Trajectories of BMI Before, During, and After the COVID-19 Pandemic Among Participants in the MACS/WIHS Combined Cohort Study

Introduction: – Obesity is increasing across the United States, with people with HIV experiencing greater risk of obesity-related adverse health outcomes including metabolic diseases. Weight gain has been shown during the widespread shutdowns during the COVID-19 pandemic. We examined weight trajectories before, during, and after the COVID-19 pandemic among people with and without HIV.Setting: – Participants in the Multicenter AIDS Cohort Study-Women's Interagency HIV Study Combined Cohort Study (MWCCS).Methods: – Study time periods were (1) prepandemic period, May 15, 2018 through March 15, 2020; (2) pandemic period, March 15, 2020 through September 30, 2021; and (3) postpandemic period, October 1, 2021 through September 30, 2024. A piecewise linear mixed effects regression model adjusted for baseline age was fitted with a random intercept for individual. Interaction terms examined differences by sociodemographic characteristics.Result: – Among 1586 participants, 66.5% were living with HIV. From the pre- to during-pandemic period, there was a statistically significant 0.14 kg/m²/visit increase in BMI (95% CI: 0.07 to 0.22). There was a 0.3 kg/m² reduction in mean BMI in the 36 months from pandemic [32 kg/m² (SD: 8.6)] to postpandemic [31.7 kg/m² (SD: 8.5)] periods. Similar trajectories were noted among sociodemographically vulnerable subgroups.Discussion: – Contrary to our hypothesis, we observed a downward BMI trajectory back to baseline with the exception of those with residential instability in the post–COVID-19 pandemic period after a statistically significant weight gain during the pandemic. Understanding factors associated with decreasing BMI trajectories in the postpandemic period is important in continuing to address the obesity epidemic in the United States.