Prevalence of Dementia in People Aged 60 Years and Above: Results from the WiSE Study.

BACKGROUND: The challenge of an aging population with its expected attendant problem of an increase in the number of people with dementia is a growing concern across the world. OBJECTIVE: The aims of this study were to establish the prevalence and risk factors of dementia in Singapore among the elderly resident population (aged 60 years and above). METHODS: The WiSE study was a comprehensive single phase, cross-sectional, epidemiological survey that adapted the 10/66 protocol to establish the 10/66 and the Diagnostic and Statistical Manual of mental disorders -fourth edition (DSM-IV) diagnosis of dementia. 10/66 and DSM-IV dementia diagnosis as established by the survey questionnaires was validated by comparing against a gold standard of clinical assessment. RESULTS: A total of 2,565 respondents completed the study giving a response rate of 65.6%. The validity of 10/66 dementia was higher (sensitivity = 95.6%, specificity = 81.8%) than that of DSM-IV dementia (sensitivity = 75.6%, specificity = 88.6%) when compared against the clinical gold standard. The study found that the prevalence of 10/66 dementia was 10% in the older adult population while the prevalence of DSM-IV dementia was 4.6%. Older age (75 years and above); no formal education, or completed primary education (versus higher education); homemaker and retired status (versus employed); and a history of stroke were associated with a higher risk of 10/66 dementia. CONCLUSION: The establishment of accurate data on the number of people with dementia is essential in the planning of services and initiatives.

Body mass index and risk of mental disorders in the general population: results from the Singapore Mental Health Study.

OBJECTIVE: The aims of the current study were to elucidate the association between body mass index (BMI) and mental disorders and to examine whether these associations are moderated by socio-demographic correlates and comorbid physical disorders. METHODS: The Singapore Mental Health Study (SMHS) surveyed adult Singapore residents (Singapore citizens and permanent residents) aged 18 years and above. The survey was conducted from December 2009 to December 2010. The diagnoses of mental disorders were established using the World Mental Health Composite International Diagnostic Interview version 3.0 (CIDI 3.0). BMI was calculated using height and weight which were self-reported by respondents. The Euro-Qol-5Dimensions (EQ-5D) was used to measure the health related quality of life (HRQoL) in the sample. RESULTS: Six thousand and six hundred sixteen respondents completed the study (response rate of 75.9%) and constituted a representative sample of the adult resident population in Singapore. Being underweight was associated with both lifetime (adjusted odds ratio (OR): 2.3) and 12-month obsessive-compulsive disorder (adjusted OR: 4.4). Obesity was associated with 12-month alcohol dependence (adjusted OR: 8.4). There were no significant differences in the EQ-5D indices or the EQ-VAS scores among the four BMI groups in the population. CONCLUSIONS: Our findings are somewhat unique and different from those reported in research from Western countries. There is a need for further cross-cultural research to explore and identify genetic, metabolic and cultural differences that underlie the interaction between obesity and mental illnesses.

A population-based survey of mental disorders in Singapore.

INTRODUCTION: Mental illnesses are not only a growing public health concern but also a major social and economic issue affecting individuals and families throughout the world. The prevalence of mental disorders, the extent of disability caused by these disorders, and services utilisation of these patients has been well studied in developed countries. The aim of this study was to establish the prevalence of select mental disorders and their associated sociodemographic correlates in the adult Singapore resident population. MATERIALS AND METHODS: This was a cross-sectional, populationbased, epidemiological study of adult Singapore residents aged 18 years and above. The subjects were randomly selected using a disproportionate stratified sampling method. The diagnoses of selected mental disorders including major depressive disorder (MDD), dysthymia, bipolar (bipolar I & II) disorders, generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD), alcohol abuse and alcohol dependence were established using the Composite International Diagnostic Interview, which is a fully structured diagnostic instrument that assesses lifetime and 12-month prevalence of mental disorders. RESULTS: Among the 6616 respondents (response rate of 75.9%), 12.0% had at least one lifetime affective, anxiety, or alcohol use disorders. The lifetime prevalence of MDD was 5.8% and that of bipolar disorder was 1.2%. The combined lifetime prevalence of the 2 anxiety disorders, GAD and OCD was 3.6%, with the latter being more common than GAD (0.9% and 3.0% respectively). The lifetime prevalence of alcohol abuse and dependence were found to be 3.1% and 0.5% respectively. Age, gender, ethnicity, marital status and chronic physical illnesses were all significant correlates of mental disorders. CONCLUSION: The identified associated factors would help guide resource allocation, policy formulation and programme development in Singapore.

The Singapore Mental Health Study: an overview of the methodology.

The Singapore Mental Health Study (SMHS) is a population-based, cross-sectional, epidemiological study on the Singapore multi-ethnic adult population. This article provides an overview of the research design and methods used which took into consideration the unique characteristics of the country and its multi-ethnic population. A face-to-face household survey of Singapore residents aged 18 years and above was undertaken from 2009 to 2010. The nationally representative probability sample was derived using a disproportionate stratified sampling method. In order to increase precision for subgroup estimations the design was stratified with over-sampling of Malays, Indians and those aged 65 years and above. Respondents were assessed using the English, Chinese (computerized) and Malay (paper and pencil based) version of the Composite International Diagnostic Interview (CIDI) 3.0 to establish lifetime and 12-month prevalence of mental disorders, the current use of mental health services (both Western and traditional services), the treatment gaps and loss of role functioning.

Cost-effectiveness of conjugate pneumococcal vaccination in Singapore: comparing estimates for 7-valent, 10-valent, and 13-valent vaccines.

INTRODUCTION: Although multiple studies of cost-effectiveness of pneumococcal conjugate vaccines have been conducted, no such study has examined Singapore's situation nor compared the licensed conjugate vaccines in an Asian population. This paper estimates the costs and public health impacts of pneumococcal conjugate vaccine programs, varying estimates of serotype replacement and herd immunity effects as key parameters in the analysis. Based in part on a 2008 analysis also presented here, Singapore has approved the PCV-7, PHiD-10, and PCV-13 pneumococcal conjugate vaccines as part of its National Childhood Immunisation Programme. METHODS: An economic evaluation was performed using a Markov simulation model populated with Singapore-specific population parameters, vaccine costs, treatment costs, and disease incidence data. The vaccinated infant and child cohort of 226,000 was 6% of the Singapore resident population of 3.8 million. Vaccine efficacy estimates were constructed for PCV-7, PHiD-10, and PCV-13 vaccines based on their serotype coverage in Singapore and compared to 'no vaccination'. The model estimated impacts over a five-year time horizon with 3% per year discounting of costs and health effects. Costs were presented in 2010 U.S. dollars (USD) and Singapore dollars (SGD). Sensitivity analyses included varying herd immunity, serotype replacement rates, vaccine cost, and efficacy against acute otitis media. RESULTS: Under base case assumptions for the revised analysis (i.e., herd effects in the unvaccinated population equivalent to 20% of direct effects) PCV-13 prevented 834 cases and 7 deaths due to pneumonia, meningitis, and bacteremia in the vaccinated population, and 952 cases and 191 deaths in the unvaccinated population over the 5-year time horizon. Including herd effects, the cost-effectiveness ratio for PCV-13 was USD $37,644 (SGD $51,854) per QALY. Without herd effects, however, the ratio was USD $204,535 (SGD $281,743) per QALY. The PCV-7 cost per QALY including herd effects was USD $43,275 (SGD $59,610) and for PHiD-10 the ratios were USD $45,100 (SGD $62,125). The original 2008 analysis, which had higher estimates of pneumonia prevention due to herd immunity and lower estimates of cost per dose, had found a cost-effectiveness ratio of USD $5562 (SGD $7661) per QALY for PCV-7. CONCLUSIONS: When compared to cost-effectiveness thresholds recommended by the World Health Organization (WHO), our 2008 analysis found that vaccination of infants in Singapore with PCV-7 was very cost-effective if herd immunity effects were present. However, knowledge on herd immunity and serotype replacement that emerged subsequent to this analysis changed our expectations about indirect effects. Given these changed inputs, our current estimates of infant vaccination against pneumococcal disease in Singapore find such programs to be moderately cost-effective compared to WHO thresholds. The different findings from the 2008 and 2011 analyses suggest that the dynamic issue of serotype replacement should be monitored post-licensure and, as changes occur, vaccine effectiveness and cost-effectiveness analyses should be re-evaluated.

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.

Review on epidemic of obesity.

There has been a growing concern about obesity worldwide. We performed a review on the prevalence and trends of obesity among adults and children. We reviewed the data on the prevalence of adult obesity and being overweight from the Global Database on Body Mass Index on the World Health Organisation (WHO) Website and prevalence of children being overweight from the International Obesity Task Force website. Various databases were also searched for relevant reviews and these include PubMed, EMBASE, NHS CRD databases and Cochrane. The prevalence of obesity is high in many parts of the world. Generally, there is an increasing trend of prevalence of adult obesity with age. The peak prevalence is reached at around 50 to 60 years old in most developed countries and earlier at around 40 to 50 years old in many developing countries. Obesity is a major health concern. Appropriate strategies need to be adopted to tackle obesity which itself brings about significant disability and premature deaths. Further observation may be needed to see if the trend of prevalence abates or increases in the near future.

Rationale for redefining obesity in Asians.

INTRODUCTION: There has been extensive research on defining the appropriate body mass index (BMI) cut-off point for being overweight and obese in the Asian population since the World Health Organisation (WHO) Expert Consultation Meeting in 2002. MATERIALS AND METHODS: We reviewed the literature on the optimal BMI cut-off points for Asian populations. We searched PubMed, EMBASE, National Institute for Health Research Centre for Reviews and Dissemination (NHS CRD) Database, Cochrane Library and Google. Attempts to identify further studies were made by examining the reference lists of all retrieved articles. There were 18 articles selected for the review. RESULTS: There were 13 studies which have identified the BMI cut-off points for Asian populations lower than the international BMI cut-off points recommended by the WHO. Many of the studies have recommended lowering BMI cut-off point specific for Asian populations. A few studies concurred with the recommended cut-off point for Asian populations recommended by International Association for the Study of Obesity (IASO), the International Obesity Task Force (IOTF) and the WHO in 2002. Asian populations were also noted to have higher cardiovascular risk factors than Western populations at any BMI level. CONCLUSIONS: Further research would be needed to look at the all-cause mortality at same BMI levels between Asians and Caucasians in order to evaluate the BMI cut-off recommendations for Asian populations. It is necessary to develop and redefine appropriate BMI cut-off points which are country-specific and ethnic-specific for Asians. These will facilitate the development of appropriate preventive interventions to address the public health problem posed by obesity.

Performance measures for mental healthcare in Singapore.

Mental disorders are both common and costly. The mental health system in Singapore lacks co-ordination as well as being underdeveloped in certain areas. To address these gaps as well to face emerging challenges like an ageing population, and other socioeconomic changes, the Ministry of Health of Singapore has commissioned a Committee to formulate a 5-year Mental Health Policy and Blueprint. A task group has been formed to implement this blueprint and evaluation of these various initiatives with performance measures are inevitable. The choice of these measures, however, can be a daunting task with the various and diverse interests of multiple stakeholders. This paper describes the process of choosing the relevant measures with the appropriate attributes, and suggests a framework, which can serve as a guide for selecting mental health performance measures.

3rd College of paediatrics and child health lecture--the past, the present and the shape of things to come

The growth trends of Singapore children spanning 5 decades are reviewed, based on 8 anthropometric studies from 1957 till 2002. The heights of pre-school children and school age children appear to have optimised according to their genetic potential, but the weights and body mass indices of children still appear to be increasing from 6 to 18 years for both sexes, probably as a consequence of increasing affluence. This trend is reflected in the increasing obesity prevalence in school children over the past 30 years, and the concomitant increased morbidity associated with the metabolic syndrome, necessitates further research into the causes of obesity. Barker's hypothesis first suggested that changes in the intra-uterine environment can cause fetal adaptations which persist into adulthood, and are responsible for many chronic diseases of adult life. More recently, intense research in the field of epigenetics suggests that the environment can also influence the phenotype through gene expression, through modification of DNA methylation and histones which, in turn, influences gene expression. The challenge for the future is to determine if there are clear epigenetic changes, which are responsible for the increased prevalence of childhood and adolescent obesity, and whether these changes are transmitted through generations. Unravelling these epigenetic mechanisms may be the key to the prevention of obesity and the metabolic syndrome.

Perilipin gene variation determines higher susceptibility to insulin resistance in Asian women when consuming a high-saturated fat, low-carbohydrate diet.

OBJECTIVE: To investigate the association between genetic variation in the adipocyte protein perilipin (PLIN) and insulin resistance in an Asian population as well as to examine their modulation by macronutrient intake. RESEARCH DESIGN AND METHODS: A nationally representative sample (Chinese, Malays, and Indians) was selected in the Singapore National Health Survey following the World Health Organization-recommended model for field surveys of diabetes. A total of 1,909 men and 2,198 women (aged 18-69 years) were studied. Genetic (PLIN 11482G-->A and 14995A-->T), lifestyle, clinical, and biochemical data were obtained. Homeostasis model assessment of insulin resistance (HOMA-IR) was used to evaluate insulin resistance. Diet was measured by a validated food frequency questionnaire in one of every two subjects. RESULTS: We did not find a significant between-genotype difference in insulin resistance measures. However, in women we found statistically significant gene-diet interactions (recessive model) between PLIN 11482G-->A/14995A-->T polymorphisms (in high linkage disequilibrium) and saturated fatty acids (SFAs; P = 0.003/0.005) and carbohydrate (P = 0.004/0.012) in determining HOMA-IR. These interactions were in opposite directions and were more significant for 11482G-->A, considered the tag polymorphism. Thus, women in the highest SFA tertile (11.8-19%) had higher HOMA-IR (48% increase; P trend = 0.006) than women in the lowest (3.1-9.4%) only if they were homozygotes for the PLIN minor allele. Conversely, HOMA-IR decreased (-24%; P trend = 0.046) as carbohydrate intake increased. These effects were stronger when SFAs and carbohydrate were combined as an SFA-to-carbohydrate ratio. Moreover, this gene-diet interaction was homogeneously found across the three ethnic groups. CONCLUSIONS: PLIN 11482G-->A/14995A-->T polymorphisms modulate the association between SFAs/carbohydrate in diet and insulin resistance in Asian women.

The V227A polymorphism at the PPARA locus is associated with serum lipid concentrations and modulates the association between dietary polyunsaturated fatty acid intake and serum high density lipoprotein concentrations in Chinese women.

Peroxisome proliferators activated receptor alpha (PPARalpha) regulates the transcription of several proteins involved in human lipoprotein metabolism. We screened the PPARA locus for polymorphisms in 20 unrelated subjects from each of three ethnic groups (Chinese, Malays and Asian Indians). Only the V227A polymorphism was observed. We genotyped 4248 subjects (2899 Chinese, 761 Malay and 588 Asian Indians) and found allele frequencies for the A227 allele of 0.04 in Chinese, 0.006 in Malays and 0.003 in Asian Indians. We examined the associations between this polymorphism and serum lipid concentrations in Chinese. In women, but not in men, the presence of the A227 allele was associated with lower serum concentrations of total cholesterol [5.38mmol/l (95%CI: 5.22-5.54) versus 5.21mmol/l (95%CI: 4.99-5.43), p=0.047] and triglycerides [1.19mmol/l (95%CI: 1.10-1.28) versus 1.09mmol/l (95%CI: 0.98-1.21), p=0.048]. We also found that the V227A polymorphism modulates the association between dietary polyunsaturated fatty acid intake and serum high density lipoprotein concentration (p-value for interaction=0.049). Our findings implicate PPARalpha in the lipid lowering associated with diets high in PUFA and suggests that genetic variation at the PPARA locus may determine the lipid response to changes in PUFA intake.

Impact of working status on breastfeeding in Singapore: evidence from the National Breastfeeding Survey 2001.

BACKGROUND: This study uses data from the 2001 Singapore National Breastfeeding Survey to examine factors, including working status, associated with breastfeeding duration. METHODS: All women who delivered in the eight hospitals with obstetric services in Singapore from 1 April to 31 May 2001 were invited to participate in a survey on infant feeding and nutrition at 2 and 6 months postpartum. A total of 2149 respondents were interviewed for variables that were known or suspected to be associated with breastfeeding initiation and duration. Cox proportional hazards model was used to determine the associated effect of working status on breastfeeding duration. Kaplan-Meier estimate and survival curves were compared between working and non-working mothers. RESULTS: Working status had no effect on initiation of breastfeeding, but had an effect on breastfeeding duration. The median breastfeeding duration for non-working and working mothers was 9 weeks and 8 weeks, respectively. This difference was significant by log rank test [hazard ratio (HR) = 1.27, 95% confidence interval (CI) 1.14-1.41, P value <0.001]. About 31% of non-working mothers breastfed for up to 6 months as compared to 20% of working mothers. Working mothers were more likely to stop breastfeeding than non-working mothers (HR = 1.61, 95% CI 1.43-1.85, P value = 0.001) after adjusting for potential confounders. The most important reason for working mothers stopping breastfeeding between 2 and 6 months was attributable to work. CONCLUSION: More breastfeeding-friendly initiatives need to be put in place at workplaces to encourage working mothers to continue breastfeeding upon returning to work.

Screening for myopia and refractive errors using LogMAR visual acuity by optometrists and a simplified visual acuity chart by nurses.

PURPOSE: To compare the sensitivity and specificity of a widespread method of screening for refractive errors in Singapore schoolchildren using a simplified acuity screening chart with a more rigorous method using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. A secondary aim is to estimate the best cutoff values for the detection of refractive errors using these two methods. METHODS: This is a population-based study, involving 1779 schoolchildren from three schools in Singapore. Logarithm of the minimum angle of resolution (logMAR) visual acuity was recorded using a modified Bailey-Lovie chart by trained optometrists, and visual acuity measurement was also undertaken using a simplified 7-line visual acuity screening chart by school health nurses. The main outcome measures were the receiver-operating characteristics (ROC's) of logMAR and the simplified screening visual acuity to detect myopia or any refractive errors. The difference between measurements, simplified screening visual acuity--logMAR visual acuity, was calculated. RESULTS: The optimal threshold using the simplified screening visual acuity chart for the detection of myopia or any refractive error was 6/12 or worse. Using logMAR visual acuity, the most efficient threshold for the detection of myopia was 0.26, but this was 0.18 for the detection of any refractive error. The area under the ROC curves was significantly greater in the case of the logMAR visual acuity measurement compared with the simplified screening visual acuity measurement for the detection of myopia or any refractive errors. The 95% limits of agreement for the two methods (simplified screening--logMAR acuity) was -0.219 to +0.339. CONCLUSIONS: Bearing in mind that the visual acuity measurements were performed by two different groups of professionals, visual acuity screening using the ETDRS method appears to be more accurate than the simplified charts for the detection of myopia or any refractive errors in children.

Differential effects of the C1431T and Pro12Ala PPARgamma gene variants on plasma lipids and diabetes risk in an Asian population.

We investigated the association of C1431T and Pro12Ala polymorphisms at the peroxisome proliferator-activated receptor gamma (PPARgamma) locus with plasma lipids and insulin resistance-related variables, according to diabetes status, in a large and representative Asian population from Singapore consisting of 2,730 Chinese, 740 Malays, and 568 Indians. Moreover, we estimated the diabetes risk and examined gene-nutrient interactions between these variants and the ratio of polyunsaturated fatty acid to saturated fat (SFA) in determining body mass index (BMI) and fasting insulin. We found differential effects of these gene variants. The Pro12Ala polymorphism was more associated with plasma lipids and fasting glucose concentrations, whereas the C1431T polymorphism was related to the risk of diabetes. Carriers of the 12Ala allele had higher HDL-cholesterol than did Pro12Pro homozygotes (P < 0.05), and the effect of the 12Ala allele on fasting glucose was modified by diabetes status (P < 0.001). After controlling for confounders, carriers of the T allele had decreased risk of diabetes compared with CC homozygotes [odds ratio (OR) 0.73, 95% confidence interval (CI) 0.58-0.93; P = 0.011]; this effect was stronger in Indians (OR 0.38, 95% CI 0.15-0.92; P = 0.032). For both polymorphisms, normal subjects carrying the less prevalent allele had higher BMI (P < 0.05). The PUFA/SFA did not modify the effect of these polymorphisms on BMI or insulin.

Dietary fat interacts with the -514C>T polymorphism in the hepatic lipase gene promoter on plasma lipid profiles in a multiethnic Asian population: the 1998 Singapore National Health Survey.

We have previously reported an interaction between -514C>T polymorphism at the hepatic lipase (HL) gene and dietary fat on high-density lipoprotein-cholesterol (HDL-C) metabolism in a representative sample of white subjects participating in the Framingham Heart Study. Replication of these findings in other populations will provide proof for the relevance and consistency of this marker as a tool for risk assessment and more personalized cardiovascular disease prevention. Therefore, we examined this gene-nutrient interaction in a representative sample of Singaporeans (1324 Chinese, 471 Malays and 375 Asian Indians) whose dietary fat intake was recorded by a validated questionnaire. When no stratification by fat intake was considered, the T allele was associated with higher plasma HDL-C concentrations (P = 0.001), higher triglyceride (TG) concentrations (P = 0.001) and higher HDL-C/TG ratios (P = 0.041). We found a highly significant interaction (P = 0.001) between polymorphism and fat intake in determining TG concentration and the HDL-C/TG ratio (P = 0.001) in the overall sample even after adjustment for potential confounders. Thus, TT subjects showed higher TG concentrations only when fat intake supplied >30% of total energy. This interaction was also found when fat intake was considered as continuous (P = 0.035). Moreover, in the upper tertile of fat intake, TT subjects had 45% more TG than CC individuals (P < 0.01). For HDL-C concentration, the gene-diet interaction was significant (P = 0.015) only in subjects of Indian origin. In conclusion, our results indicate that there are differences in the association of -514C>T polymorphism with plasma lipids according to dietary intake and ethnic background. Specifically, the TT genotype is associated with a more atherogenic lipid profile when subjects consume diets with a fat content > 30%.

Is a re-evaluation of WHO body mass index cut-off values needed? The case of Asians in Singapore.

This paper describes body composition and dietary intakes of the three major ethnic groups residing in Singapore and how these are related to cardiovascular risk factors in these groups. When the relationship between body mass index (BMI, kg/m2) and body fat percentage was studied, Singaporeans were found to have higher percentage of body fat compared with Caucasians with the same BMI. At BMIs that are much lower than WHO-recommended cut-off values for obesity, both the absolute and relative risks of developing cardiovascular risk factors are markedly elevated for all three ethnic groups. The excessive fat accumulation and increased risks at lower BMIs signal a need to re-examine cut-off values for obesity among Chinese, Malays, and Indians.