近藤 克則

BACKGROUND: Long-term care (LTC) costs create burdens on aging societies. Maintaining oral health through dental visits may result in shorter LTC periods, thereby decreasing LTC costs; however, this remains unverified. We examined whether dental visits in the past 6 months were associated with cumulative LTC insurance (LTCI) costs. METHODS: This cohort study of the Japan Gerontological Evaluation Study targeted independent adults aged ≥65 years in 2010 over an eight-year follow-up. We used data from a self-reported questionnaire and LTCI records from the municipalities. The outcome was cumulative LTCI costs, and exposure was dental visits within 6 months for prevention, treatment, and prevention or treatment. A two-part model was used to estimate the differences in the predicted cumulative LTCI costs and 95% confidence intervals (CIs) for each dental visit. RESULTS: The mean age of the 8,429 participants was 73.7 years (standard deviation [SD]=6.0), and 46.1% were men. During the follow-up period, 17.6% started using LTCI services. The mean cumulative LTCI cost was USD 4877.0 (SD=19082.1). The predicted cumulative LTCI costs were lower among those had dental visits than among those who did not. The differences in predicted cumulative LTCI cost were -USD 1089.9 (95%CI = -1,888.5 - -291.2) for dental preventive visits, -USD 806.7 (95%CI = -1,647.4 - 34.0) for treatment visits, and -USD 980.6 (95%CI = -1,835.7 - -125.5) for preventive or treatment visits. CONCLUSIONS: Dental visits, particularly preventive visits, were associated with lower cumulative LTCI costs. Maintaining oral health through dental visits may effectively reduce the LTCI costs.

AIMS: Previous studies have reported inconsistent findings regarding the association between post-traumatic stress (PTS) and post-traumatic growth (PTG). Three major issues could account for this inconsistency: (1) the lack of information about mental health problems before the disaster, (2) the concept of PTG is still under scrutiny for potentially being an illusionary perception of personal growth and (3) the overlooking of PTS comorbidities as time-dependent confounding factors. To address these issues, we explored the associations of PTS and PTG with trauma-related diseases and examined the association between PTS and PTG using marginal structural models to address time-dependent confounding, considering pre-disaster covariates, among older survivors of the 2011 Japan Earthquake and Tsunami. METHODS: Seven months before the disaster, the baseline survey was implemented to ask older adults about their health in a city located 80 km west of the epicentre. After the disaster, we implemented follow-up surveys approximately every 3 years to collect information about PTS and comorbidities (depressive symptoms, smoking and drinking). We asked respondents about their PTG in the 2022 survey (n = 1,489 in the five-wave panel data). RESULTS: PTG was protectively associated with functional disability (coefficient -0.47, 95% confidence interval (CI) -0.82, -0.12, P < 0.01) and cognitive decline assessed by trained investigators (coefficient -0.07, 95% CI -0.11, -0.03, P < 0.01) and physicians (coefficient -0.06, 95% CI -0.11, -0.02, P < 0.01), while PTS was not significantly associated with them. Severely affected PTS (binary variable) was associated with higher PTG scores, even after adjusting for depressive symptoms, smoking and drinking as time-dependent confounders (coefficient 0.35, 95% CI 0.24, 0.46, P < 0.01). We also found that an ordinal variable of the PTS score had an inverse U-shaped association with PTG. CONCLUSION: PTG and PTS were differentially associated with functional and cognitive disabilities. Thus, PTG might not simply be a cognitive bias among survivors with severe PTS. The results also indicated that the number of symptoms in PTS had an inverse U-shaped association with PTG. Our findings provided robust support for the theory of PTG, suggesting that moderate levels of psychological struggles (i.e., PTS) are essential for achieving PTG, whereas intense PTS may hinder the attainment of PTG. From a clinical perspective, interventions that encourage social support could be beneficial in achieving PTG by facilitating deliberate rumination.

BACKGROUND: It is unclear whether inactivated influenza vaccination (IIV) or pneumococcal vaccination are associated with the risk of dementia; however, both types of vaccination are recommended for older adults. Studies have shown that the IIV is negatively associated with incident dementia; however, the uptake of pneumococcal vaccinations has not been considered. We investigated the independent associations of IIV and 23-valent pneumococcal polysaccharide vaccine (PPSV23) with incident dementia in older adults. METHODS: Health-related information on older Japanese adults was obtained through a baseline survey conducted in 2013 (baseline survey). The uptake of IIV and PPSV23 was determined in a second survey conducted in 2016 (second wave). Both surveys were conducted among independent Japanese older adults aged ≥ 65 years at the two surveys and who had not been certified as needing long-term care (LTC). In the second wave, 9,865 participants were followed up for 3.5 years (short-term follow-up), and 6,995 participants were followed up for six years and five months (long-term follow-up) until they required LTC due to dementia onset (incident dementia). A competing risk model with stabilized inverse probability weighting (SIPW) was constructed to calculate the hazard ratios (HRs) and 95 % confidence intervals (CIs) of incident dementia. RESULTS: PPSV23 uptake was negatively associated with incident dementia among participants in both the short- and long-term follow-up periods after SIPW (short-term follow-up: HR: 0.77, 95 % CI: 0.63 - 0.95; long-term follow-up: HR: 0.83, 95 % CI: 0.70 - 0.97). Conversely, IIV uptake was not associated with incident dementia among participants in either follow-up group (short-term follow-up: HR: 0.86, 95 % CI: 0.63-1.16; long-term follow-up: HR: 0.99, 95 % CI: 0.76-1.29). The PPSV23 uptake was negatively associated with incident dementia in participants without the IIV uptake (short-term follow-up: HR: 0.44, 95 % CI: 0.24 - 0.81; long-term follow-up: HR: 0.47, 95 % CI: 0.29 - 0.76). Conversely, the IIV uptake was not associated with incident dementia regardless of the PPSV23 status (short-term follow-up: HR: 0.87, 95 % CI: 0.62 - 1.23; long-term follow-up: HR: 1.00, 95 % CI: 0.74 - 1.35). CONCLUSION: Our results suggest that the PPSV23 uptake was independently associated with the incidence of dementia. However, the IIV uptake was not associated with the incidence of dementia.

OBJECTIVES: This study examined the association between various socioeconomic status (SES) indicators and dental visits among older Japanese. BACKGROUND: When examining health inequalities, an adequate indicator of SES should be applied. In older adults, wealth and pensions are considered more appropriate indicators of SES than education and income, but few studies have examined. METHODS: This cross-sectional study used data from 12 391 individuals aged 65 years or older from the 2016 Japan Gerontological Evaluation Study (JAGES). The Slope Index of Inequality (SII) and the Relative Index of Inequality (RII) were applied to examine the association of education, income, wealth and pensions with dental visits for treatment and check-up adjusting for covariates. RESULTS: The mean age of the participants was 74.0 ± 6.2 years. In the previous year, 56.3% of participants had visited a dentist for a check-up, and 65.9% had visited for treatment. Inequalities in dental treatment visits were observed for wealth, pensions and income rather than education. Income was not significantly associated with check-up visits. Wealth showed the largest association with dental visits for treatment [(SII 0.09, 95% CI 0.06 to 0.13), (RII 1.14, 95% CI 1.09 to 1.21)] and check-up [(SII 0.08, 95% CI 0.05 to 0.12), (RII 1.16, 95% CI 1.09 to 1.23)]. CONCLUSION: When measuring inequalities in access to dental care among the older population, wealth and pensions could be important indicators of SES.