Background: The relationship between body temperature and body mass index is controversial. Objective: The purpose of this study was to determine the relationship between these two variables in various studies. Methods: A systematic review was conducted in Google Scholar, PubMed, Scopus, ProQuest, Web of Science, and Elsevier databases. Studies were searched and collected from May 9, 1980 to April 19, 2019. The preliminary steps before data extraction included the selection of the study and the qualitative evaluation of the studies. Mesh database was used for all search keywords. The quality of studies was assessed according to 'Cochrane's checklist, related articles and literature. This led to the inclusion of five articles. Next, all the effect sizes were converted into correlations; then, the relationship between temperature and Body Mass Index was estimated. An appropriate model was selected according to 'Cochran's Q Test. Sensitivity analysis was used to assess the stability and heterogeneity of the findings. All analyses were performed through Comprehensive CMA software, version 3. Results: Overall, the analysis showed a positive correlation between body temperature and body mass index at a 95% confidence interval (r=0.58 95% CI: 0.05-0.85). The effect of the age variable was significant in explaining inter-group variance (p<0.05, R 2 =0.43). For men, a positive and significant relationship was found between changes in body temperature and body mass index (r=0.158 95% CI: 0.11-0.19, p≤0.05). However, there was no significant relationship for women (r=0.32, 95% CI: -0.1-0.64, p=0.13).
Conclusion:A relationship between body temperature and BMI was found in the total population and men. The lack of a significant relationship in women may be due to sudden and severe secretion of luteinizing hormone (LH) in the menstrual cycle.