In our previous study, we completed a retrospective dataset of Later-stage Elderly Dental Oral Health Examination（LEDO）of older residents in Shimane Prefecture along with medical and nursing care insurance information and clarified the relationship between functional disability or death and oral health indicators using survival analysis and population attributable fraction（PAF）values. This study aimed to examine gender differences in outcomes as there are differences between men and women in terms of oral health indicators, life expectancy, and lifestyle factors such as cooking.

　The subjects of this analysis were individuals with functional disability data（9,175 men and 12,706 women）and death data（9,722 men and 13,025 women）. We conducted survival analysis using 13 oral health indicators as explanatory variables and adjusted for confounding factors using propensity scores created from age, BMI, and medical history for each gender. Subsequently, we calculated PAF to compare the impact of explanatory variables on outcomes between men and women. 　For functional disability, the top three PAF values for men were：1）first quartile of objective masticatory ability（lowest）at 23.13 %, 2）having 20-27 teeth at 13.88 %, and 3）moderate periodontal condition at 13.22 %. For women, the top three PAF values were：1）first quartile of objective masticatory ability at 21.50 %, 2）second quartile of the same at 8.28 %, and 3）having 10-19 teeth at 7.20 %.

　Similarly, for death, the top three PAF values for men were：1）first quartile of objective masticatory ability at 17.68 %, 2）having 10-19 teeth at 11.66 %, and 3）having 1-9 teeth at 9.43 %. For women, the top three PAF values were：1）first quartile of objective masticatory ability at 14.83 %, 2）poor oral hygiene at 5.84 %, and 3）second quartile of objective masticatory ability at 5.46 %.

　Objective masticatory ability had the strongest impact on both genders for both functional disability and death, but other oral health indicators had a stronger impact on men.

　Purpose：Differences in masticatory behaviors, such as number of chews and chewing speed, according to the status of oral function could be useful for the early detection of oral functional decline. To clarify the masticatory behaviors of community-dwelling older adults with slight oral functional decline, we examined the association between oral function and masticatory behaviors using the wearable bitescan^®（BS）device.

　Methods：Participants who met the inclusion criteria, such as the ability to communicate via smartphone, were recruited from the Itabashi Longitudinal Study on Aging. Based on oral function measurements, participants without any of the seven diagnostic criteria for oral hypofunction were categorized into the robust group, whereas those who met one or two diagnostic criteria were categorized into the pre-decline group. The outcome variables were masticatory behaviors（number of chews, chewing speed, number of chews per bite［average and maximum］, food intake, and chewing time）during consumption of the standardized test food measured using BS. The exposure variable was oral function（dichotomous：robust or pre-decline）. The covariates were sex, age, body mass index, educational status, and Charlson Comorbidity Index. A multiple linear regression analysis was conducted.

　Results：A total of 35 participants（mean±standard deviation age, 74.2±3.2 years）were included. Of these, 12 were women, and 30 were included in the pre-decline group. Multiple linear regression analysis showed that a slight decline in oral function was significantly associated with a lower number of chews（cycles［unstandardized regression coefficient］（B）, －79.32；95% confidence interval［CI］, －134.65, －23.99）, slower chewing speed（cycles/minute［B］, －0.01；95% CI, －0.16, －0.04）, a lower average number of chews per bite（cycles［B］, －0.41；95% CI, －0.77, －0.06）, and a reduced maximum number of chews per bite（B, －0.38；95% CI, －0.67, －0.10）.

　Conclusion：Community-dwelling older adults with slight oral functional decline had slower chewing speeds and fewer number of chews.