Aims: Low socio-economic status is a well-known risk factor for coronary heart disease (CHD), but the evidence concerning social network has been less consistent. In this prospective cohort study of men we sought to estimate the impact of social network factors on the risk of incident coronary heart disease and mortality from all causes.
Methods and results: In a population of 741 men aged 50 at baseline 92 new cases of coronary disease were identified over a follow-up period of 15 years. Social factors included occupational class, two measures of social support-- "emotional attachment" and "social integration"-- and a measure of global mental stress. Among the men in the lowest quartile of social integration, there were 13.6 cases (per 1000 observation years), compared to 8.9 in the intermediate two quartiles and 6.0 in the highest quartile (P for trend 0.003). After adjustment for all relevant risk factors the hazard ratio (HR) for the highest, compared with the lowest, quartile was 0.45 (0.24-0.84);P for trend 0.013. Emotional attachment was also associated with significantly reduced risk. The adjusted HR for the lowest quartile was 0.58 (0.37-0.91); P=0.019. No relation between mental stress and risk of CHD, or between low occupational class and risk of CHD was found.
Conclusion: In this prospective study of men, we found two dimensions of low social support-low social integration and low emotional attachment-to be predictive of coronary morbidity, independently of other risk factors.