Social Integration and Reduced Risk of Coronary Heart Disease in Women: The Role of Lifestyle Behaviors
Rationale: Higher social integration is associated with lower cardiovascular mortality; however, whether it is associated with incident coronary heart disease (CHD), especially in women, and if associations differ by case fatality is unclear.
Objective: This study sought to examine the associations between social integration and risk of incident CHD in a large female prospective cohort.
Methods and Results: 76,362 women in the Nurses' Health Study (NHS), free of CHD and stroke at baseline (1992), were followed until 2014. Social integration was assessed by a simplified Berkman-Syme Social Network Index every 4 years. Endpoints included nonfatal myocardial infarction (MI) and fatal CHD. 2,372 incident CHD events occurred throughout follow-up. Adjusting for demographic, health/medical risk factors and depressive symptoms, being socially integrated was significantly associated with lower CHD risk, particularly fatal CHD. The most socially integrated women had a hazard ratio of 0.55 (95% confidence interval, 0.41-0.73) of developing fatal CHD compared to those least socially integrated (p-for-trend < 0.0001). When additionally adjusting for lifestyle behaviors, findings for fatal CHD were maintained but attenuated (p-for-trend = 0.02) whereas the significant associations no longer remained for nonfatal MI. The inverse associations between social integration and nonfatal MI risk were largely explained by health-promoting behaviors, particularly through differences in cigarette smoking; however, the association with fatal CHD risk remained after accounting for these behaviors and thus may involve more direct biological mechanisms.
Conclusions: Social integration is inversely associated with CHD incidence in women, but is largely explained by lifestyle/behavioral pathways.
- marginal structural model
- social integration
- women and minorities
- prospective cohort study
- coronary heart disease risk
- Received June 30, 2016.
- Revision received March 15, 2017.
- Accepted March 30, 2017.