Isoflavone and soy food intake and risk of lung cancer in never smokers: report from prospective studies in Japan and China.

PURPOSE: Evidence from several cohorts has suggested that a higher intake of isoflavone is associated with lower risk of lung cancer in never smokers, but the association has not been investigated by histologic type of lung cancer. Adenocarcinoma is a common histologic type found in never smokers. We hypothesized that a higher intake of isoflavone is associated with a lower risk of lung adenocarcinoma among never smokers. Here, we examined the associations of isoflavone and soy food intake with lung cancer and its histologic types in never smokers. METHODS: We performed a pooled analysis using data from the Japan Public Health Center-based Prospective Study, Shanghai Women's Health Study and Shanghai Men's Study with 147,296 never smokers aged 40-74 years with no history of cancer. During 1,990,040 person-years of follow-up, 1247 lung cancer cases were documented. Dietary isoflavone and soy food intake were assessed using a food-frequency questionnaire. Multivariable Cox proportional hazards models assessed the associations between isoflavone and soy intake with incidence of lung cancer by histologic type. RESULTS: A higher intake of dietary isoflavone and soy food were associated with reduced risk of lung adenocarcinoma. The multivariable hazard ratios (HRs) (95% CI) of risk of lung adenocarcinoma for the highest versus lowest intakes of isoflavone and soy food were 0.74 (0.60-0.92) and 0.78 (0.63-0.96), respectively. The multivariable HRs of risk of lung adenocarcinoma associated with each 10 mg/day increase in isoflavone and each 50 g/day increase in soy food intake were 0.81 (0.70-0.94) and 0.84 (0.73-0.96), respectively. CONCLUSION: Higher intake of isoflavone and soy food was associated with lower risk of lung adenocarcinoma in never smokers.

Associations between superoxide dismutase, malondialdehyde and all-cause mortality in older adults: a community-based cohort study.

BACKGROUND: Oxidative stress is an important theory of aging but population-based evidence has been lacking. This study aimed to evaluate the associations between biomarkers of oxidative stress, including plasma superoxide dismutase (SOD) activity and malondialdehyde (MDA), with all-cause mortality in older adults. METHODS: This is a community-based cohort study of 2224 participants (women:1227, median age: 86 years). We included individuals aged 65 or above and with plasma SOD activity and/or MDA tests at baseline. We evaluated the hazard ratios (HRs) and 95% confidence intervals (CIs) by multivariable Cox models. RESULTS: We documented 858 deaths during six years of follow-up. There was a significant interaction effect of sex with the association between SOD activity and mortality (P < 0.001). Compared with the lowest quintile, the risk of all-cause mortality was inversely associated with increasing quintiles of plasma SOD activity in women(P-trend< 0.001), with adjusted HRs for the second through fifth quintiles of 0.73 (95% CI 0.53-1.02), 0.52(95% CI 0.38-0.72), 0.53(95% CI 0.39-0.73), and 0.48(95% CI 0.35-0.66). There were no significant associations between SOD activity and mortality in men (P-trend = 0.64), and between MDA and mortality in all participants (P-trend = 0.79). CONCLUSIONS: Increased activity of SOD was independently associated with lower all-cause mortality in older women but not in men. This epidemiological study lent support for the free radical/oxidative stress theory of aging.

Bilingual Text With or Without Pictograms Improves Elderly Singaporeans' Understanding of Prescription Medication Labels.

BACKGROUND AND OBJECTIVES: In Singapore, primarily English-language prescription medication labels challenge elderly Singaporeans, many of whom are unable to read English. We investigated whether bilingual text and pictograms can help them understand prescription medication labels. RESEARCH DESIGN AND METHODS: We randomized 1,414 elderly respondents of a national survey into four prescription medication labels: English-text; English-text-and-pictograms; Bilingual-text; and Bilingual-text-and-pictograms, which were similar except for the addition of another language and/or pictograms (International Pharmaceutical Federation, FIP). Respondents answered 16 label-related questions; an expert panel rated answers for correctness. Outcomes were (1) complete understanding (16 correct); (2) any understanding (≥1 correct); and (3) number of incorrect answers among those with any understanding. We evaluated associations of each prescription medication label (vs. English-text) with outcomes (1), (2), and (3) using logistic and negative binomial regression, respectively. RESULTS: The elderly respondents were similar across the four prescription medication labels (English-text, English-text-and-pictograms, Bilingual-text, Bilingual-text-and-pictograms), for which the proportions with outcomes (1) and (2) were (17.9%, 25.6%, 36.9%, 40.1%) and (50.4%, 62.6%, 75.9%, 76.5%), respectively. We observed statistically significant higher odds of outcomes (1) and (2) among those assigned the three labels (vs. English-text): English-text-and-pictograms, 1.96 and 2.51; Bilingual-text, 3.54 and 6.73; and Bilingual-text-and-pictograms, 4.51 and 7.93. Those assigned the three labels also had 0.94, 1.98, and 2.12 fewer outcome (3) on average (vs. English-text). DISCUSSION AND IMPLICATIONS: Adding bilingual text with or without pictograms on prescription medication labels considerably improved elderly Singaporeans' understanding of the labels, strongly suggesting its application in practice. Other issues in prescription medication labels design and content, including adapting FIP pictograms for elderly Singaporeans, warrant further investigation.

Serum Fatty Acid and Risk of Coronary Artery Disease　- Circulatory Risk in Communities Study (CIRCS).

BACKGROUND: Few prospective studies have explored the association between fatty acids (FA) and risk of CAD. Understanding of the role of each individual serum FA as a coronary risk or protective factor is still limited. The aim was to investigate which serum FA are associated with the incidence of CAD in Japanese subjects. Methods and Results: A prospective nested case-control study of 40-85-year-old Japanese subjects was undertaken using frozen serum samples collected from 12,840 participants who participated in cardiovascular risk surveys from 1984 to 1998 for 1 community and 1989-1997 for 2 other communities. Three control subjects per case were matched by sex, age, community, year of serum storage and fasting status. By 2005 we had identified 152 incident cases of CAD. Mean n-3-polyunsaturated and saturated FA did not differ between cases and controls, while mean n-6-polyunsaturated FA was higher in controls compared with cases. The multivariable OR of CAD for the highest vs. lowest quartiles of miristic acid (14:0), palmitic acid (16:0), palmitoleic acid (16:1), and linoleic acid (18:2) were 2.8 (95% CI: 1.5-5.2), 2.7 (95% CI: 1.4-5.5), 3.2 (95% CI: 1.7-6.1) and 0.4 (95% CI: 0.2-0.7), respectively. CONCLUSIONS: High serum miristic acid, palmitic acid and palmitoleic acid have an adverse effect, and high serum linoleic acid had a protective effect, on the risk of CAD.

Happy older people live longer.

Objective: research on the role of positive affect, such as happiness, on health outcomes is burgeoning. Within this context, evidence for an inverse effect of happiness on mortality is inconclusive. Furthermore, few studies link happiness with mortality among older people, and in Asian populations. We examine the association between happiness and all-cause mortality among older people in Singapore. Methods: data for 4,478 Singaporeans aged ≥60 years enrolled in a nationally-representative longitudinal survey (three waves: 2009; 2011; 2015) were utilised. Happiness, at baseline, in 2009, was measured using three positively-worded items from the Centre for Epidemiological Studies Depression Scale, and considered in two distinct ways in the analyses-continuous ('happiness score' [0-6]) and binary (happy [score = 6]/unhappy). All-cause mortality, until 31 December 2015, was assessed primarily using administrative databases, supplemented by data from survey waves 2 and 3. Multivariable Cox regression models assessed the association of 'happiness score' and the 'binary happiness variable' (separate models for each) with all-cause mortality. Results: the likelihood of all-cause mortality was lower by 9% (multivariable hazard ratio (HR) [95% confidence interval]: 0.91 [0.87-0.95]) for each unit increase in 'happiness score', and was 19% lower for happy, versus unhappy, older people (HR: 0.81 [0.68-0.97]). Conclusions: happiness is associated with reduced likelihood of all-cause mortality among older people in an Asian population, with the benefit observed even for incremental increases in happiness. Activities, policies and programs that maintain or improve happiness may be beneficial for a longer life among older people.

Trajectories of positive aspects of caregiving among family caregivers of stroke-survivors: the differential impact of stroke-survivor disability.

Objective To delineate positive aspects of caregiving trajectories among family caregivers of stroke-survivors and determine the impact of stroke-survivor disability, a time-varying factor, on the delineated trajectories. Methods In a longitudinal study, family caregivers of 173 stroke-survivors in Singapore were administered the Positive Aspects of Caregiving scale (PAC scale) thrice (baseline/3 months/6 months). Group-based trajectory modeling delineated positive aspects of caregiving trajectories and identified the impact of stroke-survivor disability on the trajectories. Results Two distinct positive aspects of caregiving trajectories, Persistently Low and Persistently High were delineated. Increase in stroke-survivor disability was associated with a significant downward shift (reduction in positive aspects of caregiving) of the Persistently Low trajectory and a significant upward shift (increase in positive aspects of caregiving) of the Persistently High trajectory. Older caregivers were more likely to follow the Persistently High trajectory. Conclusions Care professionals should be mindful of the heterogeneity in the longitudinal pattern of positive feelings resulting from care provision among family caregivers of stroke-survivors, and the differential impact of stroke-survivor disability on the pattern of positive feelings. Younger caregivers as well as family caregivers who have low positive feelings at the start of their caregiver journey and experience worsening functional disability of their care recipient (stroke-survivor) require greater attention and support.

Coffee, tea, caffeine, and risk of hypertension: The Singapore Chinese Health Study.

PURPOSE: The relationship between coffee and tea, and risk of hypertension remains controversial in Western populations. We investigated these associations in an Asian population. METHODS: The Singapore Chinese Health Study is a population-based prospective cohort that recruited 63,257 Chinese aged 45-74 years and residing in Singapore from 1993 to 1998. Information on consumption of coffee, tea, and other lifestyle factors was collected at baseline, and self-reported physician-diagnosed hypertension was assessed during two follow-up interviews (1999-2004, 2006-2010). RESULTS: We identified 13,658 cases of incident hypertension after average 9.5 years. Compared to those who drank one cup of coffee/day, the hazard ratios (HR) and 95% confidence intervals (CI) were 0.87 (0.83-0.91) for

A U-shaped Association Between Blood Pressure and Cognitive Impairment in Chinese Elderly.

OBJECTIVES: Higher or lower blood pressure may relate to cognitive impairment, whereas the relationship between blood pressure and cognitive impairment among the elderly is not well-studied. The study objective was to determine whether blood pressure is associated with cognitive impairment in the elderly, and, if so, to accurately describe the association. DESIGN: Cross-sectional data from the sixth wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) conducted in 2011. SETTING: Community-based setting in longevity areas in China. PARTICIPANTS: A total of 7144 Chinese elderly aged 65 years and older were included in the sample. MEASURES: Systolic blood pressures (SBP) and diastolic blood pressures (DBP) were measured, pulse pressure (PP) was calculated as (SBP) - (DBP) and mean arterial pressures (MAP) was calculated as 1/3(SBP) + 2/3(DBP). Cognitive function was assessed via a validated Mini-Mental State Examination (MMSE). RESULTS: Based on the results of generalized additive models (GAMs), U-shaped associations were identified between cognitive impairment and SBP, DBP, PP, and MAP. The cutpoints at which risk for cognitive impairment (MMSE <24) was minimized were determined by quadratic models as 141 mm Hg, 85 mm Hg, 62 mm Hg, and 103 mm Hg, respectively. In the logistic models, U-shaped associations remained for SBP, DBP, and MAP but not PP. Below the identified cutpoints, each 1-mm Hg decrease in blood pressure corresponded to 0.7%, 1.1%, and 1.1% greater risk in the risk of cognitive impairment, respectively. Above the cutpoints, each 1-mm Hg increase in blood pressure corresponded to 1.2%, 1.8%, and 2.1% greater risk of cognitive impairment for SBP, DBP, and MAP, respectively. CONCLUSION: A U-shaped association between blood pressure and cognitive function in an elderly Chinese population was found. Recognition of these instances is important in identifying the high-risk population for cognitive impairment and to individualize blood pressure management for cognitive impairment prevention.

Serum α-linolenic and other ω-3 fatty acids, and risk of disabling dementia: Community-based nested case-control study.

BACKGROUND & AIMS: It has been hypothesized that ω-3 polyunsaturated fatty acids have anti-atherosclerotic and neuronal protective functions and may benefit prevention of dementia, but the epidemiological evidence, especially for α-linolenic acid, is quite limited. The aim of this study was to examine whether serum ω-3 polyunsaturated fatty acids are associated with risk of dementia. METHODS: We performed an intracohort case-control study nested in a community-based cohort, the Circulatory Risk in Communities Study, involving 7586 Japanese individuals aged 40-74 years at the baseline period of 1984-1994. Omega-3 polyunsaturated fatty acid constituents (α-linolenic, eicosapentaenoic, and docosahexaenoic acids) in serum total lipid were measured in 315 cases of incident disabling dementia in the above-mentioned cohort between 1999 and 2004, and in 630 controls whose age, sex, area, and baseline year were matched with the cases. RESULTS: As we had postulated, serum α-linolenic acid was inversely associated with risk of disabling dementia: the multivariate odds ratios (95% confidence intervals) were 0.57 (0.39-0.85), 0.51 (0.34-0.76), and 0.61 (0.41-0.90) for persons with the second, third, and highest quartiles of serum α-linolenic acid, respectively, as compared with the lowest quartile (P for trend = 0.01). Associations of other ω-3 fatty acids with disabling dementia were not statistically significant. CONCLUSIONS: Serum α-linolenic acid was inversely associated with risk of disabling dementia. Although the causality needs to be confirmed by randomized control trials, we identified serum α-linolenic acid as a biomarker that predicts future dementia.

Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey.

BACKGROUND: Vitamin D has a neuroprotective function, potentially important for the prevention of cognitive decline. Prospective studies from Western countries support an association between lower vitamin D level and future cognitive decline in elderly people. No prospective study has examined this association in Asia. METHODS: This community-based cohort study of elderly people in China follows 1,202 cognitively intact adults aged ≥60 years for a mean duration of 2 years. Plasma vitamin D level was measured at the baseline. Cognitive state of participants was assessed using the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score <18. Cognitive decline was defined as ≥3 points decline from baseline. Multivariable logistic regression models were used to examine the association between quartiles of vitamin D levels with cognitive decline and incidence of cognitive impairment. RESULTS: Participants with low vitamin D level had an increased risk of cognitive decline. Compared with the highest quartile of vitamin D levels, the multivariable odds ratios (ORs; 95% confidence interval) for cognitive decline were 2.1 (1.3-3.4) for the second highest quartile, 2.2 (1.4-3.6) for the third highest quartile, and 2.0 (1.2-3.3) for the lowest quartile. The multivariable ORs of incident cognitive impairment for the second highest, third highest, and lowest versus highest quartiles of vitamin D levels were 1.9 (0.9-4.1), 2.6 (1.2-5.6), and 3.2 (1.5-6.6), respectively. CONCLUSIONS: This first follow-up study of elderly people, including the oldest-old, in Asia shows that low vitamin D levels were associated with increased risk of subsequent cognitive decline and impairment.

The relationship between sodium concentrations in spot urine and blood pressure increases: a prospective study of Japanese general population: the Circulatory Risk in Communities Study (CIRCS).

BACKGROUND: Although several cross-sectional and intervention studies showed that sodium intake or excretion was associated with blood pressure levels, no prospective study has examined the long-term association between sodium excretion in spot urine and blood pressure changes. METHODS: We conducted a prospective study of 889 normotensive subjects (295 men and 594 women, mean age 57.3 years) who underwent the baseline survey including spot urine test in 2005 and the follow-up survey in 2009 to 2011 (mean follow-up period: 5.8 years). We examined the association between sodium concentration in spot urine, a validated index of sodium excretion occurring over 24-h, and blood pressure changes between baseline and follow-up survey in all, non-overweight (body mass index(BMI) ≤ 25 kg/m(2)) and overweight normotensives. RESULTS: For all subjects, sodium concentrations in spot urine were not associated with either systolic or diastolic blood pressure changes. When stratified by BMI at baseline survey, sodium concentrations were positively associated with systolic blood pressure changes in non-overweight subjects, but not in overweight subjects. After adjustment for age, sex, BMI, alcohol intake status, current smoking and estimated glomerular filtration rate, the multivariable-adjusted mean values of the systolic blood pressure change among non-overweight subjects was +7.3 mmHg in the highest quartiles of sodium concentrations, while it was +3.9 mmHg in the lowest quartile (P for difference = 0.021, P for trend = 0.040). After further adjustment of baseline blood pressure levels, the association was slightly weakened; the multivariable-adjusted mean values of the systolic blood pressure changes were +7.0 mmHg and +4.2 mmHg (P for difference = 0.047, P for trend = 0.071). CONCLUSIONS: High sodium concentrations in spot urine were associated with subsequent systolic blood pressure increases among non-overweight normotensive individuals. (272 words).

Short-Term Trajectories of Depressive Symptoms in Stroke Survivors and Their Family Caregivers.

GOAL: We utilize group-based trajectory modeling (GBTM) to delineate depressive symptom trajectories among stroke survivor-caregiver dyads, to identify predictors of the delineated trajectories, and to assess the influence of time-varying covariates (stroke survivor depressive symptoms and functional disability, caregiver depressive symptoms, and foreign domestic worker [FDW] assistance) on the level of the depressive symptom trajectories. METHODS: Data on 172 stroke survivor-caregiver dyads in Singapore, for whom depressive symptoms were assessed thrice (baseline/3 months/6 months), were utilized. GBTM was applied to delineate depressive symptom trajectories, and to identify their predictors and time-varying covariates. FINDINGS: Three stroke survivor depressive symptom trajectories (low and decreasing [47.6%], low and increasing [43.1%], and high and increasing [9.3%]) and 2 caregiver depressive symptom trajectories (low and stable [71.5%] and high and decreasing [28.5%]) were delineated. Caregivers with chronic diseases were more likely (odds ratio [95% confidence interval]: 8.09[2.04-32.07]) and those caring for older stroke survivors (0.94[0.90-0.98]) were less likely to follow the high and decreasing than the low and stable depressive symptom trajectory. An increase in stroke survivor functional disability and caregiver depressive symptoms led to a rise (~worsening) in stroke survivor depressive symptom trajectories. Whereas an increase in stroke survivor depressive symptoms led to a rise in caregiver depressive symptom trajectories, FDW assistance led to a decline (~improvement). CONCLUSION: Care professionals should be mindful of heterogeneity in depressive symptom patterns over time among stroke survivor-caregiver dyads. Reciprocal association of depressive symptoms in the stroke survivor-caregiver dyad suggests that addressing mood problems in 1 member may benefit the other member, and calls for dyadic mental health interventions.

Prevalence and Risk Factors of Atrial Fibrillation in Chinese Elderly: Results from the Chinese Longitudinal Healthy Longevity Survey.

BACKGROUND: Prevalence of atrial fibrillation (AF) is increasing as the world ages. AF is associated with higher risk of mortality and disease, including stroke, hypertension, heart failure, and dementia. Prevalence of AF differs with each population studied, and research on non-Western populations and the oldest old is scarce. METHODS: We used data from the 2012 wave of the Chinese Longitudinal Healthy Longevity Survey, a community-based study in eight longevity areas in China, to estimate AF prevalence in an elderly Chinese population (n = 1418, mean age = 85.6 years) and to identify risk factors. We determined the presence of AF in our participants using single-lead electrocardiograms. The weighted prevalence of AF was estimated in subjects stratified according to age groups (65-74, 75-84, 85-94, 95 years and above) and gender. We used logistic regressions to determine the potential risk factors of AF. RESULTS: The overall prevalence of AF was 3.5%; 2.4% of men and 4.5% of women had AF (P < 0.05). AF was associated with weight extremes of being underweight or overweight/obese. Finally, advanced age (85-94 years), history of stroke or heart disease, low high-density lipoprotein levels, low triglyceride levels, and lack of regular physical activity were associated with AF. CONCLUSIONS: In urban elderly, AF prevalence increased with age (P < 0.05), and in rural elderly, women had higher AF prevalence (P < 0.05). Further exploration of population-specific risk factors is needed to address the AF epidemic.

Low-density lipoprotein cholesterol was inversely associated with 3-year all-cause mortality among Chinese oldest old: data from the Chinese Longitudinal Healthy Longevity Survey.

OBJECTIVE: Low-density lipoprotein cholesterol (LDL-C) is a risk factor for survival in middle-aged individuals, but conflicting evidence exists on the relationship between LDL-C and all-cause mortality among the elderly. The goal of this study was to assess the relationship between LDL-C and all-cause mortality among Chinese oldest old (aged 80 and older) in a prospective cohort study. METHODS: LDL-C concentration was measured at baseline and all-cause mortality was calculated over a 3-year period. Multiple statistical models were used to adjust for demographic and biological covariates. RESULTS: During three years of follow-up, 447 of 935 participants died, and the overall all-cause mortality was 49.8%. Each 1 mmol/L increase of LDL-C concentration corresponded to a 19% decrease in 3-year all-cause mortality (hazard ratio [HR] 0.81, 95% confidence interval [CI] 0.71-0.92). The crude HR for abnormally higher LDL-C concentration (≥3.37 mmol/L) was 0.65 (0.41-1.03); and the adjusted HR was statistically significant around 0.60 (0.37-0.95) when adjusted for different sets of confounding factors. Results of sensitivity analysis also showed a significant association between higher LDL-C and lower mortality risk. CONCLUSIONS: Among the Chinese oldest old, higher LDL-C level was associated with lower risk of all-cause mortality. Our findings suggested the necessity of re-evaluating the optimal level of LDL-C among the oldest old.

Presence of and correction for interviewer error on an instrument assessing cognitive function of older adults.

AIM: To determine the extent of interviewer error on the Short Portable Mental Status Questionnaire (SPMSQ), the association between interviewer-level variables and SPMSQ score, compare the prevalence of SPMSQ cognitive status categories before and after correction for interviewer error, and identify SPMSQ items prone to interviewer error. METHODS: Data of 4542 older adults from a national survey in Singapore were utilized. Multilevel models, which adjusted for respondent-level variables known to be associated with cognitive status, were utilized to determine the intraclass correlation on the SPMSQ, association of interviewer-level variables (age, ethnicity, education and number of interviews carried out) with SPMSQ and identify SPMSQ items prone to interviewer error. RESULTS: The intraclass correlation, after adjusting for respondent-level variables, was 0.265. Interviewer educational status was associated with SPMSQ score. Correction for interviewer error resulted in an "improvement" in cognitive status of a substantial proportion of those initially classified as moderately or severely impaired. Two of the SPMSQ items, "Please count backward from 20 by 3" and "When were you born?" were particularly prone to interviewer error. CONCLUSIONS: Investigators using the SPMSQ, and potentially, other instruments, for assessing cognitive function in surveys of older adults and using face-to-face interviews for data collection should be cognizant of the sensitivity of such instruments to interviewer error. Intensive training of interviewers to standardize instrument administration as well as assessment for interviewer error and its correction, using appropriate statistical models, such as multilevel models, is warranted.

Serum coenzyme Q10 and risk of disabling dementia: the Circulatory Risk in Communities Study (CIRCS).

OBJECTIVE: To examine whether coenzyme Q10, a potent antioxidant, is associated with risk of dementia, which has not yet been elucidated. APPROACH AND RESULTS: We performed a case-control study nested in a community-based cohort of approximately 6000 Japanese aged 40-69 years at baseline (1984-1994). Serum coenzyme Q10 was measured in 65 incident cases of disabling dementia with dementia-related behavioral disturbance or cognitive impairment incident between 1999 and 2004, and in 130 age-, sex- and baseline year-matched controls. Serum coenzyme Q10 was inversely associated with dementia: the multivariate odds ratios (95% confidence intervals) were 0.68 (0.26-1.78), 0.92 (0.33-2.56), and 0.23 (0.06-0.86) for individuals with the second, third, and highest quartiles of coenzyme Q10, respectively, as compared with the lowest quartile (P for trend = 0.05). A similar association was found for the coenzyme Q10/total cholesterol ratio: the respective ORs were 0.67 (0.25-1.78), 0.73 (0.28-1.92), and 0.21 (0.05-0.90) (P for trend = 0.04). CONCLUSIONS: Serum coenzyme Q10 levels were inversely associated with risk of disabling dementia.

Vitamin D levels and cognition in elderly adults in China.

OBJECTIVES: To evaluate the association between vitamin D level and cognitive impairment in individuals aged 60 and older. DESIGN: Cross-sectional cohort study. SETTING: Chinese Longitudinal Healthy Longevity Survey, a community-based cohort study in areas in China where the density of centenarians is exceptionally high. PARTICIPANTS: Individuals with mean age of 84.9 ± 12.7 (N = 2,004). MEASUREMENTS: Participants' cognitive state was evaluated using the Mini-Mental State Examination (MMSE). Vitamin D was measured in plasma using an enzyme-linked immunoassay. RESULTS: The cross-sectional association between quartiles of plasma vitamin D level and cognitive impairment (MMSE score <18) was modeled using logistic regressions. Plasma vitamin D levels were lower in individuals with cognitive impairment (31.9 ± 15.3 nmol/L) than in those without (45.6 ± 19.6 nmol/L). There was a reverse association between plasma vitamin D and cognitive impairment. After adjusting for age, sex, chronic conditions, smoking and drinking habits, outdoor activities, depression, and activity of daily living limitations, the association remained significant. The multivariable-adjusted odds ratio for lowest versus highest vitamin D levels was 2.15 (95% confidence interval (CI) = 1.05-4.41) for cognitive impairment, and the multivariable odds ratio associated with a 1-standard deviation decrement in plasma vitamin D was 1.32 (95% CI = 1.00-1.74) for cognitive impairment. CONCLUSION: Low plasma vitamin D levels were associated with greater odds of cognitive impairment. Further prospective studies in Asian populations are needed to examine the causal direction of this association.

C-reactive protein levels and risk of disabling dementia with and without stroke in Japanese: the Circulatory Risk in Communities Study (CIRCS).

OBJECTIVE: Studies have shown that elevated high-sensitivity C-reactive protein (hs-CRP) predicts stroke, which is a risk factor for dementia. It remains, however, unclear whether hs-CRP increases risk of dementia. METHODS: A prospective nested case-control study of Japanese 40-69 years of age was conducted using frozen serum samples collected from approximately 7531men and women who participated in cardiovascular risk surveys from 1984 to 1994 in one community and 1989-1995 in another community under the Circulatory Risk in Communities Study (CIRCS). Two control subjects per case were matched by sex, age, community, and year of serum storage. The hs-CRP was measured using a latex particle-enhanced immunonephelometric assay. RESULTS: Between 1999 and 2013, we identified 275 disabling dementia cases (96 cases with history of stroke and 179 without it). There was a positive association between hs-CRP levels and risk of dementia with history of stroke. No significant association was observed between hs-CRP levels and risk of dementia without history of stroke. After adjustment for hypertension, diabetes and other confounding variables, the positive association remained statistically significant. The multivariable odds ratios associated with 1-SD increment of log hs-CRP were 1.02 (0.87-1.20) for total dementia, 1.35 (1.02-1.79) for dementia with history of stroke, and 0.89 (0.72-1.10) for dementia without history of stroke. CONCLUSION: Elevated hs-CRP levels were associated with increased risk of disabling dementia in individuals with history of stroke but not in those without it.