Sarcopenic obesity — obesity with decreased muscle mass and function — is associated with a high risk of dementia, according to findings from Japan.

Obesity often coexists with muscle mass decline, and is linked to cognitive impairment, the researchers said. In their new study, they sought to reveal whether dementia is likewise tied to this condition, opening the door to new preventive therapies.

The 1,615 study subjects were aged 65 to 84 years and were participating in a long-term population health study. They were divided into four health status groups based on whether they had obesity, sarcopenia, sarcopenic obesity or none of these conditions. Sarcopenic obesity was diagnosed using body mass index and hand grip strength measures. 

When the researchers analyzed the link between various mental processes, sarcopenia and obesity status, the results showed that the sarcopenic obesity group had the greatest rate of mild cognitive impairment and dementia. Sarcopenia alone was also significantly associated with dementia, but only in women, not men. Obesity and then the control group followed those groups in prevalence of MCI and dementia.

“[S]ince we now know that there is a strong correlation between sarcopenic obesity and dementia, we may develop new treatment methods to manage the condition, thereby even reducing the prevalence of dementia,” Yoshifumi Tamura, M.D., of Juntendo University, said. 

In the current study, poor muscle strength was measured as handgrip strength of less than 28 kg in men and 18 kg in women. Obesity status was defined as a BMI greater than 25 kg/m. The combined condition affected about 4.7% of the study subjects, with many more affected by sarcopenia (15%) or obesity (21%) alone.

In general, the prevalence of sarcopenic obesity has been estimated to be as high as 20% in older adults.

Full findings were published in the journal Clinical Nutrition.

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