Gymnastik- och idrottshögskolan, GIH

AIM: To investigate the association between change in cardiorespiratory fitness (CRF) and cardiovascular disease (CVD)-related and all-cause hospital admission, and explore if the association varies dependent on prior admission, baseline CRF, sex, and age.

METHODS: 91,140 adult participants (41.5% women) with two examinations from occupational health profile assessments between 1986 and 2019 were included (mean 3.2-years between examinations). CRF was assessed as maximal oxygen consumption and estimated through a submaximal cycle test. CRF change was defined as annual percentage change in relative CRF (mL*min-1*kg-1) and further divided into "decliners" (<-1%), "maintainers" (-1%; 1%), and "increasers" (>1%). Hospital admissions were followed over a mean of 7-years. Natural cubic splines and Cox's proportional hazards model were applied. Additionally, prevented fraction for the population was calculated.

RESULTS: Increase in CRF was associated with lower risk of CVD [HR = 0.99] and all-cause hospital admission [HR = 0.99], after multilevel-adjustment for confounders and change in smoking, diet, and stress. Compared to a decline, maintenance of CRF was associated with 9% and 7% lower risk of CVD and all-cause admission, respectively. Increase in CRF reduced the risk with 13% and 11%, and for individuals with prior admission, with 20% and 14%. The burden of CVD and all-cause admission was 6% and 5% lower than if the whole cohort had declined CRF, with large potential cost-savings.

CONCLUSIONS: Efforts to maintain or improve CRF should be included in disease preventive strategies, regardless of change in other lifestyle-related risk factors. Preventing the age-associated decline in CRF can lessen healthcare utilization and costs.