Displaying publications 1 - 20 of 24 in total

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  1. Shah S, Chew SK
    J Cosmet Dermatol, 2018 Oct;17(5):830-839.
    PMID: 29193788 DOI: 10.1111/jocd.12435
    BACKGROUND: Skin hyperpigmentation is the darkening of skin due to the increased production of melanin in the body.

    OBJECTIVES: To evaluate the efficacy and safety of a botanical-based Rosa E pigmentation serum in healthy fair skin female volunteers with wrinkles, skin tone, and pigmentation.

    METHODS: This was a single-arm, open label study conducted in healthy Indian females; 18 subjects aged 30-55, having fair Caucasian-like skin with at least 2 dark skin pigments with facial wrinkles diagnosed by dermatologist were selected. Rosa E pigmentation serum was applied twice a day for 84 days. Effect was evaluated by (i) instrumental technique (spectrophotometer® 2600D), (ii) clinically by dermatologist regarding product efficacy (skin tone, antiwrinkle, pigmentation), and (iii) volunteers self-evaluation.

    RESULTS: The L* value of spectrophotometer reading represents lightness in the skin pigment. Reduction in the pigment was reported from day 14, with significant reductions observed till day 84 compared with baseline. Significant (P < .0001) skin pigmentation lightening was seen on day 14 (1.11) vastly improving on day 84 (1.94) based on photographic assessments. The significant reduction in skin pigment was 76.85%, Felix von Luschan skin color score was 30.24% (P < .0001) with a 7.38-fold reduction in skin tone and 57% reduction in facial wrinkles at day 84 from baseline.

    CONCLUSIONS: Rosa E pigmentation serum was found safe and effective in significant reduction in skin pigments, improvement of skin tone, and antiwrinkle properties instrumentally, clinically, and self-evaluation by volunteers. In these evaluations, best results were seen the longer the Rosa E was used.

  2. Lee J, Ma S, Heng D, Chew S, Hughes K, Tai E
    J Hum Hypertens, 2008 Jul;22(7):468-74.
    PMID: 18337755 DOI: 10.1038/jhh.2008.16
    The current hypertension (HTN) guidelines recommend the assessment of other cardiovascular disease (CVD) risk factors in individuals with HTN for further management. Few studies in Asian populations have been published to identify the outcome of individuals with HTN and other CVD risk factors. This study aims to assess the effect of HTN alone, and in combination with other CVD risk factors on all-cause and CVD mortality. Three cross-sectional studies carried out in Singapore (baseline 1982--1995) consisting of 5830 persons were grouped by the absence or presence of HTN and CVD risk factors. They were followed-up (mean 14.1 years) by linkage with the National Death Register. Cox's proportional hazards model was used to obtain adjusted hazard ratios (HRs) for risk of mortality. HTN individuals with either <2 CVD risk factors (adjusted HR 1.4; 95% confidence interval (CI) 1.0-1.8) or > or =2 CVD risk factors (adjusted HR 2.3; 95% CI 1.9-3.0) were at increased risk of all-cause mortality compared to normotensive individuals. The findings were similar for CVD mortality. HTN individuals who also smoked or had diabetes were at highest risk of all-cause mortality, whereas those with elevated total cholesterol/high-density lipoprotein cholesterol, smoked or diabetes had the highest risk for CVD mortality. These findings show that in HTN individuals it is important to assess the presence of other CVD risk factors and manage accordingly.
  3. Lee J, Heng D, Chia KS, Chew SK, Tan BY, Hughes K
    Int J Epidemiol, 2001 Oct;30(5):983-8.
    PMID: 11689508
    OBJECTIVE: This prospective study in Singapore investigated the relationships of established coronary risk factors with incident coronary heart disease (CHD) for Chinese, Malay, and Asian Indian males.

    SUBJECTS: A cohort (consisting of 2879 males without diagnosed CHD) derived from three previous cross-sectional surveys.

    METHODS: Individual baseline data were linked to registry databases to obtain the first event of CHD. Hazard ratios (HR) or relative risks for risk factors were calculated using Cox's proportional hazards model with adjustment for age and ethnic group and adjustment for age, ethnic group and all other risk factors (overall adjusted).

    RESULTS: There were 24,986 person-years of follow-up. The overall adjusted HR with 95% CI are presented here. Asian Indians were at greatest risk of CHD, compared to Chinese (3.0; 2.0-4.8) and Malays (3.4; 1.9-3.3). Individuals with hypertension (2.4; 1.6-2.7) or diabetes (1.7; 1.1-2.7) showed a higher risk of CHD. High low density lipoprotein cholesterol (LDL-C) (1.5; 1.0-2.1), high fasting triglyceride (1.5; 0.9-2.6) and low high density lipoprotein cholesterol (HDL-C) (1.3; 0.9-2.0) showed a lesser but still increased risk. Alcohol intake was protective with non-drinkers having an increased risk of CHD (1.8; 1.0-3.3). Obesity (body mass index > or =30) showed an increased risk (1.8; 0.6-5.4). An increased risk of CHD was found in cigarette smokers of > or =20 pack years (1.5; 0.9-2.5) but not with lesser amounts.

    CONCLUSIONS: The increased susceptibility of Asian Indian males to CHD has been confirmed in a longitudinal study. All of the examined established risk factors for CHD were found to play important but varying roles in the ethnic groups in Singapore.

  4. Chew SK, Teoh WH, Hong SL, Yusoff R
    Heliyon, 2023 Oct;9(10):e20260.
    PMID: 37810831 DOI: 10.1016/j.heliyon.2023.e20260
    Green extractive methods accompanied by resource conservation through process optimization are important in working towards sustainable processes. In the present paper, rutin was extracted from the leaf of female Carica papaya Linn using microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), sequential microwave ultrasound-assisted extraction (MUAE), and sequential ultrasound microwave-assisted extraction (UMAE) methods. Subsequently, the effect of extraction parameters on rutin yield were analyzed and compared. In addition, the extraction efficiency and energy consumption of the extraction processes were measured and discussed. In the present study, solid-liquid (S/L) ratio was determined to be the most significant extraction variable. Under optimized conditions, MUAE and UMAE were determined to yield the highest amount of rutin extracted at 18.46 ± 0.64 mg/g and 18.43 ± 0.81 mg/g, respectively. However, MUAE was determined to be the least resource efficient method as it consumed the highest amount of energy due to its relatively long extraction time. UAE was determined to be the most efficient in resource utilization as it required the least amount of energy for every mg/g of yield extracted, while the yield obtained was, nonetheless, comparatively high. The optimal condition obtained for UAE was 20 min of ultrasonic extraction time (TU), 20 % of ethanol mixture concentration (C), 710 μm of particle size (S), and 1:650 wt/wt of solid-liquid (S/L) ratio (R).
  5. Shen H, Qi L, Tai ES, Chew SK, Tan CE, Ordovas JM
    Obesity (Silver Spring), 2006 Apr;14(4):656-61.
    PMID: 16741267
    A polymorphism in the promoter region of uncoupling protein 2 gene -866G/A has been associated with its expression levels in adipose tissue, the risk of obesity, and metabolic abnormalities. Our purpose was to examine the associations of -866G/A with body fat and the risk of metabolic syndrome in a random sample of 4018 Asians (1858 men and 2160 women) from three ethnic groups (Chinese, Malay, and Indian). The minor allele frequency of -866G/A polymorphism in South Asians was similar to that in whites. After adjustment for covariates including age, cigarette smoking, and physical activity, the -866A/A genotype was associated with higher waist-to-hip ratio as compared with the wild-type genotype in Chinese and Indian men (p = 0.018 and p = 0.046, respectively). Moreover, Indian men with -866A/A genotype had a significantly increased risk of metabolic syndrome as compared with those homozygous for the wild-type (odds ratio, 2.66; 95% confidence interval, 1.21 to 5.88; p = 0.015). Such a risk was mainly caused by the excess presence of hypertriglyceridemia and central obesity. Our findings indicate that the uncoupling protein 2 gene -866G/A polymorphism may increase the risks of central obesity and metabolic syndrome, with greater effects on Asian men.
  6. Mak KH, Chia KS, Kark JD, Chua T, Tan C, Foong BH, et al.
    Eur Heart J, 2003 Jan;24(2):151-60.
    PMID: 12573272
    AIMS: We compare the myocardial infarction (MI) event and mortality rates among Chinese, Malay and Indian residents of Singapore.

    METHODS: Residents, aged 20 to 64 years, with an MI event were identified from hospital discharge listings, postmortem reports, and the Registry of Births and Deaths. All pathology laboratories flagged patients with elevated creatine phosphokinase (CPK) levels. Modified MONICA (multinational monitoring of trends and determinants in cardiovascular disease) criteria were used for determining MI events.

    RESULTS: From 1991 to 1999, 12 481 MI events were identified. Chinese patients were older and less likely to have typical symptoms or previous MI. Malays had the highest peak CPK level. Among all three ethnic groups, MI event and age-adjusted case-fatality rates declined. Compared with Chinese, MI event rates were >2-fold and >3-fold higher, and age-standardized coronary mortality rates were 2.4 and 3.0 higher times for Malays and Indians, respectively. Malays have the highest 3.1-year case-fatality, with an adjusted hazard ratio of 1.26 (95% confidence interval, 1.14 to 1.38) compared with Chinese.

    CONCLUSION: We found strong ethnic differences in MI event, case-fatality and coronary mortality rates among the three ethnic groups in Singapore. While Indians have the greatest MI event rates, Malays have the highest case-fatality.

  7. Heng DM, Lee J, Chew SK, Tan BY, Hughes K, Chia KS
    Ann Acad Med Singap, 2000 Mar;29(2):231-6.
    PMID: 10895345
    INTRODUCTION: This is the first prospective cohort study in Singapore to describe the incidence of ischaemic heart disease (IHD) and stroke among Chinese, Malays and Asian Indians.

    MATERIALS AND METHODS: The Singapore Cardiovascular Cohort Study is a longitudinal follow-up study on a general population cohort of 5920 persons drawn from 3 previous cross-sectional surveys. Morbidity and mortality from IHD and stroke were ascertained by record linkage using a unique identification number with the death registry, Singapore Myocardial Infarct Registry and in-patient discharge databases.

    RESULTS: There were 193 first IHD events and 97 first strokes during 52,806 person-years of observation. The overall incidence of IHD was 3.8/1000 person-years and that of stroke was 1.8/1000 person-years. In both males and females, Indians had the highest IHD incidence, followed by Malays and then Chinese. For males after adjusting for age, Indians were 2.78 times (95% CI 1.86, 4.17; P < 0.0001) and 2.28 times (95% CI 1.34, 3.88; P = 0.002) more likely to get IHD than Chinese and Malays respectively. For females after adjusting for age, Indians were 1.97 times (95% CI 1.07, 3.63; P = 0.03) and 1.37 times (95% CI 0.67, 2.80; P = 0.39) more likely to get IHD than Chinese and Malays respectively. For stroke, male Chinese and Indians had higher incidence than Malays (though not statistically significant). However, in females, Malays had the highest incidence of stroke, being 2.57 times (95% CI 1.31, 5.05; P = 0.008) more likely to get stroke than Chinese after adjustment for age.

    CONCLUSIONS: This prospective study of both mortality and morbidity has confirmed the higher risk of IHD in Indians. It has also found that Malay females have a higher incidence of stroke, which deserves further study because of its potential public health importance.

  8. Deurenberg-Yap M, Chew SK, Lin VF, Tan BY, van Staveren WA, Deurenberg P
    Int. J. Obes. Relat. Metab. Disord., 2001 Oct;25(10):1554-62.
    PMID: 11673781 DOI: 10.1038/sj.ijo.0801739
    OBJECTIVE: To investigate the effect of body mass index (BMI) and body fat distribution as measured by waist-to-hip ratio (WHR) on the cardiovascular risk factor profile of the three major ethnic groups in Singapore (Chinese, Malay and Indian people) and to determine if WHO recommended cut-off values for BMI and WHR are appropriate for the different sub-populations in Singapore.
    DESIGN: Cross-sectional population study.
    SUBJECTS: A total of 4723 adult subjects (64% Chinese individuals, 21% Malay individuals and 15% Indian individuals) were selected through a multi-staged sampling technique to take part in the National Health Survey in 1998.
    MEASUREMENTS: Data on socio-economic status (education level, occupation, housing type) and lifestyle habits (smoking and physical activity), body weight, body height, waist and hip circumferences and blood pressure measured using standardised protocols. Fasting venous blood samples were obtained for determination of serum total cholesterol (TC), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), triglycerides (TG). Venous blood samples were taken for 2 h oral glucose tolerance test (2 h glu).
    RESULTS: Absolute and relative risks for at least one cardiovascular risk factor (elevated TC, elevated TC/HDL ratio, elevated TG, hypertension and diabetes mellitus) were determined for various categories of BMI and WHR. At low categories of BMI (BMI between 22 and 24 kg/m(2)) and WHR (WHR between 0.80 and 0.85 for women, and between 0.90 and 0.95 for men), the absolute risks are high, ranging from 41 to 81%. At these same categories the relative risks are significantly higher compared to the reference category, ranging from odds ratio of 1.97 to 4.38. These categories of BMI and WHR are all below the cut-off values of BMI and WHR recommended by WHO.
    CONCLUSIONS: The results show that, at relatively low BMI and WHR, Singaporean adults experience elevated levels of risks (absolute and relative) for cardiovascular risk factors. These findings, in addition to earlier reported high percentage body fat among Singaporeans at low levels of BMI, confirm the need to revise the WHO cut-off values for the various indices of obesity and fat distribution, viz BMI and WHR, in Singapore.
  9. Ma S, Cutter J, Tan CE, Chew SK, Tai ES
    Am J Epidemiol, 2003 Sep 15;158(6):543-52.
    PMID: 12965880 DOI: 10.1093/aje/kwg199
    Despite the high prevalence of diabetes mellitus, little is known about mortality associated with diabetes in Asia. Therefore, the authors followed 3,492 Chinese, Malay, and Asian Indian adults randomly selected from the general population in Singapore. Data on glucose tolerance, demographic characteristics, and other cardiovascular disease risk factors (lipid profile, blood pressure, smoking status, alcohol consumption, and obesity) were obtained in 1992. Vital status was determined as of December 31, 2001. There were 108 deaths over a period of 9 years. Impaired fasting glycemia or impaired glucose tolerance (IFG/IGT) (hazard ratio (HR)=1.39, 95% confidence interval (CI): 0.84, 2.31) and diabetes mellitus (HR=2.49, 95% CI: 1.58, 3.94) were associated with increased mortality after adjustment for age, gender, ethnic group, and educational level. Compared with Chinese with diabetes, Indians with diabetes experienced significantly greater mortality (HR=3.86, 95% CI: 1.76, 8.44) after adjustment for gender, age, educational level, smoking, hypertension, alcohol intake, and obesity. Undiagnosed diabetes and IFG/IGT were more common than known diabetes and also were associated with increased mortality. For reduction of mortality associated with IFG/IGT and diabetes, the authors recommend a screening program to detect undiagnosed diabetes and IFG/IGT along with aggressive treatment of diabetes after diagnosis.
  10. Koh WP, Taylor MB, Chew SK, Phoon MC, Kang KL, Chow VT
    J Microbiol Immunol Infect, 2003 Sep;36(3):169-74.
    PMID: 14582560
    There is still substantial uncertainty concerning the association between Chlamydia pneumoniae and ischemic heart disease. This may partly be explained by the adjustment for potential confounders in different population studies. This is the first study in Singapore to look at the association of C. pneumoniae seropositivity with ischemic heart disease in a multivariate analysis. A random sample of 714 persons aged between 35 and 69 years was selected from the participants of the Singapore National Health Survey conducted in 1998. Data on clinical measurements and conditions were collected using biochemical tests and interviewer-based questionnaires. Ischemic heart disease was defined by the Rose questionnaire and included history suggestive of angina and/or myocardial infarction. Immunoglobulin G antibodies for C. pneumoniae were detected using an indirect microimmunofluorescence test, and seropositivity was defined as IgG titers > or = 1:16. There were no statistically significant differences in the prevalence rates of seropositivity to C. pneumoniae among the three ethnic groups, that is, Chinese (80.4%), Malays (74.0%), and Asian Indians (73.2%). There was no association between seropositivity and ischemic heart disease after adjustment for age alone (OR 1.00, 95% CI 0.54-1.83) or for age, sex, and other risk factors of atherosclerosis (OR 0.99, 95% CI 0.53-1.84). C. pneumoniae Immunoglobulin G seropositivity was not associated with an increased risk of ischemic heart disease as defined by the Rose angina questionnaire in Singapore.
  11. Tan CE, Tai ES, Tan CS, Chia KS, Lee J, Chew SK, et al.
    Atherosclerosis, 2003 Oct;170(2):253-60.
    PMID: 14612205
    BACKGROUND: Serum lipid concentrations are modulated by environmental factors such as exercise, alcohol intake, smoking, obesity and dietary intake and genetic factors. Polymorphisms at the Apolipoprotein E (APOE) locus have consistently shown a significant association with total and LDL-cholesterol (LDL-C). However, their impact on HDL-cholesterol (HDL-C) may be population dependent. Having three major ethnic groups within a similar social environment allows us to study the role of genetics and their interactions with lifestyle factors on the serum lipid profile and coronary risk in Asians.

    METHODS: This study included 1740 males (1146 Chinese, 327 Malays and 267 Asian Indians) and 1950 females (1329 Chinese, 360 Malays and 261 Asian Indians) with complete data on anthropometric indices, fasting lipids, smoking status, alcohol consumption, exercise frequency and genotype at the APOE locus.

    RESULTS: Malays and Asian Indians were more obese compared with the Chinese. Smoking was uncommon in all females but Malay males had significantly higher prevalence of smokers. Malays had the highest LDL-C whilst Indians had the lowest HDL-C, The epsilon 3 allele was the most frequent allele in all three ethnic groups. Malays had the highest frequency of epsilon 4 (0.180 and 0.152) compared with Chinese (0.085 and 0.087) and Indians (0.108 and 0.075) in males and females, respectively. The epsilon 2 allele was the least common in Asian Indians. Total cholesterol (TC) and LDL-C was highest in epsilon 4 carriers and lowest in epsilon 2 carriers. The reverse was seen in HDL-C with the highest levels seen in epsilon 2 subjects. The association between ethnic group and HDL-C differed according to APOE genotype and gender. Asian Indians had the lowest HDL-C for each APOE genotype except in Asian Indian males with epsilon 2, where HDL-C concentrations were intermediate between Chinese and Malays.

    CONCLUSION: Ethnic differences in lipid profile could be explained in part by the higher prevalence of epsilon 4 in the Malays. Ethnicity may influence the association between APOE genotypes and HDL-C. APOE genotype showed no correlation with HDL-C in Malay males whereas the association in Asian Indians was particularly marked. Further studies of interactions between genes and environmental factors will contribute to the understanding of differences of coronary risk amongst ethnic groups.

  12. Tai ES, Corella D, Deurenberg-Yap M, Cutter J, Chew SK, Tan CE, et al.
    J Nutr, 2003 Nov;133(11):3399-408.
    PMID: 14608050 DOI: 10.1093/jn/133.11.3399
    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%.
  13. Ang LW, Ma S, Cutter J, Chew SK, Tan CE, Tai ES
    Diabetes Res Clin Pract, 2005 Jan;67(1):53-62.
    PMID: 15620434 DOI: 10.1016/j.diabres.2004.05.003
    We used factor analysis to define and compare the manner in which the various features of the metabolic syndrome are linked or clustered in Chinese, Malays and Asian Indians. One thousand nine hundred and fifty seven men (1324 Chinese, 391 Malays and 261 Asian Indians) and 2308 women (1622 Chinese, 391 Malays and 296 Asian Indians) were examined. Anthropometry, blood pressure, serum glucose, lipid concentrations, and serum insulin were measured for all subjects. These data were then subjected to factor analysis which reduced the variables examined to three factors in all ethnic groups and both genders. The first (dyslipidemia) factor was positively loaded for obesity, insulin resistance (IR), fasting triglyceride and negatively loaded for HDL-cholesterol. The second (hyperglycemia) factor was positively loaded for IR and blood glucose. The third (hypertension) factor was positively loaded for obesity and blood pressure. IR was positively loaded in the hypertension factor in Malay women but not in others. Rather than a single entity causally associated with insulin resistance (IR), our findings support a concept in which the metabolic syndrome represents several distinct entities (dyslipidemia, hypertension and hyperglycemia). It appears that Malay females may be more prone to develop hypertension in association with IR.
  14. Tai ES, Lim SC, Chew SK, Tan BY, Tan CE
    Diabetes Res Clin Pract, 2000 Aug;49(2-3):159-68.
    PMID: 10963828 DOI: 10.1016/s0168-8227(00)00152-2
    We studied insulin resistance and beta-cell function with reference to ethnic group, glucose tolerance and other coronary artery disease risk factors in a cross section of the Singapore population which comprises Chinese, Malays and Asian Indians. 3568 individuals aged 18-69 were examined. Blood pressure, anthropometric data, blood lipids, glucose and insulin were assayed in the fasting state. Glucose and serum insulin were measured 2 h after an oral glucose challenge. Insulin resistance and beta-cell function were calculated using homeostasis model assessment. Asian Indians had higher insulin resistance than Chinese or Malays. Impaired glucose tolerance (IGT) and diabetes mellitus (DM) were associated with greater insulin resistance and impaired beta-cell function compared to normal glucose tolerance (NGT). Insulin resistance was positively correlated with blood pressure in women and total cholesterol, LDL cholesterol and triglyceride in both men and women. It was negatively correlated with HDL cholesterol and LDL/apolipoprotein B ratio. beta-cell function showed no significant correlations with the cardiovascular risk factors studied. It appears that both impaired beta-cell function and insulin resistance are important for the development of hyperglycemia whereas insulin resistance alone seems more important in the development of coronary artery disease as it correlates with several known coronary artery disease risk factors.
  15. Deurenberg-Yap M, Li T, Tan WL, van Staveren WA, Chew SK, Deurenberg P
    Asia Pac J Clin Nutr, 2001;10(1):39-45.
    PMID: 11708607
    In Singapore. there exists differences in risk factors for coronary heart disease among the three main ethnic groups: Chinese, Malays and Indians. This study aimed to investigate if differences in dietary intakes of fat, types of fat, cholesterol, fruits, vegetables and grain foods could explain the differences in serum cholesterol levels between the ethnic groups. A total of 2408 adult subjects (61.0% Chinese, 21.4% Malays and 17.6% Indians) were selected systematically from the subjects who took part in the National Health Survey in 1998. The design of the study was based on a cross-sectional study. A food frequency questionnaire was used to assess intakes of energy, total fat, saturated fat, polyunsaturated fat, monounsaturated fat, cholesterol, fruits, vegetables and cereal-based foods. The Hegsted score was calculated. Serum total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol were analysed and the ratio of total cholesterol to high density lipoprotein cholesterol was computed. The results showed that on a group level (six sex-ethnic groups), Hegsted score, dietary intakes of fat, satutrated fat, cholesterol, vegetables and grain foods were found to be correlated to serum cholesterol levels. However, selected dietary factors did not explain the differences in serum cholesterol levels between ethnic groups when multivariate regression analysis was performed, with adjustment for age, body mass index, waist-hip ratio, cigarette smoking, occupation, education level and physical activity level. This cross-sectional study shows that while selected dietary factors are correlated to serum cholesterol at a group level, they do not explain the differences in serum cholesterol levels between ethnic groups independently of age, obesity, occupation, educational level and other lifestyle risk factors.
  16. Tan CE, Emmanuel SC, Tan BY, Tai ES, Chew SK
    Atherosclerosis, 2001 Mar;155(1):179-86.
    PMID: 11223440 DOI: 10.1016/s0021-9150(00)00534-7
    AIMS: To compare cardiovascular risk factors in diabetic subjects of different ethnic groups, and between new and known diabetic subjects, in the Singapore National Health Survey '92.

    METHODS: Disproportionate stratified sampling followed by systematic sampling were used in 3568 (total) respondents of whom 2743 were non-diabetics, 179 newly diagnosed diabetics and 150 known diabetics. Amongst the diabetics, there were 185 Chinese, 66 Malays and 78 Asian Indians. Diagnosis of diabetes mellitus (DM) was based on the 2 h glucose alone, after a 75 g oral glucose tolerance test. Blood pressure (BP), lipid profile, glucose, insulin and anthropometric indices were obtained from all subjects.

    RESULTS: Subjects with diabetes (new and known) exhibited significantly higher triglyceride (TG), lower high density lipoprotein cholesterol (HDL-C) and low density lipoprotein (LDL)/apolipoprotein B (apo B) ratio (LDL size) compared with normoglycaemic subjects. They were more obese (generalised and central) and had higher systolic and diastolic BP. There was no difference in lipid risk factors between the two groups with diabetes although those with new diabetes were more obese whilst those with known diabetes had higher fasting glucose. Amongst subjects with diabetes, there were no significant differences between ethnic groups in TG, HDL-C, LDL/apo B ratio, or waist to hip ratio (WHR). Female Malays with diabetes had higher total cholesterol and were more obese whilst male Asian Indians with diabetes had higher fasting insulin.

    CONCLUSION: Asian Indians had lower HDL-C and LDL/apo B ratio than Chinese or Malays amongst normoglycaemic subjects. However, these differences between ethnic groups were not seen in subjects with DM.
  17. Tan KH, Tan TY, Tan J, Tan I, Chew SK, Yeo GS
    Singapore Med J, 2005 Oct;46(10):545-52.
    PMID: 16172775
    To study characteristics of birth defect cases among live births, stillbirths and abortions in Singapore between 1994 and 2000.
  18. Mak KH, Kark JD, Chia KS, Tan C, Foong BH, Chew SK
    Clin Cardiol, 2004 May;27(5):275-80.
    PMID: 15188942
    BACKGROUND: Ethnic differences in coronary mortality have been documented, and South Asians from the Indian subcontinent are particularly vulnerable.

    HYPOTHESIS: This study sought to determine whether there was a difference in the utilization of invasive cardiac procedures and long-term mortality in survivors of myocardial infarction (MI) among Chinese, Malays, and South Asians in Singapore.

    METHODS: All MI events in the country were identified and defined by the Singapore Myocardial Infarction Register, which uses modified procedures of the World Health Organization MONICA Project. Information on utilization of coronary angiography, coronary angioplasty, coronary artery bypass graft, and survival was obtained by data linkage with national billing and death registries. Hazard ratios (HR) were calculated using the Cox proportional hazards model with adjustment for baseline characteristics.

    RESULTS: From 1991 to 1999, there were 10,294 patients who survived > or = 3 days of MI. Of these, 40.6% underwent coronary angiography and 16.5% a revascularization procedure < or = 28 days. Malays received substantially less angiography (34.0%) and revascularization (11.4%) than Chinese (41.9%, 17.9%) and South Asians (40.0%, 16.3%). The ethnic disparity increased during the 1990s, particularly in the performance of coronary angiography (p = 0.038). While fatality declined during the study period for Chinese and South Asians, the rate remained stable for Malays. After a median follow-up period of 4.1 years, survival was lowest among Malays (adjusted HR, 1.28; 95% confidence interval, 1.15-1.42, compared with Chinese).

    CONCLUSION: Ethnic inequalities in invasive cardiac procedures exist in Singapore and were exacerbated in the 1990s. Inequalities in medical care may contribute to the poorer longterm survival among Malays.

  19. Qi L, Tai ES, Tan CE, Shen H, Chew SK, Greenberg AS, et al.
    J Mol Med (Berl), 2005 Jun;83(6):448-56.
    PMID: 15770500
    Perilipin is a lipid droplet surface protein present in adipocytes and steroidogenic cells. We examined five common single nucleotide polymorphisms (SNPs) at the perilipin (PLIN) locus (PLIN 6209C>T, 10171A>T, 11482G>A, 13041A>G, and 14995A>T) to investigate their association with obesity risk. The study population included 4,131 subjects of three ethnic groups (Chinese, Malay, and Indian) from Singapore. The prevalence of obesity in Malays and Indians was much higher than in Chinese. Moreover, in these groups the prevalence of obesity was three times higher in women than in men. Crude analysis indicated that haplotype 11212 (CAAAT) is shared by Malays and Indians and is significantly associated with increased obesity risk as compared to the most common haplotype 21111 (TAGAA): OR 1.65 (95% CI 1.11-2.46) in Malays and 1.94 (95% CI 1.06-3.53) in Indians. No associations between PLIN haplotypes and obesity risk were found in Chinese. To simplify the haplotype analyses we used a subgroup of three SNPs (11482G>A, 13041A>G, and 14995A>T) in positive linkage disequilibrium. These analyses revealed similar associations, showing that haplotypes XX212 (XXAAT) and XX222 (XXAGT) are associated with increased obesity risk in Malays OR 2.04 (95% CI 1.28-3.25) and 2.05 (95% CI 1.35-3.12) respectively, and that haplotype XXX212 (XXAAT) is significantly associated with increased obesity risk in Indians OR 2.16 (95% CI 1.10-4.26) after adjusting for covariates including age, sex, smoking, alcohol consumption, exercise, and diabetes status. Moreover, individual SNP analyses demonstrated that the PLIN 14995A>T SNP is the most informative single genetic marker for the observed haplotype association, being significantly associated with increased obesity risk in both Malays OR 2.28 (95% CI 1.45-3.57) and Indians OR 2.04 (95% CI 1.08-3.64). These results support the role of the PLIN locus as an ethnically dependent modulator of obesity risk in humans.
  20. Koh WP, Taylor MB, Hughes K, Chew SK, Fong CW, Phoon MC, et al.
    Int J Epidemiol, 2002 Oct;31(5):1001-7.
    PMID: 12435775 DOI: 10.1093/ije/31.5.1001
    BACKGROUND: Chlamydia pneumoniae, a bacterium that causes respiratory infections, is probably under-diagnosed. There is also interest in its possible role in the aetiology of coronary heart disease. This is the first population-based seroprevalence survey of C. pneumoniae infection in Singapore.

    METHODS: A random sample of 1,068 people aged 18-69 years was selected from the participants of the Singapore National Health Survey conducted in 1998. Sera and data on certain clinical measurements and conditions had been collected. IgG antibodies for C. pneumoniae were detected using an indirect microimmunofluorescence test and positivity graded. Seropositivity was defined as IgG titre >/=1:16.

    RESULTS: There were no statistically significant differences in the prevalence rates of seropositivity to C. pneumoniae for age group 18-69 years among the three ethnic groups, i.e. Chinese (males 76.7%, females 68.3%), Malays (males 75.4%, females 59.1%), and Asian Indians (males 74.6%, females 59.4%). The seropositivity rate for people aged 18-69 years in Singapore was 75.0% for males and 65.5% for females (difference of 9.5%, P < 0.001). In both genders combined, seropositivity increased from 46.5% in the age group 18-29 to reach a plateau of 78.9% in the age group 40-49, which remained stable to 60-69 years. There was no association of seropositivity with smoking, diabetes mellitus, hypertension or body mass index after adjustment for age and gender.

    CONCLUSION: The high prevalence rates in our study population and the higher rate in males compared to females are consistent with studies from other parts of the world. No significant difference in prevalence rates was observed among Chinese, Malays and Indians. The pattern of rising and levelling off of seropositivity with age suggests that C. pneumoniae infection occurs early in life, and in older ages the high level of seropositivity is probably maintained by re-infections or chronic infections. Chlamydia pneumoniae infection was not found to be associated with the cardiovascular risk factors examined.
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