Projecting the impact of the coronavirus disease-2019 pandemic on childhood obesity in the United States: A microsimulation model

Abstract

Purpose: The coronavirus disease-2019 (COVID-19) pandemic in the United States led to nationwide stay-at-home orders and school closures. Declines in energy expenditure resulting from canceled physical education classes and reduced physical activity may elevate childhood obesity risk. This study estimated the impact of COVID-19 on childhood obesity.

Methods: A microsimulation model simulated the trajectory of a nationally representative kindergarten cohort's body mass index z-scores and childhood obesity prevalence from April 2020 to March 2021 under the control scenario without COVID-19 and under the 4 alternative scenarios with COVID-19-Scenario 1: 2-month nationwide school closure in April and May 2020; Scenario 2: Scenario 1 followed by a 10% reduction in daily physical activity in the summer from June to August; Scenario 3: Scenario 2 followed by 2-month school closure in September and October; and Scenario 4: Scenario 3 followed by an additional 2-month school closure in November and December.

Results: Relative to the control scenario without COVID-19, Scenarios 1, 2, 3, and 4 were associated with an increase in the mean body mass index z-scores by 0.056 (95% confidence interval (95%CI): 0.055-0.056), 0.084 (95%CI: 0.084-0.085), 0.141 (95%CI: 0.140-0.142), and 0.198 (95%CI: 0.197-0.199), respectively, and an increase in childhood obesity prevalence by 0.640 (95%CI: 0.515-0.765), 0.972 (95%CI: 0.819-1.126), 1.676 (95%CI: 1.475-1.877), and 2.373 (95%CI: 2.135-2.612) percentage points, respectively. Compared to girls and non-Hispanic whites and Asians, the impact of COVID-19 on childhood obesity was modestly larger among boys and non-Hispanic blacks and Hispanics, respectively.

Conclusion: Public health interventions are urgently called to promote an active lifestyle and engagement in physical activity among children to mitigate the adverse impact of COVID-19 on unhealthy weight gains and childhood obesity.

Keywords: COVID-19; Childhood obesity; Coronavirus; Microsimulation; Physical activity.

Graphical abstract

Fig. 1

Simulated kernel density distributions of body mass index z-scores (BMIz) in March 2021 under the control and 4 alternative scenarios. A microsimulation model was built to simulate the trajectory of a U.S. nationally representative kindergarten cohort's BMIz from April 2020 to March 2021 under the control scenario without coronavirus disease-2019 (COVID-19) and under the 4 alternative scenarios with COVID-19—Scenario 1: a 2-month nationwide school closure in April and May 2020; Scenario 2: Scenario 1 followed by a 10% reduction in daily physical activity (PA) in the summer from June to August; Scenario 3: Scenario 2 followed by a 2-month school closure in September and October; and Scenario 4: Scenario 3 followed by an additional 2-month school closure in November and December.

Fig. 2

Simulated trend in body mass index z-scores (BMIz) from April 2020 to March 2021 under the control and 4 alternative scenarios. A microsimulation model was built to simulate the trajectory of a U.S. nationally representative kindergarten cohort's BMIz from April 2020 to March 2021 under the control scenario without coronavirus disease-2019 (COVID-19) and under the 4 alternative scenarios with COVID-19—Scenario 1: a 2-month nationwide school closure in April and May 2020; Scenario 2: Scenario 1 followed by a 10% reduction in daily physical activity (PA) in the summer from June to August; Scenario 3: Scenario 2 followed by a 2-month school closure in September and October; and Scenario 4: Scenario 3 followed by an additional 2-month school closure in November and December. The error bars denote the estimated standard errors.

Fig. 3

Simulated trend in childhood obesity prevalence from April 2020 to March 2021 under the control and 4 alternative scenarios. A microsimulation model was built to simulate the trajectory of a U.S. nationally representative kindergarten cohort's childhood obesity prevalence from April 2020 to March 2021 under the control scenario without coronavirus disease-2019 (COVID-19) and under the 4 alternative scenarios with COVID-19—Scenario 1: a 2-month nationwide school closure in April and May 2020; Scenario 2: Scenario 1 followed by a 10% reduction in daily physical activity (PA) in the summer from June to August; Scenario 3: Scenario 2 followed by a 2-month school closure in September and October; and Scenario 4: Scenario 3 followed by an additional 2-month school closure in November and December. Childhood obesity is defined as body mass index (BMI) z-scores at the 95th percentile or higher in the 2000 U.S. Centers for Disease Control and Prevention age- and sex-specific growth chart. The error bars denote the estimated standard errors.

Fig. 4

Simulated increase in body mass index z-scores (BMIz) between the control and 4 alternative scenarios in March 2021 by (A) sex and (B) race/ethnicity. A microsimulation model was built to simulate the trajectory of a U.S. nationally representative kindergarten cohort's BMIz from April 2020 to March 2021 under the control scenario without coronavirus disease-2019 (COVID-19) and under the four alternative scenarios with COVID-19—Scenario 1: a 2-month nationwide school closure in April and May 2020; Scenario 2: Scenario 1 followed by a 10% reduction in daily physical activity (PA) in the summer from June to August; Scenario 3: Scenario 2 followed by a 2-month school closure in September and October; and Scenario 4: Scenario 3 followed by an additional 2-month school closure in November and December. The error bars denote the estimated standard errors.

Fig. 5

Simulated increase in childhood obesity prevalence between the control and 4 alternative scenarios in March 2021 by (A) sex and (B) race/ethnicity. A microsimulation model was built to simulate the trajectory of a U.S. nationally representative kindergarten cohort's childhood obesity prevalence from April 2020 to March 2021 under the control scenario without coronavirus disease-2019 (COVID-19) and under the 4 alternative scenarios with COVID-19—Scenario 1: a 2-month nationwide school closure in April and May 2020; Scenario 2: Scenario 1 followed by a 10% reduction in daily physical activity (PA) in the summer from June to August; Scenario 3: Scenario 2 followed by a 2-month school closure in September and October; and Scenario 4: Scenario 3 followed by an additional 2-month school closure in November and December. Childhood obesity is defined as body mass index (BMI) z-scores at the 95th percentile or higher in the 2000 U.S. Centers for Disease Control and Prevention age- and sex-specific growth chart. The error bars denote the estimated standard errors.