Authors of a study published in the March edition of BMC Public Health state that the cause of coronary disease infra (unusually low) mortality in Spain is unknown. Their study identified Spanish towns with very low ischemic heart disease mortality, described their health and social characteristics, and analysed the relationship with a series of contextual factors.
The researchers obtained the number of deaths registered for each of 8,122 Spanish towns in the periods 1989-1998 and 1999-2003. Infra mortality was defined as any town that displayed a Relative Risk below the 10th percentile. All the remaining towns, except for those with high mortality classified as ‘tourist towns’, were selected as controls. The association among socioeconomic, health, dietary, lifestyle and vascular risk factors was analysed using sequential mixed logistic regression models, with province as the random-effects variable.
32 towns were identified in which ischemic heart disease mortality was half the national rate and four times lower than the European Union rate, situated in lightly populated provinces spread across the northern half of Spain, and revealed a surprising pattern of geographic aggegation for 23 of the 32 towns. Variables related with infra mortality were: a less aged population (OR 0.93, 95% CI 0.89-0.99); a contextual dietary pattern marked by a high fish content (OR 2.13, 95% CI 1.38-3.28) and wine consumption (OR 1.50, 95% CI 1.08-2.07); and a low prevalence of obesity (OR 0.47, 95% CI 0.22-1.01); and, in the case of towns of over 1000 inhabitants, a higher physician-population ratio (OR 3.80, 95% CI 1.17-12.3).
Results indicate that dietary and health care factors have an influence on infra mortality. The geographical aggregation suggests that other factors with a spatial pattern, e.g. genetic or environmental might also be implicated. The authors state that results should be confirmed by further studies.
Source: Towns with extremely low mortality due to ischemic heart disease in Spain Medrano MJ; Boix R; Palmera A; Ramis R; Galan I; Lopez Abente G. BMC Public Health. Published early online 9 March 2012