By Melissa Kluczynski, M.S.
Forty seven million people worldwide had dementia in 2015; and hypertension is one of the strongest risk factors for stroke and dementia. A new research study published in the Lancet Healthy Longevity journal examined the association between blood pressure levels and cognitive impairment in older women (ages 65-79 years) enrolled in the Women’s Health Initiative Memory Study, or WHIMS, from 39 clinical centers across the United States. WHIMS was a study of community-dwelling women designed to evaluate whether hormone therapy reduced the incidence of dementia. The current study included 7,207 women of which 45.4% had hypertension at the start of the study. Over a median follow-up of 9 years, 15.7% of participants developed mild cognitive impairment (precursor to dementia), 10.3% had probable dementia, and 21.3% had cognitive loss (defined as mild cognitive impairment or probable dementia or both).
Elevated systolic blood pressure and pulse pressure (measure of arterial stiffness) were associated with increased risk of mild cognitive impairment and cognitive loss among all participants, even after taking into account differences in age, body mass index, education level, race, ethnicity, health insurance, smoking and alcohol status, and diabetes. However, participants with controlled hypertension targeting systolic blood pressure of less than 120/80 mmHg or pulse pressure less than 50 mmHg did not have a significantly increased risk of mild cognitive impairment and of cognitive loss. These findings suggest that controlling blood pressure with the use of anti-hypertensive medication and/or lifestyle changes can help preserve cognitive health in older women. Since this study was limited to primarily White older women, the findings may not be applicable to younger women and other racial and ethnic groups. This work builds on previous research which has found that lowering blood pressure can reduce the risk of mild cognitive impairment and/or dementia.