National Registry of Diseases Office

Singapore, Singapore

National Registry of Diseases Office

Singapore, Singapore

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Jin A.,National Registry of Diseases Office | Koh W.-P.,National University of Singapore | Chow K.Y.,National Registry of Diseases Office | Yuan J.-M.,University of Pittsburgh | Jafar T.H.,National University of Singapore
PLoS ONE | Year: 2013

Background:The relationship between smoking and risk of kidney failure, especially in people of Chinese origin, is not clear. We analyzed data from the Singapore Chinese Health Study to investigate whether smoking increases the risk of kidney failure.Methods:The Singapore Chinese Health Study is a population-based cohort of 63,257 Chinese adults enrolled between 1993 and 1998. Information on smoking status was collected at baseline. Incidence of kidney failure was identified via record linkage with the nationwide Singapore Renal Registry until 2008. Kidney failure was defined by one of the following: 1) serum creatinine level of more than or equal to 500 μmol/l (5.7 mg/dl), 2) estimated glomerular filtration rate of less than 15 ml/min/1.73 m2, 3) undergoing hemodialysis or peritoneal dialysis, 4) undergone kidney transplantation. Cox proportional hazard regression analysis was performed for the outcome of kidney failure after adjusting for age, education, dialect, herbal medications, body mass index, sex, physician-diagnosed hypertension and diabetes mellitus.Results:The mean age of subjects was 55.6 years at baseline, and 44% were men. Overall 30.6% were ever smokers (current or former) at baseline. A total of 674 incident cases of kidney failure occurred during a median follow-up of 13.3 years. Among men, smokers had a significant increase in the adjusted risk of kidney failure [hazard ratio (HR): 1.29; 95% CI: 1.02-1.64] compared to never smokers. There was a strong dose-dependent association between number of years of smoking and kidney failure, (p for trend = 0.011). The risk decreased with prolonged cessation (quitting ≥10 years since baseline). The number of women smokers was too few for conclusive relationship.Limitation:Information on baseline kidney function was not available.Conclusions:Cigarette smoking is associated with increased risk of kidney failure among Chinese men. The risk appears to be dose- and duration-dependent and modifiable after long duration of cessation. © 2013 Jin et al.


Cheung C.Y.-L.,Singapore Eye Research Institute | Cheung C.Y.-L.,National University of Singapore | Cheung C.Y.-L.,Quantitative Medicine | Tay W.T.,Singapore Eye Research Institute | And 8 more authors.
Stroke | Year: 2013

Background and Purpose - To examine the relationship between retinal microvascular measures and incident stroke in an Asian Malay population. Methods - We conducted a prospective, population-based cohort study of Asian Malay persons 40 to 80 years at baseline. Retinal microvascular signs were assessed from baseline retinal photographs including quantitative retinal microvascular parameters (caliber, branching angle, tortuosity, and fractal dimension) and qualitative retinopathy signs. Incident stroke cases were identified during the follow-up period. Cox proportional-hazards regression and incremental usefulness analysis (calibration, discrimination, and reclassification) were performed. Results - A total of 3189 participants were free of prevalent stroke at baseline. During the follow-up (median, 4.41 years), 51 (1.93%) participants had an incident stroke event. In Cox proportional-hazards models adjusting for established stroke predictors (age, sex, systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, smoking, glycosylated hemoglobin, and antihypertensive medication), retinopathy (hazard ratio, 1.94; 95% confidence interval, 1.01-3.72) and larger retinal venular caliber (hazard ratio, 3.28; 95% confidence interval, 1.30-8.26, comparing fourth versus first quartiles) were associated with risk of stroke. Compared with the model with only established risk factors, the addition of retinal measures improved the prediction of stroke (C-Statistic 0.826 versus 0.792; P=0.017) and correctly reclassified 5.9% of participants with incident stroke and 3.4% of participants with no incident stroke. Conclusions - Retinal microvascular changes are related to an increased risk of stroke in Asian Malay, consistent with data from white populations. Retinal imaging improves the discrimination and stratification of stroke risk beyond that of established risk factors by a significant but small margin. © 2013 American Heart Association, Inc.


Ainslie-Waldman C.E.,University of Minnesota | Koh W.-P.,National University of Singapore | Jin A.,National Registry of Diseases Office | Yeoh K.G.,National University of Singapore | And 4 more authors.
Cancer Epidemiology Biomarkers and Prevention | Year: 2014

Background: Despite experimental evidence showing chemopreventive effects of coffee-related compounds on gastric carcinogenesis, epidemiologic studies generally do not support coffee-gastric cancer associations. Observational data are lacking among high-risk populations with sufficient regular coffee consumption. Methods: We examined the association between caffeinated coffee intake and gastric cancer risk in a population-based cohort that enrolled 63,257 Chinese men and women ages 45 to 74 years between 1993 and 1998 in Singapore. Incident gastric cancer cases (n = 647) were identified after a mean follow-up of 14.7 years. Biomarkers of Helicobacter pylori (H. pylori) infection were measured in a subset of gastric cancer cases with blood collected before cancer diagnosis and their matched controls. Results: In the total cohort, daily versus nondaily coffee intake was associated with a statistically nonsignificant decrease in gastric cancer risk [HR = 0.85; 95% confidence interval (CI), 0.69-1.04]. In women, the inverse association strengthened and reached statistical significance (HR = 0.63; 95% CI, 0.46-0.87). In analyses restricted to never smokers and nondrinkers of alcohol, inverse associations strengthened in the total cohort (HR = 0.69; 95% CI, 0.52-0.91) and in women (HR = 0.52; 95% CI, 0.37-0.74). There was no coffee-gastric cancer risk association among men, regardless of smoking status or alcohol consumption. Similar results were observed in the nested case-control study after adjustment for H. pylori infection. Conclusion: Daily coffee consumption may reduce the risk of gastric cancer in high-risk populations, especially among women. Impact: Research aimed at identifying the compounds in coffee that may protect against gastric carcinogenesis is warranted. © 2014 AACR.


Lim W.-Y.,National University of Singapore | Tan C.S.,National University of Singapore | Loy E.Y.,National Registry of Diseases Office | Omkar Prasad R.,National University of Singapore | And 2 more authors.
Lung Cancer | Year: 2014

Objectives: Lung cancer is the leading cause of cancer death in Singapore. We examine trends of lung cancer from 1968 to 2007, explore ethnic and gender-specific incidence rates, and examine period and cohort effects in Chinese and Malays using Age-Period-Cohort (APC) analysis. Methods: Aggregated data for cancer incidences and estimated person-years for the period 1968-2007 were obtained from the Singapore Cancer Registry. An APC analysis was performed using a Poisson regression model. Results: Lung cancer incidence rates were more than two times higher in males compared to females, and also higher in Chinese compared to Malays and Indians. While rates in Chinese men, and, to a lesser extent, Chinese women, had been declining since the early 1980s, rates in Malay men continued to increase. The full APC model described the cancer trend in Chinese males, Chinese females and Malay males, while an age-drift model described the cancer trend in Malay females. Among Chinese males, Chinese females and Malay males, there was no clear pattern to the period curvature effects, although similar cohort curvatures were seen, with positive curvature effects in older cohorts that declined towards zero and negative effects in younger cohorts. Conclusion: There are strong gender and ethnic differences in lung cancer incidence in Singapore. Differences in smoking rates and differential ethnic effects of smoking may explain some but not all of these differences. The similar cohort curvatures suggest that environmental factors in Singapore occurring in the past but no longer present at similar intensity or frequency may explain the positive deviation from a linear trend. Apart from smoking, other environmental factors such as changes in diet, improved sanitation and ventilation, and declines in infectious diseases like tuberculosis may play a role. © 2014 Elsevier Ireland Ltd.


Koh W.-P.,National University of Singapore | Nelson H.H.,University of Minnesota | Yuan J.-M.,University of Minnesota | van den Berg D.,University of Southern California | And 3 more authors.
Carcinogenesis | Year: 2011

Cigarette smoking is a risk factor for colorectal cancer. Putative colorectal procarcinogens in tobacco smoke include polycyclic aromatic hydrocarbons and heterocyclic aromatic amines that are known substrates of glutathione S-transferases (GSTs). This study examined the influence of functional GST gene polymorphisms on the smoking-colorectal cancer association in a population known to be minimally exposed to dietary sources of these procarcinogens. Incident cases of colorectal cancer (n = 480) and matched controls (n = 1167) were selected from the Singapore Chinese Health Study, a population-based prospective cohort of 63 257 men and women who have been followed since 1993. We determined the deletion polymorphisms of GSTM1 and GSTT1 and the functional polymorphism at codon 105 of GSTP1 for each subject. A three level composite GST index was used to examine if GST profile affected a smoker's risk of developing colorectal cancer. While there was no statistically significant association between cigarette smoking and colorectal cancer risk among subjects absent of any at-risk GST genotypes, smokers possessing two to three at-risk GST genotypes exhibited a statistically significant increased risk of colorectal cancer compared with nonsmokers (P = 0.0002). In this latter stratum, heavy smokers exhibited a >5-fold increased risk relative to never-smokers (odds ratio, 5.43; 95% confidence interval, 2.22-13.23). Subjects with one at-risk GST genotype displayed a statistically significant but weaker association with smoking. These findings suggest that GST gene polymorphisms influence interindividual susceptibility to smoking-associated colorectal cancer. Our data indicate an important role for GST enzymes in the detoxification of colorectal carcinogens in tobacco smoke. © The Author 2011. Published by Oxford University Press. All rights reserved.


Koh W.-P.,National University of Singapore | Van Den Berg D.,University of Southern California | Jin A.,National Registry of Diseases Office | Wang R.,University of Minnesota | And 2 more authors.
Breast Cancer Research and Treatment | Year: 2011

The MDM2 oncoprotein regulates the p53 pathway and, while functional polymorphisms of the MDM2 and p53 genes have been investigated for association with breast cancer risk, results are largely null or non-conclusive. We have earlier reported that the increased intake of soy isoflavones reduces risk of postmenopausal breast cancer, and experimental studies suggest that dietary isoflavones can down-regulate the expression of the MDM2 oncoprotein. In this study, we investigated the association between the MDM2 SNP309 and TP53 R72P polymorphisms and breast cancer risk using a case-control study of 403 cases and 662 controls nested among 35,303 women in The Singapore Chinese Health Study, a population-based, prospective cohort of middle-aged and elderly men and women who have been continuously followed since 1993. The G allele of the TP53 R72P polymorphism and T allele of the MDM2 SNP309 polymorphism were putative high-risk alleles and exhibited a combined gene-dose-dependent joint effect on breast cancer risk that was more clearly observed in postmenopausal women. Among postmenopausal women, the simultaneous presence of G allele in TP53 and T allele in MDM2 polymorphisms was associated with an odds ratio (OR) of 2.42 [95% confidence interval (CI) 1.06-5.50]. Furthermore, the protective effect of dietary soy isoflavones on postmenopausal breast cancer was mainly confined to women homozygous for the high activity MDM2 allele (GG genotype). In this genetic subgroup, women consuming levels of soy isoflavones above the median level exhibited risk that was half of those with below median intake (OR 0.52; 95% CI 0.28-0.99). Our findings support experimental data implicating combined effects of MDM2 protein and the p53-mediated pathway in breast carcinogenesis, and suggest that soy isoflavones may exert protective effect via down-regulation of the MDM2 protein. © 2011 Springer Science+Business Media, LLC.


Gay G.M.W.,National University of Singapore | Lim J.S.P.,National University of Singapore | Chay W.Y.,National Cancer Center Singapore | Chow K.Y.,National Registry of Diseases Office | And 2 more authors.
Cancer Causes and Control | Year: 2015

Purpose: The aim of this study was to assess associations of breastfeeding, adiposity and reproductive risk factors with ovarian cancer risk in a Singaporean population. In addition to the main analysis, interaction effects of parity on other risk factors were examined. Methods: A retrospective cohort consisting of 28,201 women with 107 incident ovarian cancers in up to 17 years of follow-up from the Singapore Breast Cancer Screening Project (1994–1997) was studied. Hazard ratios (HRs) for risk factors were estimated using Cox proportional hazards models. Results: Body mass index and breastfeeding were found to have no statistical significant association with ovarian cancer risk. Gravidity was inversely associated with ovarian cancer risk [each pregnancy, adjusted HR 0.89, 95 % confidence interval (CI) 0.81, 0.97], while results for parity were very similar (per delivery, HR 0.89, 95 % CI 0.81, 0.98). Each additional year of ovulatory period was found to increase ovarian cancer risk by 2 % (HR 1.02, 95 % CI 1.00, 1.04). Each year increase in total duration of oral contraceptive use reduced ovarian cancer risk by 6 % (HR 0.94, 95 % CI 0.85, 1.02). Conclusions: Parity, gravidity and shorter ovulatory period were associated with lower ovarian cancer risk. Breastfeeding and body mass index were not associated with ovarian cancer risk, while increased duration of oral contraceptive use resulted in borderline risk reduction. No significant evidence was found to suggest that parity had an interaction effect on any risk factor. © 2015, Springer International Publishing Switzerland.


Lim G.H.,National Registry of Diseases Office | Lim G.H.,Health Services Research and Evaluation Division | Chow K.Y.,National Registry of Diseases Office | Lee H.P.,National University of Singapore
Singapore Medical Journal | Year: 2012

In this review, we examine the trends in cancer incidence, mortality and survival in the last decade, using published data from the Singapore Cancer Registry in the period 1998 to 2009. While overall cancer incidences have remained stable, overall cancer mortality rates have declined for both genders. Thus, it is not surprising that there was an improvement in cancer survival. A steady decrease in lung cancer among males and females was observed, thereby leading to a drop in its cancer ranking. In the last five years, the most frequently occurring cancer was colorectal cancer among the male population and breast cancer among females. Survival for both cancers remained relatively optimistic. There is good reason to pay special attention to colorectal cancer due to its high frequency of occurrence among the Singapore population and because it is amenable to early detection via screening.


Jin A.Z.,National Registry of Diseases Office | Louange E.C.,Health Integrated | Chow K.Y.,National Registry of Diseases Office | Fock C.W.L.,Health Integrated
Singapore Medical Journal | Year: 2013

INTRODUCTION A retrospective observational study was performed to evaluate the effectiveness of CervicalScreen Singapore (CSS), a National Cervical Cancer Screening Programmme. METHODS National trends on incidence, mortality of cervical cancer and carcinoma in situ of the cervix before and after the launch of CSS were examined. Linear regression was used to calculate the average annual percentage change in age-standardised incidence and mortality rates. We also examined the operational measures of CSS, such as the women who joined the CSS programme and the diagnostic accuracy of Pap smears. The study was confined to women who consented to join CSS at government-funded polyclinics. RESUlTS Nationally, there was a greater decline in the age-standardised incidence and mortality rates in the period 2004-2008 as compared to the period 1987-2003. Under CSS, a total of 99,759 Pap smears were performed on 81,087 women in the period 2004-2008. However, the number of first screens decreased from 18,434 in 2004 to 11,624 in 2008. Among women aged 25-69 years who had their first Pap smear screening and who were recommended for routine rescreen in three years, 10% had a subsequent rescreen within three years. Overall, the CSS programme was able to detect 0.37 invasive cancers per 1,000 screens in women aged 25-69 years. CONClUSION The CSS programme has contributed to a decline in the mortality and incidence of cervical cancer in Singapore. However, the challenges of increasing the screening uptake among eligible women need to be addressed.


Loy E.Y.,National Registry of Diseases Office
Annals of the Academy of Medicine, Singapore | Year: 2013

The aim of this study is to investigate the risk of cancer among end-stage renal disease (ESRD) patients on dialysis in Singapore. The study looks at a retrospective cohort of 5505 ESRD patients who had received dialysis between 1998 and 2007. The cancer risk of these patients would be compared against the risk of the general population. During a median follow-up time of 3.9 years, 267 (4.9%) dialysis patients developed cancer. The risk of cancer (excluding non-melanoma skin cancer) is 1.66 times higher in dialysis patients than the general population, and is highest at age less than 35 years old and at first year after dialysis. Cancer risk was found to be significantly higher among Chinese dialysis patients, followed by Malays, compared to the general population. The 3 sites with highest elevated cancer risks among dialysis patients compared to the general population are kidney, tongue and multiple myeloma. The finding of elevated cancer risk among younger dialysis patients is similar to other international studies. High cancer risks among specific cancer sites were also consistent with other studies. In view of the lack of screening procedures for these cancers and shortened expected survival of ESRD patients, cancer screening of ESRD patients should be individualised and based on a reasonable life expectancy and transplant candidacy, keeping in mind the competing risk of cardiovascular mortality.

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