Key result
SBP ≥130 mmHg at age 50 linked to higher dementia risk independent of CVD.
Why the study?
Does systolic blood pressure ≥130 mmHg at midlife increase the risk of dementia in a general adult cohort?
Cohort (n=8,639)
Does systolic blood pressure ≥130 mmHg at midlife increase the risk of dementia in a general adult cohort?
Hazard Ratio: 1.38 (95% CI 1.11–1.7)
Systolic blood pressure ≥130 mmHg at age 50 is associated with an increased risk of dementia, independent of cardiovascular disease.
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Our analysis suggests that the importance of mid-life hypertension on brain health is due to the duration of exposure. So we see an increased risk for people with raised blood pressure at age 50, but not 60 or 70, because those with hypertension at age 50 are likely to be 'exposed' to this risk for longer.”
“These data support the notion that the longer you have hypertension, the higher your risk of dementia is. The lifetime exposure is the key.”
“Previous research has not been able to test the link between raised blood pressure and dementia directly by examining the timing in sufficient detail. In our paper we were able to examine the association at age 50, 60 and 70, and we found different patterns of association. This will have important implications for policy guidelines, which currently only use the generic term 'midlife'.”
Supports midlife BP in dementia risk assessment; leaves open causality and whether lowering SBP <130 mmHg prevents dementia.
AIMS: To examine associations of diastolic and systolic blood pressure (SBP) at age 50, 60, and 70 years with incidence of dementia, and whether cardiovascular disease (CVD) over the follow-up mediates this association. METHODS AND RESULTS: Systolic and diastolic blood pressure were measured on 8639 persons (32.5% women) from the Whitehall II cohort study in 1985, 1991, 1997, and 2003. Incidence of dementia (n dementia/n total = 385/8639) was ascertained from electronic health records followed-up until 2017. Cubic splines using continuous blood pressure measures suggested SBP ≥130 mmHg at age 50 but not at age 60 or 70 was associated with increased risk of dementia, confirmed in Cox regression analyses adjusted for sociodemographic factors, health behaviours, and time varying chronic conditions [hazard ratio (HR) 1.38; 95% confidence interval (95% CI) 1.11, 1.70]. Diastolic blood pressure was not associated with dementia. Participants with longer exposure to hypertension (SBP ≥ 130 mmHg) between mean ages of 45 and 61 years had an increased risk of dementia compared to those with no or low exposure to hypertension (HR 1.29, 95% CI 1.00, 1.66). In multi-state models, SBP ≥ 130 mmHg at 50 years of age was associated with greater risk of dementia in those free of CVD over the follow-up (HR 1.47, 95% CI 1.15, 1.87). CONCLUSION: Systolic blood pressure ≥130 mmHg at age 50, below the conventional ≥140 mmHg threshold used to define hypertension, is associated with increased risk of dementia; in these persons this excess risk is independent of CVD.
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Abell et al. (2018) conducted a cohort in Dementia (n=8,639). Systolic blood pressure ≥130 mmHg at age 50 vs. Systolic blood pressure <130 mmHg was evaluated on Incidence of dementia (HR 1.38, 95% CI 1.11-1.70). Systolic blood pressure ≥130 mmHg at age 50 was associated with an increased risk of incident dementia (HR 1.38; 95% CI 1.11-1.70), independent of cardiovascular disease.
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