Systolic Blood Pressure Variability Increases Dementia Risk Among Older Adults

Higher systolic blood pressure over time among adults over 65 years of age is associated with increased risk of dementia later in life but may be modified with calcium channel blockers. These findings were published in Alzheimer’s & Dementia.

Researchers evaluated the association between blood pressure variability (BPV) over time and subsequent risk of dementia and assessed the modifying effect of antihypertensive medications among community-dwelling older adults in the US.

They conducted a community-based study that included 2234 older adults (78±7 years of age; 74% women; 94% White) with normal cognition or mild cognitive impairment. The study population consisted of participants from the Rush Memory and Aging Project and the Religious Orders Study, both ongoing prospective cohort studies of aging and cognition in the US. These studies enroll adults at least 65 years of age without known dementia with annual follow-up rates of 95% and 90%, respectively. Participants were followed for up to 27 years through annual assessments. BPV measured annually was quantified over 3, 6, 9, and 12 years.

Researchers found 668 participants developed dementia during the median follow-up of 10 years (IQR 6-14 years). Mean systolic blood pressure (SBP) over 3, 6, 9, and 12 years was 134±15, 133±13, 132±13, and 131±12mmHg, respectively. They noted the mean higher systolic BPV (SBPV) over those measurement times showed increases (8.3%±5%, 9.2%±4%, 10.0%±3%, and 10.0%±3%, respectively).

Researchers found that SBPV during the 3, 6, 9, and 12-year quantifications associated with subsequent increased dementia risk. Hazard ratios ranged from 1.02 (95% CI, 1.01-1.04) to 1.10 (95% CI, 1.05-1.16). They noted participants with SBPV of at least 10% had increased risk of all-cause dementia vs those with SBPV of less than 8% (all P <.05).

After model adjustments, SBPV of at least 10% still associated with increased dementia risk with the highest hazard ratios for SBPV over 12 years. They noted each unit increase in SBPV over 3, 6, 9, and 12 years was associated with 1.02-, 1.04-, 1.06-, and 1.10-fold increased dementia risk, respectively (all P <.05).

Among participants not taking calcium channel blockers, researchers noted a stronger association between SBPV and dementia risk (P for interaction <.05). Antihypertensive medication class analyses suggested that participants specifically taking calcium channel blockers over the first 3 years had lower SBPV vs those taking other antihypertensive medications.                               

Researchers found no association between SBP or mean SBP and risk of all-cause dementia.

Study limitations include the observational study design, limited generalizability with a preponderance of White participants at least 65 years of age, BPV measured annually leaving impact of shorter variations in BPV unknown, selection bias including only survivors in period-specific analyses, and elements of study design underestimating true effect estimates.

“Higher systolic BPV of up to 12 years is associated with an increased risk of all-cause dementia and Alzheimer’s disease later in life, independent of mean BP levels,” researchers concluded. They added, “Calcium channel blockers may moderate the link between SBPV and dementia risk.” They urge using SBPV as a target beyond mean BP levels for risk stratification in older adults.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.