“Oral Frailty”: Could the Early Signs of Physical Frailty Be in Your Mouth?

Physical frailty in elderly patients can severely reduce their well-being and quality of life, and it may also reduce their life expectancy. What if there were a way to predict the onset of physical frailty before it becomes a severe impairment in the lives of elderly patients? In the last decade, dentistry has become an important part of monitoring and potentially delaying the onset of physical frailty. In 2013, the Japanese conceptualised “oral frailty”, and research is showing that it can serve as an early marker of physical frailty.

What is “oral frailty”?

In the scientific community, there is not yet a consensus on the official definition of “oral frailty” [1]. Although it is generally understood that the term describes a decline in oral function that is associated with a reduced quality of life.

Although various criteria have been used to assess oral frailty, in 2023, an updated checklist which includes objective criteria was put forward to assist health care practitioners in diagnosing oral frailty. The new criterion is called the Oral Frailty Five-Item Checklist (OF-5), and it includes: a reduced number of teeth, difficulty chewing, impaired swallowing, xerostomia (dry mouth), and reduced oral motor function involved in speech articulation [2].

How could oral frailty influence physical frailty?

A study conducted by Kugimiya et al. [3] found that there are direct and indirect links between oral frailty and sarcopenia (loss of skeletal muscle mass), which is a very common phenotype of physical frailty in elderly patients. The direct pathway can be described as follows: the loss of oral functions such as chewing and swallowing may alter food choices, which in turn increases the risk of an unbalanced diet and poor nutrition, contributing to the onset of sarcopenia.

Alternatively, oral frailty may also indirectly lead to sarcopenia by increasing “social frailty”, which can be described as a decline in social interactions due to an individual living alone or going out less frequently [4]. A decline in social interactions may predispose individuals to a decline in oral health literacy, which may be connected to a change in their lifestyle habits. Individuals appear to become less aware of or motivated to practice self-care, including oral hygiene. The consequence of this may be dental caries and periodontitis, and eventually tooth loss, one of the five factors that form part of the oral frailty checklist. Social frailty may also be associated with a decline in speaking, which can cause a reduction in tongue pressure, which can lead to a decline in mastication functionality, another factor that forms part of the oral frailty checklist.

What is the relationship between oral frailty and physical frailty over time?

Up until recently, most of the studies on oral frailty have been cross-sectional, meaning that they only evaluated the association between oral and physical frailty at one time point. These studies are helpful in identifying an association between oral and physical frailty, but they are limited in that they don’t explain how this relationship progresses and changes over time. To better understand how it unfolds, it is also important to consider longitudinal studies.

In a longitudinal study by Kusinoki et al. [2], they evaluated oral and physical frailty at two checkup points, with the second checkup taking place 2-3 years later. Physical frailty was not characterised solely in terms of sarcopenia, as seen in the previously mentioned cross-sectional study. In addition to sarcopenia, the researchers also used a broader assessment that included gait speed, weakness (including hand grip strength), fatigue, levels of physical activity, and weight loss.

The benefit of evaluating oral and physical frailty over two time periods is that researchers were able to identify that oral frailty had worsened in both men and women. However, there were no significant changes in physical frailty. This was an important finding as it shows that oral frailty progressed independently of physical frailty during this time period. This might mean that there is a window of opportunity to address the symptoms of oral frailty, in an attempt to prevent the onset or worsening of physical frailty [2].

Additionally, when comparing the results from the baseline screening to the second checkup, 2-3 years later, they found that a higher oral frailty score (according to OF-5) at the baseline was associated with a greater risk of physical frailty worsening at the second time point [2]. This is similar to a finding in another longitudinal study, which showed that oral frailty is not only linked to physical frailty at a single time point, but it can also serve as a predictor of future physical frailty [5]. It is also worth noting that although oral frailty can be used as a predictor of physical frailty in both men and women, it seems that women experience a more severe worsening of frailty than men do [2].

Conclusion

These findings emphasise the importance of oral frailty screening in elderly patients. By utilising the Oral Frailty Five-Item Checklist (OF-5), dental professionals may be able to conduct an effective assessment of oral function and implement an early intervention before it progresses to physical frailty.

Oral Frailty is already a well-accepted concept within the Japanese community, and in 2018, it was even included in their public insurance system [3]. They serve as an example of how oral screening can be proactively used to predict future physical frailty. This new knowledge presents an opportunity for dental professionals all around the world to create more awareness around subtle losses in oral functions. In doing so, they can play a role in improving the quality of life and life expectancy of elderly patients.