Association between heat exposure and urolithiasis in workers

Heat exposure can trigger stone formation in persons more susceptible to urolithiasis, due to concentrated urine causing crystal precipitation. The risk also is increased in people who are significantly exposed to heat in their jobs or who have a sedentary lifestyle. We determined the relationship between heat exposure and urolithiasis in workers. A search of PubMed and Google Scholar databases ultimately yielded only one study describing the most relevant appropriate approach to answer the PICO clinical question. The cross-sectional study measured the rate of heat conducted qualitatively. Although there was no follow-up, the data were complete and the study long enough. The odds ratio was 9.97, indicating that workers exposed to high temperatures have an up to nine times greater risk of urolithiasis (95% confidence level [CI], 7:38-13:47, P < 0.0001). The number needed to harm was 14 (i.e., for every 14 workers exposed to heat, one will suffer urolithiasis). Heat exposure in the workplace increased urolithiasis risk in workers. Our review still lacked evidence to answer the clinical question because only one study was considered relevant. A cross-sectional design does not best prove a causal relationship. For etiology, the best design is a cohort study.