Commentary: short days--shorter lives: studying winter mortality to get solutions

Life span of people who died from cardiovascular diseases in Siberia: a comparative study of two populations

OBJECTIVES

To assess associations between mean age at death from cardiovascular disease (myocardial infarction, acute heart failure, ischemic heart disease and stroke) and sex, education, socio-professional status, marital status, region of residence at birth, month and season of birth and of death in dependence of climatic conditions.

DESIGN

A retrospective analysis of death certificates in two Siberian cities from 1971 to 1978 (Novosibirsk, south-western Siberia) and from 1968 to 1985 (Mirny, western Yakutia).

METHODS

Analysis of variance, test for seasonality.

RESULTS

A remarkable effect of birthplace on longevity was observed in Novosibirsk. West Russia-born decedents were older than their cause-of-death-matched counterparts born in Siberia. In this city, men died at younger age in spring months compared to the rest of the year. In Mirny, an extreme northern town with a very harsh climate, the life span depended on the duration of living in this region prior to death.

CONCLUSION

There was some difference among cardiovascular diagnoses and between the two cities. However, overall, the results offer some support for theories suggesting that early "imprinting" is responsible for the association between life span and region/season of birth.

Effects of cold weather on mortality: results from 15 European cities within the PHEWE project

Weather-related health effects have attracted renewed interest because of the observed and predicted climate change. The authors studied the short-term effects of cold weather on mortality in 15 European cities. The effects of minimum apparent temperature on cause- and age-specific daily mortality were assessed for the cold season (October-March) by using data from 1990-2000. For city-specific analysis, the authors used Poisson regression and distributed lag models, controlling for potential confounders. Meta-regression models summarized the results and explored heterogeneity. A 1 degrees C decrease in temperature was associated with a 1.35% (95% confidence interval (CI): 1.16, 1.53) increase in the daily number of total natural deaths and a 1.72% (95% CI: 1.44, 2.01), 3.30% (95% CI: 2.61, 3.99), and 1.25% (95% CI: 0.77, 1.73) increase in cardiovascular, respiratory, and cerebrovascular deaths, respectively. The increase was greater for the older age groups. The cold effect was found to be greater in warmer (southern) cities and persisted up to 23 days, with no evidence of mortality displacement. Cold-related mortality is an important public health problem across Europe. It should not be underestimated by public health authorities because of the recent focus on heat-wave episodes.