A report in Monday's Archives of Neurology has found that an increased presence of the hormone adiponectin can increase the risk for loss of brain function and Alzheimer's disease.
According to the World Alzheimer's Report, currently, 36 million people are affected by dementia worldwide, and that number is expected to double in the next 20 years. Alzheimer's disease is the most common form of dementia, impacting 80% of the elderly. The Alzheimer's Association says two-thirds of those with Alzheimer's are women, and today, of the 5.4 million Americans with Alzheimer's, 96% are over the age of 65.
Adiponectin is a hormone produced by fat cells that helps regulate the body's response to insulin and metabolism. Higher levels of adiponectin have been shown to help lower the risk for Type 2 Diabetes. But, the authors found that older women who had developed dementia also had higher levels of the hormone.
Dr. Ernst Schaefer, director of the Tufts University Lipid Metabolism Laboratory, one of the study's authors was surprised by the findings. " We expected adiponectin to protect against dementia, and it turned out to be just the opposite."
The authors of the study tracked 841 men and women who were part of the original generation of patients enrolled in the famed Framingham Heart Study. That study began tracking over 5,000 patients in 1948, to get a better sense of what factors led to cardiovascular disease. While the Framingham Heart Study initially had similar numbers of men and women enrolled, by the time the patients were tracked for the dementia study, beginning in the late 1980s, most of the surviving patients left were women.
Of the 541 women that were tracked for dementia over the following 13 years, 159 developed some form of dementia, including 125 cases of Alzheimer's disease. The study authors found that increased levels of adiponectin increased the likelihood of dementia development by 60%, and of Alzheimer's by 90%.
In addition to adiponectin, the study also tracked homocysteine and glucose levels.
Schaefer suggested that the dementia study might indicate a connection between nutrition and dementia. Adiponectin levels were found to be inversely correlated to body mass index, or BMI. Older women with higher BMIs were found to have lower levels of adiponectin, and lower rates of dementia.
While Schaefer mentioned that these factors probably also hold true for men, he said that unfortunately, the numbers weren't there to support it because of the low number of men still participating in the study.
He said for women over 60, "it may be that being very thin may not be a good thing." But carrying to much weight can lead to other diseases like diabetes and heart disease. As people age, Schaefer says nutrition should be of big concern. "We need to make sure that people are involved in eating three square meals and getting the nutrients they need. It may be vital to their mental health.
The study was supported in part by the National Institute of Health, the US Department of Agriculture, and the Framingham Heat Study.