International cancer seminars: a focus on kidney cancer.

Recent years have seen important advances in our understanding of the etiology, biology and genetics of kidney cancer. To summarize important achievements and identify prominent research questions that remain, a workshop was organized by IARC and the US NCI. A series of 'difficult questions' were formulated, which should be given future priority in the areas of population, genomic and clinical research.

Geographic differences in the associations between impaired glucose regulation and cardiovascular risk factors among young adults.

AIMS: To assess geographic differences in the association between BMI, blood pressure and lipid levels with impaired glucose regulation among young adults from various geographical regions. METHODS: This was a cross-sectional study including data from 6987 participants aged ≤ 30 years from India, Singapore, Australia, Greenland, Kenya and Tanzania. Impaired glucose regulation was determined by the 75-g oral glucose tolerance test. For each geographical region, BMI, blood pressure and lipids were examined and compared between participants with normal glucose tolerance and those with impaired glucose regulation. Multiple logistic regression models were used to assess the association between risk factors and impaired glucose regulation. RESULTS: Indian and East African people had a higher prevalence of impaired glucose regulation compared with participants from other regions, despite their lower BMI. Compared with the other regions, blood pressure was lower among Indian and Singaporean people but higher in those from Greenland. Greenlanders had the highest, while Indian and East-African people, had the lowest level of HDL cholesterol. BMI was positively associated with impaired glucose regulation in all regions, and there were no statistically significant geographic differences. In the Indian, Singaporean and Australian participants, there was a positive association between blood pressure and impaired glucose regulation. Triglycerides were positively associated with and HDL cholesterol had no association with impaired glucose regulation in all geographical regions. CONCLUSIONS: Higher BMI and triglyceride levels were positively associated with prevalent impaired glucose regulation in all geographical regions. There were geographic differences in the association between impaired glucose regulation and blood pressure and lipids, probably reflecting environmental and genetic factors.

Association between the APOA2 promoter polymorphism and body weight in Mediterranean and Asian populations: replication of a gene-saturated fat interaction.

OBJECTIVE: The APOA2 gene has been associated with obesity and insulin resistance (IR) in animal and human studies with controversial results. We have reported an APOA2-saturated fat interaction determining body mass index (BMI) and obesity in American populations. This work aims to extend our findings to European and Asian populations. METHODS: Cross-sectional study in 4602 subjects from two independent populations: a high-cardiovascular risk Mediterranean population (n = 907 men and women; aged 67 ± 6 years) and a multiethnic Asian population (n = 2506 Chinese, n = 605 Malays and n = 494 Asian Indians; aged 39 ± 12 years) participating in a Singapore National Health Survey. Anthropometric, clinical, biochemical, lifestyle and dietary variables were determined. Homeostasis model assessment of insulin resistance was used in Asians. We analyzed gene-diet interactions between the APOA2 -265T>C polymorphism and saturated fat intake (C polymorphism on body-weight-related measures was modulated by saturated fat in Mediterranean and Asian populations.

Mortality among tuberculosis patients on treatment in Singapore.

OBJECTIVE: To identify the risk factors associated with mortality among tuberculosis (TB) patients on treatment in Singapore. DESIGN: A retrospective cohort study of 7433 TB patients notified and started on TB treatment from 2000 to 2006 was conducted. Cox regression analysis was used to determine independent risk factors for mortality. RESULTS: Of 7433 patients who started TB treatment between 2000 and 2006, there were 884 deaths (11.9%) from any cause. Older age, male sex, being in a long-term care facility, having comorbidity, absence of cough, more than one site of TB, bacteriologically confirmed laboratory results, resistance to at least isoniazid (INH) and rifampicin (RMP) and absence of cavity were strongly associated with all-cause mortality among TB patients. A total of 203 patients (2.7%) died of TB. Risk factors for death due to TB were older age, male sex, Malay ethnicity, being in a long-term care facility, absence of cough, more than one site of TB, bacteriologically confirmed laboratory results and resistance to at least INH and RMP or to at least INH but not RMP. CONCLUSION: It is important to identify TB patients with risk factors related to mortality so that appropriate and timely interventions can be instituted to prevent deaths among TB patients.

Changes in the levels of major cardiovascular risk factors in the multi-ethnic population in Singapore after 12 years of a national non-communicable disease intervention programme.

INTRODUCTION: The National Healthy Lifestyle Programme, a population-wide non-communicable disease intervention programme, was started in 1992. A National Health Survey is carried out every six years to evaluate the impact of this programme on the cardiovascular risk factor profile of the resident population of Singapore. METHODS: The 2004 National Health Survey (NHS 04) was a population-based survey carried out over a period of four months from September to December 2004. A combination of disproportionate stratified sampling and systematic sampling was used to select a representative sample (n=7,078) for the survey. The reference population comprised 2.4 million multi-racial Singaporeans aged 18-69 years. Anthropometric and blood pressure measurements were carried out on all subjects and blood samples were taken for biochemical analysis. The results were compared with those of a similar survey conducted in 1998. RESULTS: A total of 4,084 Singapore residents took part in the survey, giving a response rate of 57.7 percent. The age-standardised prevalence of hypertension (greater than or equal to 140/90 mmHg) in Singapore residents aged 30-69 years decreased from 28.0 percent in 1998 to 24.0 percent (p-value is less than 0.001) in 2004. The prevalence of high total cholesterol (greater than or equal to 6.2 mmol/L) among those aged 18-69 years fell from 26.0 percent in 1998 to 18.1 percent (p-value is less than 0.001) in 2004. The prevalence of diabetes mellitus in residents aged 18-69 years in 2004 was 7.8 percent, compared to the 1998 level of 9.5 percent (p-value is less than 0.01). The level of obesity (body mass index is greater than or equal to 30 kg/sqm) increased slightly from 6.2 percent in 1998 to 6.8 percent (p-value equals 0.1627). The prevalence of daily smoking decreased from 15.0 percent in 1998 to 12.5 percent in 2004 (p-value is less than 0.001), while that of regular exercise increased from 17.0 percent to 25.0 percent (p-value is less than 0.001). Ethnic differences in the prevalence of diabetes mellitus, hypertension, hypercholesterolaemia, and exercise were observed. CONCLUSION: The NHS 04 results suggest that the National Healthy Lifestyle Programme significantly decreased daily smoking, high blood cholesterol and hypertension, and increased regular exercise over 1998 levels. The results also suggest that the programme stabilised the prevalence of obesity and diabetes mellitus.

Treatment outcome of Singapore residents with pulmonary tuberculosis in the first year after introduction of a computerised treatment surveillance module.

INTRODUCTION: A key intervention of the Singapore Tuberculosis Elimination Programme (STEP) was the introduction in 2001 of a computerised treatment surveillance module (TSM) for the real-time monitoring of the treatment progress of the country's notified tuberculosis (TB) cases until a final outcome. We report the treatment outcome as at December 31, 2002 for the cohort of Singapore residents with new and relapsed pulmonary TB in whom treatment was commenced in 2001. METHODS: Each TB notification will activate the TSM, which requires a return on the patient's treatment progress, treatment delivery mode and the treating physician's management decision at each clinic visit to the STEP Registry until an outcome is reached. RESULTS: There were 1,354 Singapore residents with new or relapsed pulmonary TB who started treatment in 2001. Of these, 620 (45.8 percent) underwent directly-observed therapy (DOT) at their nearest polyclinic. As at December 31, 2002 , 79 percent of patients completed treatment, nine percent died (two percent from TB), nine percent interrupted treatment (they were either lost to follow-up or refused treatment), 1.8 percent were still on treatment, 0.6 percent left the country, and 0.5 percent had permanent cessation of treatment due to drug reactions. Factors associated with treatment completion were Chinese ethnicity (odds-ratio [OR] 1.5, 95 percent confidence interval [Cl] 1.1-2, p-value is 0.02), age younger than 65 years (OR 1.8, 95 percent Cl 1.3-3.0, p-value is 0.003) and the use of DOT (OR 3.1, 95 percent Cl 2.3-4.1, p-value is less than 0.05). CONCLUSION: The findings from the TSM's first year provide a baseline for future programme evaluation.

Isolated low HDL cholesterol: an insulin-resistant state only in the presence of fasting hypertriglyceridemia.

Individuals with isolated low HDL cholesterol are at increased risk of coronary artery disease. It has been reported previously that this is an insulin-resistant state. We analyzed data from the 1992 Singapore National Health Survey with the objective of defining the clinical and metabolic parameters associated with isolated low HDL cholesterol. A total of 3,568 individuals were selected by stratified random sampling. Subjects with low HDL cholesterol (<0.9 mmol/l) and "ideal" total cholesterol (<5.2 mmol/l) were identified. Data on anthropometry, blood pressure (BP), insulin resistance, glucose tolerance, sex, smoking habit, and ethnic group were examined. We found that this group was heterogeneous. Those with fasting triglyceride (TG) >1.7 mmol/l (low HDL/high TG) displayed features of the insulin resistance syndrome characterized by obesity, higher diastolic BP, greater insulin resistance, and a greater tendency to have diabetes or impaired glucose tolerance (IGT). If fasting TG was <1.7 mmol/l (isolated low HDL cholesterol), individuals were similar to the general population in terms of insulin resistance and obesity. Both groups were more commonly men and Asian Indian. The ethnic difference in prevalence could not be explained by differences in diet, exercise, alcohol ingestion, or smoking. Our data support the view that Asian Indians are genetically predisposed to isolated low HDL cholesterol as well as the insulin resistance syndrome. The higher prevalence of isolated low HDL cholesterol, the young age at which individuals exhibit this phenotype (mean age 32.5 years), along with the greater propensity for Asian Indians to develop insulin resistance and IGT contribute to the threefold increased incidence of myocardial infarction in those <65 years of age in this ethnic group.

Birth defects in Singapore: 1994-2000.

INTRODUCTION: To study characteristics of birth defect cases among live births, stillbirths and abortions in Singapore between 1994 and 2000. METHODS: Index cases for the National Birth Defects Registry (NBDR) were obtained from all neonatal nurseries in Singapore, all hospital discharge summaries, cytogenetic and pathology reports from all pathology laboratories in Singapore, and from the compulsory reporting of all termination of pregnancy cases and stillbirths delivered. Further information was obtained from case notes retrieved from the medical record offices, antenatal clinics, cytogenetic laboratories, pathology departments and the Registry of Births and Deaths. The notified cases (live births, stillbirths and abortions) between 1994 and 2000 were extracted from the NBDR and analysed with regard to ethnicity, maternal age, trend over the seven years and types of birth defects using the British Paediatric Association Classification. RESULTS: Between 1994 and 2000, a total of 7,870 cases (6,278 births and 1,592 abortuses) were notified, giving a rate of 23.99 birth defect cases per 1000 live births. There was a decreasing trend in birth defect incidence (19.76 to 16.85 per 1,000 live births) among live births and stillbirths and an increasing trend of abortion (3.25 to 7.57 per 1,000 live births) for birth defects. Malays had a higher rate of congenital defects at birth (24.4/1,000 live births) compared to Chinese (18.4/1,000 births). The 25-29 years age group had the lowest overall rate (22.6/1,000 live births) compared to the 19 years and below group at 31.6/1,000 live births and the 45-49 years group at 126.6/1,000 live births. The five most common groups of anomalies (per 1,000 live births) were those of heart (9.07), musculoskeletal (4.98), chromosomal (4.35), urinary (3.12) and nervous systems (2.90). The five most common aborted anomalies (per 1,000 live births) were those of chromosomal (2.40), nervous (1.23), heart (0.95), musculoskeletal (0.85) and urinary systems (0.36). CONCLUSION: There was an increasing trend of abortion for birth defects, accompanied by a falling trend in the congenital anomalies of live births. Both extremes of maternal age were at higher risk of non-chromosomal birth defects while advanced maternal age was at higher risk of chromosomal defects.

Measurable predictive factors for progression to AIDS among HIV-infected patients in Singapore.

INTRODUCTION: This study identifies measurable factors at the time of diagnosis that predict the progression to Acquired Immunodeficiency Syndrome (AIDS) among Human Immunodeficiency Virus (HIV)-infected patients in Singapore. MATERIALS AND METHODS: We carried out a retrospective study of 790 HIV-infected patients from 16 May 1985 to 31 December 2001. The end-point was the onset of AIDS-defining illness listed in the 1987 and 1991 revised Centers for Disease Control and Prevention criteria, but excluded CD4 cell counts as a criterion. Using the Kaplan-Meier method, AIDS-free survival curves were plotted for age groups at diagnosis, baseline CD4 counts and periods for utilisation of antiretroviral treatment. A Cox regression model was constructed to determine independent predictors of disease progression. RESULTS: Univariate analysis showed that patients of older age at diagnosis had a significantly higher risk of progression compared to younger patients, and patients with higher baseline CD4 cell counts had a lower risk of progression to AIDS. Adjusting for the simultaneous influence of several covariates on the rate of HIV progression to AIDS, multivariate analysis using the Cox model showed a significantly higher risk of progression for older patients at diagnosis, and the progressive lowering of risk with increasing baseline CD4 cell counts. CONCLUSIONS: This study found older age at diagnosis and baseline CD4 cell counts to be measurable predictors for HIV progression to AIDS at time of diagnosis. Identification of these risk factors enables physicians to provide counselling and advice, and to start appropriate treatment early. This could lower the risk of progression and improve survival.

Cardiovascular risk profile in individuals with borderline glycemia: the effect of the 1997 American Diabetes Association diagnostic criteria and the 1998 World Health Organization Provisional Report.

OBJECTIVE: In 1997, the American Diabetes Association (ADA) recommended a new diagnostic category, impaired fasting glucose (IFG), to describe individuals with borderline glucose tolerance. On the other hand, the World Health Organization (WHO) suggested retaining the category of impaired glucose tolerance (IGT). We studied the prevalence of IFG and IGT in a multiethnic society and compared the cardiovascular risk profiles of subjects with IFG, IGT, or both IFG and IGT. RESEARCH DESIGN AND METHODS: A total of 3,568 subjects were examined from the 1992 National Health Survey of Singapore, which involved a combination of disproportionately stratified sampling and systematic sampling. Anthropometric, blood pressure, insulin, lipid profile, and uric acid measurements were taken, and a standard 75-g oral glucose tolerance test was performed after a 10-h overnight fast. RESULTS: The prevalence rates of IFG only, IGT only, and both IFT and IGT were 3.45, 10.2, and 3.4%, respectively. The degree of agreement (kappa) between the two diagnostic criteria (the ADA IFG and the WHO IGT) was only 0.25. A fasting glucose level of 5.5 mmol/l was the optimal cutoff for predicting a 2-h postload glucose level of > or =7.8 mmol/l. The following cardiovascular risk factors were higher in subjects with both IFG and IGT compared with those with either IFG or IGT alone: systolic blood pressure (131 +/- 20 vs. 125 +/- 21 and 125 +/- 19 mmHg, respectively; P < 0.05 and P < 0.001, respectively); diastolic blood pressure (77 +/- 12 vs. 73 +/- 12 and 74 +/- 12 mmHg, respectively; P < 0.05); BMI (26.2 +/- 4.2 vs. 24.4 +/- 4.0 and 24.6 +/- 4.4 kg/m2, respectively; P < 0.01 and P < 0.001, respectively); waist circumference (84.1 +/- 10.3 vs. 79.3 +/- 10.7 and 79.3 +/- 10.6 cm, respectively; P < 0.001); waist-to-hip ratio (0.84 +/- 0.08 vs. 0.82 +/- 0.09 and 0.81 +/- 0.08, respectively; P < 0.05 and P < 0.001, respectively); fasting insulin (12.1 +/- 9.7 vs. 9.2 +/- 5.3 and 9.9 +/- 7.7 mU/l; P < 0.01); insulin resistance (by homeostasis model assessment [HOMA]) (3.41 +/- 2.77 vs. 2.58 +/- 1.50 and 2.43 +/- 1.83, respectively; P < 0.01 and P < 0.001, respectively); total cholesterol (5.81 +/- 1.1 vs. 5.51 +/- 1.1 and 5.53 +/- 1.1 mmol/l, respectively; P < 0.05) and apolipoprotein(B) [apo(B)] (1.5 +/- 0.38 vs. 1.40 +/- 0.34 and 1.39 +/- 0.35 mmol/l, respectively; P < 0.01). The pattern of difference remained significant only for fasting insulin, insulin resistance (HOMA), and apo(B) (borderline) after adjustment for age, sex, and ethnic differences. CONCLUSIONS: Obvious discordance was evident in the classification of glycemic status when applying the criteria proposed by the ADA (IFG) or WHO (IGT) in a multiethnic society like Singapore. However, subjects with either IFG or IGT had similar cardiovascular risk profiles. Therefore, both criteria identified individuals at high risk for cardiovascular disease. Individuals with both IFG and IGT had a greater incidence of the cardiovascular dysmetabolic syndrome.

Elevated body fat percentage and cardiovascular risks at low body mass index levels among Singaporean Chinese, Malays and Indians.

The aim of this study was to investigate the relationship between body mass index (BMI) and body fat percentage (BF%) in Singaporean Chinese, Malays and Indians, and to determine the risk for selected comorbidities at various BMI categories and abdominal fat distributions, as assessed by waist circumference (WC). The study was a cross-sectional (population) design. In total, 4723 subjects participated in the National Health Survey of 1998 in which the risks were investigated. A selected subsample of 291 subjects participated in a detailed body composition study, where weight, height and WC were measured, as were blood pressure, total and high-density lipoprotein (HDL) cholesterol, serum triglycerides and fasting glucose. In the subsample, BF% was determined by means of a chemical four-compartment model. At any given BF% the BMI of Singaporeans was about 3 kg m(-2) lower than that of Caucasians. There were slight differences in the BF%/BMI relationship between the three ethnic groups. For all the ethnic groups, it was found that at low categories of BMI (between 22 and 24 kg m(-2)) and WC (between 75 and 80cm for women and between 80 and 85 cm for men), the absolute risks for having at least one of the aforementioned risk factors were high, ranging from 41 to 81%. At these same categories the relative risks were significantly higher compared to the reference category, odds ratios ranging from 1.97-4.38. These categories of BMI and WC were all far below the cut-off values of BMI and WC as currently recommended by the World Health Organization (WHO). The data from the current study, which includes evidence that not only risk factors, but also BF% are elevated at low BMI values, presents a strong case for lowering the BMI cut-off value for overweight and obesity among Singaporeans, from 25 kg m(-2) and 30 kg m(-2) to 23 kg m(-2) and 27 kg m(-2), respectively.

Diabetes mellitus abolishes ethnic differences in cardiovascular risk factors: lessons from a multi-ethnic population.

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.

APOE polymorphism and lipid profile in three ethnic groups in the Singapore population.

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.

Risk factors and incident coronary heart disease in Chinese, Malay and Asian Indian males: the Singapore Cardiovascular Cohort Study.

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.

Seroprevalence of IgG antibodies against Chlamydia pneumoniae in Chinese, Malays and Asian Indians in Singapore.

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.

Prevalence of hepatitis B virus (HBV) infection in Singapore men with sexually transmitted diseases and HIV infection: role of sexual transmission in a city state with intermediate HBV endemicity.

STUDY OBJECTIVES: To describe the prevalence of hepatitis B virus (HBV) infection in patients with sexually transmitted diseases (STD) and human immunodeficiency virus (HIV) infection, and to determine the role of sexual transmission of HBV infection in Singapore. DESIGN: A cross sectional study of all consecutive men presenting with a new episode of STD at a government outpatient clinic and all men with HIV infection on routine follow up at a government hospital. The prevalence of various HBV markers was compared with that of healthy males aged 15 years and above (controls). SETTING: Singapore, a city state of intermediate HBV endemicity. SUBJECTS: These comprised 497 STD patients, 47 HIV infected patients, and 418 controls. MAIN RESULTS: The overall seroprevalences of HBV infection in STD patients, HIV infected patients, and control subjects were 41.2%, 61.7%, and 33.3%, respectively (p < 0.001). The seroprevalences of hepatitis B surface antigen (6.2%, 8.5%, and 4.5%, respectively) were comparable in the three groups. Using stepwise logistic regression analysis, the adjusted seroprevalences of HBV infection in STD and HIV infected patients were respectively 2.4 times (95% confidence interval (CI), 1.7, 3.3) and 3.3 times (95% CI 1.7, 6.3) higher than in controls. HBV infection rates were higher among Chinese (odds ratio (OR), 1.9; 95% CI 1.6, 3.4) than non-Chinese, and among those aged 25-34 years (OR 2.4; 95% CI 1.6, 3.4), 35-44 years (OR 3.9; 95% CI 2.5, 5.9), and 45+ years (OR 6.2; 95% CI 3.8, 10.2) than in those aged 15-24 years. Sex related factors significantly associated with higher infection rates, independent of age and ethnic group, were reactive VDRL test (OR 2.4; 95% CI 1.2, 4.7), participation in anal intercourse (OR 2.3; 95% CI 1.2, 4.3), and having 10 or more lifetime sexual partners (OR 1.5; 95% CI, 1.0, 2.1). CONCLUSION: The importance of sexual transmission of HBV in an area of intermediate HBV endemicity was confirmed. Patients attending STD clinics should be routinely screened for HBV markers and those found to be seronegative should be strongly advised to be immunised against this virus.

Homeostasis model assessment in a population with mixed ethnicity: the 1992 Singapore National Health Survey.

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.

Typhoid fever in hospitalized children in Singapore.

A study was conducted to determine the clinical features and severity of typhoid fever in children admitted to the Communicable Disease Centre, Singapore. Over a 5 year period (1990-94), 40 children had documented culture-proven typhoid fever. Nine of the 40 children (22.5%) were below the age of 5 years. The predominant presenting symptoms were fever and diarrhoea. Pneumonia and ileus were the only complications observed. No patient in the series died. Ten Salmonella typhi isolates were multi-drug resistant. The majority of the children were treated with chloramphenicol and ceftriaxone. Typhoid fever appears to be a mild disease in Singapore children.

A 7-day course of ciprofloxacin for enteric fever.

A prospective, open and non-randomised clinical trial using a 7-day short course of oral ciprofloxacin 500 mg twice daily was conducted on 25 adult patients with bacteraemic enteric fever. Twenty-four patients (96%) were cured and there was one treatment failure. Two patients with typhoid fever relapsed 6 weeks after finishing treatment. Defervescence of fever was rapid (median: 4 days) and the duration of hospitalisation was short (median: 8 days). Both factors resulted in patient satisfaction. A short-course regime of ciprofloxacin for the treatment of enteric fever, is therefore, highly promising.

A population-based study on the association between parental occupations and some common birth defects in singapore (1994-1998).

We sought to study the association between some common birth defects and parental occupations. The live births and congenital malformation born between January 1994 and December 1998 were obtained from the Singapore National Registry of Births and Deaths (the National Birth Defect Registry). The prevalence of overall birth defects among Singapore live births during the study period is 13.9 per 1,000 live births. The most frequent single coding defects were "bulbus cordis anomalies and anomalies of cardiac septal closure (BCA)," "congenital anomalies of urinary system (CUS)," "cleft palate and cleft lip (CPL)," and "certain congenital musculoskeletal deformities (CMD)." Using the "Legislators, Senior Officers & Managers" as reference and adjusting for possible confounders, there were significant associations for: (1) paternal "clerical workers" (adjusted RR 2.25) with the BCA; (2) maternal "professionals" with CUS (adjusted risk ratio [RR] 3.58); (3) paternal "production craftsmen and related workers" with both the BCA (adjusted RR 2.04), and the CMD (adjusted RR 2.83); (4) paternal "plant and machine operators and assemblers" with the BCA (adjusted RR 2.49), and the CUS (adjusted RR 5.19), and the CMD (adjusted RR 3.01). Paternal rather than maternal exposure might be more important in the causation of some common birth defects in Singapore.