Internal migration, coffee drinking, and nonfatal myocardial infarction in Italy

We conducted a hospital-based case-control study of 153 patients who had been recently diagnosed with myocardial infarction; there were 157 hospital controls. All subjects were 35-70-y-old males who lived in the province of Torino (northern Italy). These individuals were nonsmokers or had quit smoking for at least 6 mo. A protective role of migration from southern Italy was found (age-adjusted odds ratio for northern versus southern origin = 1.82, 95% confidence interval = 1.0, 3.3). Although fat consumption differed greatly between those born in northern Italy and those in southern Italy (i.e., the former used mainly butter and the latter used mainly olive oil during their early lives), it did not explain the migration effect. A family history of myocardial infarction increased the risk of a myocardial infarction (odds ratio = 2.4, 95% confidence interval = 1.1, 4.9). Moderate coffee consumption also increased the risk and was not explained by the known coronary risk factors. Relative risks were up to 4 among both nonsmokers and exsmokers who drank more than 4 cups of coffee each day. We controlled for coffee drinking and found that the association with southern origin appeared strengthened.