Comparative analysis of temporal trends of obesity and physical inactivity in Brazil and the USA (2011-2021).

Background: The prevalence of obesity is rising in all subregions of America, including Brazil. To understand the obesity problem in Brazil better, a possible approach could be to analyze its obesity trend by comparing it with the reality of a country that went previously through the epidemiological transition, such as the USA. In addition, the obesity trend must be analyzed in comparison with obesity risk factors trends, such as the physical inactivity (PI) trend. Our aim was comparatively to analyze the temporal trends of obesity between Brazil and the USA from the perspective of temporal trends of PI.

Methods: We conducted a temporal trend study based on data from national cross-sectional surveys: the VIGITEL (Surveillance System for Factors of Health Risk and Protection for Chronic Diseases by Telephone Survey) for Brazil and the BRFSS (Behavioral Risk Factor Surveillance System) for the USA, comparing the annual prevalence of obesity and PI between 2011 and 2021. For the analysis of each temporal variation, linear regressions were performed with the Prais-Winsten test, and Pearson's correlation coefficient was conducted to correlate the trends of the same variables between countries and of different variables within each country.

Results: Considering the total sample, Brazil [coefficient (95%CI) 0.6 (0.4;0.7), p = 0.000] and the USA [coefficient (95%CI) 0.5 (0.5;0.6), p = 0.000] showed increasing trends in obesity. The tendency of PI was of stabilization in the two countries [Brazil: coefficient (95%CI) -0.03 (-0.3;0.2), p = 0.767 and USA coefficient (95%CI) -0.03 (-0.2;0.1), p = 0.584]. In addition, there was a correlation between obesity trends between Brazil and the USA (r = 0.971; p = 0.000), but there was no correlation between PI trends between the two countries, nor with obesity and PI trends within each country.

Conclusions: In the last decade, there was a trend towards increasing obesity and stabilization in PI, both in Brazil and the USA. However, there was no association between temporal trends in obesity and physical inactivity in both countries. Our data reinforce a call to action to prevent and control obesity, going with and beyond PI reduction.