Neighbourhood social interactions and risk of acute myocardial infarction.

STUDY
OBJECTIVE: Previous studies of neighbourhood effects on ischaemic heart disease (IHD) have used census or administrative data to characterise the residential context, most commonly its socioeconomic level. Using the ecometric approach to define neighbourhood social interaction variables that may be relevant to IHD, neighbourhood social cohesion and safety were examined to see how they related to acute myocardial infarction (AMI) mortality, after adjustment for individual and neighbourhood confounders.
DESIGN: To construct social interaction variables, multilevel models were used to aggregate individual perceptions of safety and cohesion at the neighbourhood level. Linking data from the Health Survey in Scania, Sweden, and the Population, Hospital, and Mortality Registers, multilevel survival models were used to investigate determinants of AMI mortality over a three year and nine month period. PARTICIPANTS: 7791 Individuals aged 45 years and over. MAIN
RESULTS: The rate of AMI mortality increased with decreasing neighbourhood safety and cohesion. After adjustment for individual health and socioeconomic variables, low neighbourhood cohesion, and to a lesser extent low safety, were associated with higher AMI mortality. Neighbourhood cohesion effects persisted after adjustment for various neighbourhood confounding factors (income, population density, percentage of residents from low-income countries, residential stability) and distance to the hospital. There was some evidence that neighbourhood cohesion effects on AMI mortality were caused by effects on one-day case-fatality, rather than on incidence.
CONCLUSIONS: Beyond commonly evoked effects of the physical environment, neighbourhood social interaction patterns may have a decisive influence on IHD, with a particularly strong effect on survival after AMI.