Social contacts and ischaemic heart disease.

The association between measures of social connections and mortality from ischemic heart disease was studied using data from the Alameda County Study in California and the North Karelia Study in Eastern Finland. In both studies, there is a significant association between the extent of social connections and mortality from ischemic heart disease. Those who are socially isolated are at 2 to 3-fold increased risk of death over 5 to 9 years when compared to those most connected. These results are found when there is extensive adjustment for traditional cardiovascular risk factors. Analyses using a variety of techniques provide no evidence that this association is due to the impact of prevalent disease on the extent of social contacts. Furthermore, changes in social connections during one 9-year period are prospectively associated with increased risk of death from ischemic heart disease in a subsequent 9-year period. Finally, evidence is presented indicating that the level of social connections modifies the association between diastolic blood pressure and risk of death from ischemic heart disease.