Hypertension Guidelines

Association Between ABCA1 Gene Polymorphisms and the Risk of Hypertension in the Chinese Han Population

Background

Hypertension is rising as a major public health burden around the world. This study explored the association between single-nucleotide polymorphisms (SNPs) in the adenosine triphosphate (ATP)-Binding Cassette Subfamily A1 (ABCA1) gene and hypertension among Chinese Han adults.

Method

A total of 2,296 Han Chinese in southeast China were recruited for this study. We collected medical reports, lifestyle details, and blood samples from individuals. The polymerase chain reaction-ligase detection reaction (PCR-LDR) method was used to detect the genotypes of these SNPs in the ABCA1 gene.

Results

After adjusting some covariates, the additive and recessive models of the rs2472510 and rs2515614 were significantly associated with hypertension. The haplotypes TCTA (rs2297406-rs2472433-rs2472510-rs2515614) were associated with high SBP, and the haplotypes CCTA, TCTA, and TTTA were associated with high diastolic blood pressure (DBP).

Conclusion

The results of the relationship between the polymorphisms of rs2297406, rs2472433, rs2472510, and rs2515614 in ABCA1 and hypertension in southeastern China would provide a theoretical basis for genetic screening and disease prevention.

Association of Systolic Blood Pressure With Dementia Risk and the Role of Age, U-Shaped Associations, and Mortality

IMPORTANCE

The optimal systolic blood pressure (SBP) to minimize the risk of dementia in older age is unknown.

OBJECTIVE

To investigate whether the association between SBP and dementia risk is U-shaped and whether age and comorbidity play a role in this association.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used an individual participant data approach to analyze 7 prospective, observational, population-based cohort studies that were designed to evaluate incident dementia in older adults. These studies started between 1987 and 2006 in Europe and the US. Participants had no dementia diagnosis and had SBP and/or diastolic blood pressure (BP) data at baseline and incident dementia status during follow-up. Data analysis was conducted from November 7, 2019, to October 3, 2021.

EXPOSURES

Baseline systolic BP.

MAIN OUTCOMES AND MEASURES

All-cause dementia (defined using Diagnostic and Statistical Manual of Mental Disorders [Third Edition Revised] or Diagnostic and Statistical Manual of Mental Disorders [Fourth Edition] and established at follow-up measurements or in clinical practice), mortality, and combined dementia and mortality were the outcomes. Covariates included baseline antihypertensive medication use, sex, educational level, body mass index, smoking status, diabetes, stroke history, myocardial infarction history, and polypharmacy. Cox proportional hazards regression models were used, and nonlinear associations were explored using natural splines.

RESULTS

The study analyzed 7 cohort studies with a total of 17 286 participants, among whom 10 393 were women (60.1%) and the mean (SD) baseline age was 74.5 (7.3) years. Overall, dementia risk was lower for individuals with higher SBP, with the lowest risk associated with an SBP of approximately 185 mm Hg (95% CI, 161-230 mm Hg; P = .001). Stratified by overlapping 10-year baseline age groups, the lowest dementia risk was observed at somewhat lower systolic BP levels in those older than 75 years (158 [95% CI, 152-178] mm Hg to 170 [95% CI, 160-260] mm Hg). For mortality, there was a clear U-shaped association, with the lowest risk at 160 mm Hg (95% CI, 154-181 mm Hg; P < .001). This U-shape occurred across all age groups, with the lowest dementia risk associated with an SBP of 134 mm Hg (95% CI, 102-149 mm Hg; P = .03) in those aged 60 to 70 years and increasing to between 155 mm Hg (95% CI, 150-166 mm Hg; P < .001) and 166 mm Hg (95% CI, 154-260 mm Hg; P = .02) for age groups between 70 and 95 years. Combined dementia and mortality risk curves closely resembled those for mortality. Associations of diastolic BP with dementia risk were generally similar but were less distinct.

CONCLUSIONS AND RELEVANCE

This cohort study found that dementia risk was lower for older individuals with higher SBP levels and that more distinctly U-shaped associations appeared for those older than 75 years, but these associations cannot be explained by SBP-associated changes in mortality risk. The findings may warrant future trials on tailored BP management in older age groups that take life expectancy and health context into consideration.

Discontinuation of Antihypertensive Medication, Cognitive Complaints, and Incident Dementia

OBJECTIVES

To evaluate whether discontinuation of antihypertensive medication in community-dwelling older people is associated with a reduction in memory complaints and/or incident dementia.

DESIGN

Prospective observational cohort study within the Prevention of Dementia by Intensive Vascular Care (preDIVA) trial.

SETTING AND PARTICIPANTS

Community-dwelling participants (aged 70-78 years at baseline) who underwent 2-yearly assessments during 6-8 years of follow-up.

MEASURES

Cox regression analyses of the relation between discontinuation of antihypertensive medication during the study and change in subjective memory complaints, incident dementia, and mortality.

RESULTS

Dementia occurred more often in participants discontinuing antihypertensive treatment (13.4% vs 6.2%, P = .02); mortality was similar (16.5% vs 13.9%, P = .52). Discontinuation of antihypertensive medication was associated with a double dementia hazard [hazard ratio (HR) (95% confidence interval) = 2.15 (1.15-4.03)], which somewhat attenuated after adjustment for sex, blood pressure, number of antihypertensives and other medications [HR = 1.92 (1.01-3.65)], and additionally for stroke, cardiovascular disease, diabetes, smoking, memory complaints, and MMSE score [HR = 1.79 (0.93-3.44)]. Antihypertensive discontinuation was associated with an approximately 50% higher hazard of dementia and/or mortality combined [HR = 1.58 (1.04-2.40); model 2: HR = 1.64 (1.07-2.51); model 3: HR = 1.49 (0.96-2.30)]. Antihypertensive discontinuation was not associated with change in memory complaints [odds ratio (95% confidence interval) = 0.96 (0.55-1.67)]. Subgroup and sensitivity analyses addressing possible sources of bias and confounding gave similar results.

CONCLUSIONS/IMPLICATIONS

Our results suggest that antihypertensive withdrawal in community-dwelling older people does not preserve cognition and may in fact increase dementia risk. This is not due to reduced mortality as competing risk. Additional analyses suggest results are unlikely to be explainable by confounding, reverse causality, or observational biases. Studies with person-specific reasons for antihypertensive discontinuation may be able to exclude reverse causality completely. Given the beneficial effects of antihypertensive medication on cardiovascular risk, observational data may be the best currently obtainable on the pressing issue of when withdrawal of antihypertensives in older people is acceptable and what consequences need to be weighed.