Unhealthy effects of atmospheric temperature and pressure on the occurrence of myocardial infarction and coronary deaths - A 10-year survey: The Lille-World Health Organization MONICA Project (Monitoring trends and determinants in cardiovascular disease)

Background-Associations between an increase in coronary heart disease occur rence and low atmospheric temperatures have been reported from mortality da ta and hospital admission registries, However, concomitant increases in non cardiovascular case fatality rates and selection bias of hospital cases may weaken this observation. In this study, we addressed the question of the r elationships between fatal and nonfatal coronary diseases and meteorologica l variables in 10-year data (1985 to 1994) collected in a morbidity registr y (Lille-WHO MONICA Project) monitoring 257 000 men from 25 to 64 years of age. Methods and Results-The impacts of atmospheric temperature (in Celsius) and pressure (in millibars) on daily rates of myocardial infarction (MI) and c oronary deaths were studied. Percentages of variation of event rates accord ing to meteorological variations were derived from the relative risks estim ated with a Poisson regression model. During the 10-year longitudinal surve y, 3616 events occurred. Rates of events decreased linearly with increasing atmospheric temperature. For atmospheric pressure, we detected a V-shaped relationship, with a minimum of daily event rates ai 1016 mbar. A 10 degree s C decrease was associated with a 13% increase in event rates (P < 0.0001) ; a 10-mbar decrease <1016 mbar and a 10-mbar increase >1016 mbar were asso ciated with a 12% increase (P = 0.001) and an 11% increase (P = 0.01) in ev ent rates, respectively. These effects were independent and influenced both coronary morbidity and mortality rates, with stronger effects in older age groups and for recurrent events. Conclusions-This longitudinal study is the first to estimate the attributab le effect of meteorological variables on MI morbidity in population and str ongly argues for a systematic fight against cold in cardiovascular disease prevention, particularly in older ages and after a first MI.