It’s the global epidemic that affects two in five adults, but as obesity continues to expand the waistline around the world, researchers from the University of South Australia warn that harmful body fat can also increase the risk of dementia and stroke.
When examining the gray matter of about 28,000 people, the world’s first research showed that increasing body fat gradually leads to increased atrophy of the gray matter in the brain and, consequently, a higher risk of deterioration in brain health.
Gray matter is an essential part of the brain responsible for execution control, muscular and sensory activity, as well as learning, attention and memory.
Obesity is a major problem worldwide, with the number almost tripling since 1975. World Health Organization data shows that more than 1.9 billion adults are overweight, of which 650 million are obese. More than 340 million children (ages 5-19) are overweight or obese, and 39 million children under the age of five also fall into this category.
Lead researcher Dr. UniSA’s Anwar Mulugeta says the results add to the growing problems associated with being overweight or obese.
Obesity is a genetically complex disease that is characterized by excess body fat. “
Dr. Anwar Mulugeta, lead researcher, UniSA
“Obesity, which is often associated with cardiovascular disease, type 2 diabetes and chronic inflammation (a marker of dementia), currently costs about $ 8.6 billion a year for Australia’s economy.
“Although the burden of disease from obesity has increased over the past five decades, the complex nature of the disease means that not all obese individuals are metabolically unhealthy.
“Obviously, being overweight generally increases the risk of cardiovascular disease, type 2 diabetes, and mild inflammation, but understanding the level of risk is important to better manage support.
“In this study, we examined the causal relationships of individuals within three metabolically different types of obesity – unfavorable, neutral and favorable – to determine whether certain weight groups are more at risk than others.
“In general, the three subtypes of obesity have higher body mass index characteristics, but each type varies in terms of body fat and visceral fat distribution with a different risk of cardiometabolic disease.
“We found that people with higher levels of obesity, especially those with metabolically unfavorable and neutral obesity subtypes, had much less gray matter, suggesting that these people may have impaired brain function that needed further investigation.
“However, we haven’t found conclusive evidence that any particular subtype of obesity is associated with dementia or stroke. Instead, our study suggests the possible role of inflammation and metabolic abnormalities and how they contribute to obesity and gray matter volume reduction can contribute. “
The study used Mendelian randomization to examine the genetic data of up to 336,000 individual records in the UK biobank, with self-reported information and linked hospital and death register records to link dementia and stroke.
It was found that the gray matter in middle to older age groups (37-73) decreased by 0.3 percent for every additional 1 kg / m2, which corresponds to an additional weight of 3 kg for people of average height (173 cm).
Lead researcher, Professor Elina Hyppönen, director of UniSA’s Australian Center for Precision Health, based at SAHMRI, says maintaining a healthy weight is important to overall public health.
“It is increasingly recognized that obesity is a complex clinical picture and that excess fat in particular, which is located around the internal organs, has particularly harmful effects on health,” says Professor Hyppönen.
“Here we used the individuals’ genetic and metabolic profiles to confirm different types of obesity. In practice, our results greatly support the need to consider the type of obesity when assessing the type of likely health effects.
“Even in a person of relatively normal weight, being overweight in the abdominal area can be a cause for concern.”
University of South Australia