People having longer arms and legs are more predisposed to develop memory problems later in life, according to U.S. researchers.

Researchers at Johns Hopkins University in Baltimore led by Dr. Tina Huang, PhD., of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts found a link between short limbs and an increased risk of dementia in both sexes.

For the study, they turned to the Cardiovascular Health Cognition Study and measured the arm length and knee height of 2,798 men and women with an average age of 72. Five years later, 480 of the participants developed Alzheimer’s disease, 245 had possible or probable Alzheimer’s disease, 213 had possible or probable vascular dementia, and 22 had other dementias.

The researchers found that women in the lowest quartile of arm span had a 1.42-fold greater risk of dementia and a 1.72-fold increased risk of Alzheimer’s disease compared with other women. Moreover, every one-inch increase in knee height in women was associated with a 16 percent lower risk of dementia and a 22 percent risk of Alzheimer’s disease.

As far as men were concerned, only arm span was linked with a lower risk of dementia. With every increased inch in arm length, the risk of dementia was reduced by 6 percent while the risk of Alzheimer’s by 7 percent.

"Our findings with knee height and arm span are consistent with previous reports and suggest early life environment may play an important role in the determination of future dementia risk," the researchers wrote in their study.

They also say the association between short limbs and dementia risk may be due to poor nutrition in early life. In fact, previous studies have shown that early life environment plays an important role in predisposition to chronic disease later in life.

“Body measures such as knee height and arm span are often used as biological indicators of early life deficits, such as a lack of nutrients. Reduced height for age, or stunting, is thought to be most closely tied to environment and the quality of diet in early life, which corresponds with periods of the fastest leg growth. As a result, environment in the first years of life may play an important role in determining future dementia risk. Our findings are consistent with other studies that have been done in Korean populations, where shorter limb length was associated with greater risk of dementia,” Dr. Huang said as quoted by Reuters.

According to the World Health Organization, there are about 18 million people worldwide with Alzheimer’s disease. By 2025, that number is expected to reach 34 million, as existing drugs can ease symptoms but do not stop the disease. Alzheimer’s causes a progressive loss of memory and mental faculties, which can be devastating for the patients concerned and those around them.

The study, supported by grants from the National Institute on Aging, the National Heart, Lung and Blood Institute and the National Institutes of Health, appeared in the May 6 issue of the journal Neurology.