Pandemic effect on body composition. Single center analysis of 2.771 cases.

Background: The COVID-19 pandemic has led to a dramatic increase in the levels of sedentary lifestyle and unhealthy dietary habits. A worsening in populational obesity levels and body composition (BC) is strongly awaited but so far not documented. Objective: To compare BC profile measured by bioelectrical impedance analysis (BIA) between pre-pandemic (P1-03/15th/2017 to 03/16th/2020) and pandemic (P2-3/17th/2020 to 3/10th/2021) period of time. Materials and Methods: BIA were grouped according to the time it was performed. Two comparisons were done: an independent sample comparison (ISC) and a paired sample comparison (PSC) considering patients with at least one BIA in P1 and P2. Age, height, gender, weight, body mass index (BMI), body fat mass (BFM), free fat mass (FFM), skeletal muscle mass (SMM), percentage of body fat (PBF), visceral fat area (VFA) were compared. Statistical significance level was defined for a p value<0.05. Results and Discussion: A total of 3.358 BIA were performed, and 2.771 and 112 were selected for IS and PS, respectively. In ISC, despite an unchanged weight, BFM, FFM, PBF and VFA increased and SSM decreased on P2(p<0.015 for all). A multivariated linear regression model using PBF as dependent variable showed P2 as an independent predictor ({beta}=0.38 95%CI 0.19 to 0.56). In the PSC, PBF also increased from P1 to P2 (p=0.015). To our knowledge this is the first documentation of worsening BC after pandemic. Health authorities should be alert for this phenomenon and their clinical consequences in the days to come.