Association between systolic blood pressure and dementia in the Whitehall II cohort study: role of age, duration, and threshold used to define hypertension

Abstract

AimsTo 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 resultsSystolic 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).ConclusionSystolic 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.

Blood pressure and risk of dementia and its subtypes: a historical cohort study with long‐term follow‐up in 2.6 million people

“…A fall in BP is known to occur prior to clinical diagnosis of dementia [12]; hence the inverse associations during the first 10 years are probably due to reverse causation and the weaker associations observed beyond 10 years after measurement may be more reliable. The association with dementia is also known to vary by age, with a previous study reporting that BP measurements taken in mid-life, but not later life, are associated with increased risk of dementia [13]. However, similar analyses in our dataset suggest that mid-life BP is at most weakly associated with dementia risk.…”

Risk of dementia associated with cardiometabolic abnormalities and depressive symptoms: a longitudinal cohort study using the English longitudinal study of ageing

“…37,38 However, this assumption is complicated by the fact that different studies will find opposing results when examining the same cardiometabolic abnormality. Other studies find that obesity, 40,41 hypertension, 42 diabetes, 43 and high lipids 44 are risk factors for incident dementia. Other studies find that obesity, 40,41 hypertension, 42 diabetes, 43 and high lipids 44 are risk factors for incident dementia.…”

“…For instance, some studies have found that abdominal obesity, 11 hypertension, 39 and high lipids 11,35 are protective against risk of dementia. Other studies find that obesity, 40,41 hypertension, 42 diabetes, 43 and high lipids 44 are risk factors for incident dementia. Finally, some studies find no association between any individual cardiometabolic risk factors with incident dementia.…”

Comparison of antihypertensive drug classes for dementia prevention

“…In part, because of research to better understand the observed associations between midlife hypertension and later-life risk of Alzheimer's disease and vascular dementia. (3)(4)(5)(6) There is also increasing recognition that one of the earliest pathological events in the development of Alzheimer's disease is vascular dysregulation. [8] As well as suggestions that some antihypertensives, specifically those that block angiotensin receptor and calcium channel signalling, may have other neurological benefits.…”