Study Shows That Midlife Obesity, High Blood Pressure, And High Total Cholesterol are all Significant Risk Factors for Dementia and Alzheimer’s
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.
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.