Waist size is an indicator of one's increased vulnerability to certain physical illnesses. But can one's waist size also predict one’s vulnerability to Alzheimer’s and other forms of dementia?

A large waist circumference is known to be associated with an increased risk for type 2 diabetes, hypertension and cardiovascular diseases (CVD) in patients with a body mass index (BMI) ranging from 25 to 34.9 kg/m2.

Monitoring changes in waist circumference over time and measuring BMI may be helpful to maintaining one's health since it can provide an estimate of increased abdominal fat even in the absence of a change in BMI. In obese patients with metabolic complications, changes in waist circumference are useful predictors of changes in CVD risk factors.

A medical study published last February in the Journal of the American Heart Association suggests the "waist-to-hip ratio measurement" might be a better indicator of heart attack risk for both men and women than BMI. That's because one flaw with BMI is that it doesn't discern between fat (adipose tissue) and muscle content (lean tissue).

The link between dementia and waist size has long been suspected but never adequately explored. This omission was corrected by a new medical study recently published in the journal Obesity and conducted in South Korea by a team led by corresponding author Dr. Hye Jin Yoo, an associate professor at Korea University Guro Hospital in Seoul. The study was limited to an Asian population.

Researchers examined 872,082 participants, ages 65 and over, who had taken part in the Korean national health screening in 2009. The study followed the participants from 2009 until 2015, or until they developed dementia. During the study, the participants answered questions about their physical activity levels, smoking and alcohol intake.

The study results were a wake-up call. It discovered that participants whose waist circumference was equal to or higher than 90 cm (35 inches) for men and 85 cm (33 inches) for women had a significantly higher risk of developing dementia.

This association held true when researchers adjusted for age, BMI, blood pressure, cholesterol levels and several other lifestyle factors.

"For all the physicians who deal with geriatric medicine, obesity, and dementia, this study emphasizes that waist circumference should be considered in the assessment of obesity-related dementia risk in the elderly," Dr. Yoo noted.

"This study doesn't let us know why there is this discrepancy but might point to the different roles of subcutaneous fat and visceral fat in the development of dementia, with subcutaneous fat being protective and visceral fat having harmful effects," Dr. Dan Bessesen, of the University of Colorado School of Medicine in Aurora, who wasn't involved in the research, said.

Obese women may be unknowingly shortening their children's lifespan. Photo Courtesy of Pixabay