Temperature, hospital admissions and emergency room visits in Lhasa, Tibet: A time-series analysis

Abstract

BackgroundTibet of China, with an average altitude of over 4000m, has experienced noticeable changes in its climate over the last 50years. The association between temperature and morbidity (most commonly represented by hospital admissions) has been documented mainly in developed countries. Little is known about patterns in China; nor have the health effects of temperature variations been closely studied in highland areas, worldwide. ObjectiveWe investigated the temperature–morbidity association in Lhasa, the capital city of Tibet, using sex- and age-specific hospitalizations, excluding those due to external causes. MethodsA distributed lag non-linear model (DLNM) was applied to assess the nonlinear and delayed effects of temperature on morbidity (including total emergency room visits, total and cause-specific hospital admissions, sex- and age-specific non-external admissions). ResultsHigh temperatures are associated with increases in morbidity, to a greater extent than low temperatures. Lag effects of high and low temperatures were cause-specific. The relative risks (RR) of high temperature for total emergency room visits and non-external hospitalizations were 1.162 (95% CI: 1.002–1.349) and 1.161 (95% CI: 1.007–1.339) respectively, for lag 0–14days. The strongest cumulative effect of heat for lag 0–27days was on admissions for infectious diseases (RR: 2.067, 95% CI: 1.026–4.027). Acute heat effects at lag 0 were related with increases of renal (RR: 1.478, 95% CI: 1.005–2.174) and respiratory diseases (RR: 1.119, 95% CI: 1.010–1.240), whereas immediate cold effects increased admission for digestive diseases (RR: 1.132, 95% CI: 1.002–1.282). Those ≥65years of age and males were more vulnerable to high temperatures. ConclusionWe provide a first look at the temperature–morbidity relationship in Tibet. Exposure to both hot and cold temperatures resulted in increased admissions to hospital, but the immediate causes varied. We suggest that initiatives should be taken to reduce the adverse effects of temperature extremes in Tibet.