The Relationship Between Ambient Temperature and FPG, A Series of Cross-Sectional Studies in Guangdong Province, China

Abstract

Background: There existed evidence that the incidence and glycemic control rate of T2DM have seasonal variation, which can be attributed to the effect of temperature on FPG. The present study aimed to examine the associations between short-term ambient temperature exposure and FPG among different populations and calculate temperature-FPG association adjusted prevalence and glycemic control rate of T2DM.Methods: Four cross-sectional health surveys with 26,350 respondents were conducted in Guangdong Province from 2007 to 2015. Multistage cluster sampling was used to recruit study participants. Gaussian generalized additive model was employed to evaluate the associations between daily mean ambient temperature and FPG among different populations (total, non-T2DM, old-T2DM and new-T2DM populations). Prevalence and glycemic control rate of T2DM were calculated based on the exposure-response association between temperature and FPG. Results: The exposure-response curve of temperature and FPG were downward parabola in total, non-T2DM and old-T2DM populations, while the curve was “U”-shaped but not significant in new T2DM population. When temperature increased from 10th percentile to 50th percentile, the FPG significantly decreased 0.14 (95%CI: -0.17, -0.11) mmol/L, 0.11 (95%CI: -0.12, -0.11) and 0.44 (95%CI: -0.80, -0.08) in total, non-T2DM and old-T2DM populations, respectively. When temperature increased from 50th to 90th percentile, the FPG significantly decreased 0.19 (95%CI: -0.22, -0.16) mmol/L, 0.17 (95%CI: -0.17, -0.17) and 0.51 (95%CI: -0.79, -0.23) in total, non-T2DM and old-T2DM populations, respectively. The alteration of rate related to the temperature difference was observed from 5℃ to 30℃, with gently decreases from 10.03% to 9.39% in prevalence of T2DM and greatly increases from 32.1% to 58.6% in glycemic control rate of T2DM, respectively.Conclusion: FPG, the prevalence and glycemic control rate of T2DM are affected by ambient temperature, which suggests temperature and FPG association should be considered and adjusted when estimating T2DM epidemiology and developing clinical management of T2DM.