Warm season temperatures and emergency department visits in Atlanta, Georgia

Purpose Extreme heat events will likely increase in frequency with climate change. Heat-related health effects are better documented among the elderly than among younger age groups. We assessed associations between warm-season ambient temperature and emergency department (ED) visits across ages in Atlanta during 1993–2012. Methods We examined daily counts of ED visits with primary diagnoses of heat illness, fluid/electrolyte imbalances, renal disease, cardiorespiratory diseases, and intestinal infections by age group (0–4, 5–18, 19–64, 65+years) in relation to daily maximum temperature (TMX) using Poisson time series models that included cubic terms for TMX at single-day lags of 0–6 days, controlling for maximum dew-point temperature, time trends, week day, holidays, and hospital participation periods. We estimated rate ratios (RRs) and 95% confidence intervals (CI) for TMX changes from 27 °C to 32 °C (25th to 75th percentile) and conducted extensive sensitivity analyses. Results We observed associations between TMX and ED visits for all internal causes, heat illness, fluid/electrolyte imbalances, renal diseases, asthma/wheeze, diabetes, and intestinal infections. Age groups with the strongest observed associations were 65+years for all internal causes [lag 0 RR (CI)=1.022 (1.016–1.028)] and diabetes [lag 0 RR=1.050 (1.008–1.095)]; 19–64 years for fluid/electrolyte imbalances [lag 0 RR=1.170 (1.136–1.205)] and renal disease [lag 1 RR=1.082 (1.065–1.099)]; and 5–18 years for asthma/wheeze [lag 2 RR=1.059 (1.030–1.088)] and intestinal infections [lag 1 RR=1.120 (1.041–1.205)]. Conclusions Varying strengths of associations between TMX and ED visits by age suggest that optimal interventions and health-impact projections would account for varying heat health impacts across ages.