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Obese
mid-lifers at higher risk of dementia By Pippa Wysong PHILADELPHIA
– People who are obese in middle age are twice as likely to develop dementia
in later life as people who are not obese.
But,
if high cholesterol and hypertension are added to the equation, the risk of
dementia increases six times, according to research from Sweden and Finland.
The
findings are from a long-term epidemiologic investigation of the interactions of
lifestyle, genetic factors and vascular health on cognitive health. The first
cohort for the study was enrolled in 1972.
The
findings were presented here at the ninth International Conference on
Alzheimer's Disease by Dr. Miia Kivipelto from the Karolinska Institute in
Stockholm.
Included
in the analysis were 1,449 elderly subjects from the cohort who had been
followed for an average of 21 years.
Evaluations
were done twice, in 1972 or 1977 and again in 1982 or 1987. At
mid-life, the mean BMI (body mass index) of this study population was 26.6
kg/m2. A third of the group had BMI of less than 25 kg/m2, or normal weight, she
said.
Half
of the study population had a BMI of 25 to 20 kg/m2. The remaining 16% had BMI
of 30 kg/m2 and were considered obese.
In
late-life, the mean BMI was 27.8 kg/m2.
Almost
40% of obese subjects had a high systolic blood pressure of 160 mm Hg or more,
and high diastolic blood pressure of at least 95 mm Hg. Overall, cholesterol
levels were similar in the different BMI groups.
A
total of 61 subjects was diagnosed with dementia and, of these, 48 met the
diagnostic criteria of Alzheimer's disease. Thus, dementia developed in 9.1% of
obese people compared with 2.8% of non-obese people (BMI less than 25 kg/m2).
Various
other factors were taken into account in the analyses, including age, education,
gender, followup time, other mid-life vascular risk factors and diabetes.
Borderline
significance
After
all the adjustments, an association between obesity and dementia remained but
was of borderline significance.
Analyses
suggested "the effect of obesity on dementia might be partly mediated
through vascular factors," Dr. Kivipelto said.
She
added: "Mid-life obesity, high systolic blood pressure and high total
cholesterol were all significant risk factors for dementia, each of them
increasing the risk around two times."
When
vascular risk factors were clustered together, "persons with all three risk
factors had around six times higher risk for dementia than persons having none
of them," she said.
The
study showed that BMI can be used as an indicator of increased risk for dementia
in later life.
Obesity
is related to several of the risk factors for dementia and Alzheimer's disease,
especially vascular disease factors.
"The
more vascular risk factors, the greater the risk for dementia. Therefore,
elimination of even one risk factor could substantially decrease this
risk," she said.
And,
reducing BMI can affect vascular risk factors.
The
study adds fodder for the push to encourage patients to try to attain or
maintain a normal body weight and get treatment for vascular disease.
After
all, losing weight could "increase the chances of eluding dementia and
Alzheimer's disease," she said. |