Relating Ambient Heat to Site Clinic Visits for Heat-Related Symptoms Among Four Middle Eastern Aluminum Smelters

OBJECTIVE: This study aimed to describe the relation between clinic visits for symptoms of heat-related illness (heat-related visits [HRV]) and ambient Heat Index among aluminum smelters in the Arab Gulf States. METHODS: Four smelters provided HRV data. Meteorological data from nearby airports provided data for Heat Index (HI). Three approaches to finding a smelter-specific trigger for heat stress management were examined. RESULTS: The rate ratios from Poisson regressions were 1.2/°C for one smelter, 1.1/°C for two others, and 0.96 (not significant) for the fourth; all showed no carry-over effect from preceding day. Using a logistic distribution provided a reasonable trigger. CONCLUSIONS: HRVs increased with the Heat Index for three of the four smelters. In this limited study, the trigger point based on the logistic distribution at P = 0.05 was the most protective.