Cardiorespiratory fitness in midlife and subsequent incident depression, long-term sickness absence, and disability pension due to depression in 330,247 men and women

Abstract

ObjectiveSpecific information for whom and when cardiorespiratory fitness (CRF) is associated with depression risk is lacking. We aimed to study the association between adulthood CRF and incident depression, long-term sickness absence, and disability pension due to depression, as well as examine moderation of sex, age, education, and occupation on associations. MethodsA large prospective cohort study follows participants over time with Swedish occupational health screenings data. The study includes 330,247 individuals (aged 16–79 years, 46% women) without a depression diagnosis at baseline. CRF was estimated from a submaximal cycle test. ResultsCRF was associated beneficially from low to higher levels with incident depression and long-term sickness absence due to depression. Further, CRF at high levels (≥46 ml/min/kg) was associated with a decreased risk of receiving disability pension due to depression. The associations remained after adjustment for age and sex, but not lifestyle-related factors and co-morbidity. Participants with moderate and high CRF had 16% and 21%, respectively, lower risk for incident depression, and participants with high CRF had 11% lower risk for long-term sickness absence due to depression. Associations between higher CRF and the outcomes were mainly evident in men, younger participants, and individuals with low education. ConclusionIn a large sample of adults without a depression diagnosis at baseline, higher CRF was shown to be beneficially related to the risk of incident depression and, to some extent, long-term sickness absence due to depression. If causal, targeted interventions focusing on increasing CRF in these sub-groups should be prioritized.