Effect of cold temperatures on mortality in Cantabria (Northern Spain): A case–crossover study

SummaryObjectivesTo determine the impact of low temperatures on mortality in a Spanish region that includes both rural and urban areas.Study designCase–crossover study.MethodsA case–crossover study was conducted on the impact of cold temperatures on mortality in Cantabria, a Spanish region which includes both rural and urban areas, in 2004–2005. Odds ratios for several cold weather indicators were estimated using conditional logistic regression, adjusting for humidity and wind speed. Zero- to 6-day lags in the temperature effect were considered.ResultsTemperatures lower than the 5th percentile were strongly associated with mortality compared with temperatures above the 5th percentile (OR 3.40, 95% confidence interval 2.95–3.93 for 6-day lag). All temperature indices show a negative association with mortality; for instance, the maximum temperature had ORs of 0.71, 0.58, 0.32 and 0.16 for Quintiles 2–5 (reference: Quintile 1). This effect was common to all age groups.ConclusionCold weather is strongly associated with mortality in small cities and rural areas.