Low blood pressure and blood glucose levels in Alzheimer's disease. Evidence for a hypometabolic disorder?

Abstract

Objective: To test possible differences between patients with Alzheimer's disease (AD) and patients with other forms of dementia and the healthy population concerning body composition, blood pressure, metabolic data and leukoaraiosis (LA).

Design: Retrospective study on data collected according to a predefined protocol.

Setting: A geriatric, neuropsychiatric diagnostic unit.

Subjects: Seventy-one consecutive patients with dementia.

Main outcome measures: Body mass index, blood pressure, metabolism and LA in AD compared to other dementia forms.

Results: Mean blood pressure and fasting blood glucose levels were lower in patients with AD, 94 +/- 12 mmHg and 4.3 +/- 0.5 mmol l-1, compared to patients with unspecified dementia (NUD), 100 +/- 10 mmHg and 5.5 +/- 2.5 mmol l-1 (P < 0.05) and vascular dementia (VAD), 114 +/- 12 mmHg and 5.6 +/- 1.6 mmol l-1 (P < 0.001) and the age-matched healthy population. Body mass index, serum cholesterol and cortisol were similar in all groups of dementia patients whereas triglycerides were highest in the VAD group. No cases of diabetes or treatment for hypertension were found in the AD group while the prevalence was 21% and 36% for diabetes in the NUD and VAD groups and 8% in the population from the same region. There were 16% with antihypertensive treatment in dementia NUD, 50% in VAD, and 30% in the general population. Treated or newly detected hypothyreosis was present in 11% of the AD patients, none in the other dementia groups and 2% in the general population. Smoking was least common in AD. Degree of LA correlated with blood pressure and blood glucose levels.

Conclusions: AD was clearly different to other dementia patients. They had lower blood pressure, blood glucose and higher prevalence of hypothyreosis than the healthy, age-matched population. These findings may indicate that AD could be a hypometabolic disorder.