Association between ambient temperature and serum uric acid in autumn and winter in Guangdong Province

Background Previous studies have reported seasonal variation in serum uric acid, and a higher hyperglycemia risk is observed in workers exposed to high temperature. However, there is limited evidence on the acute effect of temperature exposure on serum uric acid among general population.

Objective This study estimates the association between temperature exposure and serum uric acid, and provides evidence for disease prevention and control.

Methods From October 2015 to February 2016, a multi-stage cluster sampling method was adopted to select study subjects from the Guangdong Provincial Residents' Chronic Disease and Nutrition Monitoring Survey, and retrieved their socioeconomic characteristics, health status, dietary status, physical fitness, and laboratory test information. Meteorological data including daily mean temperature (MT) and relative humidity (RH) in 698 monitoring stations across China were collected from the China Meteorological Science Data Sharing Service Platform. The Australian National University Splines (ANUSPLN) plugin was employed to interpolate the daily MT and RH grid at 0.01°×0.01° resolution. Daily gridded meteorological data of Guangdong Province were extracted and then matched with participants' residential addresses. Distributed lag nonlinear model (DLNM) was used to investigate the relationship between daily MT and serum uric acid, and stratified analysis was conducted by sex, age (< 65 and ≥ 65 years), body mass index (< 24 and ≥ 24 kg·m^-2), hypertension (yes and no), or hyperlipidemia (yes and no). The degree of freedom of daily MT and the number of lag days, PM_2.5, PM₁₀, NO₂, O₃, and the intake of aquatic products were adjusted in the model. A sensitivity analysis of the model was performed.

Results A total of 6670 people were included in this study. The concentration of total population serum uric acid was (335.7±92.4) μmol·L^-1, and the median of daily MT was 17.3 (P₅-P₉₅: 8.5-25.0)℃. There was a non-linear exposure-response relationship between MT and 14day serum uric acid level. Taking the lowest MT (2℃) as reference, when the MT rose to 25℃ (P₉₅), the serum uric acid level increased by 113.8 (95% CI: 71.1-156.6) μmol·L^-1. The effect of P₉₅ of MT (25℃) on serum uric acid appeared since the first day, then rose after reaching the lowest value on the fourth day, and finally decreased after reaching the highest value on the fourteenth day. The effects of P₉₅ temperature (25℃) on serum uric acid among females, age < 65 years, overweight-obesity, hypertensive, hyperlipidemia groups were greater than among males, age ≥ 65 years, normal weight, normotensive, non-hyperlipidemia groups, respectively, but with no statistically significance. The sensitivity analysis results showed that after adjusting above mentioned variables, the results of the model were still stable.

Conclusion Temperature has a certain lag effect on human serum uric acid, and rising temperature may increase the population's serum uric acid level.