that found the number of states with an obesity rate of at least 35 percent among adults almost doubled in two years. In 2020, 16 states made the list — more than the 12 states in 2019 and the nine in 2018.