Preventive impact of social participation on the onset of non-communicable diseases among middle-aged adults: A 10-wave hazards-model analysis in Japan.

Social participation (SP) is known to have a favorable impact on the health of older adults by reducing the risk of functional disability, psychological distress, cognitive impairment, and mortality. However, the preventive impact of SP on non-communicable diseases (NCDs) among middle-aged adults is largely understudied. Using the dataset from a population-based, 10-wave longitudinal survey that started with Japanese adults aged 50-59 years in 2005 (16,290 men and 17,248 women), we estimated Cox proportional hazards models to estimate the preventive impact of SP adjusted for baseline covariates. After controlling for baseline covariates, baseline participation in at least one of six types of SP prevented diabetes both for men (hazard rate [HR] = 0.86; 95% confidence interval [CI] = 0.77, 0.95) and women (HR = 0.75; 95% CI = 0.66, 0.85) and stroke both for men (HR = 0.83; 95% CI = 0.70, 0.99) and women (HR = 0.78; 95% CI = 0.64, 0.97). SP also had a preventive impact on hypertension only for women (HR = 0.91; 95% CI = 0.84, 0.99). SP did not prevent heart disease, hyperlipidemia, or cancer for either gender. We also found that SP tended to have a stronger preventive effect when it was conducted with other persons than done alone, highlighting personal interactions as a key aspect of SP for later health outcomes. Overall, the results showed that SP can prevent the onset of selected NCDs, suggesting that policy measures to encourage SP may be favorable for the health of middle-aged adults.