Individual and combined associations of physical activity and cognitive function with all-cause mortality in older men and women: A prospective analysis of the German National Cohort (NAKO).
ObjectivesLow
physical activity (PA) and poor cognitive function are associated with
higher mortality risks. However, little is known about their
interaction, including whether PA may moderate cognition-related
mortality risks. This study examines the combined associations of PA and
cognition with all-cause mortality, with attention to sex differences.MethodsUsing
data from the German National Cohort and its mortality follow-up, we
analyzed mortality risk based on: a) baseline low vs. sufficient PA
(assessed via the global physical activity questionnaire using a
threshold of < vs. ≥ 600 MET-minutes/week), b) baseline low vs.
medium vs. high semantic memory (SM) and executive function/processing
speed (EF/PS), assessed through factor analyses of a neurocognitive test
battery, and c) their interaction on mortality in individuals aged
65 + up to 10 years of follow-up (N = 28,892). Cox models were estimated
both in the total sample and stratified by sex, adjusting for relevant
confounders and reporting both distinct and combined associations.ResultsDuring
follow-up, 1,605 individuals (5.6%) died: 1,097 men (7.5%) and 508
women (3.6%). Compared to individuals with low cognitive function, those
with high SM (Hazard Ratio (HR) = 0.83 [95%CI: 0.67–1.02]), as well as
high EF/PS (HR = 0.66 [0.53–0.83]) and medium EF/PS (HR = 0.68
[0.60–0.78]) had lower mortality risks. PA was associated with a 29%
decreased mortality risk (HR = 0.71 [0.62–0.82]) compared to low PA. PA
moderated the elevated risk from low cognition, with regard to EF/PS
(low EF/PS*PA: HR = 0.65 [0.50–0.84] vs. low EF/PS*low PA: HR = 1
(ref.)) and SM (low SM*PA: HR = 0.60 [0.46–0.77] vs. low SM*low PA:
HR = 1 (ref.)). The associations did not differ between men and women.ConclusionMaintaining
cognitive function and PA in older age is relevant for reducing
mortality risk in both men and women. PA may offset risks linked to low
cognition in both sexes, though mechanisms require further study.Trial registrationClinical trial number: not applicable.