Changes in access to structural social capital and its influence on self-rated health over time for middle-aged men and women: a longitudinal study from northern Sweden.

Until recently, most studies on social capital and health have been cross-sectional making it difficult to draw causal conclusions. This longitudinal study used data from 33,621 individuals (15,822 men and 17,799 women) from the Västerbotten Intervention Program, to analyse how changes in access to individual social capital influence self-rated health (SRH) over time. Two forms of structural social capital, i.e. informal socializing and social participation, were measured. Age, sex, education, marital status, smoking, snuff, physical activity, alcohol consumption, high blood pressure, and body mass index were analysed as potential confounders. The association between changes in access to structural social capital and SRH in the follow-up was adjusted for SRH at baseline, as well as for changes in the socio-demographic and health-risk variables over time. The results support that changes in access to structural social capital over time impact on SRH. Remaining with no/low level of informal socializing over time increased the odds ratio for poor SRH for both men and women (OR of 1.45; 95%CI = 1.22-1.73 among men and OR of 1.56; 95%CI = 1.33-1.84 among women). Remaining with no/low levels of social participation was also detrimental to SRH in men and women (OR 1.14; 95%CI = 1.03-1.26 among men and OR 1.18; 95%CI = 1.08-1.29 among women). A decrease in informal socializing over time was associated with poor SRH for women and men (OR of 1.35; 95%CI = 1.16-1.58 among men and OR of 1.57; 95%CI = 1.36-1.82 among women). A loss of social participation had a negative effect on SRH among men and women (OR of 1.16; 95%CI = 1.03-1.30 among men and OR of 1.15; 95%CI = 1.04-1.27 among women). Gaining access to social participation was harmful for SRH for women (OR 1.17; 95%CI = 1.05-1.31). Structural social capital has complex and gendered effects on SRH and interventions aiming to use social capital for health promotion purposes require an awareness of its gendered nature.