The role of physical activity in the bidirectional association between depressive symptoms and chronic disease incidence: A prospective analysis of the Irish longitudinal study on ageing.

AIM: To examine the bidirectional associations between depressive symptoms and chronic disease incidence and to investigate the moderating role of physical activity in the above-presented associations.

METHODS

Data from the Irish Longitudinal Study on Ageing were analyzed, including 7279 participants (55.7 % women, mean age = 62.5 ± 9.2 years) across four waves (2012-2018), comprising six years of follow-up. Depressive symptoms were assessed using the 8-item Center for Epidemiologic Studies Depression scale, while chronic disease incidence covered 13 self-reported conditions. Random-intercept cross-lagged panel models examined bidirectional associations, adjusting for confounders and stratifying by baseline physical activity levels.

RESULTS

A significant bidirectional association was observed between depressive symptoms and incident chronic diseases. Depressive symptoms predicted future chronic disease incidence (unstandardized beta coefficient [B] = 0.005; 95 %CI: 0.001-0.008), while chronic disease incidence predicted future depressive symptoms (B = 0.216; 95 %CI: 0.100-0.331). Notably, these associations were only significant among participants with low and moderate baseline physical activity levels, where chronic diseases predicted depressive symptoms (Low baseline PA level: B = 0.006; 95 %CI = 0.001 to 0.012. Moderate baseline PA level: B = 0.008; 95 %CI = 0.002 to 0.014) and depressive symptoms predicted chronic disease incidence (Low baseline PA level: B = 0.234; 95 %CI = 0.002 to 0.466. Moderate baseline PA level: B = 0.318; 95 %CI = 0.126 to 0.511).

CONCLUSION

This study confirms bidirectional associations between depressive symptoms and chronic disease incidence. Physical activity may be a moderating factor as this bidirectional association was only significant among participants with low or moderate levels of physical activity.