[The oral function of community-dwelling older adults complaining of an oral function deterioration: An examination using the oral function-related items of the Questionnaire for Latter-stage Elderly People]

Poor oral health and dementia risk under time-varying confounding: A cohort study based on marginal structural models

BACKGROUND

Bidirectional association between oral health, including tooth loss and oral hypofunction, and cognitive impairment can induce time-varying confounding in association with dementia. This study aimed to investigate the association between oral health and the development of dementia among older adults, considering cognitive impairment as a time-varying confounder.

METHODS

This nine-year follow-up cohort study targeted independent older adults aged ≥65 years who participated in the Japan Gerontological Evaluation Study. The exposure variables were self-reported poor oral health (≤19 remaining teeth, edentulousness, chewing difficulty, swallowing problems, and xerostomia), which were assessed in 2010 and 2013. The outcome variable was the incidence of dementia between 2013 and 2019, which was obtained from the municipalities' administrative database. Furthermore, in 2010 and 2013, we considered cognitive impairment as a time-varying confounder and treated it based on a marginal structural model (MSM), including possible baseline confounders. Oral health and cognitive impairment were assessed using the items of Kihon checklist. We employed a Cox proportional hazards model with a stabilized inverse probability weight and estimated hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Among 37,556 participants (mean age: 72.8 years [1 SD = 5.5], males: 46.8%), the dementia incidence rate was 2.2/100 person-year. The proportions of those with ≤19 remaining teeth, edentulousness, chewing difficulty, swallowing problems, and xerostomia were 61.3%, 11.0%, 24.4%, 14.7%, and 19.2%, respectively. From the regression analysis based on MSM, ≤19 remaining teeth (HR = 1.12, 95% CI = 1.03-1.23), edentulousness (HR = 1.20, 95% CI = 1.09-1.32), chewing difficulty (HR = 1.11, 95% CI = 1.02-1.21), and xerostomia (HR = 1.10, 95% CI = 1.01-1.20) were significantly associated with an increased risk of dementia; however, swallowing problems were not significantly associated with dementia onset (p > 0.05).

CONCLUSIONS

Even after considering time-varying confounding by cognitive function at baseline and follow-up, we observed significant associations between poor oral health and increased risk of dementia among older adults.

Physical function decline predictors in nursing home residents using new national quality indicators

AIM

To determine the predictors of physical function (PF) decline among nursing home residents using items from the Long-term care Information system For Evidence (LIFE), a system launched in 2021 to ensure the quality of long-term care.

METHODS

The LIFE data of 1648 residents from 45 nursing homes in Japan were retrospectively collected in July 2021 (T0) and January 2022 (T1), including demographics, PF assessed by the Barthel index (BI), nutrition and oral health, and cognitive function. The Dementia Behavior Disturbance scale was used to assess the frequency of certain behaviors, such as "waking at midnight." The predictors of PF decline, defined as a decrease ≥5 in the BI score at T1 compared with that at T0, were determined using mixed-effects logistic regression analyses. PF at T0 was classified into high (>60 BI) and low (≤60 BI) groups.

RESULTS

The participants' mean age was 87.2 ± 7.1 years, and 45.3% experienced PF decline. The significant predictors of PF decline were age ≥ 90 years, body mass index <18.5 kg/m2 , dementia diagnosis, moderate and severe cognitive impairments, not vocalizing reciprocal exchanges at will, always "waking at midnight," and high PF at T0.

CONCLUSIONS

The LIFE items predicted PF decline among nursing home residents, suggesting that LIFE data can be used to ensure the quality of long-term care. Geriatr Gerontol Int 2024; 24: 123-132.