Longitudinal association between frequency of Internet use and incident disability among community-dwelling older people during the COVID-19 pandemic.

BACKGROUND: There is limited evidence of a protective effect of Internet use for incident disability (ID) during the COVID-19 pandemic. We investigated the association between frequency of Internet use (FIU) and ID among community-dwelling older people. METHODS: We used longitudinal data from the 2019 and 2022 surveys, including 7,913 residents aged ≥65 without disability at baseline. ID was defined as a new public long-term care insurance certification. FIU at baseline was categorized into daily, weekly, monthly, yearly, and non-users. Changes in FIU before and during the COVID-19 pandemic were categorized into continuing frequent (i.e., daily or weekly), continuing moderate (i.e., monthly or yearly), increase in frequency, from non-users to users, decrease in frequency, from users to non-users, and continuing non-users. Covariates included age, gender, education, perceived economic situation, family structure, body mass index, chronic medical conditions, dietary variety, working status, walking time, and cognitive functioning. Multivariable Poisson regression models were used to estimate adjusted cumulative incidence ratio (aCIR) and 95% confidence interval (CI) for ID. RESULTS: During the 3-year follow-up, 132 of 4,453 people aged 65-74, 595 of 3,460 people aged ≥75, 287 of 3,660 men, and 440 of 4,253 women developed ID. For FIU at baseline, among people aged ≥75 or men, there was a dose-response relationship between more frequent Internet use at baseline and a lower risk of ID (P-trend was 0.005 in people aged ≥75, and <0.001 in men). Compared to non-users, daily users had a significantly lower risk of ID [aCIR (95% CI) = 0.69 (0.53-0.90) in people aged ≥75, and 0.49 (0.34-0.70) in men]. For changes in FIU, "continuing frequent" and "from non-users to users" had a lower risk of ID than continuing non-users. After stratified analyses, "continuing frequent" remained a significant association in people aged ≥75 or in men, while "from non-users to users" had a significant association in those with daily walking time <30 minutes. CONCLUSIONS: Although FIU may act as a marker of disability, or indicate individual adaptability, our findings suggest that Internet use may be a potential preventive measure against ID in community-dwelling older people when social distancing is required.

Risk of severe COVID-19 in unvaccinated patients during the period from wild-type to Omicron variant: real-world evidence from Japan.

BACKGROUND: Many studies have reported that the Omicron variant is less pathogenic than the Delta variant and the wild-type. Epidemiological evidence regarding the risk of severe COVID-19 from the wild-type to the Omicron variant has been lacking. METHODS: Study participants were COVID-19 patients aged 18 and older without previous COVID-19 infection who were notified to the Nara Prefecture Chuwa Public Health Center from January 2020 to March 2023, during the periods from the wild-type to the Omicron variant. The outcome variable was severe COVID-19 (i.e., ICU admission or COVID-19-related death). The explanatory variable was SARS-CoV-2 variant type or the number of COVID-19 vaccinations. Covariates included gender, age, risk factors for aggravation, and the number of general hospital beds per population. The generalized estimating equations of negative binomial regression models were used to estimate the adjusted incidence proportion (AIP) with 95% confidence interval (CI) for severe COVID-19. RESULTS: Among 77,044 patients included in the analysis, 14,556 (18.9%) were unvaccinated and 520 (0.7%) developed severe COVID-19. Among unvaccinated patients, the risk of severe COVID-19 increased in the Alpha/Delta variants and decreased in the Omicron variant compared to the wild-type (AIP [95% CI] was 1.55 [1.06-2.27] in Alpha/Delta and 0.25 [0.15-0.40] in Omicron), but differed by age. Especially in patients aged ≥80, there was no significant difference in the risk of severe COVID-19 between the wild-type and the Omicron variant (AIP [95% CI] = 0.59 [0.27-1.29]). Regarding the preventive effect of vaccines, among all study participants, the number of vaccinations was significantly associated with the prevention of severe COVID-19, regardless of variant type. After stratified analyses by age, patients aged ≥80 remained a significant association for all variant types. On the other hand, the number of vaccinations had no association in Omicron BA.5 of patients aged 18-64. CONCLUSIONS: Patients aged ≥80 had less reduction in risk of severe COVID-19 during the Omicron variant period, and a greater preventive effect of vaccines against severe COVID-19, compared to younger people. Our findings suggest that booster vaccination is effective and necessary for older people, especially aged ≥80.

Smaller household size and higher prevalence of serious psychological distress in younger people and never-married people: a nationwide cross-sectional survey in Japan.

Background: Small-member households are increasing worldwide. However, most previous studies have focused on older people and living alone. Using the latest national survey data, we investigated a dose-response relationship between household size and serious psychological distress (SPD). Methods: We analyzed data from the 2019 Comprehensive Survey of Living Conditions in Japan. The study participants were 405,560 community-dwelling adults aged 20 or older. Household size was classified into 5 or more, 3 or 4, two, and one (i.e., living alone). SPD was defined as ≥13 points based on the Kessler 6-item Psychological Distress Scale. We used multivariable logistic regressions and included age, education, equivalent household expenditures, housing tenure, employment contract, smoking, and illness under treatment as covariates. Results: After stratified analyses by age and gender, a dose-response relationship between smaller household size and more common SPD was significant for younger, but not for older people (p-trend was <0.001 in men aged 20-59 and women aged 20-39). After stratified analyses by gender and marital status, a dose-response relationship was significant only for the never-married group in both genders (p-trend was <0.001 in never-married men and women). Conclusion: Smaller households were associated with higher prevalence of SPD in younger adults and in never-married individuals, regardless of gender. Our findings suggest a need to focus on younger people and never-married people to reduce the mental health risks due to small household sizes.

Association between vaccination status and severe health consequences among community-dwelling COVID-19 patients during Omicron BA.1/BA.2 and BA.5-predominant periods in Japan.

BACKGROUND: Many previous studies have reported that COVID-19 vaccine effectiveness decreased over time and declined with newly emerging variants. However, there are few such studies in Japan. Using data from a community-based retrospective study, we aimed to assess the association between vaccination status and severe COVID-19 outcomes caused by the Omicron variant, considering the length of time since the last vaccination dose. METHODS: We included all persons aged ≥12 diagnosed with COVID-19 by a doctor and notified to the Chuwa Public Health Center of Nara Prefectural Government during the Omicron BA.1/BA.2 and BA.5-predominant periods in Japan (January 1 to September 25, 2022). The outcome variable was severe health consequences (SHC) (i.e., COVID-19-related hospitalization or death). The explanatory variable was vaccination status of the individuals (i.e., the number of vaccinations and length of time since last dose). Covariates included gender, age, risk factors for aggravation, and the number of hospital beds per population. Using the generalized estimating equations of the multivariable Poisson regression models, we estimated the cumulative incidence ratio (CIR) and 95% confidence interval (CI) for SHC, with stratified analyses by period (BA.1/BA.2 or BA.5) and age (65 and older or 12-64 years). RESULTS: Of the 69,827 participants, 2,224 (3.2%) had SHC, 12,154 (17.4%) were unvaccinated, and 29,032 (41.6%) received ≥3 vaccine doses. Regardless of period or age, there was a significant dose-response relationship in which adjusted CIR for SHC decreased with an increased number of vaccinations and a longer time since the last vaccination. On the one hand, in the BA.5 period, those with ≥175 days after the third dose had no significant difference in people aged 65 and older (CIR 0.77; 95% CI, 0.53-1.12), but significantly lower CIR for SHC in people aged 12-64 (CIR 0.47; 95% CI, 0.26-0.84), compared with those with ≥14 days after the second dose. CONCLUSION: A higher number of vaccinations were associated with lower risk of SHC against both BA.1/BA.2 and BA.5 sublineages. Our findings suggest that increasing the number of doses of COVID-19 vaccine can prevent severe COVID-19 outcomes, and that a biannual vaccination is recommended for older people.

An ecological association of number of civil servants and physicians with prefectural-level rapid COVID-19 vaccination of older people in Japan.

BACKGROUND: Civil servants and physicians play an important role in combating COVID-19. However, it is unclear whether the number of civil servants and physicians is associated with rapid COVID-19 vaccine uptake among older people (i.e., smoother rollout of priority vaccination for older people). METHODS: Using Poisson regression models of the generalized estimating equations, we examined the ecological association of the number of civil servants and physicians with prefectural-level rapid COVID-19 vaccination in older people. Prefectural-level data were based on publicly available government surveys. The outcome variable was the proportion of fully vaccinated people aged 65 and older on the day with the largest standard deviation across 47 prefectures (i.e., July 6, 2021). The explanatory variable was the number of civil servants and physicians per population by prefecture. RESULTS: After adjusting for population density, influenza vaccination coverage, socioeconomic factors, natural environmental factors, health indicators, and the number of civil servants and physicians, in all 3 models, prefectures with the highest number of civil servants and physicians had faster COVID-19 vaccine uptake than prefectures with the lowest number. A significant trend between higher staffing levels and more rapid vaccination was observed for the number of physicians in all 3 models, but for the number of civil servants only in one model. CONCLUSION: We found that COVID-19 vaccine uptake among older people was more rapid in prefectures with more civil servants and physicians per population, with the number of physicians having a stronger association. This study may point the way to future areas of research on vaccine policies that include other age groups and infectious diseases.

Association between vaccination status and COVID-19-related health outcomes among community-dwelling COVID-19 patients in Nara, Japan.

BACKGROUND: Many previous studies have reported COVID-19 vaccine effectiveness, but there are few studies in Japan. This community-based, retrospective observational study investigated the association between vaccination status and COVID-19-related health outcomes in COVID-19 patients by SARS-CoV-2 variant type. METHODS: The study participants were 24,314 COVID-19 patients aged 12 or older whose diagnoses were reported to the Nara Prefecture Chuwa Public Health Center from April 2021 to March 2022, during periods when the alpha, delta, and omicron variants of COVID-19 were predominant. The outcome variables were severe health consequences (SHC) (i.e., ICU admission and COVID-19-related death), hospitalization, and extension of recovery period. The explanatory variable was vaccination status at least 14 days prior to infection. Covariates included gender, age, population size, the number of risk factors for aggravation, and the number of symptoms at diagnosis. The generalized estimating equations of the multivariable Poisson regression models were used to estimate the adjusted incidence proportion (AIP) and 95% confidence interval (CI) for each health outcome. We performed stratified analyses by SARS-CoV-2 variant type, but the association between vaccination status and COVID-19-related health outcomes was stratified only for the delta and omicron variants due to the small number of vaccinated patients during the alpha variant. RESULTS: Of the 24,314 participants, 255 (1.0%) had SHC; of the 24,059 participants without SHC, 2,102 (8.7%) were hospitalized; and of the 19,603 participants without SHC, hospitalization, and missing data on recovery period, 2,960 (15.1%) had extension of recovery period. Multivariable Poisson regression models showed that regardless of SARS-CoV-2 variant type or health outcome, those who received two or more vaccine doses had significantly lower risk of health outcomes than those who did not receive the vaccine, and there was a dose-response relationship in which the AIP for health outcomes decreased with an increased number of vaccinations. CONCLUSION: A higher number of vaccinations were associated with lower risk of COVID-19-related health outcomes, not only in the delta variant but also in the omicron variant. Our findings suggest that increasing the number of COVID-19 vaccine doses can prevent severe disease and lead to early recovery of patients not requiring hospitalization.

Number of public health nurses and COVID-19 incidence rate by variant type: an ecological study of 47 prefectures in Japan.

BACKGROUND: Community health activities by public health nurses (PHNs) are known to improve lifestyle habits of local residents, and may encourage the practice of infectious disease prevention behaviors during the COVID-19 pandemic. We investigated the association between prefecture-level COVID-19 incidence rate and the number of PHNs per population in Japan, by the COVID-19 variant type. METHODS: Our data were based on government surveys where prefectural-level data are accessible to the public. The outcome variable was the COVID-19 incidence rate (i.e., the cumulative number of COVID-19 cases per 100,000 population for each variant type in 47 prefectures). The explanatory variable was the number of PHNs per 100,000 population by prefecture. Covariates included socioeconomic factors, regional characteristics, healthcare resources, and health behaviors. The generalized estimating equations of the multivariable Poisson regression models were used to estimate adjusted incidence rate ratio (IRR) and 95% confidence interval (CI) for the COVID-19 cases. We performed stratified analyses by variant type (i.e., wild type, alpha variant, and delta variant). RESULTS: A total of 1,705,224 confirmed COVID-19 cases (1351.6 per 100,000 population) in Japan were reported as of September 30, 2021. The number of PHNs per 100,000 population in Japan was 41.9. Multivariable Poisson regression models showed that a lower number of PHNs per population was associated with higher IRR of COVID-19. Among all COVID-19 cases, compared to the highest quintile group of the number of PHNs per population, the adjusted IRR of the lowest quintile group was consistently significant in the models adjusting for socioeconomic factors (IRR: 3.76, 95% CI: 2.55-5.54), regional characteristics (1.73, 1.28-2.34), healthcare resources (3.88, 2.45-6.16), and health behaviors (2.17, 1.39-3.37). These significant associations were unaffected by the variant type of COVID-19. CONCLUSION: We found that the COVID-19 incidence rate was higher in prefectures with fewer PHNs per population, regardless of the COVID-19 variant type. By increasing the number of PHNs, it may be possible to contain the spread of COVID-19 in Japan and provide an effective human resource to combat emerging infectious diseases in the future.

Age differences in the association of physical leisure activities with incident disability among community-dwelling older adults.

BACKGROUND: The relationship between leisure activities (LA) in old age and prevention of disability has not been fully investigated, and age and gender differences of these relationships are unknown. This study aimed to investigate whether physical and cognitive LA predicted incident disability among community-dwelling older adults by age and gender. METHODS: We prospectively observed 8,275 residents aged 65 or above without disability at baseline for 3 years. Incident disability was defined as a new certification of the public long-term care insurance system. LA were classified into two types: physical LA and cognitive LA. The frequency of LA was categorized into frequent (i.e., once a week or more), moderate (i.e., monthly or yearly), and non-engagement. Covariates included age, gender, family number, education, perceived economic situation, body mass index, chronic medical conditions, alcohol consumption, smoking status, regular dental visits, depression, cognitive functioning, and social participation. Multivariable Poisson regression models were used to estimate adjusted cumulative incidence ratio (CIR) and 95% confidence interval (CI) for incident disability. We performed stratified analyses by age groups (i.e., the young-old aged 65-74 and the old-old aged 75-97) and gender (i.e., men and women). RESULTS: The 3-year cumulative incidence of disability was 7.5%. After adjustment for covariates and mutual adjustment for both types of LA, a significant dose-response relationship between more frequent LA and lower risk of incident disability was found in young-old physical LA (P-trend < 0.001), in old-old cognitive LA (P-trend = 0.012), in male cognitive LA (P-trend = 0.006), and in female physical LA (P-trend = 0.030). Compared with people without LA, adjusted CIR (95% CI) of frequent LA was 0.47 (0.30-0.74) in young-old physical, 0.75 (0.58-0.96) in old-old cognitive, 0.65 (0.46-0.89) in male cognitive, and 0.70 (0.52-0.95) in female physical. Regarding the effect modification according to age and gender, only interaction between age and physical LA significantly prevented incident disability (P for interaction = 0.019). CONCLUSION: We found age differences in the association of physical LA with incident disability among community-dwelling older adults. An effective measure to prevent long-term care in the community would be to recommend frequent physical LA for the young-old.

Occupational status and self-reported low back pain by gender: a nation-wide cross-sectional study among the general population in Japan.

BACKGROUND: We aimed to examine the cross-sectional association between occupational class and self-reported low back pain (LBP) in a representative sample of the Japanese general population. METHODS: We used anonymized data from a nationwide survey (31,443 men and 35,870 women aged ≥ 20). Occupational class variables included working status, occupation, employment status, and company size (number of employees). Covariates included age, socio-economic status, lifestyle, and comorbidities. Poisson regression models stratified by gender were used to estimate adjusted prevalence ratio (APR) and 95% confidence interval (CI) for self-reported LBP. RESULTS: The prevalence of self-reported LBP was 11.7% in men and 14.2% in women. After adjustment for covariates and mutual adjustment for all occupational class variables, among both genders, agricultural/forestry/fishery workers and non-workers had a significantly higher prevalence of self-reported LBP: APR (95% CI) of agricultural/forestry/fishery was 1.36 (1.08-1.70) in men and 1.59 (1.30-1.93) in women; that of non-workers was 1.42 (1.18-1.70) in men and 1.23 (1.08-1.40) in women. Among men, non-regular employees were more likely to have self-reported LBP than regular employees: APR (95% CI) was 1.25 (1.07-1.46) in part-timers and casual staff and 1.18 (1.03-1.35) in other types of non-regular employees. Moreover, compared to men working at companies with ≥ 100 employees, men working at companies with 30-99 employees had a significantly higher prevalence of self-reported LBP (APR 1.17; 95% CI, 1.03-1.34). Among women, professionals and technicians (1.26; 1.11-1.43) and sales workers (1.22; 1.04-1.43) had a significantly higher prevalence of self-reported LBP than clerks. Neither employment status nor company size was associated with self-reported LBP in women. After stratified analyses by age group, similar patterns were observed in participants aged 20-64, but not in those aged ≥ 65. CONCLUSION: Our results suggest that self-reported LBP is highly prevalent among agricultural/forestry/fishery workers and the unemployed, regardless of gender, and that there are also gender differences in the association of occupational class factors with self-reported LBP. It is necessary, therefore, to take preventive measures against LBP based on gender and occupational class factors in Japan.

Fraction and Number of Unemployed Associated with Self-Reported Low Back Pain: A Nation-Wide Cross-Sectional Study in Japan.

This study examined a cross-sectional association between self-reported low back pain (LBP) and unemployment among working-age people, and estimated the impact of self-reported LBP on unemployment. We used anonymized data from a nationally representative survey (24,854 men and 26,549 women aged 20-64 years). The generalized estimating equations of the multivariable Poisson regression models stratified by gender were used to estimate the adjusted prevalence ratio (PR) and 95% confidence interval (CI) for unemployment. The population attributable fraction (PAF) was calculated using Levin's method, with the substitution method for 95% CI estimation. The prevalence of self-reported LBP was 9.0% in men and 11.1% in women. The prevalence of unemployment was 9.3% in men and 31.7% in women. After adjusting for age, socio-economic status, lifestyle habits, and comorbidities, the PR (95% CI) for the unemployment of the LBP group was 1.32 (1.19-1.47) in men and 1.01 (0.96-1.07) in women, compared with the respective non-LBP group. The PAF (95% CI) of unemployment associated with self-reported LBP was 2.8% (1.6%, 4.2%) in men. Because the total population of Japanese men aged 20-64 in 2013 was 36,851 thousand, it was estimated that unemployment in 1037 thousand of the Japanese male working population was LBP-related.

Association between heaviness of cigarette smoking and serious psychological distress is stronger in women than in men: a nationally representative cross-sectional survey in Japan.

BACKGROUND: Higher smoking prevalence in people with serious psychological distress (SPD) is well-recognized. However, gender and age differences in the association between heaviness of cigarette smoking and SPD have not been fully investigated. METHODS: We used anonymized data from a nationally representative survey in Japan (33,925 men and 37,257 women). SPD was measured using the Kessler 6-item Psychological Distress Scale and defined as ≥ 13 points. Multiple logistic regression analyses stratified by gender and age-groups (20-44 years, 45-64 years, and ≥ 65 years) were used to estimate adjusted odds ratio (aOR) and 95% confidence interval (CI) for SPD. RESULTS: After adjusting for sociodemographic confounders including education, equivalent household expenditures, and employment contract, women had a significant association between heavier smoking and more frequent SPD: compared to never-smokers, aORs (95% CIs) of ex-smokers, current light smokers who smoked 1-10 cigarettes per day (CPD), current moderate smokers 11-20 CPD, and current heavy smokers ≥ 21 CPD were 1.22 (0.92-1.63), 1.52 (1.25-1.84), 1.75 (1.46-2.09), and 2.22 (1.59-3.10), respectively (P-trend < 0.001). A significant positive association among women was consistent across all age-groups. Among men, there was no association between heaviness of cigarette smoking and SPD in all age-groups, and only current heavy smokers aged 20-44 years had a significantly higher OR for SPD (aOR, 1.37 [95% CI, 1.02-1.85]) than never-smokers. CONCLUSIONS: There was a positive association between heaviness of cigarette smoking and SPD only among women, but not among men. For female smokers experiencing mental disorders, there is a need not only to improve mental health services but also to improve smoking-cessation support.

Mental component of health-related quality of life is an independent predictor of incident functional disability among community-dwelling older people: a prospective cohort study.

PURPOSE: Previous studies have reported a positive association between poor health-related quality of life (HRQOL) and disability mainly in relation to the physical component of HRQOL. Given the mental component's responsivity to interventions, this study aimed to investigate whether the mental component of HRQOL independently predicted functional disability. METHODS: We targeted all residents aged ≥ 65 years in one municipality and analyzed 3858 men and 4475 women without disability at baseline (November 2016). HRQOL was measured using the physical component summary (PCS) and mental component summary (MCS) of the SF-8 Health Survey. At 3-year follow-up (October 2019), incident functional disability was measured, defined as a new certification according to the Japanese long-term care insurance system. Multivariable Poisson regression models stratified by gender were used to estimate adjusted cumulative incidence ratio (CIR) and 95% confidence interval (CI) for functional disability. RESULTS: Among both genders, there was a significant dose-response relationship between better MCS and lower risk of functional disability, independent of potential confounders including the PCS (P for trend = 0.026 in men and 0.003 in women). Compared with the worst MCS group, the CIRs (95% CIs) for functional disability in the second worst, the middle, the second best, and the best MCS quintile groups were 1.09 (0.80-1.48), 0.58 (0.40-0.85), 0.90 (0.59-1.37), and 0.70 (0.48-1.02) for men, and 0.76 (0.58-1.00), 0.62 (0.46-0.84), 0.73 (0.53-0.99), and 0.63 (0.48-0.85) for women, respectively. CONCLUSION: The MCS is an independent predictor of functional disability among high-functioning older adults. This suggests that strategies focused on mental HRQOL are important for realizing a healthy, long-lived society.

Longitudinal association between lifetime workforce participation and risk of self-reported cognitive decline in community-dwelling older adults.

BACKGROUND: Although many governments are promoting workforce participation (WP) by older people, evidence of WP's effects on active aging is inadequate. We examined whether there is a gender-specific beneficial effect of lifetime WP from adulthood though old age against self-reported cognitive decline (CD) among community-dwelling older adults. METHODS: We used data from a community-based prospective study of 2,422 men and 2,852 women aged ≥65 with neither poor cognition nor disability in basic activities of daily living at baseline. Self-reported CD was measured using the Cognitive Performance Scale. Lifetime WP evaluated the presence or absence of WP at baseline, the longest-held occupation, and lifetime working years (total working years throughout lifetime). Generalized estimating equations of the multivariable Poisson regression model were applied to evaluate a cumulative incidence ratio (CIR) for self-reported CD and a 95% confidence interval (CI), controlled for age, education, self-perceived economic status, chronic medical conditions, smoking history, physical activity, depression, and instrumental activities of daily living. To examine any gender-specific association, stratified analyses by gender were performed. RESULTS: The 33-month cumulative incidence of self-reported CD was 15.7% in men and 14.4% in women. After covariate adjustments and mutual adjustment for three items of lifetime WP, men who had their longest held job in a white-collar occupation reported significantly decreased self-reported CD compared to men engaged in blue-collar jobs (CIR 0.72; 95% CI, 0.57-0.91), and women had a significant dose-response relationship between longer lifetime working years and less decline in subjective cognitive functioning (P for trend <0.029). Among both genders, WP at baseline was not associated with self-reported CD. CONCLUSIONS: Our results suggest that lifetime WP, especially lifetime principal occupation in men and lifetime working years in women, may play a more prominent role in preventing self-reported CD than later-life WP.

Regular dental visits may prevent severe functional disability: A community-based prospective study.

BACKGROUND: Previous studies have shown that regular dental visits can affect the relationship of tooth loss with mortality and functional disability. However, the independent association between regular dental visits and incident functional disability is unclear. METHODS: Our study participants were community-dwelling individuals aged ≥65 years, without disability at baseline. The outcome was the level of incident functional disability, as defined in a new certification of the public long-term care insurance. We defined no disability as no certification at follow-up, mild disability as support levels 1-2 and care level 1 (i.e., independent in basic ADL, but requiring some help in daily activities), and severe disability as care levels 2-5 (i.e., dependent in basic ADL). The exposure variable, based on the questionnaire, was regular dental visits at baseline. Covariates included gender, age, socio-economic status, health status, lifestyle habits, physical and mental functioning, and oral health variables. Using multinomial logistic regression, we calculated adjusted odds ratio (aOR) and 95 % confidence interval (CI) for mild disability and severe disability, with no disability as a reference category. RESULTS: Among 8,877 participants, the 33-month cumulative incidence of mild and severe disability was 6.0 % and 1.8 %, respectively. After controlling for all covariates, regular dental visits at baseline were significantly associated with a lower risk of incident severe disability (aOR 0.65; 95 % CI, 0.46-0.91) but not the incidence of mild disability (aOR 0.96; 95 % CI, 0.79-1.17). CONCLUSIONS: Encouraging dental visits may contribute to prevention of severe functional disability and extension of healthy life expectancy among community-dwelling older adults.

The Association Between Education and Smoking Prevalence, Independent of Occupation: A Nationally Representative Survey in Japan.

BACKGROUND: Higher smoking prevalence in less educated persons and manual workers is well known. This study examines the independent relationship of education and occupation with tobacco use. METHODS: We used anonymized data from a nationwide population survey (30,617 men and 33,934 women). Education was divided into junior high school, high school, or university attainment. Occupation was grouped into upper non-manual, lower non-manual, and manual. Poisson regression models stratified by age and gender were used to estimate adjusted prevalence ratio (PR) and 95% confidence interval (CI) for current smoking. RESULTS: After adjustment for covariates, education, and occupation, education was significantly related to current smoking in both genders; compared to university graduates, PRs of junior high school graduates aged 20-39, 40-64, and ≥65 were 1.74 (95% CI, 1.53-1.98), 1.50 (95% CI, 1.36-1.65), and 1.28 (95% CI, 1.08-1.50) among men, and 3.54 (95% CI, 2.92-4.30), 2.72 (95% CI, 2.29-3.23), and 1.74 (95% CI, 1.14-2.66) among women, respectively. However, significantly higher smoking prevalence in manual than in upper non-manual was found only in men aged 20-64; compared to upper non-manual, the PRs of manual workers aged 20-39, 40-64, and ≥65 were 1.11 (95% CI, 1.02-1.22), 1.18 (95% CI, 1.10-1.27), and 1.10 (95% CI, 0.89-1.37) among men, and 0.95 (95% CI, 0.75-1.20), 0.92 (95% CI, 0.75-1.12), and 0.46 (95% CI, 0.22-0.95) among women, respectively. CONCLUSIONS: Independent of occupation, educational disparities in smoking existed, regardless of age and gender. Occupation-smoking relationship varied with age and gender. Our study suggests that we should pay attention to social inequality in smoking as well as national smoking prevalence.

The interaction effect between physical and cultural leisure activities on the subsequent decline of instrumental ADL: the Fujiwara-kyo study.

BACKGROUND: Maintenance of instrumental activities of daily living (IADL) and social role (SR) is crucial to keep independent life because the decline in SR and IADL was a significant predictor of dependence in basic ADL in later. The independent effect of physical and cultural leisure activities and their effect modification on the IADL remains unknown. METHODS: We prospectively observed 3241 elderly with intact IADL at baseline for 5 years. Higher level functional capacity such as IADL and SR was assessed using the Tokyo Metropolitan Institute of Gerontology Index of competence (TMIG index). RESULTS: The mean age of the participants was 72.3 years (standard deviation 5.1), and 46.9% were male, and 90.9% of them received a follow-up assessment. Of the participants, 10.4% developed an IADL decline. Engagement in leisure physical activity was associated with a significantly lower risk of IADL decline (adjusted risk ratio, 0.73; 95% confidence interval [CI], 0.60 to 0.89), and cultural leisure activity was also associated with lower risk of IADL decline (adjusted risk ratio, 0.77; 95% CI, 0.63 to 0.95) independent of potential confounders. We also found significant and positive interaction between physical and cultural leisure activities at risk for IADL decline (P = 0.024) and SR decline (P = 0.004). CONCLUSIONS: We found an independent association of physical and cultural leisure activities with a lower risk for functional decline in IADL and SR with positive interaction. Combined engagement in physical and cultural activities may effectively prevent from IADL decline and SR decline.

Association between housing tenure and self-rated health in Japan: Findings from a nationwide cross-sectional survey.

BACKGROUND: Many studies have reported that housing tenure (HT) is associated with health, but little is known about its association in Japan. We investigated the cross-sectional association between HT and self-rated health (SRH) among Japanese adults, taking demographic characteristics and socioeconomic status (SES) into consideration. METHODS: We used data from a nationally representative survey conducted by the Japanese Ministry of Health, Labour and Welfare (28,641 men and 31,143 women aged ≥20 years). HT was divided into five categories: owner-occupied, privately rented, provided housing, publically subsidized, and rented rooms. SRH was evaluated using a single-item inventory and dichotomized into poor (very poor/poor) and good (very good/good/fair). We calculated adjusted odds ratios (OR) and their 95% confidence intervals (CI) for poor SRH with logistic regression models. Covariates included demographic factors (i.e., age, gender, marital status, family size, smoking status, and chronic medical conditions) and SES factors (i.e., education, equivalent household expenditures, and occupation). RESULTS: Among analyzed participants, 75.9% were owner-occupiers and 14.6% reported poor SRH. After adjustment for all covariates, compared with owner-occupiers, private renters (OR = 1.36, 95% CI = 1.26-1.47), publically subsidized renters (OR = 1.33, 95% CI = 1.19-1.48), and residents in rented rooms (OR = 1.41, 95% CI = 1.22-1.62) were more likely to report poor SRH. Stratified analyses by SES factors showed that the association between HT and poor SRH was stronger in the socially disadvantaged than in the higher socioeconomic group. CONCLUSIONS: Our results show a significant association between HT and SRH, independent of socio-demographic factors. HT may deserve greater attention as an indicator of socioeconomic position in Japan.

Older Adult Males Who Worked at Small-Sized Workplaces Have an Increased Risk of Decline in Instrumental Activities of Daily Living: A Community-Based Prospective Study.

BACKGROUND: To examine the relationship of working history from early adulthood through old age with instrumental activities of daily living (IADL). METHODS: Analyzed participants were 5,857 community-dwelling older Japanese people aged ≥65 years. Using the Tokyo Metropolitan Institute of Gerontology Index of Competence, IADL decline was defined as individuals who had no IADL dependence at baseline but were deemed as dependent in IADL at follow-up. Work history was based on working status at baseline, total working years, and information concerning the longest held job, including occupation, employment pattern, and workplace size (number of employees). We conducted multiple logistic regression analyses and estimated the odds ratios (ORs) for IADL decline with 95% confidence intervals (CIs) by gender. RESULTS: At the 33-month follow-up, 428 men (16.6%) and 275 women (8.4%) developed IADL decline. After covariate adjustments, men with unstable employment reported significantly increased IADL decline (OR 1.52; 95% CI, 1.19-1.95) compared to men with stable employment, and men who worked in small workplaces with 1-49 employees had an increased risk for IADL decline (OR 1.53; 95% CI, 1.21-1.93) compared to men in large-sized workplaces with ≥50 employees. After mutual adjustment for all working history items, only the association between small workplaces and IADL decline remained significant in men (OR 1.37; 95% CI, 1.03-1.84). Among women, none of the working history items were associated with IADL decline. CONCLUSION: Our results suggest that not only promoting older people's workforce participation, but also providing workers employed at small workplaces with sufficient occupational health services, may be effective in helping men retain IADL in later life.

Cross-Sectional Association Between Types of Leisure Activities and Self-rated Health According to Gender and Work Status Among Older Japanese Adults.

BACKGROUND: Participation in leisure activities (LA) is essential for successful aging. Our aim was to investigate the cross-sectional association of types of LA with self-rated health (SRH) by gender and work status. METHODS: The target population was all residents aged ≥65 years in a municipality (n = 16,010; response rate, 62.5%). We analyzed 4,044 men and 4,617 women without disabilities. LA were categorized into 14 types. SRH was assessed through the SF-8. Excellent or very good SRH was defined as positive SRH. Covariates included age, marital status, education, subjective economic status, body mass index, chronic diseases, alcohol, smoking, walking time, depression, and cognitive functioning. Multiple logistic regressions were used to calculate the odds ratio (OR) and 95% confidence interval (CI) for positive SRH, with non-participation as the reference. RESULTS: After adjustment for covariates and mutual adjustment for other LA, participation in the following types of LA was positively associated with positive SRH: sports activities among working men (OR 1.46; 95% CI, 1.07-2.00), non-working men (OR 1.33; 95% CI, 1.04-1.69), and non-working women (OR 1.74; 95% CI, 1.41-2.15); cooking among non-working men (OR 1.65; 95% CI, 1.18-2.33) and non-working women (OR 1.28; 95% CI, 1.03-1.60); musical activities among working men (OR 1.44; 95% CI, 1.01-2.05) and non-working women (OR 1.59; 95% CI, 1.29-1.95); and technology usage only among working men (OR 1.41; 95% CI, 1.01-1.96). In contrast, TV watching was negatively associated with positive SRH among non-working women (OR 0.69; 95% CI, 0.56-0.85). CONCLUSIONS: Our results suggest that encouraging older adults to participate in types of LA appropriate to their gender and work status might be a key to positive SRH.