Poor oral health linked to muscle loss and diabetes

• Previous research has found that poor oral health is a predictor of cardiovascular disease and mortality from all causes.
• A new study suggests that having fewer remaining teeth and poor chewing ability increases the risk of muscle loss, weakness, and diabetes in older people.
• Improvements in oral health, including the use of dentures — which might mitigate the risk of losing remaining teeth — could help prevent these conditions.

One of the many indirect negative impacts of the COVID-19 pandemic is that many people have been unable to see their dentists for routine care.

The strict measures implemented to prevent the spread of infection have severely reduced access to dental services. This situation led to a rapidly growing backlog of patients in need of oral treatment and care.

In the United Kingdom, for example, a survey revealed major delays in appointments for National Health Service dentistry. In response, many people have resorted to paying extra for private care.

Beyond physical discomfort, poor oral health has significant knock-on effects, including an increased risk of cardiovascular diseaseTrusted Source, research suggests.

One longitudinal study found that “oral frailty,” a measure that includes the number of remaining teeth, chewing ability, and difficulties eating and swallowing, was a risk factor for physical frailty, disability, and mortality from all causes.

A new study led by researchers at Shimane University, in Izumo, Japan, has found small but significantly increased risks of diabetes and sarcopenia, which is loss of muscle and weakness due to aging, among older adults with oral frailty.

The study paper has been published in PLOS ONETrusted Source.

“Although oral health might affect the overall health of an individual, it has been neglected in the public health domain,” the authors write.

Annual health examination

The research was part of the university’s Center for Community-Based Healthcare Research and Education study, which collaborates with an annual health examination program in Ohnan, a small town in Japan’s Shimane prefecture.

A total of 635 people aged between 40 and 74 years took part in the study.

To assess the participants’ chewing ability, or “masticatory function,” the researchers asked them to chew a gummy jelly as energetically as possible for 15 seconds without swallowing it, then spit out what was left.

The team then counted the number of the pieces of the candy that remained.

They also counted how many teeth each participant had and measured their calf circumference twice for both legs, as well as their skeletal muscle mass and handgrip strength.

To assess sarcopenia, the researchers applied a standard diagnostic algorithm that incorporates muscle strength, mass, and physical performance.

The investigators noted the participants’ self-reported diagnoses of diabetes and also screened them for the condition by testing their levels of serum hemoglobin A1C.

In their analysis, they adjusted the results to account for the participants’ sex, age, body mass index, smoking status, alcohol consumption, and level of physical activity.

They found that having fewer remaining teeth and poor chewing ability were significantly associated with a weaker handgrip and possible sarcopenia. Fewer teeth and poor chewing ability were also significantly associated with diabetes.

There were no statistically significant associations with calf circumference or skeletal muscle mass.

Possible links with diabetes

The researchers write:

    “Our findings suggest that improvement in oral health, including the maintenance of masticatory function and remaining teeth, may contribute to the prevention of sarcopenia and diabetes mellitus in older adults.”

They speculate that people with reduced chewing ability or fewer teeth may have an increased risk of diabetes as a result of eating more soft, sugar-rich foods and having shorter mealtimes.

Both factors would cause a bigger spike in blood glucose levels after eating.

Interventions to maintain chewing ability, through the prevention of tooth loss and use of dentures, could therefore reduce the likelihood of these aging-related conditions.

“According to our data, improving mastication and denture use may reduce the risk of diabetes and sarcopenia,” senior author Shozo Yano, M.D., Ph.D., told Medical News Today

The authors also cite evidence that gum disease, which can cause tooth loss, can lead to decreased insulin sensitivity and impaired glucose tolerance.

“Loss of teeth is strongly related to periodontal disease and probably to systemic inflammation, which may play a role in the pathogenesis of diabetes and sarcopenia,” said Dr. Yano, who is part of the Nutrition Support Team at Shimane University Hospital.

He advised older people to eat more slowly and brush their teeth after meals. By taking care of their oral health, they would help maintain their overall health, he emphasized.

Limitations of the study

The associations between oral frailty, sarcopenia, and diabetes that the study identified were statistically significant but relatively small, in the order of 2–6%. The authors acknowledge that increasing the number of patients could lead to a statistically powerful association.

The researchers also acknowledge that their study was unable to establish any causal relationships due to its cross-sectional design.

In addition, they did not account for potentially important features of oral health, such as gum disease, denture use, and brushing teeth.

“Thus, future longitudinal studies are essential for investigating these associations,” they conclude.