Researchers have discovered a new possible link to dementia: being underweight.
In the largest study ever to look at relationships between body weight and likelihood of developing dementia, nearly two million people in the U.K. were observed over a period of about nine years. Those who were underweight had the highest dementia risk in old age, with body mass index (BMI) being inversely proportional to the likelihood of developing dementia.
Dementia is a term used to describe a number of conditions associated with a decline in memory and thinking skills. Alzheimer’s disease is the most common form of dementia, accounting for around 60-80% of cases in the US.
Study author Prof. Stuart Pocock, of the London School of Hygiene & Tropical Medicine in the UK, and colleagues published their findings in The Lancet Diabetes & Endocrinology. The authors adjusted for some other possible factors that could influence dementia risk, such as age, sex, smoking, alcohol use, history of stroke and heart attack and use of blood pressure or statin drugs.
Of course, this study contradicts the widely held theory that obesity is correlated with dementia. Researchers have been looking increasingly at how weight influences a person’s risk of dementia, but results have been conflicting.
Now if only we could figure out why.
The study covered 1,958,191 people who were between 45 and 66 years old at the start of the observations and had no dementia. After being followed for an average of nine years, some 45,000 people had been diagnosed. Looking at a period of 20 years, the researchers took their data from the Clinical Practice Research Datalink (CPRD) – a large database that holds the medical records of approximately 9 percent of the UK population.
The adults included in the study were an average age of 55 at baseline and had a median body mass index (BMI) of 26.5 kg/m2, which falls into the overweight category. Relating diagnoses to initial BMIs, researchers found a link.
Those who were underweight, with a BMI less than 20, had a 34 percent higher risk of dementia when compared with people of a healthy weight (BMI of 20-24.9). The risk of dementia continued to fall as BMI increased. Ultimately, very obese people (with a BMI over 40) had a 29 percent lower risk of dementia than people at a healthy weight. Compared to people at the median BMI for the entire group (around 26-27), underweight people had a 64 percent higher risk of dementia.
The only caveat for the study is that it only covered older people to begin with, and a person’s risk of the condition increases with age. A more comprehensive study might target people across a wider range of ages. Still, this is the largest study ever to focus on the correlation between weight and dementia.
While this certainly isn’t the be-all, end-all conclusion of the relationship between weight and dementia, it indicates that there’s more than meets the eye. For more information about Alzheimer’s care visit Freedom Home Care or call us at (877) 262-1223.