Spatiotemporal Correlation between Obesity Prevalence and the Percentage of Households using Air-conditioners in the United States

Abstract

Purpose: The axiom that obesity epidemic was driven by steady increases in energy intake has been challenged by empirical evidence, including the failure to make meaningful progress either treating or preventing obesity. Adopting new paradigm were urgently needed. We aimed to collect ecological evidences to support an alternative hypotheses that increased usage of air-conditioners (AC) may contribute to obesity epidemic in the U.S. Method: U.S. national survey data were retrieved from public domains, including the % of homes with AC units (AC ownership), dietary energy intake, and obesity prevalence. Correlation efficient were estimated, and Joint point regressions were ran to describe time segments and estimate annual percentage change (APC). Results: Nationally, Obesity prevalence significantly associated with the increasing trend of AC ownership (partial r=0.046, and p < 0.05) not dietary energy intake (r < 0.0001, and p = 0.58). When stratified by region, the rank of obesity prevalence across regions was consistent with that of AC ownership throughout the study period; the South led the increasing trends for both AC ownership and obesity prevalence. The climbing national trend of obesity slowed down around 2002 (before 2002 APC=4.38, and APC=2.22 after) following the saturation of AC penetration in the South (before 1994, APC=1.04, p < 0.05, and APC=0.05 after 1994, p > 0.05. Conclusions: Spatiotemporal correlations support the hypothesis that penetration of AC may contribute to the obesity epidemic. Further investigation may lead to novel therapies and a new avenue to explore the strategies addressing twin clusters of pandemics, obesity, and climate change.