When the study began, none of the participants had dementia, and their average BMI was 27.4. During the follow-up period, 151 of the participants (18.4 percent) developed AD. Both baseline BMI and the annual rate of change in BMI were linked to the risk of developing AD.
People who lost approximately one unit of BMI per year had a 35 percent greater risk of developing AD than that of people with no change in BMI over the course of the study. Those with no change in BMI had a 20 percent greater risk of developing the disease than that of people who gained six-tenths of a unit of BMI per year.
The findings held true even after adjusting for factors such as chronic health problems, age, sex, and education. They also held true when those who developed AD in the first 4 years of follow-up--and might have had mild, undiagnosed AD early in the study--were excluded from the analysis.
The investigators found a similar relationship between changes in BMI and rate of cognitive decline, which is the clinical hallmark of AD. Even when controlling for baseline cognitive function, baseline BMI, age, sex, and education, the rate of cognitive decline among people losing approximately one unit of BMI per year was more than 35 percent higher than that of people with no change in BMI and 80 percent higher than that of people who gained six-tenths of a unit of BMI per year.
Further analyses showed that depressive symptoms, participants' physical activity levels, and female participants' use of estrogen replacement did not explain the link between BMI loss and development of AD.
In addition, when the researchers looked at changes in weight rather than BMI, they found that a loss of 1 pound p
'"/>
Contact: Vicky Cahan
cahanv@nia.nih.gov
301-496-1752
NIH/National Institute on Aging
26-Sep-2005