Tze Pin Ng

Determinants of Successful Aging Using a Multidimensional Definition Among Chinese Elderly in Singapore

OBJECTIVEnMost 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.nnnMETHODSnCross-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.nnnRESULTSnSuccessful 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).nnnCONCLUSIONnIn 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.

Continued work employment and volunteerism and mental well-being of older adults: Singapore longitudinal ageing studies

OBJECTIVEnto examine the effect of late life engagement in continued work involvement or volunteer activities during retirement on mental well-being.nnnMETHODSntwo waves of data from the Singapore Longitudinal Ageing Studies were analyzed for 2,716 Singaporeans aged 55 or above at baseline and 1,754 at 2-year follow-up. Trained research nurses interviewed participants (non-volunteering retiree, volunteering retiree, and working seniors) on mental health status (geriatric depression scale, Mini Mental State Examination, positive mental wellbeing and life satisfaction).nnnRESULTSnabout 88% of seniors were retired (78% non-volunteering, 10% volunteering) and 12% were still working in paid employment or business. At baseline and 2 year follow up, and regardless of physical health status, volunteering retirees and working seniors gave significantly better MMSE cognitive performance scores, fewer depressive symptoms, and better mental well-being and life satisfaction than non-volunteering retirees.nnnCONCLUSIONnthe results of this study suggest that continued work involvement or volunteerism provides opportunities for social interaction and engagement and may be associated with enhanced mental well-being. Future research should clarify which specific aspects of volunteerism are related to long-term mental well-being.

Anxiety and depression, chronic physical conditions, and quality of life in an urban population sample study

ObjectiveNo previous studies have empirically demonstrated a multiplicative interactive effect of anxiety disorders and/or depression (ADD) and chronic medical conditions on quality of life (QOL). We hypothesized that QOL impairment was worsened by the presence of ADD and medical co-morbidity, more than when it was with either medical co-morbidity alone or ADD alone.MethodsComplete data of 2,801 participants from the National Mental Health Survey of Adults in Singapore were analyzed, using SCAN diagnoses of anxiety disorders and depression, self-reports of chronic medical conditions, and SF-12 measures of QOL (Mental Component Summary, MCS, and Physical Component Summary, PCS).ResultsPersons diagnosed with ADD (compared to those without) had considerably more medical co-morbidities (59 vs. 33%, pxa0<xa00.001). In multiple regression analyses, ADD (vs. no ADD) was associated with lower PCS (bxa0=xa0−1.013, pxa0=xa00.045) and MCS scores (bxa0=xa0−9.912, pxa0<xa00.001), as was number of medical co-morbidities (0, 1–2, 3xa0+), PCS scores (bxa0=xa0−2.058, pxa0<xa00.001) and MCS scores (bxa0=xa0−1.138, pxa0<xa00.001). There were significant interactive effects of medical co-morbidities and ADD on PCS (pxa0<xa00.001), and MCS (pxa0=xa00.086), suggesting that the negative effects of medical conditions on quality of life was aggravated non-additively by the co-morbid presence of ADD, and vice versa.ConclusionThe individual effects of medical and psychiatric morbidity on functional status and quality of life were considerably worse when both were present in the same individual. Future studies should examine the impact of identifying and treating anxiety and depressive disorders in patients with medical problems for better outcomes.

Associations Between Elevated Homocysteine, Cognitive Impairment, and Reduced White Matter Volume in Healthy Old Adults

OBJECTIVESnElevated homocysteine has emerged as a risk factor for cognitive impairment even in healthy elderly persons. Reduced brain volume and white matter hyperintensities also occur in healthy elderly as well, but the interrelationships between these have not been well studied. We report these interrelationships in non demented, relatively healthy, community-dwelling older adults from a single East Asian population.nnnMETHODSnTwo hundred twenty-eight right-handed participants age 55 years and above were evaluated. Persons with medical conditions or neurological diseases other than well-controlled diabetes mellitus and hypertension were excluded. Participants underwent quantitative magnetic resonance imaging of the brain using a standardized protocol and neuropsychological evaluation. Plasma homocysteine, folate, vitamin B(12), and markers for cardiovascular risk: blood pressure, body mass index, fasting blood glucose, and lipid profile were measured.nnnRESULTSnElevated homocysteine was associated with reduced global cerebral volume, larger ventricles, reduced cerebral white matter volume, and lower cognitive performance in several domains. Elevated homocysteine was associated with reduced white matter volume (βxa0=xa0-20.80, txa0=xa0-2.9, dfxa0= 223, pxa0= 0.004) and lower speed of processing (βxa0=xa0-0.38, txa0=xa0-2.1, dfxa0= 223, pxa0= 0.03), even after controlling for age, gender, and education. However, the association between homocysteine and lower speed of processing disappeared after controlling for white matter volume. Elevated homocysteine was not associated with white matter hyperintensity volume or with hippocampal volume. Although homocysteine and folate levels were correlated, their effects on white matter volume were dissociated.nnnCONCLUSIONnIn non demented, relatively healthy adults, elevated homocysteine is associated with lower cognitive scores and reduced cerebral white matter volume. These effects can be dissociated from those related to white matter hyperintensities or reduced folate level.

A study of silica nephrotoxicity in exposed silicotic and non-silicotic workers.

The possible human nephrotoxicity of silica has often been suggested by previous anecdotal reports and uncontrolled clinical studies of silicotic patients. Urinary excretions of albumin, alpha-1-microglobulin (AMG), and beta-N-acetyl-glucosaminidase (NAG) were measured in 33 male workers exposed to silica (mean duration of employment 16 years) and 19 male age matched non-exposed subjects with no history of primary or secondary renal diseases. Significantly higher urinary excretions of albumin and AMG were found in the workers exposed to silica. Silicotic subjects (n = 7) also had significantly high excretions of albumin, AMG, and NAG. All but one of the silicotic patients had ceased exposure from three to 17 years before the study. Our findings suggest that prolonged exposure to silica is associated with chronic irreversible nephrotoxicity in exposed workers.

Adjunctive benzodiazepine treatment of hospitalized schizophrenia patients in Asia from 2001 to 2008

Benzodiazepines are commonly prescribed to patients with schizophrenia in many countries, but as little is known about such treatment in Asia, we evaluated their adjunctive use for 6761 in-patients diagnosed with schizophrenia in nine Asian countries using a cross-sectional study design in 2001, 2004 and 2008. Multivariate logistic regression and multivariate linear regression analyses were performed to assess predictors of benzodiazepine use and dose, respectively. Overall, 54% of the patients received adjunctive benzodiazepines at an average daily dose equivalent to 30.3 mg diazepam, with minor changes over the years sampled. Benzodiazepine use was highest in Taiwan and Japan, lowest in Thailand and China, and was associated with fewer years ill, presence of delusions (OR 1.24), hallucinations (OR 1.22), disorganized speech (OR 1.17), social or occupational dysfunction (OR 1.16), and use of mood stabilizers (OR 3.15), antiparkinsonian (OR 1.79) or antidepressant drugs (OR 1.33), and lower doses of antipsychotics (all p=0.016 to <0.001). Benzodiazepine doses were highest in Taiwan and China, lowest in Korea and Singapore; higher doses were associated with being young, male, physically aggressive, receiving mood stabilizers, and having electroconvulsive treatment (all p=0.019 to <0.001). Benzodiazepine use was associated with neurological and systemic adverse effects. In conclusion, benzodiazepine use was common in Asian patients with schizophrenia. Predictors of benzodiazepine use and dose differed in this population. Critical clinical guidelines should be developed specifically for Asian countries to address sound practices in regard to use of benzodiazepines for psychotic disorders.

Asthma, life events and psychiatric disorders: a population-based study

PurposeAlthough asthma and other chronic physical conditions have been shown to be associated with psychiatric symptoms, the relative contributions of negative life events to this association and impaired quality of life (QOL) are not clear.MethodsThis is a cross-sectional study of a nationally representative sample of Singaporean adults aged 20–59 (nxa0=xa02,847). Individuals were grouped by asthma, other chronic physical conditions, and no chronic physical conditions. Participants were assessed life events (list of threatening experiences questionnaire), psychiatric disorders [schedule for clinical assessment in neuropsychiatry diagnoses of psychiatric disorder including any psychiatric disorder, major depressive disorder (MDD) and generalized anxiety disorder (GAD)], and QOL (medical outcomes study 12-item short form).ResultsIn multivariate analyses controlling for confounding variables, asthma and other chronic physical conditions, compared to no chronic physical conditions, both showed similarly (two- to four-fold) elevated odds ratio (OR) of association with MDD and GAD. However, the asthma group reported more life events as compared to other chronic physical conditions (ORxa0=xa04.33, 95xa0% CI: 2.09–8.95) or no chronic physical conditions (ORxa0=xa07.64, 95xa0% CI: 3.87–15.06). Life events accounted significantly for excess coexistence of psychiatric disorders with asthma over participants without chronic physical conditions. It also contributed significantly to relatively worse QOL observed among individuals with asthma.ConclusionsIn this cross-sectional study, life events among adults in Singapore appeared to mediate the co-occurrence of psychiatric disorders and functional impairment with asthma, more than with other chronic physical conditions. This should be further investigated in longitudinal studies.

Long-Term Digital Mobile Phone Use and Cognitive Decline in the Elderly

Research on long-term exposure to electromagnetic fields on cognition is lacking. We investigated the associations between frequent digital mobile phone use and global and domain-specific cognitive changes in older persons, a vulnerable group experiencing age-associated cognitive decline. We assessed 871 non-demented Chinese participants in the Singapore Longitudinal Ageing Studies cohort on the frequency of digital mobile phone use, neurocognitive performance and confounding variables at baseline, and neurocognitive performance at the 4-year follow-up. Findings showed that digital mobile phone users were typically self-selected to possess characteristics favoring better cognitive functioning and concomitantly demonstrate better performance on cognitive tasks. There was evidently no significant deleterious effect of digital mobile phone use on cognitive functioning in older people. Findings suggest, however, that digital mobile phone use may have an independent facilitating effect on global and executive functioning.

Improving treatment access and primary care referrals for depression in a national community-based outreach programme for the elderly.

Mental illness is highly prevalent and disabling, but is under‐treated. Outreach services attempt to overcome system and personal barriers to care, but there are few reports of their effects in improving access and use of mental health services. In the Community‐based Early Psychiatric Interventional Strategy (CEPIS) programme in Singapore, community nurses routinely screened seniors for depressive symptoms, and provided psychoeducation and referral for primary care treatment. We evaluated the impact of the outreach programme and the extent to which determinants of treatment‐seeking were altered by removing socioeconomic, physical and cognitive barriers to care.

Validation of a Brief Seven-Item Response Bias-Free Geriatric Depression Scale

OBJECTIVEnShortened 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.nnnMETHODSnThe 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.nnnRESULTSnAfter 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.nnnCONCLUSIONSnBy removing items with culturally based response bias, the GDS-7 showed excellent scaling and test performance for screening MDD in an Asian elderly population.