Joint impact of common risk factors on incident dementia: A cohort study of the Swedish Twin Registry.

BACKGROUND: As common risk factors of dementia, nine factors (low education, hearing loss, obesity, hypertension, smoking, depression, physical inactivity, diabetes and social isolation) were proposed. However, the joint impact of these factors on incident dementia is still uncertain; hence, we aimed to examine this impact. METHODS: We conducted a cohort study of 9017 cognitively intact individuals aged ≥ 65 years in the Swedish Twin Registry. The main exposure was the total number of reported risk factors (ranging from 0 to 9). Data on dementia diagnoses were based on clinical workup and national health registers. After estimating the adjusted hazard ratios of incident dementia, the population attributable fraction (PAF) was calculated. We then conducted additional analyses, including APOE ε4 status in a genotyped subsample (n = 2810) to check the relative impact of the main exposure and discordant twin pair (n = 1158) analysis to consider confounding by familial effects (shared genetic or familial environmental factors). RESULTS: The number of dementia cases was 1950 (21.6%). A dose-response relationship between the number of risk factors and incident dementia was observed; hazard ratio (95% confidence interval) per one-unit increment in number of risk factors was 1.07 (1.03 to 1.11). The PAF for the combination of the nine risk factors was 10.4%. The PAF of all nine risk factors was smaller than that of APOE ε4 genotype (20.8%) in the subsample. Discordant pair analysis suggested that the observed association was not likely explained by familial effects. CONCLUSION: The nine risk factors may have considerable impact as modifiable factors on incident dementia.

Maximum Occlusal Force and Incident Functional Disability in Older Adults: The Tsurugaya Project.

The purpose of the current study was to investigate the association between maximum occlusal force, which is an objective predictor of masticatory performance, and incident functional disability in an elderly Japanese population. A prospective cohort study was conducted targeting 815 (51.7% female) community-dwelling older adults aged ≥70 y residing in the Tsurugaya district, Sendai, Japan. The outcome measurement was incident functional disability, defined as a first certification of long-term care insurance in Japan, which is determined on the basis of a strictly established, uniform, nationwide standard. During a median follow-up of 7.9 y (interquartile range, 4.8-7.9 y), information on long-term care insurance was obtained from the Sendai Municipal Authority. Bilateral maximum occlusal forces of the participants were measured using a horseshoe-shaped pressure-indicating film, and the participants were categorized into quartiles based on occlusal force. Adjusted hazard ratios for functional disability were estimated with Cox proportional hazard models, adjusted for age, sex, body mass index, medical history, smoking status, alcohol consumption, duration of education, depressive symptoms, cognitive impairment, physical functioning, marital status, history of falls, and number of remaining teeth. The multiple-adjusted hazard ratios and 95% confidence intervals (CIs) for incident functional disability compared to the greatest occlusal force quartile were 1.53 (95% CI, 1.02-2.33), 1.64 (95% CI, 1.06-2.55), and 1.64 (95% CI, 1.01-2.68) for the third, second, and first quartiles, respectively ( P for trend = 0.011). A lower maximum occlusal force was significantly associated with an increased risk of functional disability independently of possible confounders, including the number of remaining teeth. Occlusal force may be a useful indicator of the relationship between oral function and geriatric health. Knowledge Transfer Statement:This prospective cohort study demonstrated that lower maximum occlusal force was associated with an increased risk of functional disability in older adults, even after adjustment for possible confounding factors, including the number of remaining teeth. This strengthens the rationale regarding the association between oral function and geriatric health. Particularly in older adults, occlusal force is reduced by several factors other than tooth loss, such as the absence of a dental prostheses, sarcopenia in the masticatory muscle, poor periodontal condition, and orofacial pain. Our findings suggest that maximum occlusal force may be a useful biomarker associated with diverse parameters aside from the number of remaining teeth.

High circulating adiponectin levels predict decreased muscle strength among older adults aged 70 years and over: A prospective cohort study.

BACKGROUND AND AIMS: Population-based researches indicate that circulating adiponectin is inversely associated with muscle strength. However, interpretation of the findings has been limited by the use of a cross-sectional design. This study aimed to examine the prospective relationship between baseline circulating adiponectin concentration and change in muscular function-related physical performance in older adults. METHODS AND RESULTS: A 1-year prospective cohort study of Japanese community-dwelling elderly was conducted between 2002 and 2003. Four hundred thirty-four older persons participated in the measurements of physical function, including leg extension power, functional reach, timed up-and-go test, and 10-m maximum walking speed, at baseline and follow-up. After adjustment for potential covariates, higher serum adiponectin concentration was found to be significantly associated with poorer physical performance at baseline (leg extension power [watt], P < 0.001; functional reach [cm], P < 0.001; log timed up-and-go test, P = 0.007; log 10-m maximum walking speed, P < 0.001). The results of the prospective analysis by analysis of covariance indicated that the elderly with higher serum adiponectin concentrations (tertiles) at baseline tended to have a decreased performance in leg extension power (means [95% confidence interval]: lowest, -105 [-125, -85.7]; middle, -117 [-135, -97.8]; highest, -140 [-160, -120], watt, P for trend = 0.021) and timed up-and-go test (lowest, -0.08 [-0.28, -0.12]; middle, -0.10 [-0.29, 0.10]; highest, 0.28 [0.07, 0.48], s, P for trend = 0.019), but not two other functioning. CONCLUSION: High circulating adiponectin concentration may be an indicator of decreased physical performance, especially muscle strength, in older adults.

Coffee consumption and the risk of prostate cancer: the Ohsaki Cohort Study.

BACKGROUND: Epidemiological evidence regarding the effect of coffee on the incidence of prostate cancer is inconsistent. We aimed to investigate coffee consumption and the risk of prostate cancer risk in a general Japanese population. METHODS: We conducted a prospective cohort study in Ohsaki city, Japan, where 18 853 men aged 40-79 years participated in a baseline survey. Coffee consumption was assessed via a validated self-administered questionnaire. During 11 years of follow-up (from January 1 1995 to December 31, 2005), 318 incident cases of prostate cancer were detected. The Cox proportional hazards regression model was used to calculate the hazard ratios (HRs) and 95% confidence interval (CIs). RESULTS: There was a significant inverse association between coffee consumption and the incidence risk of prostate cancer. Compared with those who did not drink coffee, the multivariate adjusted HRs were 0.81 (95% CI: 0.61-1.07), 0.73 (95% CI: 0.53-1.00), and 0.63 (095% CI: 0.39-1.00) for those who drank coffee occasionally, 1-2 cups per day, and > or =3 cups per day, respectively, with a P for trend of 0.02. CONCLUSION: This prospective finding from a Japanese population adds evidence that coffee intake is inversely associated with the incidence of prostate cancer.