Health profile of workers from different industries in Singapore.

Introduction: Workplace safety and health are interrelated - a worker who is not healthy may cause safety lapses at the workplace; conversely, safety lapses could affect the health of the workers. This study was part of a larger Total Workplace Safety and Health (WSH) programme run by the Workplace Safety and Health Council, Singapore. The objectives were to obtain a baseline health profile of workers across four major industries and identify important health risks for targeted workplace interventions. Methods: Five service providers (SPs) were appointed to run the Total WSH programme. As part of the programme, SPs conducted an anonymous basic health survey among workers of participating companies. Results: The responses of 6,373 respondents from the cleaning, construction, manufacturing, and transport and storage industries were studied. The overall response rate was 62%. Key health issues identified were high rates of obesity (22%) and smoking (24%) and low prevalence of regular exercise and healthy dietary habits. Chronic disease rates were similar to population self-reported rates (hypertension 15%, high lipid 12% and diabetes mellitus 6%). The workers reported high work stress (13%). Conclusion: Health issues are prevalent in the workforce and may affect work and employee safety. It is increasingly important for employees' health to be considered in risk assessments and prioritised in workplace safety and health management systems and strategies. Health promotion interventions should be targeted, and multilevel and multicomponent initiatives should be integrated with pre-existing occupational safety programmes.

Determinants of residential greenness and its association with prostate cancer risk: A case-control study in Singapore.

BACKGROUND: Exposure to greenness has been shown to be beneficial to health, but few studies have examined the association between residential greenness and prostate cancer (PCa) risk. Our main objectives were to identify the determinants of residential greenness, and to investigate if residential greenness was associated with PCa risk in Singapore. METHODS: The hospital-based case-control study was conducted between April 2007 and May 2009. The Singapore Prostate Cancer Study (SPCS) comprised 240 prostate cancer cases and 268 controls, whose demographics and residential address were collected using questionnaires. Residential greenness was measured by normalized difference vegetation index (NDVI) around the participants' homes using a buffer size of 1 km. Determinants of NDVI were identified using a multivariable linear regression model. Logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of associations between NDVI and PCa risk, adjusting for potential confounders. RESULTS: Having a BMI within the second quartile, as compared to the lowest quartile, was associated with higher levels of NDVI (ß-coefficient = 0.263; 95% CI = 0.040-0.485) after adjusting for covariates. Additionally, being widowed or separated, as compared to being married, was associated with lower levels of NDVI (ß-coefficient = -0.393; 95% CI = -0.723, -0.063). An interquartile range (IQR) increase in NDVI was positively associated with prostate cancer risk OR = 1.45; 95% CI = 1.02-2.07). Stratified analysis by tumour grade and stage showed that higher NDVI was associated with higher risk of low grade PCa. CONCLUSION: Our findings suggested that residential greenness was associated with higher risk of PCa in Singapore. Future studies on the quality and type of green spaces, as well as other factors of residential greenness, in association with PCa risk should be conducted to better understand this relationship.

Association between Vitamin A and E Forms and Prostate Cancer Risk in the Singapore Prostate Cancer Study.

PURPOSE: This study aimed to assess associations between forms of vitamin A and E (both individually and collectively) and the risk of prostate cancer, as well as identify potential effect modifiers. METHODS: Utilizing data from the Singapore Prostate Cancer Study, a hospital-based case-control study, we measured the serum concentrations of 15 different forms of vitamins A and E in 156 prostate cancer patients and 118 control subjects, using a high-performance liquid chromatography technique. These forms included retinol, lutein, zeaxanthin, α-cryptoxanthin, ß-cryptoxanthin, α-carotene, ß-carotene, lycopene, ubiquinone, δ-tocopherol, γ-tocopherol, α-tocopherol, δ-tocotrienol, γ-tocotrienol, and α-tocotrienol. The odds ratio and 95% confidence interval for associations between vitamin A and E and prostate cancer risk were estimated using logistic regression models after adjustment for potential confounders. The analyses were further stratified by smoking and alcohol consumption status. The mixture effect of micronutrient groups was evaluated using weighted quantile sum regression. RESULTS: Higher concentrations of retinol, lutein, α-carotene, ß-carotene, ubiquinone, α-tocopherol, δ-tocotrienol, γ-tocotrienol, and α-tocotrienol were significantly and positively associated with overall prostate cancer risk. Among ever-smokers, associations were stronger for lutein, ß-cryptoxanthin and ß-carotene compared with never-smokers. Among regular alcohol drinkers, associations were stronger for lutein, ß-cryptoxanthin, ubiquinone, γ-tocotrienol and α-tocotrienol compared with non-regular alcohol drinkers. Retinol and α-tocotrienol contributed most to the group indices 'vitamin A and provitamin A carotenoids' and 'vitamin E', respectively. CONCLUSIONS: Several serum vitamin A and E forms were associated with prostate cancer risk, with significant effect modification by smoking and alcohol consumption status. Our findings shed light on prostate cancer etiology.

Association between serum heavy metals and prostate cancer risk - A multiple metal analysis.

BACKGROUND: Prostate cancer is one of the most prevalent cancers in men. Exposure to heavy metals and their association with prostate cancer risk has been studied extensively, but combined effects remain largely inconclusive. OBJECTIVES: To elucidate the association between serum concentrations of heavy metals and prostate cancer risk. METHODS: Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentrations of a panel of 10 heavy metals (Mn, Cu, Zn, As, Se, Sb, Co, Cu, Cd and Pb) in serum samples of 141 cases and 114 controls in the Singapore Prostate Cancer Study. Linear probit regression models were used to estimate risk differences (RDs) and 95% confidence intervals (CIs) for the associations between log-centered serum metal concentrations and prostate cancer risk with adjustment for potential confounders. Bayesian kernel machine regression (BKMR) models were used to account for nonlinear, interactive, and joint metal effects. RESULTS: Using probit regression, four heavy metals (As, Zn, Mn, Sb) were significantly and positively associated with prostate cancer risk in the unadjusted models. Using BKMR analysis, both As and Zn had positive risk differences on prostate cancer risk when all other metals were held fixed at the 25th and 50th percentiles (RD, 25th percentile: As: 0.15, Zn: 0.19, RD, 50th percentile: As: 0.45, Zn: 0.37). In addition, the overall mixture risk difference was positive and the 95% credible intervals did not include 0 when all metals in the mixture were jointly above their 55th percentile, as compared to when all metals were below their median values. CONCLUSIONS: In summary, we found positive associations between the serum levels of As and Zn and prostate cancer risk on the risk difference scale using BKMR models. The overall mixture effect was also associated with increased prostate cancer risk. Future studies are warranted to validate these findings in prospective studies.

Comparison of hepatic and serum lipid signatures in hepatocellular carcinoma patients leads to the discovery of diagnostic and prognostic biomarkers.

We compared hepatic and serum lipid changes in hepatocellular carcinoma (HCC) patients to have a better understanding of the molecular pathogenesis of this disease and discovery novel lipid biomarkers. Hepatic and serum lipid profiling was conducted in paired liver and serum samples from 50 HCC patients and 24 healthy controls. A total of 20 hepatic and 40 serum lipid signatures were identified, yet there was hardly any significant correlation between them. The results indicated that triglycerides and phosphatidylcholines contributed significantly to altered hepatic lipids, whereas triglycerides and phosphatidylethanolamine-based plasmalogens (PEp) contributed most to altered serum lipids. In serum, PEp (36:4) and (40:6) showed a fair capability to discriminate HCC patients from healthy controls, and were significantly associated with HCC tumor grades (p < 0.05), and thus were identified as potential diagnostic and prognostic biomarkers of HCC. These findings were confirmed by a validation study conducted in an independent cohort consisting of 18 HCC, 20 cirrhosis patients, and 20 healthy controls. This study suggests that hepatic and serum lipid signatures of HCC have to be considered as mostly independent, and the results imply potential roles of PEp species, particularly PEp (36:4) and (40:6), as serum biomarkers for HCC diagnosis and progression.

Associations of serum organohalogen levels and prostate cancer risk: Results from a case-control study in Singapore.

There is increasing evidence that elevated exposure to organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) may lead to an increased risk of prostate cancer. As part of a hospital-based case-control study of the Singaporean male population, we investigated associations between organohalogen exposure and risk of prostate cancer. Trace residue concentrations of 74 organohalogen contaminants, including several PCBs, OCPs and halogenated flame retardants (HFRs), were determined in serum samples (n = 120) using gas chromatography tandem mass spectrometry (GC-MS/MS). A variety of OCPs, PCBs and HFRs were detected in samples of both patients and controls. Mean concentrations of p,p' DDT, p,p' DDE, PCB 118, PCB 138, PCB 153 and PCB 187 were significantly higher (p < 0.05) in serum of patients. p,p' DDE measured in serum of patients was relatively high (mean:13,700 ng/g lipid, 95% CI:7000-26,800). Odds ratios (ORs) of OCPs and PCBs in many cases exceeded 1. ORs for p,p' DDE and PCB-153 at the highest tertile (>67th) were 5.67 (95% CI, 2.37-13.54) and 2.14 (95% CI, 0.99 to 4.66), respectively. The results suggest that exposure to DDTs and PCBs may be associated with prostate cancer risk in Singaporean males. No such association was observed for the organohalogen flame retardants studied, including polybrominated diphenyl ethers (PBDEs). The study provides novel information regarding the occurrence, levels and potential associations with prostate cancer risk for several organohalogen contaminants in the Singapore population. However, further investigation and analyses should be conducted to confirm these findings.

Prevalence of Chronic Mental and Physical Disorders, Impact on Work Productivity and Correlates of Alcohol Use Disorders and Nicotine Dependence across Occupations.

INTRODUCTION: This study assessed occupational differences in the prevalence of mental and physical disorders in an employed general population sample in Singapore and investigated the impact of these disorders on work productivity losses in terms of work-loss days and work-cutback days. The association of occupation with alcohol use disorders (AUD) and nicotine dependence (ND) was also investigated. MATERIALS AND METHODS: Data from a population-based mental health survey of a representative sample of multi-ethnic residents aged 18 years and above were used. The World Health Organization's (WHO) Composite International Diagnostic Interview (CIDI) was administered to establish the lifetime diagnosis of key mental disorders. Self-report on sociodemographic characteristics, productivity loss, ND, and lifetime physical conditions were obtained. Nine occupational groups were included in this analysis. RESULTS: The sample comprised 4361 participants with a mean (SD) age of 42.2 (11.9) years, ranging between 19 to 80 years. 'Associate professionals and technicians' (26.2%), 'Services and sales workers' (17.7%) and 'Professionals' (15.4%) were the 3 predominant occupational categories. Sociodemographic characteristics differed significantly across occupations (P <0.001). The lifetime prevalences of having 'any mental disorder' and 'any physical disorder' were 13.0% and 37.9%, respectively; major depressive disorder was the most prevalent mental disorder (5.9%) and hypertension was the most common physical disorder (15.6%). There were no significant differences in work productivity loss across occupations. Sociodemographic and occupational correlates for AUD and ND were identified. CONCLUSION: Sociodemographic and health disparities exist in the major occupational categories in Singapore. The strength of the associations between occupation and AUD and ND are significant, indicating the need for preventative measures in select occupations.

Photorefractive keratectomy in young Asian aviators with low-moderate myopia.

INTRODUCTION: The high prevalence of myopia among Asians led the Republic of Singapore Air Force (RSAF) to introduce photorefractive keratectomy (PRK) as a means of enlarging its pilot recruitment pool at the end of 2005. This study aims to address the efficacy and safety of PRK performed on young Asian patients with low-moderate myopia, as well as audit the RSAF's corneal refractive surgery (CRS) program. METHODS: This is a retrospective case series of 149 eyes of 76 consecutive patients that underwent PRK as part of the RSAF CRS program over the 5-yr period from 1 January 2006 to 31 December 2010. RESULTS: The median patient age was 21 yr (range, 18-26 yr) and the mean preoperative spherical equivalent (SE) refraction was -3.39 - 1.19 D. Of the patients, 96.1% were men and all were of Asian origin. At the 12-mo follow-up, 98.5% of eyes had an uncorrected distance visual acuity (UDVA) of < or = 0.00 LogMAR, 100.0% of eyes had an SE refraction of within + 0.50 D of intended correction, and 2.300% of eyes had a loss of corrected distance visual acuity (CDVA) of 0.20 LogMAR. The cumulative incidence of retreatments was 6.7% and cumulative incidence of grade II or worse corneal haze requiring retreatment was 6.0%. Refractive stability was achieved at 3 mo postsurgery. CONCLUSION: The results of this study suggest that PRK performed within the context of a stringent and structured CRS program on young Asian eyes with low-moderate myopia is both efficacious and safe, with refractive stability achieved by 3 mo.

8q24 and 17q prostate cancer susceptibility loci in a multiethnic Asian cohort.

OBJECTIVES: Recently, several genome-wide association studies have demonstrated a cumulative association of 5 polymorphic variants in chromosomes 8q24 and 17q with prostate cancer (CaP) risk in Caucasians, particularly those harboring aggressive clinicopathologic characteristics. The purpose of this study was to evaluate the influence of these variants on CaP susceptibility in Singaporean Asian men. MATERIALS AND METHODS: We performed a case-control study in 289 Chinese CaP patients and 412 healthy subjects (144 Chinese, 134 Malays, and 134 Indians), and examined the association of the 5 single nucleotide polymorphisms (SNPs) with CaP. RESULTS: In the healthy subjects, rs16901979 A-allele frequency was highest amongst Chinese (0.32) compared with Malays (0.13; P < 0.0001) or Indians (0.09; P < 0.0001); rs6983267 G-allele was highest in Indians (0.51) compared with Chinese (0.42; P = 0.041) or Malays (0.43; P = 0.077); whereas rs1859962 G-allele frequency was highest amongst Indians (0.56) compared with Chinese (0.40; P = 0.0002) or Malays (0.38; P < 0.0001). Individuals with the rs4430796 TT genotype were at increased CaP risk in the Chinese via a recessive model (odds ratios (OR) = 1.56, 95% CI = 1.04-2.33). Significant associations were observed for rs4430796 TT with Gleason scores of ≥ 7 (OR = 1.76, 95% CI = 1.14-2.73) and prostate-specific antigen (PSA) levels of ≥ 10 ng/ml at diagnosis (OR = 1.63, 95% CI = 1.01-2.63), as well as for rs6983267 GG with stage 3-4 CaPs (OR = 1.91, 95% CI = 1.01-3.61). A cumulative gene interaction influence on disease risk, which approximately doubled for individuals with at least 2 susceptibility genotypes, was also identified (OR = 2.18, 95% CI = 1.10-4.32). CONCLUSIONS: This exploratory analysis suggests that the 5 genetic variants previously described may contribute to prostate cancer risk in Singaporean men.

Prevalence of cardiovascular risk factors among healthcare staff in a large healthcare institution in Singapore.

INTRODUCTION: This study aimed to determine the prevalence of modifiable cardiovascular risk factors among health workers (HWs) and non-health workers (NHWs) in a large hospital in Singapore. METHODS: A cross-sectional prevalence survey of 3,384 hospital staff was conducted. The study comprised a self-administered questionnaire, body mass index, systolic and diastolic blood pressure measurements, and laboratory analysis of fasting blood samples of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides and plasma glucose. HWs were doctors and nurses, while NHWs were health administrators, facility staff, clerks and administrative personnel. RESULTS: A total of 3,384 out of 3,987 eligible staff (response rate 84.9%) participated in the survey. The majority of the participants were female (81%, n = 2,755), and 64% (n = 2,179) were 20-39 years old. HWs comprised almost two-thirds of the staff employed (61.3%, n = 2076), of whom 87.7% were female, while 72.5% of NHWs were female. Compared to HWs, NHWs had a higher adjusted (age, ethnic group and gender) prevalence of personal history of diabetes mellitus (adjusted prevalence rate ratio [PRR] 1.64, 95% confidence interval [CI] 1.02-2.64), cigarette smoking (adjusted PRR 1.85, 95% CI 1.48-2.32), obesity (adjusted PRR 1.36, 95% CI 1.05-1.75) and elevated systolic pressure (adjusted PRR 1.74, 95% CI 1.31-2.31). CONCLUSION: The prevalence of modifiable cardiovascular risk factors in NHWs is higher than that in HWs. Health promotion programmes should address this captive and neglected audience in healthcare organisations.

Sun exposure and the risk of prostate cancer in the Singapore Prostate Cancer Study: a case-control study.

BACKGROUND: Most of the epidemiology studies on the effects of sun exposure and prostate cancer were conducted among the temperate countries of North America and Europe. Little is known about the influence on Asian populations. The purpose of current study was to evaluate any association of sun exposure with risk of prostate cancer in Chinese, Malays and Indians who reside in the tropics. METHODS: The Singapore Prostate Cancer Study is a hospital-based case-control study of 240 prostate cancer incident cases and 268 controls conducted in Singapore between April 2007 and May 2009. Detailed information on outdoor activities in the sun, skin colour, sun sensitivity and other possible risk factors were collected in personal interviews. Cases were further classified by Gleason scores and TNM staging. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression analysis, adjusted for age, ethnicity, education, family history of any cancers, BMI and skin colour. RESULTS: We found that prostate cancer risk was increased in subjects with black/dark-brown eyes (OR 5.88, 95%CI 3.17-10.9), darker skin colour e.g. tan/dark brown/black (OR 7.62, 95%CI 3.41-17.0), frequent sunburn in lifetime (OR 4.30, 95%CI 1.7-11.2) and increased general sun exposure in adulthood per week (OR 2.03, 95%CI 1.09-3.81). The increased risk was consistent for high grade tumours and advanced stage prostate cancers. CONCLUSION: The findings from this study suggest that excessive sun exposure is a risk factor for prostate cancer in Asians.

A comparative population-based study of prostate cancer incidence and mortality rates in Singapore, Sweden and Geneva, Switzerland from 1973 to 2006.

BACKGROUND: Prostate cancer is the most commonly diagnosed malignancy in men in Sweden and Geneva, and the third most common in men in Singapore. This population-based study describes trends in the incidence and mortality rates of prostate cancer in Singapore, Sweden and Geneva (Switzerland) from 1973 to 2006 and explores possible explanations for these different trends. METHODS: Data from patients diagnosed with prostate cancer were extracted from national cancer registries in Singapore (n = 5,172), Sweden (n = 188,783) and Geneva (n = 5,755) from 1973 to 2006. Trends of incidence and mortality were reported using the Poisson and negative binomial regression models. The age, period and birth-cohort were tested as predictors of incidence and mortality rates of prostate cancer. RESULTS: Incidence rates of prostate cancer increased over all time periods for all three populations. Based on the age-period-cohort analysis, older age and later period of diagnosis were associated with a higher incidence of prostate cancer, whereas older age and earlier period were associated with higher mortality rates for prostate cancer in all three countries. CONCLUSIONS: This study demonstrated an overall increase in incidence rates and decrease in mortality rates in Singapore, Sweden and Geneva. Both incidence and mortality rates were much lower in Singapore. The period effect is a stronger predictor of incidence and mortality of prostate cancer than the birth-cohort effect.

Sun exposure and risk of lymphoid neoplasms in Singapore.

BACKGROUND: Epidemiologic studies have reported an inverse association between sun exposure and non-Hodgkin lymphoma (NHL), but these have been almost exclusively conducted in Western populations residing in temperate locations. We evaluated the association between personal outdoor sun exposure and risk of malignant lymphomas in Singapore. METHODS: A hospital-based case-control study of 541 incident cases of lymphoid neoplasms and 830 controls were recruited during 2004-2008. Participants were interviewed regarding recreational or occupational outdoor activities during childhood and in adulthood. Basic demographics and potential confounders were also collected. Odds ratios (OR) and 95 % confidence intervals (CI) were calculated using unconditional logistic regression analysis. RESULTS: Compared with individuals who did not have regular sun exposure, a lower risk of NHL was observed for those who reported regular exposure on non-school days during childhood [OR, 0.62; 95 % CI, 0.46-0.83] and non-working days in adulthood [OR, 0.70; 95 % CI, 0.51-0.97]. The protective effect was more evident among women. CONCLUSION: Our findings support an inverse relationship between intermittent sun exposure and the risk of NHL. These findings are consistent with the growing evidence from various countries, but further studies, especially prospective studies, are needed in Asian populations.

Incidence, mortality and five-year relative survival ratio of prostate cancer among Chinese residents in Singapore from 1968 to 2002 by metastatic staging.

INTRODUCTION: This paper examines the incidence, mortality and survival patterns among all Chinese residents with prostate cancer reported to the Singapore Cancer Registry in Singapore from 1968 to 2002 by metastatic staging. MATERIALS AND METHODS: This is a retrospective population-based study including all prostate cancer cases aged over 20 reported to the Singapore Cancer Registry (SCR) from 1968 to 2002 who are Singapore Chinese residents. Follow-up was ascertained by matching with the National Death Register until 2002. Metastatic status was obtained from the SCR. Age-standardised incidence and mortality rates, as well as the 5-year relative survival ratios (RSRs), were obtained for each 5-year period and grouped by metastatic stage. A weighted linear regression was performed on the log-transformed age-standardised incidence and mortality rates over the study period. RESULTS: In the most recent period of 1998 to 2002, the age-standardised incidence and mortality rates (per 100,000) for prostate cancer among the Chinese were 30.9 (95% CI, 29.1 to 32.8) and 9.6 (95% CI, 8.6 to 10.7), respectively. The percentage increase in the age-standardised incidence and age-standardised mortality rates per year were 5.6% and 6.0%, respectively, for all Chinese Singapore residents. There was an improvement in the 5-year RSRs for Chinese diagnosed with non-metastatic cases from 51.3% in 1973 to 1977, to 76.1% in 1998 to 2002. However, the RSR remains poor (range, 11.1% to 49.7%) for Chinese diagnosed with metastatic prostate cancer. CONCLUSIONS: Both age-standardised incidence and mortality rates for prostate cancer among Chinese Singapore residents are still on the rise especially since the 1990s. Since the 1990s, the improvement in RSRs was substantial for the Chinese non-metastatic cases.

Effect of ageing and body mass index on prostate-specific antigen levels among Chinese men in Singapore from a community-based study.

OBJECTIVE To assess the effect of ageing and body mass index (BMI) on prostate-specific antigen (PSA) among Chinese men from the results of the 2005 Prostate Awareness Week in Singapore. SUBJECTS AND METHODS In all, 2714 men participated in the programme, consisting of 2431 Chinese, 114 Malays, 117 Indians and 52 'others'. Of these, 2410 Chinese men who had a PSA level of <20 ng/mL and were aged >50 years but <80 years were included in the analysis. Height and weight were used to calculate the BMI. The relationship between age and PSA levels was analysed using linear regression and bivariate correlation, and the associations among different groups of BMI and PSA levels were analysed using analysis of variance and covariance. RESULTS PSA levels were significantly correlated with age (correlation coefficient, r = 0.27, P < 0.001). Analyses showed a significant inverse association between PSA level and BMI; mean PSA levels decreased with increasing BMI for both standards (standard classification; geometric mean, GM, PSA of 1.08, 1.06, 0.96, 0.83 ng/mL for a BMI of <18.5, 18.5-24.9, 25-29.9 and > or =30 kg/m(2), respectively, P trend <0.01; and for Asian classification, GM PSA 1.08, 1.09, 0.96, 0.91 ng/mL for a BMI of <18.5, 18.5-22.9, 23-27.5 and > or =27.5, respectively, P trend <0.001). There were significant differences (P < 0.05) in the age-adjusted GM PSA levels for the groups with BMI <25 (1.05 ng/mL) and BMI > or =25 kg/m(2) (0.97 ng/mL). Similarly, there were significant differences (P < 0.05) in the age-adjusted GM PSA levels in those with a BMI of <30 (1.03 ng/mL) and > or =30 kg/m(2) (0.85 ng/mL). CONCLUSION These data suggest that the BMI in Chinese men in Singapore is significantly associated with PSA levels, especially among the obese men aged 70-79 years.

Incidence, mortality and survival patterns of prostate cancer among residents in Singapore from 1968 to 2002.

BACKGROUND: From 1968 to 2002, Singapore experienced an almost four-fold increase in prostate cancer incidence. This paper examines the incidence, mortality and survival patterns for prostate cancer among all residents in Singapore from 1968 to 2002. METHODS: This is a retrospective population-based cohort study including all prostate cancer cases aged over 20 (n = 3613) reported to the Singapore Cancer Registry from 1968 to 2002. Age-standardized incidence, mortality rates and 5-year Relative Survival Ratios (RSRs) were obtained for each 5-year period. Follow-up was ascertained by matching with the National Death Register until 2002. A weighted linear regression was performed on the log-transformed age-standardized incidence and mortality rates over period. RESULTS: The percentage increase in the age-standardized incidence rate per year was 5.0%, 5.6%, 4.0% and 1.9% for all residents, Chinese, Malays and Indians respectively. The percentage increase in age-standardized mortality rate per year was 5.7%, 6.0%, 6.6% and 2.5% for all residents, Chinese, Malays and Indians respectively. When all Singapore residents were considered, the RSRs for prostate cancer were fairly constant across the study period with slight improvement from 1995 onwards among the Chinese. CONCLUSION: Ethnic differences in prostate cancer incidence, mortality and survival patterns were observed. There has been a substantial improvement in RSRs since the 1990s for the Chinese.

Prostate-specific antigen levels among Chinese, Malays and Indians in Singapore from a community-based study.

The purpose of this study was to examine the distribution of prostate-specific antigen levels among Chinese, Malays and Indians in Singapore, taking the effect of age into consideration. The study was carried out as part of the Singapore Prostate Awareness Week from 23-26th February 2004. Men above 50 years old went to four government-restructured hospitals to participate in the study. Participants filled up a questionnaire and provided 5 ml of blood for measurement of PSA levels using the Abbott IMx Total PSA assay (Abbott Laboratories). 3,486 men responded to the study, comprising 92.8% Chinese, 3.0% Malays, 2.5% Indians and 1.8% Others. 92.7% of them had PSA levels of 4 microg/L or less. There were no significant differences (p<0.05) between the mean PSA levels of Chinese (1.60 microg/L), Malays (1.39 microg/L), Indians (1.23 microg/L) and Others (1.70 microg/L). PSA levels were significantly associated with age (Spearman's r= 0.27, p<0.01). PSA levels increased with each 10-year age group and these trends were significant (p<0.0001) across both PSA group levels and age groupings. In the 50-60 years age groups, the prevalence of PSA levels >4 mug/L were 1.1% and 3.7% respectively. This rose rapidly to 11.3% and 23.5% for age groups >60-70 and >80 years respectively. Our study shows that the median PSA levels in the Caucasian population in the USA are higher than those of Chinese, Malays and Indians in Singapore. PSA levels were positively associated with age. It may be more appropriate to offer PSA testing to men who are >60 years old rather than the current >50 years.

Secular trends of nasopharyngeal carcinoma incidence in Singapore, Hong Kong and Los Angeles Chinese populations, 1973-1997.

Nasopharyngeal carcinoma (NPC) is a rare cancer in most parts of world, but rather common in Southern China and Southeast Asia. This study used IARC published datasets to explore the secular trends of incidence rates of NPC among different Chinese populations in Singapore, Hong Kong and Los Angeles, over the time period 1973-1997. We observed great disparity in the risks and time trends of NPC in those selected Chinese populations. The highest risk was in Hong Kong where the incidence rates have declined rapidly throughout the whole study period in both males and females. For Singapore Chinese, the incidence rates also dropped recently in both genders, but the low incidence rates in Los Angeles Chinese have remained essentially unchanged over time. We further assessed the contribution of period and cohort effects to the observed trends in Hong Kong and Singapore populations through age-period-cohort modeling and found that an age-cohort model provided the best fit to the data in both populations, although for Singapore females a simple age-drift model fit the data well. There was a statistically significant decrease in the drop in incidence of NPC for cohorts born around 1940 in Hong Kong and 1958 in Singapore. This indicates that environmental and lifestyle changes play an important role in the declining incidence of NPC over time.

The associations among semen quality, oxidative DNA damage in human spermatozoa and concentrations of cadmium, lead and selenium in seminal plasma.

To explore the associations among semen quality, oxidative DNA damage in human spermatozoa and concentrations of cadmium, lead and selenium in seminal plasma, 56 non-smoking subjects were asked to collect semen by masturbation into a sterile wide-mouth metal-free plastic container after 3 days of abstinence. The conventional semen parameters were analysed. The concentrations of Cd, Pb and Se in seminal plasma were detected using atomic absorption spectrophotometer. 8-OHdG levels in sperm DNA were measured using HPLC-EC. The results showed that the geometric mean concentrations of Cd, Pb and Se were 0.78, 7.8 and 51.4 microg/l, respectively. The geometric mean of 8-OHdG/10(6) dG was 51.4 (95% CI: 21.5-123.0). A significant inverse correlation exists between Cd and sperm density (r=-0.28, P<0.05), and between Cd and sperm number per ejaculum (r=-0.27, P<0.05). In contrast, there was a significantly positive correlation between Se and sperm density (r=0.50, P<0.01), between Se and sperm number (r=0.49, P<0.01), between Se and sperm motility (r=0.40, P<0.01), and between Se and sperm viability (r=0.38, P<0.01). No statistically significant correlation was observed between Pb and semen quality. A significant inverse correlation was observed between 8-OHdG and sperm density (r=-0.34, P<0.01), between 8-OHdG and sperm number per ejaculum (r=-0.30, P<0.01), and 8-OHdG and sperm viability (r=-0.24, P<0.05). 8-OHdG was significantly correlated with Cd in seminal plasma (r=0.55, P<0.01). A significant but weak positive correlation was found between 8-OHdG and Pb concentration in seminal plasma (r=0.28, P<0.05). In contract, a significant inverse correlation was observed between 8-OHdG and Se concentration in seminal plasma (r=-0.40, P<0.01). The results indicate that Cd in seminal plasma could affect semen quality and oxidative DNA damage in human spermatozoa. Se could protect against oxidative DNA damage in human sperm cells. Pb did not appear to have any association with the semen quality when concentration of Pb in seminal plasma was below 10 microg/l.