Being obese can increase the risk of Alzheimer's disease by as much as 80%, according to a study published recently in Obesity Reviews. However, the same study reports that being underweight also causes an increased risk compared to people who are normal weight or overweight without being obese.
Youfa Wang and colleagues from the Johns Hopkins Bloomberg Schoold of Public Health, Baltimore, reviewed 10 international studies published since 1995, which included more than 37 000 people, including 2 500 with dementia. Study subjects were aged between 40 and 80 and were followed up for between three and 36 years.
All kinds of dementia were included, specifically Alzheimer's disease and vascular dementia. The analysis showed that being obese increased the risk of any type of dementia by 42% and being underweight increased the risk by 36%. However, when researchers looked specifically at Alzheimer's disease they found that obesity increased the risk by 80% and the increased risk of vascular dementia was 73%. The risks were greater in studies where sufferers developed Alzheimer's Disease or vascular dementia before the age of 60 or in studies with follow-up periods of more than 10 years and were also greater in women.
