Two new studies highlight body mass index (BMI) in children during the COVID-19 pandemic, with one finding a 25% and 42% higher risk of long COVID among obese and severely obese children, respectively, and the other showing that the proportion of overweight or obese youth rose 5% amid the 18-month public-school closure in San Francisco.
'A substantial threat to children'
For the first study, published this week in JAMA Network Open, a University of Pennsylvania–led research team used electronic health records (EHRs) to assess rates of post-acute sequelae of SARS-CoV-2 (PASC, or long COVID) among 172,136 COVID-19 survivors aged 4 to 17 years at 26 US children's hospitals from March 2020 to May 2023. Half of the participants had obesity or severe obesity.
This need to unravel the complexities of pediatric PASC continues to be crucial even after the COVID-19 pandemic.
"PASC continues to pose a substantial threat to children, necessitating an urgent and deeper understanding of pediatric PASC causes," the researchers wrote. "This need to unravel the complexities of pediatric PASC continues to be crucial even after the COVID-19 pandemic."
BMI was measured 18 months before COVID-19 infection, and participants were followed up for at least 6 months. Average participant age was 12.6 years, and 52.4% were girls.
During follow-up, 0.8% of participants received a PASC diagnosis, of whom 53.6% were obese or severely obese, and 26.4% had any of 24 PASC symptoms and conditions at least once, 52.8% of whom had obesity or severe obesity.
The median time from infection to PASC diagnosis or symptoms was 50 and 63 days, respectively. The median number of new PASC symptoms and conditions was 0, indicating that at least half of the participants didn't have symptoms.
Significant dose-response relationship
Relative to participants with a healthy BMI, those with obesity were at a 25.4% higher risk for long COVID, and those with severe obesity were at a 42.1% higher risk.
Addressing obesity as a modifiable risk factor could alleviate the burden of PASC and improve pediatric health postpandemic.
The risk of encountering any manifestation of potential PASC symptoms and conditions was also greater among participants with obesity (11%) and severe obesity (17%), and the risk persisted when analyzing total incidents among those who were overweight (5%), obese (13%), or severely obese (18%).
There was a significant dose-response relationship with increasing BMI category and the risk of PASC. A post hoc analysis of racial subgroups revealed a consistent link between BMI with PASC or PASC symptoms for White participants only.
"In this cohort study, elevated BMI was associated with a significantly increased PASC risk in a dose-dependent manner, highlighting the need for targeted care to prevent chronic conditions in at-risk children and young adults," the study authors wrote.
"Public health efforts should focus on raising awareness and promoting healthy lifestyle behaviors to reduce severe outcomes," they concluded. "Addressing obesity as a modifiable risk factor could alleviate the burden of PASC and improve pediatric health postpandemic."
Disrupted daily routines
The second study, by University of California at San Francisco researchers, was published in BMC Public Health. The EHR-based study involved 15,401 children aged 4 to 17 years receiving care at two medical centers in San Francisco during three periods: two of them prepandemic (March 2018 to February 2019 and March 2019 to February 2020), plus the COVID-related school-closure period (March 2020 to August 2021).
The median age at baseline was 10 years, 34% were Latino, 26% were White, 20% were Asian, 9% were Black, and 47% were publicly insured.
"Policies to reduce the spread of COVID-19, including closures of schools, playgrounds, and recreational programs, led to significant changes in children and adolescents' daily routines, with more time spent at home and, for many, fewer opportunities to engage in physical activity and access healthy meals," the authors wrote. "These policies may have had unintended impacts."
Increased risk of poor cardiometabolic outcomes
The average BMI-z score (relative age- and sex-adjusted BMI) climbed 0.06 per year during period 2 and 0.12 per year in period 3. The proportion of overweight or obese children rose 1.4 percentage points per year in period 2 and 4.9 percentage points per year in period 3.
If these increases in BMI status persist over time, they are likely to increase these children's risk for numerous adverse cardiometabolic outcomes.
An effect-modification analysis showed that the youngest participants, those with public rather than private health insurance, and Black, Latino, and Asian children saw greater increases in BMI-z. The youngest age-group and publicly insured children also had greater increases in the proportion with overweight or obesity.
At the end of period 2, the difference in the prevalence of overweight or obesity between children with private and public insurance was 12.8 percentage points (21.5 vs 34.3 percentage points), but by the end of period 3, the gap had widened to 20 percentage points (26.6 vs 46.6 percentage points).
This contributed to increasing disparities for Black and Latino children, the researchers noted. Asian children, who initially had the lowest BMI-z score, caught up to their White peers during the pandemic.
"If these increases in BMI status persist over time, they are likely to increase these children's risk for numerous adverse cardiometabolic outcomes," the researchers wrote. "These results highlight the need for more effective public policies for obesity prevention and treatment, through support for physical activity programs and access to healthy foods."
"In addition, given the consequences of excess weight gain and new or worsening obesity on future cardiometabolic risk, policy makers must consider the risk of increasing weight gain when considering future pandemic policies, including school and recreational program closure and efforts to alleviate economic distress and improve access to healthy foods," they concluded.
