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BackgroundAlthough 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.MethodsWe 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.ResultsThe 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 ConclusionsOur 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.

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.

To determine whether there is a significant association between prior cataract surgery and cognitive function in an elderly Japanese cohort.Nara Medical University, Nara, Japan.The Fujiwara-kyo Eye Study was a cross-sectional epidemiological study.The subjects were ≥ 68-years who lived in the Nara Prefecture and responded to recruitment notices. All of the subjects received comprehensive ophthalmological examinations, and answered questionnaires on their socio-demographic and medical history including prior cataract surgery. The association between prior cataract surgery and cognitive function was determined.A total of the 2764 subjects whose mean age was 76.3±4.8 years (±standard deviation) was studied. Of these, 668 individuals (24.2%) had undergone cataract surgery. Of these, 150 (5.4%) had dementia as determined by the Mini-Mental State Examination (MMSE) score ≤23, and 877 individuals (31.7%) had mild cognitive impairment (MCI; MMSE score 24-26). The subjects who had prior cataract surgery had significantly lower odds ratio (OR) of having MCI (OR = 0.78, 95% confidence interval; CI 0.64-0.96, P = 0.019) than those who had not had cataract surgery after adjusting for age, sex, body mass index, education, hypertension, diabetes, depression, and history of stroke. The OR was still lower when the visual acuity was also added to the adjusted factors (OR 0.79, 95% CI 0.64-0.97, P = 0.025). However, prior cataract surgery did not contribute significantly to the low OR for dementia.Cataract surgery may play a role in reducing the risk of developing MCI independently of visual acuity but not for dementia.

BACKGROUND:Although social participation (SP) is valid in active aging, it is vague which types and the frequency of SP are effective in maintaining instrumental activities of daily living (IADL). We conducted a community-based prospective cohort study and investigated the association of the types and frequency for SP with IADL decline in community-dwelling older adults. METHODS:The target population were all individuals aged ≥65 living in a commuter town in Nara, Japan. A total of 6,013 participants with independent IADL at baseline were analyzed. IADL was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Six SP types were assessed: volunteer groups, sports groups, hobby clubs, senior citizens' clubs, neighborhood community associations, and cultural clubs. The frequency of SP was categorized into frequent (i.e., weekly or more), moderate (i.e., monthly or yearly), and non-participation. Using multiple logistic regression models, the odds ratio (OR) and a 95% confidence interval (CI) for IADL decline were calculated. Covariates included age, marital status, education, subjective economic status, work status, body mass index, chronic medical conditions (i.e., hypertension, diabetes mellitus, heart disease, and cerebrovascular disease), lifestyle factors (i.e., alcohol, smoking, and exercise), self-rated health, depression, and cognitive functioning. To examine gender differences, stratified analyses by gender were performed. RESULTS:During the 33-month follow-up, 16.4% of men and 8.7% of women exhibited IADL decline. After adjustment for all covariates, compared to those who never participated, women with moderate participation had significantly lower odds of IADL decline in volunteer groups (OR = 0.53, 95% CI = 0.31-0.88), hobby clubs (OR = 0.55, 95% CI = 0.38-0.79), neighborhood community associations (OR = 0.58, 95% CI = 0.42-0.81), and cultural clubs (OR = 0.51, 95% CI = 0.31-0.82), and women with frequent participation had lower odds of IADL decline in hobby clubs (OR = 0.63, 95% CI = 0.43-0.93). In contrast, among men, the significant association between SP and less risk of IADL decline was limited to moderate participation in neighborhood community associations (OR = 0.79, 95% CI = 0.63-0.99), and there were no differences between frequent participation and non-participation in all types of SP. Regarding volunteer groups, compared to women with frequent participation, women with moderate participation had a significantly lower risk of IADL decline (OR = 0.37, 95% CI = 0.18-0.77). The results of additional stratified analyses by self-rated health, depression, and cognitive functioning showed that the associations of the type and frequency of SP with IADL decline varied according to physical and mental functioning. CONCLUSIONS:Several types of SP have a favorable effect on IADL through moderate participation rather than frequent participation, and women with moderate participation in volunteer groups have a more beneficial effect on IADL than women with frequent participation. When advising community-dwelling older adults on SP for IADL maintenance, health professionals may need to take into account plateau effects, gender differences, and physical and mental functioning.

[This corrects the article DOI: 10.1371/journal.pone.0139065.].

We examined the association between a decline in effectance and social participation (SP) from the perspective of the number and the type of SP in a prospective cohort study.Included in this analysis were community-dwelling elderly aged ≥ 65 without dependency on the basic activities of daily living and reporting a perfect baseline effectance score (n = 4,588; mean age 72.8 ± 5.7). SP was categorized into 5 types: neighborhood associations, hobby groups, local event groups, senior citizen clubs, and volunteer groups. Effectance was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Using logistic regression analysis, odds ratio (OR) and a 95% confidence interval (CI) for a decline in effectance were calculated. Age, family, BMI, pensions, medical history, medications, alcohol, smoking, cognitive function, depression, social support, ADL, and IADL were used as covariates.During the 3-year follow-up, 17.8% of eligible participants reported a decline in effectance. After adjustment for covariates, participation in various groups was associated with the preservation of effectance for both genders. Regarding the type of SP, among females, participation in neighborhood associations (OR: 0.62, 95%CI: 0.48-0.81), hobby groups (0.58, 0.43-0.77), local event groups (0.63, 0.47-0.86), and volunteer groups (0.53, 0.35-0.82) was inversely associated with a decline in effectance. Among males, the beneficial effect was more likely limited to hobby groups (0.59, 0.43-0.81) and volunteer groups (0.57, 0.39-0.83).Our results suggest that participation in a variety of social groups is effective for maintenance of older people's effectance, while the beneficial effect of each type of SP on effectance is stronger for females than for males. Recommending community-dwelling elderly to participate in social groups appropriate for their gender may be effective for successful aging.

This study examined the factors related to intellectual activity in community-dwelling elderly persons.Self-administered questionnaires mailed to all people aged ≥65 years in a dormitory suburb in Japan (n = 15,210). The response rate was 72.2%. Analytical subjects (n = 8,910) were those who lived independently and completely answered questions about independent and dependent variables and covariates. Independent variables included psychosocial conditions (i.e., social activities, hobbies, and a sense that life is worth living (ikigai)), oral health (i.e., dental health behaviors and oral function evaluated by chewing difficulties, swallowing difficulties, and oral dryness), and dietary variety measured using the dietary variety score (DVS). A dependent variable was intellectual activity measured using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Covariates included age, gender, family structure, pensions, body mass index, alcohol, smoking, medical history, self-rated health, medications, cognitive function, depression, and falling. Logistic regression was used to estimate the odds ratio (OR) for poor intellectual activity.Poor intellectual activity was reported by 28.9% of the study population. After adjustment for covariates and independent variables, poor intellectual activity was significantly associated with nonparticipation in social activities (OR = 1.90, 95%CI = 1.61-2.24), having neither hobbies nor ikigai (3.13, 2.55-3.84), having neither regular dental visits nor daily brushing (1.70, 1.35-2.14), the poorest oral function (1.61, 1.31-1.98), and the lowest DVS quartile (1.96, 1.70-2.26).These results indicate that psychosocial conditions, oral health, and dietary variety are independently associated with intellectual activity in elderly persons. The factors identified in this study may be used in community health programs for maintaining the intellectual activity ability of the elderly.

Renal α-Klotho (α-KL) plays a fundamental role as a co-receptor for fibroblast growth factor 23 (FGF23), a phosphaturic hormone and regulator of 1,25(OH)2 vitamin D3 (1,25VitD3). Disruption of FGF23-α-KL signaling is thought to be an early hallmark of chronic kidney disease (CKD) involving reduced renal α-KL expression and a reciprocal rise in serum FGF23. It remains unclear, however, whether the rise in FGF23 is related to the loss of renal α-KL. We evaluated α-KL expression in renal biopsy samples and measured levels of several parameters of mineral metabolism, as well as soluble α-KL (sKL), in serum and urinary samples from CKD patients (n = 236). We found that although renal α-KL levels were significantly reduced and serum FGF23 levels were significantly elevated in early and intermediate CKD, serum phosphate levels remained within the normal range. Multiple regression analysis showed that the increases in FGF23 were significantly associated with reduced renal function and elevated serum phosphate, but were not associated with loss of renal α-KL. Moreover, despite falling renal α-KL levels, the increase in FGF23 enhanced urinary fractional excretion of phosphate and reduced serum 1,25VitD3 levels in early and intermediate CKD, though not in advanced CKD. Serum sKL levels also fell significantly over the course of CKD, and renal α-KL was a significant independent determinant of sKL. These results demonstrate that FGF23 levels rise to compensate for renal failure-related phosphate retention in early and intermediate CKD. This enables FGF23-α-KL signaling and a neutral phosphate balance to be maintained despite the reduction in α-KL. In advanced CKD, however, renal α-KL declines further. This disrupts FGF23 signaling, and serum phosphate levels significantly increase, stimulating greater FGF23 secretion. Our results also suggest the serum sKL concentration may be a useful marker of renal α-KL expression levels.

OBJECTIVE: The 15D is a self-administered questionnaire for assessment of health-related quality of life, which contains 15 questions with 5 response options each. This study was conducted to evaluate the reliability and validity of the Japanese 15D. METHODS: The subjects were 430 community-dwelling elderly people. Each item of the 15D was scored on a 5-point Likert scale, with level 1 being the best, score 1. Reliability was assessed by determination of the internal consistency and test-retest reliability. Criterion-based validity was assessed using the Japanese version of the Nottingham Health Profile (NHP) and Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG index). Acceptability was assessed by inquiring about the time required to complete the questionnaire and the burden felt in responding to it. RESULTS: The answers of 423 individuals who responded to all items were analyzed. The median time required to complete the questionnaire was 5.0 minutes, and the proportion of subjects who indicated that the questionnaire was easy to complete was 98.3%. The Cronbach's alpha coefficients for all 15 items in the 2 surveys were 0.793 and 0.792, respectively. The intraclass correlation coefficients for the 15 items ranged from 0.44 to 0.72. In the relationship between the 15D and the NHP, the correlation coefficients between the corresponding domains were higher than those between non-corresponding domains. The prevalence of disability in higher-level functional capacity was higher in the "level 2 to 5" group than in the "level 1" group. CONCLUSIONS: The Japanese version of the 15D showed sufficient internal consistency and moderate repeatability. Because of the short time required to complete the Japanese 15D and the significant relationships between the scores on the 15D and the NHP, and between the 15D and higher-level functional capacity, the acceptability and validity of the Japanese 15D were considered to be sufficient.