Avoidable mortality among temperature-attributable deaths in South Korea, 1990-2023

Non-optimum temperatures contribute substantially to excess mortality but estimates of this burden rarely distinguish premature deaths from causes targeted by public health prevention and healthcare from other deaths. We examined how temperature-attributable mortality in South Korea was distributed between avoidable and non-avoidable mortality.

Nationwide mortality data for 1990-2023 were obtained from Statistics Korea, and avoidable mortality was defined based on the OECD/Eurostat lists of preventable and treatable causes of death. A time-stratified case-crossover design with a distributed lag nonlinear model was used to estimate temperature-related risks for avoidable and non-avoidable mortality. We calculated attributable numbers, attributable fractions within each category, and each category's share of all temperature-attributable deaths.

The attributable fraction was lower for avoidable [5.9%; 95% empirical confidence interval (eCI): 4.9%-7.0%] than for non-avoidable mortality (8.1%; 7.4%-8.9%), and higher for treatable (9.7%; 8.1%-11.3%) than for preventable mortality (4.3%; 3.1%-5.4%). Of all temperature-attributable deaths, 30.1% (24.2%-35.6%) were classified as avoidable, comprising 15.3% (11.4-19.0%) preventable, and 14.8% (12.8%-16.7%) treatable. Among avoidable causes, circulatory diseases were associated with both cold and heat and accounted for the largest share.

Although temperature-related risks and attributable fractions were higher for non-avoidable mortality, nearly one-third of temperature-attributable deaths occurred in the avoidable category. While limiting exposure to non-optimum temperatures remains the principal strategy for alleviating this burden, preventive care and disease management may provide a complementary approach.