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.

Relationship between implementation of systematic advance care planning and the quality of death among nursing home residents: a survey

Background

Advance care planning (ACP) is beneficial for the quality of death (QOD). However, the effects of ACP on the QOD may vary across cultures.

Objectives

This study aimed to explore the relationship between the 15-step ACP program and the QOD among Japanese nursing home residents.

Design

A cross-sectional survey.

Methods

A cross-sectional survey was conducted among the family members of 39 nursing home residents who died between April 2017 and March 2019 by distributing the survey questionnaire by post. The survey included questions about the QOD of residents, and responses were evaluated using the Good Death Inventory (GDI) scale.

Results

Responses were obtained from 30 of the 39 bereaved families (76.9%). Data were analyzed using hierarchical clustering to determine five groups and conduct multiple comparisons. The following three domains of interest were identified: 'Dying in a favorite place', 'Good relationship with the medical staff', and 'Independence'. GDI scores were significantly higher for residents with higher ACP completion rates than for those with lower rates (p < 0.01). Residents who had taken ACP interviews had significantly higher GDI scores (p < 0.01) than those who had not taken interviews.

Conclusion

Overall, these findings suggest that systematic ACP might be related to the QOD among Japanese nursing home residents in the above mentioned three domains. Limitations of the present study were small sample size, cross-sectional survey design as opposed to a cohort survey design, and multiple biases, including the emotional instability of bereaved family members, the length of stay of the residents, the degree of dementia of the residents, and their tendency to talk about the place of death and to develop good relationships with the medical staff.

Changes in care managers' positive attitudes toward dying patients compared to that of nurses by one-day online advance care planning communication training

Background

Culturally appropriate communication training programs for a wide range of professions that can be used during infection epidemics are crucial for advance care planning implementation. Starting in 2018, the Japanese Ministry of Health, Labour and Welfare made a major policy change, and doctors, nurses, and social workers, and care managers were identified in the guidelines as the professions that promote advance care planning. Motivated by the lack of online programs for Japanese care managers, we proposed a new one-day program.

Objectives

This study aimed to determine the changes in the positive attitude of care managers toward dying patients compared to that of nurses, which has been used in past literature as an outcome of advance care planning educational interventions, after administering the program in Japan.

Design

Before-after comparison study.

Methods

Care managers were recruited through our website, ACP-Piece, http://plaza.umin.ac.jp/~acp-piece/piece.html. A questionnaire survey concerning positive attitudes toward dying patients was administered before and after the program on 28 August 2021. Sixty-six subjects participated in the training and 60 participants, including 14 care managers, consented to the study and completed the questionnaire surveys before and after the program.

Results

The Frommelt attitude toward care of the dying scores for care managers increased after the program (p-values, confidence intervals, and effect sizes: p < 0.001, -11.90 to -4.388, -1.252). After training, care managers had a significantly higher maximum score occurrence than nurses. Older care managers with advance care planning experience may have had a higher maximum score occurrence compared to younger, inexperienced participants.

Conclusion

To our knowledge, this is the first to demonstrate the increased positive attitude scores toward dying patients after online communication training for Japanese care managers. The limitations of this study include the lack of evidence regarding reasons for score changes, long-term score changes, and effectiveness for patients and their families.

The Priming Potential of Interferon Lambda-1 for Antiviral Defense in the Oral Mucosa

The oral mucosa is one of the first lines of the innate host defense system against microbial invasion. Interferon (IFN) lambda-1 (IFN-λ1), a type III IFN, exhibits type I IFN-like antiviral activity. In contrast to ubiquitously expressed type I IFN receptors, IFN-λ receptor 1 (IFN-λR1), which has higher affinity for type III IFNs than low-affinity interleukin (IL)-10 receptor 2, is mainly expressed on epithelial cells. Although IFN-λ1 has been shown to exert antiviral effects in the respiratory tract, gastrointestinal tract, and skin, the regulation of type III IFN receptor expression and its functions in the oral mucosa remain unclear. We herein showed the expression of IFN-λR1 in human gingival keratinocytes. The expression of IL-6, angiotensin-converting enzyme 2 (a critical molecule for severe acute respiratory syndrome coronavirus 2 infection), and IL-8 in human primary gingival keratinocytes (HGK) were significantly higher following treatments with either type I IFN (IFN-β) or type II IFN (IFN-γ) than with IFN-λ1. However, the IFN-λ1 treatment strongly induced toll-like receptor (TLR) 3 and retinoic acid-inducible gene I (RIG-I), which mainly recognize viral nucleic acids, via the STAT1-mediated pathway. Furthermore, a stimulation with a RIG-I or TLR3 agonist promoted the production of IL-6, IL-8, and IFN-λ in HGK, which was significantly enhanced by a pretreatment with IFN-λ1. These results suggest that IFN-λ1 may contribute to the activation of innate immune responses to oral viral infections by up-regulating the expression of RIG-I and TLR3 and priming their functions in keratinocytes.

Community social capital and the onset of functional disability among older adults in Japan: a multilevel longitudinal study using Japan Gerontological Evaluation Study (JAGES) data

OBJECTIVE

The present study examined the association between community social capital and the onset of functional disability among older Japanese people by using validated indicators of social capital and a prospective multilevel design.

DESIGN

Prospective cohort study SETTING: We used data from the Japan Gerontological Evaluation Study, established from August 2010 to January 2012 in 323 districts.

PARTICIPANTS

The target population was restricted to non-institutionalised people aged 65 years or older who were independent in activities of daily living. Participants included 73 021 people (34 051 men and 38 970 women) who were followed up over a 3-year period.

PRIMARY OUTCOME MEASURE

The primary outcome measure was the onset of functional disability, defined as a new registration in public long-term care insurance system records with a care-needs level of two or above, analysed with multilevel Cox proportional hazards regression models by community social capital (civic participation, social cohesion and reciprocity).

RESULTS

The mean age of participants was 73.3 years (SD=6.0) for men and 73.8 years (SD=6.2) for women. During the study period, the onset of functional disability occurred in 1465 (4.3%) men and 1519 (3.9%) women. Of three community social capital variables, social cohesion significantly reduced the risk of onset of functional disability (HR 0.910; 95% CI 0.830 to 0.998) among men, after adjusting for individual social and behavioural variables. There was no significant effect among women.

CONCLUSIONS

Living in a community with rich social cohesion is associated with a lower incidence of onset of functional disability among older Japanese men.

Qualitative analysis of the vocabulary used in work logs of a preventive programme for elderly oral function and nutrition

BACKGROUND

In Japan, day care services for elders include programmes aimed at improving nutrition and oral and motor functions. Few studies have qualitatively assessed these interventions.

OBJECTIVE

To qualitatively search for the characteristic words used in the work logs of a preventive programme on oral function and nutrition for elders by intervention period and intervention type． METHODS: We included 83 participants (81.3 ± 8.2 years) from four day care services in Japan and divided them into the following groups randomly: those who received oral function intervention only, nutritional intervention only and those who received combined oral function plus nutritional intervention. The interventions were conducted twice per month for 24 months. Data from handwritten work logs were entered into a computer as text files. Monitoring of frequently appearing words, co-occurrence analysis and cross-tabulation by intervention period and intervention types was conducted using text mining analysis.

RESULTS

Correspondence analysis revealed that the words used during 1-6 months and 7-12 months were similar in participants' subjective content, and those used in objective content in 13-18 months and 19-24 months were similar. These results indicate that subjective improvements increased after 13 months, and it was maintained within 24 months. The combined intervention type is ideal for oral and nutrition problems.

CONCLUSION

Because this text mining approach revealed the changes in the words used and could be used to monitor any subjective improvement, this approach may help evaluate the effects of preventive care.

Neighborhood food environment and mortality among older Japanese adults: results from the JAGES cohort study

BACKGROUND

Previous research has linked lower availability of food stores selling fruits and vegetables to unhealthy diet. However, the longitudinal association between the availability of healthy food stores and mortality is unknown. This study examined the association between neighborhood availability of food stores and mortality by driving status among older adults.

METHODS

This study drew upon a three-year follow up of participants in the Japan Gerontological Evaluation Study, a population-based cohort study of Japanese adults aged 65 years or older. Mortality from 2010 to 2013 was analyzed for 49,511 respondents. Neighborhood availability of food stores was defined as the number of food stores selling fruits and vegetables within a 500-m or 1-km radius of a person's residence. Both subjective (participant-reported) and objective (geographic information system-based) measurements were used to assess this variable. Cox regression models were used to estimate hazard ratios (HR) for mortality.

RESULTS

A total of 2049 deaths occurred during the follow up. Lower subjective availability of food stores was significantly associated with increased mortality. Compared with participants reporting the highest availability, the age- and sex-adjusted HR for those reporting the lowest availability was 1.28 (95% CI: 1.04-1.58; p = 0.02). The association remained significant after adjustment for sociodemographic (education, income, cohabitation, marital status, and employment status) and environmental (driving status, use of public transportation, and study site) status (HR = 1.24, 95% CI: 1.01-1.53, p = 0.04). This association was stronger among non-car users, among whom the HR for those reporting the lowest availability of food stores was 1.61 (95% CI: 1.08-2.41, p = 0.02). In contrast, no significant association was seen between objective availability and mortality.

CONCLUSIONS

Lower availability of healthy food stores measured subjectively, but not objectively, was associated with mortality, especially among non-car users. Considering the decline in mobility with age, living in a neighborhood with many options for procuring fruits and vegetables within walking distance may be important for healthy aging.

Impact of frontal white matter hyperintensity on instrumental activities of daily living in elderly women with Alzheimer disease and amnestic mild cognitive impairment

Background

Instrumental activities of daily living (IADL) start to decline during the progression of amnestic mild cognitive impairment (aMCI) to Alzheimer disease (AD). Cognitive and physical decline are involved in the loss of functional independence. However, little is known about AD-related neural change that leads to IADL impairment. The purpose of this study was to clarify the effects of regional white matter hyperintensity (WMH) on IADL impairment in persons with AD and aMCI.

Methods

The participants were 347 female subjects aged 65–85 years diagnosed with AD (n = 227), aMCI (n = 44) or normal cognition (n = 76). IADL was assessed by the Lawton Index. Cognition, mood and mobility function were evaluated by comprehensive geriatric assessment batteries. WMH and brain atrophy were analyzed with brain magnetic resonance imaging, using an automatic segmentation program. Regional WMH was measured in the frontal, temporal, occipital and parietal lobes.

Results

Ability to carry out IADL of shopping, food preparation, mode of transportation, responsibility for own medication, and ability to handle finances was obviously impaired in the early stage of AD. Frontal WMH was specifically associated with disability to do shopping and food preparation even after adjusting for several confounders including brain atrophy.

Conclusions

IADL subcategories were differentially impaired along with cognitive status in persons with AD and aMCI. Frontal WMH was an important predictor of impaired ability to do shopping and food preparation. A preventive strategy for WMH might lead to suppression of IADL disability and slow the progression of AD.