Obesity And Dementia
Researchers had previously looked into the possibility of being obese increasing a person’s risk of suffering dementia later in life, but results have been inconclusive. Findings in a new British study suggest that this is a potential risk factor that must be guarded against.
Researchers reported in the study published in the medical journal Neurology that excess body fat, especially in the middle region, may have a link to reduction in brain sizes.
Obesity was assessed in the current research using body mass index (BMI) of participants. The researchers combined this with waist-hip ratio measurements.
It was found that those who had higher readings of both measures showed the lowest brain volume. They had lower gray matter volume.
Before now, researchers had observed that reduction in brain sizes occurred in cases of dementia and memory decline. But findings on possible relationship between obesity and dementia have been largely unconvincing.
“While our study found that obesity, especially around the middle, was associated with lower gray matter brain volumes,” said author Mark Hamer, PhD, of Loughborough University in England, “it’s unclear if abnormalities in brain structure lead to obesity or if obesity leads to these changes in the brain.”
Findings in the current study somewhat contradicted a large-scale study in which it was found that obese people suffered dementia less.
Scientists in this current research worked with data of more than 9,600 subjects having an average age of 55 years. Around 19 percent of them were described as being obese – with a BMI reading higher than 30.
These individuals were evaluated as part of the U.K. Biobank study in the period from 2014 to 2016. Along with BMI and waist-hip ratio, the researchers made use of other measures such as total fat mass and images of the brain.
It was found that subjects with central obesity and high BMI readings had the lowest gray matter brain volume after adjusting for different factors, including age, sex, education and physical activity.
Obese subjects with a high BMI had an average brain volume of 786 cubic centimeters. The reading was 793 cubic centimeters for those with a high BMI but no central obesity. For healthy-weight subjects, gray matter brain volume was 798 cubic centimeters, on average.
Majority of nerve cells in the brain can be found in the gray matter. It also incorporates regions of the organ involved in functions such as sensory perception and muscle control.
Study authors reported that obesity also exhibited links to reduction in putamen, caudate, nucleus accumbens, and pallidal volumes.
But they did not observe considerable changes in white matter volume, which includes nerve fiber bundles linking different regions of the brain.
Need for further research
This study, however, has its limitations. Hamer and co-author David Batty acknowledged need for further research on the observed link between obesity and dementia.
“This will need further research but it may be possible that someday regularly measuring BMI and waist-to-hip ratio may help determine brain health,” Hamer said.
A major limitation of this research was that just about 5 percent of the population targeted participated in the U.K. Biobank study. People who were healthy were more open to taking part than those who were not, which means results may not be adequately representative.
Sudha Seshadri of San Antonio’s University of Texas Health Sciences Center, who was not part of the study, told MedPage Today that the study was still “important and exciting.”
“Although it is simple in design, it adds data about the potential huge impact of obesity on brain structure, and thus risk of age-related brain diseases such as dementia,” she said. “That the effect was seen in persons who were only 55 years old on average makes it more important, and reiterates that it is not too early to think dementia prevention in middle-aged adults.”