Aim: Mastication ability is well documented as a risk factor for disability in the elderly. The aim of the present study was to assess occlusal force, one index of mastication ability, among elderly Japanese and clarify related factors through both physical measurements and questionnaires.
Methods: Subjects were 372 community-dwelling persons (101 men, 271 women) aged 60-87 years and registered at five welfare centers for the aged in a metropolitan suburb. Occlusal force was measured with dental prescale/occluzer system. Physical measurements and questionnaires were performed to explore related factors.
Results: Occlusal force was 502.4 N in men and 372.2 N in women. In the 60-69 and 70-79 age stratifications, men had significantly higher occlusal force than women. Occlusal force correlated significantly with age (r=-0.2, p<0.01), and number of residual teeth (r=0.6, p<0.01). After adjustment for age and the number of residual teeth, occlusal force had positive partial correlation with handgrip strength in men, and positive partial correlations with usual walking speed and body muscle mass, and negative partial correlation with timed up and go in women. From the questionnaire, high occlusal force was significantly associated with "can bite hard food" in both men and women; and with lifestyle factors ("walking regularly", "no smoking", and "alcohol consumption") in men; and with psychological factors ("intraoral satisfaction" and "no depression tendency") and physical factors ("can walk 1-km" and "can go out alone to distant places") in women.
Conclusion: Occlusal force was related to physical fitness, ability of movement, and lifestyle.