Increasing waistline increases your dementia risk

Harmful body fat could increase your risk of dementia, Australian researchers have found. 

Researchers at the University of South Australia looked at the grey brain matter of about 28,000 people, and saw that increased body fat incrementally leads to increased atrophy of grey matter in the brain, and consequently a higher risk of declining brain health.

Data from the WHO shows that more than 1.9 billion adults are overweight, with 650 million being obese.

UniSA's Dr Anwar Mulugeta, who led the study, said that being overweight is linked to  cardiovascular disease, type 2 diabetes, and chronic inflammation (a marker of dementia).

“Obesity is a genetically complex condition characterised by excessive body fat,” said Mulugeta.

“While the disease burden of obesity has increased over the past five decades, the complex nature of the disease means that not all obese individuals are metabolically unhealthy, which makes it difficult to pinpoint who is at risk of associated diseases, and who is not."

His team looked at three categories of obesity ­– unfavourable, neutral and favourable – to establish whether specific weight groups were more at risk than others.

"We found that people with higher levels of obesity, especially those with metabolically unfavourable and neutral adiposity subtypes, had much lower levels of grey brain matter, indicating that these people may have compromised brain function which needed further investigation," he said.

"However, we did not find conclusive evidence to link a specific obesity subtype with dementia or stroke. 

"Instead, our study suggests the possible role of inflammation and metabolic abnormalities and how they can contribute to obesity and grey matter volume reduction.”

The researchers found that grey matter decreased by 0.3 per cent for every extra 1 kg/m², which is equivalent to an extra 3kg of weight for a person of average height (173 cm).

Senior investigator Professor Elina Hyppönen said that a healthy weight is associated with overall health and excess fat, which is located around the internal organs, is particularly harmful.

"Even in a relatively normal weight individual, excess weight around the abdominal area may be a cause of concern," Professor Hyppönen said.

In 2017–18, an estimated 2 in 3 (67 per cent) of Australians aged 18 and over were overweight or obese (36 per cent were overweight but not obese, and 31 per cent were obese). 

That’s around 12.5 million adults, according to the Australian Institute of Health and Welfare. 

It is estimated that 41 per cent of Australian adults aged 65–74 are obese.

Obesity currently costs Australia’s economy about $8.6 billion dollars each year.

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