A previous study found that occlusal force was associated with factors related to health status in the elderly, such as physical 4) − 6), cognitive functions 7), nutritional status 8), and all-cause mortality 9), 10). In addition, many studies have shown that endothelial dysfunction was associated with cerebrovascular disease and myocardial infarction13), 14) that may have residual sequelae even after recovery, and can be considered to be risk factors for shorted healthy life expectancy. Both occlusal force and FMD are useful understanding the general condition of the elderly in preventative care. However, to the best of our knowledge, this is the first study to investigate the relationship between occlusal fore and FMD. In the present study we investigated the relationship between occlusal force and endothelial function in a community-dwelling sample of > 65 years old individuals.
Many previous studies have focused on occlusal force and grip strength 5)-7). In this study we found a relationship between occlusal force and grip strength, consistent with the results reported in previous studies.
In this study, AGEs were measured as indicators of aging. Some previous studies have shown that AGEs accumulate with increasing age17), 18). However, in the present study, no relationship between AGEs and age was found. In our study, we selected elderly individuals who participated in their community salon programs or participated in preventative care more than once a week. Therefore, these individuals may be highly concerned for their health. Therefore, these may be no correlation between age and AGEs in this study. Accumulation of AGEs causes mutations in collagen crosslinks and reduces elastic force. A similar phenomenon has been considered to occur in collagen layer of the vascular endothelium; furthermore, we found a relationship between AGEs and FMD in this study.
To the best our knowledge, few studies have investigated the relationship between occlusal force and endothelial function. This is a novel finding. From a functional and structural point of view, endothelial dysfunction may result in reduced flow though microcirculation, and reduced microcirculation may lead to muscle fiber atrophy. A previous study has reported a strong correlation between changes in blood flow volume and changes in muscle protein synthesis 20). Furthermore, endothelial dysfunction also leads to decreased secretion of vascular endothelial growth factor (VEGF), facilitating functional muscle ischemia; moreover, decreased secretion of VEGF in association with endothelial dysfunction may lead to negative muscle protein balance 21). Correlation among endothelial function, occlusal force, and grip strength was observed in this study.
It is important for local residents to understand their health condition and live consciously in preventative care. Therefore, a simple indicator is necessary. Both occlusal force and FMD are useful for understanding the general condition of the elderly. However, to measure FMD, a specialized medicated institution must be visited, which is time consuming. Occlusal force measurement can be easily performed without the requirement of difficult techniques or time for measurement, measuring equipment is portable, and can also be measured during weekly community salon visits. Logistic regression analysis showed that that occlusal force was independently associated with the presence of endothelial dysfunction after adjusting for age, AGEs, and grip strength. This study suggests that occlusal force can be a good indicator of the general condition of physical, and mental function, and nutritional status among the elderly, and can help determine early countermeasures against high risk diseases that shorten healthy life expectancy.
This study has a few limitations. First, this study was designed as a cross-sectional study and could not evaluate the causal relationship between reduced occlusal force and decreased endothelial function. Second, we could not rule out the possible effects of medications and existing diseases on the outcomes. Third, elderly men were excluded. Further research is needed to improve overcome these limitations.