Physical activity and brain volumes in older adults: The Washington Heights‐Inwood Columbia Aging Project (WHICAP)

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AbstractBackgroundLeisure time physical activity (LTPA) has been shown to be protective against cognitive decline, dementia, and Alzheimer's disease. Understanding whether LTPA is associated with MRI‐assessed brain measures will help elucidate the underlying mechanisms.MethodThis cross‐sectional study included 1557 older participants of the Washington Heights‐Inwood Columbia Aging Project study, a community‐based, multi‐ethnic elderly cohort. Current LTPA level was measured using metabolic equivalent of energy expenditure (MET‐minutes/2‐wk), calculated from self‐reported Godin Leisure Time Exercise Questionnaire. Total brain volume, gray matter volume, white matter volume, hippocampal volume, and white matter hyperintensity volume were derived from MRI scans with established methods and were adjusted for intracranial volume. We examined the association of LTPA with these imaging markers using multivariable regression models.ResultsThe participants of the study had a mean (SD) age of 74.9(6.0) years, 64% were women; 26%, 34% and 38% were non‐Hispanics whites, African‐Americans, and Hispanics, respectively; and 28% carried Apolipoprotein ɛ4 allele. One SD (2860 MET‐minutes/2‐wk) increase in LTPA was significantly associated with 4.02 (95%CI=1.15‐6.88; p=0.006), 2.87 (95%CI=1.13‐4.62; p=0.001), and 0.043 (95%CI=0.004‐0.082; p=0.032) cm3 larger total brain, gray matter, and hippocampal volumes, respectively. Compared to those in the lowest tertile of LTPA, those with the highest tertile of LTPA had larger (in cm3) total brain volume (b=13.23, p=0.001; p‐trend=0.001), total gray matter volume (b=8.41, p<0.0001; p‐trend=0.001), and total white matter volume (b=7.25, p=0.005; p‐trend=0.013), hippocampal volumes (b=0.11, p=0.04; p‐trend=0.08), after adjusting for age, sex, race/ethnicity, education, Apolipoprotein E4 status, intracranial volume, and recruitment waves. The effect size comparing the highest to the lowest tertile LTPA was equivalent to about 3 years of aging (b for 1‐year older=‐3.14, ‐2.72, ‐2.16, ‐0.059 for total brain, gray matter, white matter, and hippocampal volumes, respectively). The associations were attenuated slightly but remained similar after further adjusting for body mass index and vascular comorbidities. LTPA was not associated white matter hyperintensity volume. The results remained similar after excluding 296 participants with mild cognitive impairment.ConclusionMore physical activity is associated with larger brain volumes in the elderly. Future longitudinal studies are needed to establish a temporal relationship between physical activity and brain health.