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

•Evidence on the association between tooth loss and hearing impairment is limited.•The degree of tooth loss was positively associated with hearing impairment.•Tooth loss may be associated with an increased prevalence of hearing impairment. 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. 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. 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). The results suggest that tooth loss may be associated with an increased prevalence of HI.