Browsing by Author "Chei, Choy-Lye"
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Item Open Access A Smartphone Application to Deliver a Treat-to-Target Insulin Titration Algorithm in Insulin-Naive Patients With Type 2 Diabetes: A Pilot Randomized Controlled Trial.(Diabetes Care, 2016-10) Bee, Yong Mong; Batcagan-Abueg, Ada Portia M; Chei, Choy-Lye; Do, Young Kyung; Haaland, Benjamin; Goh, Su-Yen; Lee, Phong Ching; Chiam, Priscilla Pei Sze; Ho, Emily Tse Lin; Matchar, David BItem Open Access A U-shaped Association Between Blood Pressure and Cognitive Impairment in Chinese Elderly.(Journal of the American Medical Directors Association, 2017-02) Lv, Yue-Bin; Zhu, Peng-Fei; Yin, Zhao-Xue; Kraus, Virginia Byers; Threapleton, Diane; Chei, Choy-Lye; Brasher, Melanie Sereny; Zhang, Juan; Qian, Han-Zhu; Mao, Chen; Matchar, David Bruce; Luo, Jie-Si; Zeng, Yi; Shi, Xiao-MingObjectives
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.Item Open Access Associations between superoxide dismutase, malondialdehyde and all-cause mortality in older adults: a community-based cohort study.(BMC geriatrics, 2019-04-15) Mao, Chen; Yuan, Jin-Qiu; Lv, Yue-Bin; Gao, Xiang; Yin, Zhao-Xue; Kraus, Virginia Byers; Luo, Jie-Si; Chei, Choy-Lye; Matchar, David Bruce; Zeng, Yi; Shi, Xiao-MingBackground
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.Item Open Access 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.(Atherosclerosis, 2015-03) Lv, Yue-Bin; Yin, Zhao-Xue; Chei, Choy-Lye; Qian, Han-Zhu; Kraus, Virginia Byers; Zhang, Juan; Brasher, Melanie Sereny; Shi, Xiao-Ming; Matchar, David Bruce; Zeng, YiObjective
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.Item Open Access Older person behavioral and psychological symptoms (BPS) and functional limitations mediate the association between older person cognitive impairment and depressive symptoms in the caregiver.(Archives of gerontology and geriatrics, 2014-03) Malhotra, Rahul; Chei, Choy-Lye; Østbye, Truls; Chan, Angelique; Matchar, David BWe assess for the mediation of the association between older person cognitive impairment and caregiver depressive symptoms through older person BPS and functional limitations, and whether the mediation varies by caregiver-older person relationship (spouse/adult child). Data for 1111 older person (aged 75+ with activity of daily living (ADL) limitation)-caregiver dyads from Singapore were used. The outcome variable was dichotomous (caregiver clinically significant depressive symptoms [CSDS]: yes/no) in the primary analysis and continuous (caregiver depressive symptoms score) in the sensitivity analysis. The causal steps approach assessed for the mediation of the association between older person cognitive impairment (yes/no) and the outcome variable through the two potential mediators. A bootstrapping approach calculated point estimates and confidence intervals (CIs) of the indirect (∼mediated) effects. Variation of the indirect effects by caregiver-older person relationship was also assessed. In the primary analysis, the causal steps approach supported older person BPS and functional limitations as mediators. The bootstrapping approach confirmed both as significant mediators, though BPS (indirect effect odds ratio (OR) 1.32 [95% bootstrap CI 1.19,1.48]; %mediation: 70.6%) was a stronger mediator than functional limitations (1.04 [1.01,1.11]; %mediation: 11.5%). Variation of the indirect effects by caregiver-older person relationship was not supported. Results of the sensitivity analysis confirmed these results. We conclude that while caring for an older person with cognitive impairment is detrimental for the caregiver's mood, management of associated BPS and functional limitations, especially the former, among such older persons may reduce depressive symptoms among their caregivers. Spouse as well as adult child caregivers benefit.Item Open Access Presence of and correction for interviewer error on an instrument assessing cognitive function of older adults.(Geriatrics & gerontology international, 2015-03) Malhotra, Rahul; Haaland, Benjamin A; Chei, Choy-Lye; Chan, Angelique; Malhotra, Chetna; Matchar, David BAim
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.Item Open Access Prevalence and Risk Factors of Atrial Fibrillation in Chinese Elderly: Results from the Chinese Longitudinal Healthy Longevity Survey.(Chinese medical journal, 2015-09) Chei, Choy-Lye; Raman, Prassanna; Ching, Chi Keong; Yin, Zhao-Xue; Shi, Xiao-Ming; Zeng, Yi; Matchar, David BBackground
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.Item Open Access Short-Term Trajectories of Depressive Symptoms in Stroke Survivors and Their Family Caregivers.(Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 2016-01) Malhotra, Rahul; Chei, Choy-Lye; Menon, Edward; Chow, Wai Leng; Quah, Stella; Chan, Angelique; Matchar, David BruceGoal
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.Item Open Access Trajectories of positive aspects of caregiving among family caregivers of stroke-survivors: the differential impact of stroke-survivor disability.(Topics in stroke rehabilitation, 2018-05) Malhotra, Rahul; Chei, Choy-Lye; Menon, Edward Balan; Chow, Wai-Leng; Quah, Stella; Chan, Angelique; Ajay, Shweta; Matchar, David BruceObjective 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.Item Open Access Vitamin D levels and cognition in elderly adults in China.(Journal of the American Geriatrics Society, 2014-11) Chei, Choy-Lye; Raman, Prassanna; Yin, Zhao-Xue; Shi, Xiao-Ming; Zeng, Yi; Matchar, David BObjectives
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.Item Open Access Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey.(The journals of gerontology. Series A, Biological sciences and medical sciences, 2016-10) Matchar, David B; Chei, Choy-Lye; Yin, Zhao-Xue; Koh, Victoria; Chakraborty, Bibhas; Shi, Xiao-Ming; Zeng, YiBackground
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.