Association of Obesity Prevalence and Ambient Temperature: A Systematic Review

Ambient temperature is considered to be an influential factor in metabolism, and reduced/increased ambient temperature to the thermoneutral zone (TNZ) (20.3-23°C for covered populations) lead to metabolic changes, while also affecting the prevalence of obesity. The present study aimed to review the findings on the correlation of ambient temperature with obesity in various regions with ambient temperature. 

This systematic review was conducted in July 2019 via searching in databases such as PubMed and Scopus using three terms to describe the exposure and four terms for the outcome. The quality of the articles was assessed using the Newcastle-Ottawa quality assessment. Among 461 selected articles, four cross-sectional studies were systematically reviewed. The quality of these studies was graded nine based on a nine-point scale. In addition, the four cross-sectional studies reported a correlation between the prevalence of obesity and ambient temperatures in various regions in Spain, Korea, England, and the United States. 

An association has been reported between ambient temperature and obesity in various regions with ambient temperature, and increased ambient temperature to the TNZ has been associated with the higher prevalence of obesity, while higher temperature than the TNZ range has been reported to decrease the prevalence of obesity. 

Evidence suggests that ambient temperature may affect the prevalence of obesity. However, further investigations are required in different countries with wider temperature ranges in order determine the correlation between ambient temperature and the prevalence of obesity.