Seasonal difference in onset of coronary heart disease in young Japanese patients - A comparison with older patients

Background The aim of the present multicenter study was to investigate whether there is a seasonal difference in the onset of coronary heart disease (CHD) in young patients compared with older patients living in Nagano Prefecture, Japan. Methods and Results The study group comprised 101 young (aged <= 40 years) and 94 older (aged >= 50 years) patients diagnosed with CHD from 1992 to 2002. In young patients, the prevalence of the onset of CHD events was significantly higher from June to September than from December to March (odds ratio =2.23, p=0.035). Obesity was found in 56%, hypertension in 29%, dyslipidemia in 54%, diabetes in 24%, smoking history in 82%, and habitual physical activity in 13% in young patients. There was a trend for an association between the presence of acute myocardial infarction (p=0.082) and history of smoking and the onset of CHD events during the summer months in young patients (p=0.077). Conclusions There is a seasonal difference in the onset of CHD events, with an increase in the prevalence during the summer months in young patients. The data may provide insights into preventive approaches to CHD in the young population.