Impact of physical activity on self-rated health in older people: do the effects vary by socioeconomic status?

Background Many studies have demonstrated the relevance of socioeconomic status (SES) and physical activity (PA) on health among older people. However, little is known about the existence of interaction effects between PA and SES on self-rated health. Methods The following questions were investigated among people aged 65-84: (i) What is the impact of SES (school education and income) and PA on good self-rated health of the following year? and (ii) Do individuals with higher SES benefit more from PA than those with lower SES? Based on data of the German Socioeconomic Panel (GSOEP), binary logistic regression analyses were used to calculate odds ratios and synergy indices (SAB). Results High education in women and high income in men were positively associated with good self-rated health. Physically active older people with lower SES had a better chance of good health than those with higher SES and without PA. In the presence of PA, the effect of SES on health was attenuated. Conclusions Poor evidence was found for synergistic effects between PA and SES, indicating that the effect of PA on health does not differ across SES groups. In support of the mediation hypothesis, our findings suggest that PA accounted for some of the effects of SES on health.