Deal with Risk Factors for Alzheimer's, Now

Summarized by Robert W. Griffith, MD
January 2, 2006

Introduction

On January 1, 2006, the first baby-boomer turned 60. This sobering thought should encourage all the other baby boomers to look at their lifestyles, general health, and disease risk factors, and assess where they are likely to be in 20 years. Unfortunately, many of them will be in nursing homes, suffering from Alzheimer's and other dementias.

Swedish researchers have just published an interesting study on this problem. Although we don't know what causes Alzheimer's, there's no disputing that the frequency of the disease is increasing, and there are a number of 'risk factors' closely linked with it. Elimination of an individual's risk factors reduces the chances of their developing the condition. The study was reported in the Archives of Neurology, and we summarize the main points here.

What was done

Participants in the Finnish Cardiovascular Risk Factors, Aging, and Dementia Study were examined at 5-year intervals between 1972 and 1987; they were aged 50, on average, at their initial exam. They were re-examined in 1998, after an average follow-up of 21 years.

The main risk factors assessed at baseline were body mass index (BMI), blood pressure, lipid levels, smoking status, cardiovascular disease history, and socioeconomic factors. The subjects were categorized into three groups according to their BMI values: less than 25, 25 to 30, and over 30 kg/m2.

At the final exam in 1998 the surviving participants underwent a 3-stage testing for dementia - Alzheimer's and non-Alzheimer's dementia.

What the results showed

At baseline (i.e. mid-life, about 50 years of age) one third of the participants had a normal BMI (less than 25). Half the group were overweight (BMI 25-30) and 16% were obese (BMI over 30).

Twenty years later, even after adjusting for socioeconomic factors like income and education levels, obesity was linked to an almost 2½ times greater risk for dementia and Alzheimer's. When adjustments were made for raised cholesterol, smoking, and high blood pressure, the effect of obesity was a bit less - about twice the risk for dementia.

A systolic blood pressure (that's the upper number) of 140 mmHg or above was associated with double the risk for dementia, when compared with people with systolic pressure below 140 mmHg.

Having a total cholesterol level above 250 mg/dL was also linked to an almost doubling of the risk for dementia.

The authors calculated whether these risk factors had an additive effect. They found that someone with all three risk factors (obesity, high systolic pressure and raised cholesterol) was about 6 times more likely to develop dementia than someone with none of them.

What these findings mean

This study showed that midlife obesity, high systolic blood pressure, and high total cholesterol were all significant risk factors for dementia, each of them doubling the risk, and acting in an additive fashion. In other words, someone with all three risk factors would be 6 times as likely to develop Alzheimer's as someone with none of them.

It's clear from this that elimination of these risk factors should begin early, as soon as they are recognized. It's possible that the effect of obesity may be partly due to other cardiovascular factors e.g. obesity is associated with high blood pressure. Even so, body weight shouldn't be seen as unimportant; lowering the BMI has plenty of other health benefits, and it still has a relevant role in vascular dementia.

The lesson for baby-boomers about to enjoy their 60th birthdays: if you haven't already dealt with the Alzheimer risk factors you can control - smoking, weight, blood pressure, cholesterol - it's high time to do so, now, so that you are more likely to enjoy your 80th birthday with a sound mind.

Source

• Obesity and vascular risk factors at midlife and the risk of dementia and Alzheimer's disease. M. Kivipelto, T. Ngandu, L. Fratiglioni,   et al., Arch Neurol, 2005, vol. 62, pp. 1556--1560

Related Links
How Likely Are You To Become Obese?
Diagnosing Pre-Alzheimer's Disease
BMI Calculator

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.