Is there a critical life stage to promote physical activity for preserving cognitive function? Results from a population‐based birth cohort

Abstract

AbstractBackgroundPhysical activity improves cognitive function across the life course, reducing the risk of all‐cause dementia in older ages. We aimed to identify the life course model that best describes the association between physical activity throughout life and cognitive performance at age 50.MethodAdults aged 50 participants of the National Child Development Survey (NCDS) were followed from birth (1958) to 2013. Physical activity was accessed using a self‐reported questionnaire in each wave. Participants were classified as physically active or inactive. Short‐term memory was assessed by word recall test while the executive function was assessed by letter cancelation and animal naming tests. Scores from both cognitive domains were reported as standard deviation (SD). The most appropriate life course model (critical, sensitive, or accumulation) to explain cognitive performance at age 50 was identified by partial F‐tests.ResultData from 4,103 adults were analyzed (53.8% women). At age 50, most participants were employees (74.3%), non‐smokers (80.3%), and overweight or obese (64.7%). Whilst 175 (4.0%) of participants were physically inactive at age 7, 44.9% practiced physical activity once a week or less at age 50. Physical activity at age 42 was defined as a critical period for better memory and executive function at age 50 in men. Among women, physical activity at age 23 was identified as a critical period for executive function while the sensitive model best explained the association between physical activity through the life course and memory at age 50. Women who were physically active at age 23 had a better executive function (1.13 [95%CI 1.06, 1.20] SD) than inactive counterparts. Better performance on memory test was observed in women physically active at age 7 (0.18 [95%CI: 0.02, 0.34] SD), 23 (0.11 [95%CI: 0.03, 0.18] SD) and 50 (0.08 [95%CI: 0.01, 0.15] SD). Physically active men at age 42 showed better performance in memory test (0.12 [95%CI: 0.03, 0.21] SD) and executive function (0.11 [95%CI: 0.04, 0.18] SD) than inactive respondents.ConclusionEarly childhood and adulthood for women and late‐adulthood for men were identified as important life stages to promote physical activity for preserving cognitive function at age 50.