Accelerometer-measured physical activity and sitting with incident mild cognitive impairment or probable dementia among older women

IntroductionPhysical activity (PA) is prospectively inversely associated with dementia risk, but few studies examined accelerometer measures of PA and sitting with rigorously-adjudicated mild cognitive impairment (MCI) and dementia risk. MethodsWe examined the associations of accelerometer measures (PA and sitting) with incident MCI/probable dementia in the Women's Health Initiative (n = 1277; mean age = 82 +/- 6 years) ResultsOver a median follow-up of 4.2 years, 267 MCI/probable dementia cases were identified. Adjusted Cox regression HRs (95% CI) across moderate-to-vigorous PA (MVPA) min/d quartiles were 1.00 (reference), 1.28 (0.90 to 1.81), 0.79 (0.53 to 1.17), and 0.69 (0.45 to 1.06); P-trend = 0.01. Adjusted HRs (95% CI) across steps/d quartiles were 1.00 (reference), 0.73 (0.51 to 1.03), 0.64 (0.43 to 0.94), and 0.38 (0.23 to 0.61); P-trend < 0.001. The HR (95% CI) for each 1-SD increment in MVPA (31 min/d) and steps/d (1865) were 0.79 (0.67 to 0.94) and 0.67 (0.54 to 0.82), respectively. Sitting was not associated with MCI/probable dementia. DiscussionFindings suggest >= moderate intensity PA, particularly stepping, associates with lower MCI and dementia risk. HighlightsFew studies have examined accelerometer-measured physical activity, including steps, and sitting with incident ADRD.Moderate-to-vigorous physical activity and steps, but not light physical activity or sitting, were inversely associated with lower ADRD risk.Among older women, at least moderate intensity physical activity may be needed to reduce ADRD risk.

Automated summary

Accelerometer measures of physical activity and sitting are associated with the risk of mild cognitive impairment and dementia, with at least moderate intensity physical activity and steps showing a lower risk for these conditions.