Higher number of teeth is associated with decreased prevalence of hearing impairment in Japan.

ABSTRACT

BACKGROUND/OBJECTIVES: There is limited evidence on the association between tooth loss and hearing impairment (HI). The present cross-sectional study investigated the association between tooth loss and the prevalence of HI in 1004 Japanese adults aged 36 to 84 years. METHODS: HI was defined as present when pure-tone average was > 25 dB at a frequency of 0.5, 1, 2, and 4 kHz in the better hearing ear. Visual oral examinations were performed. Adjustments were made for age, sex, smoking status, leisure-time physical activity, hypertension, dyslipidemia, diabetes mellitus, history of depression, body mass index, waist circumference, employment, education, and household income. RESULTS: Of 1004 study subjects, the prevalence of HI was 24.8% (n = 249). Compared with having 28 teeth, having < 22 teeth, but not having 26 to < 28 or 22 to < 26 teeth, was associated with an increased prevalence of HI; the multivariate adjusted ORs (95% CI) of having 26 to < 28, 22 to < 26, and < 22 teeth were 1.41 (0.85-2.38), 1.51 (0.90-2.57), and 1.96 (1.18-3.30), respectively (p for trend = 0.01). CONCLUSIONS: The results suggest that tooth loss may be associated with an increased prevalence of HI.