Validation of a brief seven-item response bias-free geriatric depression scale.

OBJECTIVE: Shortened versions of various depression scales have typically been based on conventional techniques such as factor analysis, without simultaneously considering the removal of culturally biased items that show differential item functioning (DIF). The authors recently showed that eight items in the 15-item Geriatric Depression Scale (GDS-15) evidenced DIF, associated with gender, age, ethnicity, and chronic illnesses. By selecting out these items, the authors derived a shortened 7-item GDS and compared it with derivations based on conventional factor analysis and logistic regression techniques and validated its test performance in Asian elderly. METHODS: The GDS-15 and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of major depressive disorder (MDD) was independently administered by interviewers to 4,253 noninstitutionalized community-living elderly subjects aged 60 years and older. Concurrent methods of data reduction and item selection included factor analyses and logistic regression modeling. The GDS-7 was compared with GDS-15 test performance using Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders diagnosis of MDD as gold standard criterion and receiver operating characteristics analysis. RESULTS: After removal of eight DIF items, the derivation was consistent with and complements the results from factor analysis and logistic regression analyses. The short GDS-7 fit a unidimensional model with high explained total variance and demonstrated high sensitivity (0.93) and specificity (0.91) at a cutoff of one-half that was comparable with GDS-15. CONCLUSIONS: By removing items with culturally based response bias, the GDS-7 showed excellent scaling and test performance for screening MDD in an Asian elderly population.

Determinants of successful aging using a multidimensional definition among Chinese elderly in Singapore.

OBJECTIVE: Most studies of successful aging have used restricted definitions based on the absence of disability and identified a small number of predictors. The authors aimed to examine whether a broad multidimensional definition of successful aging has good construct validity and identified a wider range of predictors that are relevant for multifaceted interventions. METHODS: Cross-sectional and longitudinal data analyses were performed on 1,281 community-living Chinese elderly of 65 years and above in the Singapore Longitudinal Aging Study cohort. Successful aging was measured in multiple dimensions of functioning and wellness: cognitive and affective status, physical health, social functioning and engagement and life satisfaction, and a summary composite measure created across dimensions to form a dichotomous variable. Potential determinants included sociodemographic, psychosocial, behavioral variables. RESULTS: Successful aging was determined in 28.6% of respondents and in multivariate models was significantly (p <0.05) associated with age (OR = 0.90), female gender (OR = 1.37), > or =6 years of education (OR = 2.31), better housing (OR = 1.41), religious or spiritual beliefs (OR = 1.64), physical activities and exercise (OR = 1.90), and low or no nutritional risk (OR = 2.16). CONCLUSION: In contrast to findings based on more restricted biomedical definitions of successful aging, a multidimensional definition of successful aging identified more variables including demographic status, psychosocial support, spirituality, and nutrition as salient determinants.

Diagnostic accuracy of anthropometric indices for obesity screening among Asian adolescents.

INTRODUCTION: Weight-and-height-based anthropometric indices have long been used for obesity screening among adolescents.However, the ability of their age-and-sex-specific reference values in classifying adolescent as "obese" in different populations was not fully established. Our study aimed to validate the existing international (BMI-for-age charts from WHO, CDC, IOTF) and local cut-offs [percent weight for height (PWH)] for obesity against body fat percentage, as assessed by 4 skinfolds measurement. MATERIALS AND METHODS: A cross-sectional sample of 6991 adolescents aged 12 to 18 years was measured. All anthropometric measurements were compliant with the internationally accepted protocol. Obesity was defined as percentage body fat greater than or equal to 95 percentile, specific to age and sex. The validity of the existing classification criteria in detecting obesity was evaluated by comparing their respective diagnostic accuracy. RESULTS: Both prevalence of obesity and diagnostic accuracy indices varied by the classification criteria. While all criteria generated very high specificity rates with the lowest being 95%, their sensitivity rates were low ranging from 43% to 71%. Youden's index suggested that CDC and WHO criteria had optimal sensitivity and specificity. ROC analysis showed that overall performance could be improved by refining the existing cut-offs. CONCLUSIONS: Clinical validity of weight-and-height-based classification systems for obesity screening in Asian adolescents is poorer than expected, and this could be improved by refining the existing cut-offs.

Physical, social and productive leisure activities, cognitive decline and interaction with APOE-epsilon 4 genotype in Chinese older adults.

BACKGROUND: We evaluated the combined and differential effects of physical, social and productive activities on cognitive decline and whether they were modified by the presence of the APOE-epsilon 4 allele. METHODS: In a prospective cohort study of 1635 community-dwelling Chinese older adults aged 55 or older participating in the ongoing Singapore Longitudinal Aging Study, physical, social and productive leisure activities were assessed at baseline, and cognitive decline (at least one point drop) in MMSE scores between baseline and follow-up after one year. RESULTS: Cognitive decline was observed in 30% of the respondents. Controlling for age, gender, education and other risk factors, odds ratios (ORs) were significantly reduced in those with medium (OR: 0.60, 95% CI: 0.45-0.79) and high activity levels (OR: 0.62, 95% CI: 0.46-0.84). A stronger association was shown for productive activity (OR = 0.36), than for physical (OR = 0.78) and social activities (OR = 0.85). These associations showed statistically significant interactions with APOE genotype, being more pronounced in those with the APOE-epsilon 4 allele. CONCLUSION: Increased leisure activity, especially productive activities more than physical or social activities, was associated with a lowered risk of cognitive decline. APOE-epsilon 4 genotype individuals appeared to be more vulnerable to the effects of low and high levels of leisure activities.

Body mass index, waist circumference, waist-hip ratio and depressive symptoms in Chinese elderly: a population-based study.

BACKGROUND: Studies that investigated the relationship between obesity and depressive symptoms in the elderly have generated conflicting findings, partly because of the use of body mass index (BMI) alone to measure obesity in the elderly. The use of BMI fails to account for varying proportions of muscle, fat and bone, and few studies have used other measures of central obesity, such as waist-hip ratio (WHR) and waist circumference (WC). OBJECTIVES: We examined whether individually BMI, WHR and WC were consistently associated with depressive symptoms in the elderly. METHODS: Analysis of cross-sectional data of 2604 community dwelling Chinese elderly aged 55 and above, including socio-emotional characteristics, self-rated health and functional status, anthropometric measurements and Geriatric Depression Scale (15 items, GDS-15). RESULTS: There was a negative trend in the prevalence of depressive symptoms (GDS > or =5) across increasing BMI categories: 16.9% in low BMI, 14.2% in normal weight, 12.1% in moderate to high BMI. The associations for moderate to high BMI (OR, 0.77; p = 0.04) relative to normal BMI, were statistically significant after controlling for confounding variables. However, no consistent trends in the prevalence of depressive symptoms and OR's were observed for increasing WHR and WC categories. CONCLUSION: Our results suggest that waist-hip and circumference measures of central obesity did not support an inverse relationship of obesity and depressive symptoms. An inverse relationship of BMI with depressive symptoms may indicate greater physiologic and functional reserve from greater muscle mass that protects against depressive symptoms.

Depression and chronic medical illnesses in Asian older adults: the role of subjective health and functional status.

OBJECTIVE: Depression in elderly is reportedly associated with a number of specific chronic illnesses. Whether each of these co-morbid associations results uniquely from disease-specific psychobiological responses or is mediated by non-specific factors like subjective health and functional status is unclear. METHOD: Analysis of data of 2,611 community-dwelling Chinese aged 55 and older, including depressive symptoms defined by Geriatric Depression Scale score >or= 5 and self-reports of specific chronic illnesses. RESULTS: The prevalence of depressive symptoms was 13.3%, lower in those without chronic illness (7.5%), and higher in those with illnesses (13.2-24.2%). Crude Odds Ratios (OR) were significantly elevated for hypertension, eye disorders, diabetes, arthritis, ischemic heart disease, asthma/COPD, stroke, osteoporosis, heart failure, thyroid problem, and gastric problem. In multivariable analyses, only asthma/COPD [OR:2.85, 95% Confidence Intervals (CI): 1.36, 5.98], gastric problem (OR:2.64, 95% CI: 1.11, 6.29), arthritis (OR:1.87, 95% CI: 1.02, 3.42) and heart failure (OR:2.11, 95% CI: 0.98, 4.58) remained independently associated with depressive symptoms, after adjusting for comorbidities, subjective health and functional status, cognitive functioning, smoking, alcohol, psychosocial and demographic variables. CONCLUSION: Most comorbid associations of depressive symptoms with specific chronic illnesses are explained by accompanying poor self-reported health and functional status, but some illnesses probably have a direct psychobiological basis.

Ethnic and educational differences in cognitive test performance on mini-mental state examination in Asians.

OBJECTIVE: The objective of this study is to examine ethnic differences in Mini-Mental State Examination (MMSE) test performance in discriminating between demented and nondemented elderly Asians. METHODS: A nationally representative population sample (N = 1,092) of community-living elderly, comprising Chinese, Malays, and Indians in Singapore, was interviewed using MMSE, Geriatric Mental State, and demographic and health questionnaires. RESULTS: There were significant ethnic differences in mean MMSE scores among Chinese (26.2), Indians (25.0), and Malays (23.6), but only in noneducated subjects. No ethnic differences in MMSE were observed in higher educated subjects. The sample proportion of subjects with dementia was 4.2% in Chinese, 9.4% in Malays, and 8.8% in Indians. Overall, MMSE discriminated well between subjects with and without dementia (cutoff: 23/24, area under the curve: 95%, sensitivity: 97.5%, specificity: 75.6%). MMSE test performance was much better in higher educated subjects (higher specificity: 85.2%). Lower specificities were shown in less educated subjects (57.3%), and in Malays (62.8%), and especially in less educated Malays (35.3%) and Indians (50.0%). Significant differences in MMSE scores in less educated subjects persisted after adjusting for differences in sociodemographic, health, and behavioral variables CONCLUSION: Ethnic nonequivalence in MMSE test performance should be taken into account in dementia screening in Asians in less educated subjects. Known correlates of cognitive functioning did not sufficiently explain these differences.

Validation of the English version of the Asthma Quality of Life Questionnaire in a multi-ethnic Asian population.

The purpose of study was to assess the validity, reliability and acceptability of the English version of the Asthma Quality of Life Questionnaire in a multi-ethnic Asian population. The English version of the Standardized Asthma Quality of Life Questionnaire (AQLQ-S) and the Asthma Control Questionnaire (ACQ) were self-completed by 119 English-speaking Chinese, Malay and Indian asthmatic subjects, aged 17-78. Spirometric measurements, peak expiratory flow rate, current clinical symptoms and treatment requirements were documented. Reliability and responsiveness were analyzed in a subgroup of 57 patients who were reassessed 6 weeks later. The Cronbach alpha reliability coefficient for internal consistency of the AQLQ-S was 0.97 (0.96-0.98) for the overall score. The intraclass correlation coefficient (ICC) overall score was 0.97 (95% CI: 0.94-0.99) while the responsiveness index was 1.29 with strong longitudinal validity for clinical and spirometric measures of asthma severity and asthma control score (p < 0.001). The results of this study showed that the English version of the AQLQ-S is a sensitive and valid instrument for measuring health-related quality of life in asthmatic subjects from a multi-ethnic Asian population.