Age is one of the biggest risk factors for dementia. The older we get, the higher our of dementia. But what is it about advanced age that makes us more likely to develop this debilitating disease?
Cardiovascular issues, chronic inflammation, and even hearing loss are all correlated with dementia and are more common in seniors. Japanese scientists have added a new and rather surprising risk factor - sarcopenic obesity - to that list.
Dementia in Japan
The latest statistical estimates suggest that 15% of older adults in Japan (aged 65 and older) suffer from dementia, and the statistics are gradually increasing every year. To compare, the Population Reference Bureau suggests that around 10% of American seniors aged 70 and older suffer from this severe medical issue. For Japan, a country that historically had one of the lowest rates of dementia in the world, this was a wake-up call.
For understandable reasons, Japanese scientists were concerned. Why are the cognitive abilities of more and more seniors withering away before their eyes?
To investigate this alarming tendency, researchers at the Juntendo University in Japan involved 1615 Japanese seniors in the 65-84 age range from the Bunkyo Health Study, an ongoing cohort study of over 10 years. Their theory was that the increase in dementia is linked to two other factors - sarcopenia and obesity - both of which have been shown to increase the risk of cognitive issues in past studies.
As Dr. Yoshifumi Tamura, the lead researcher of the study, pointed out to Scitech Daily, “If the association between sarcopenic obesity and dementia is established, appropriate preventive measures can be taken to reduce the occurrence of this condition and the risk of dementia in elderly patients.”
The study was published in the March 2022 issue of the Clinical Nutrition journal.
What is sarcopenic obesity?
Like dementia, obesity has gradually become increasingly common in Japan. In the senior population, this condition often appears hand in hand with sarcopenia - an age-related loss of muscle mass and strength that typically begins after age 40. Together, these two factors create a condition called sarcopenic obesity, where weakness co-occurs with excessive weight.
Sarcopenic obesity is assessed by taking two measures into consideration: handgrip strength to test sarcopenia and body mass index (BMI) to measure obesity.
Having considered these measures, the participants were evaluated based on their sarcopenia and obesity status and divided into four groups: participants with obesity, sarcopenia, sarcopenic obesity, and control subjects with neither obesity nor sarcopenia. The researchers then compared each group’s cognitive and mental functions to see if there’s a connection between sarcopenic obesity and dementia or moderate cognitive impairment (MCI).
The four groups were divided as follows:
- 4.7% of the participants had sarcopenic obesity
- 14.6% had sarcopenia
- 21.2% had obesity
- 59.4% had neither obesity nor sarcopenia.
Despite making up the smallest percentage of the study population, the sarcopenic obesity group had the greatest rate of dementia and MCI. Sarcopenia was the second most significant risk factor, followed by obesity. The study also pointed out sarcopenia is a significant risk factor for dementia in females but not males. As expected, the controls came last, meaning they had the lowest prevalence of MCI and dementia.
To sum up, the results of the study are pretty clear-cut: sarcopenic obesity can increase one’s risk of developing dementia and moderate cognitive impairment. As Dr. Tamura stated, “This study clearly demonstrates that sarcopenic obesity, defined by the combination of BMI and hand grip strength is associated with MCI and dementia among Japan’s elderly people.” We’ll be eagerly waiting if studies with a more diverse population confirm these findings too.
Meanwhile, for the average person, the results of this study can be translated into real-world, actionable advice. The research proves that maintaining a healthy weight and exercising to keep muscle strength in your senior years can do a lot more than make you look fit. It means having a clear and healthy mind within a capable and fit body.
H/T: Scitech Daily