Ambient temperature, humidity, and urinary system diseases: a population-based study in Western China

Climate has received an increasing attention due to its adverse effects on human health, but the effects on the urinary system are still short of enough evidence. Therefore, we carry out this study to analyze the relationship between meteorological factors and urinary system health in arid areas of western China. In this study, the daily numbers of outpatients with the urinary system diseases from multiple hospitals in three cities in Gansu province (Lanzhou, Zhangye, and Tianshui city) were collected and used for analysis. The distributed lag non-linear models (DLNM) with a quasi-Poisson distribution were used to estimate the associations between meteorological factors and daily outpatients for urinary system diseases in these three cities, and then a multivariate meta-analysis was applied to pool the estimates of city-specific effects. We found that the ambient temperature (AT) and relative humidity (RH) were significantly associated with the outpatient visits of urinary system diseases. The effects of meteorological factors on outpatients with urinary system diseases for both males and females were statistically significant at different lag days. The higher AT and lower RH were associated with the higher risk of urinary system diseases. We also observed substantial lag effects of meteorological factors on outpatients for both males and females. Among all disease types, renal tubule-interstitial diseases had the strongest relationships with meteorological factors. Our results indicate that the higher AT and lower RH may increase the outpatient visits for urinary system diseases, with significant lag effects in semi-arid areas.