Data quality at the Singapore Cancer Registry: An overview of comparability, completeness, validity and timeliness.

AIM: To provide a comprehensive evaluation of the quality of the data at the Singapore Cancer Registry (SCR). METHODS: Quantitative and semi-quantitative methods were used to assess the comparability, completeness, accuracy and timeliness of data for the period of 1968-2013, with focus on the period 2008-2012. RESULTS: The SCR coding and classification systems follow international standards. The overall completeness was estimated at 98.1% using the flow method and 97.5% using the capture-recapture method, for the period of 2008-2012. For the same period, 91.9% of the cases were morphologically verified (site-specific range: 40.4-100%) with 1.1% DCO cases. The under-reporting in 2011 and 2012 due to timely publication was estimated at 0.03% and 0.51% respectively. CONCLUSION: This review shows that the processes in place at the SCR yields data which are internationally comparable, relatively complete, valid, and timely, allowing for greater confidence in the use of quality data in the areas of cancer prevention, treatment and control.

Evaluation of health outcomes in osteoarthritis patients after total knee replacement: a two-year follow-up.

OBJECTIVES: To quantify the improvement in health outcomes in patients after total knee replacement (TKR). METHODS: This was a two-year non-randomized prospective observational study in knee osteoarthritis (OA) patients undergone TKR. Patients were interviewed one week before, six months after, and two years after surgery using a standardized questionnaire including the SF-36, the Oxford Knee Score (OKS), and the Knee Society Clinical Rating Scale (KSS). A generalized estimating equation (GEE) model was used to estimate the magnitudes of the changes with and without the adjustment of age, ethnicity, BMI, and years with OA. RESULTS: A total of 298 (at baseline), 176 (at six-months), and 111 (at two-years) eligible patients were included in the analyses. All the scores changed significantly over time, with the exception of SF-36 social functioning, vitality, and mental health. With the adjustment of covariates, the magnitude of changes in these scores was similar to those without the adjustment. CONCLUSIONS: Both general and knee-specific physical functioning had been significantly improved after TKR, while other health domains have not been substantially improved after the surgery.

Total or partial knee replacement? Cost-utility analysis in patients with knee osteoarthritis based on a 2-year observational study.

The objective of this study was to evaluate incremental cost-utility of total knee replacement (TKR) versus unicompartmental knee arthroplasty (UKA) in patients with knee osteoarthritis (OA) of the medial compartment. A 2-year non-randomised prospective observational cohort study was conducted in unicompartmental knee osteoarthritis patients scheduled for TKR (n = 431) or UKA (n = 102). Costs were identified using administrative databases and health outcomes were measured using the SF-36 and the Oxford knee score (OKS) 1 week before, 6 months after, and 2 years after surgery. The incremental cost-utility ratio (ICUR) for TKR versus UKA was calculated and its 95% confidence interval estimated using a nonparametric bootstrapping technique. Cost-effectiveness acceptability curves were constructed from different perspectives. On average, from the societal perspective, the ICUR was US $65,245 per quality-adjusted life-year (QALY). In the scenario with costs calculated from the perspective of patients, the ICUR was $60,382/QALY. This value decreased to $4,860/QALY in the scenario with costs calculated from the governmental perspective. However, the 95% confidence interval of ICURs cannot be defined because more than 5% bootstrapped samples fell into the upper left quadrant of the cost-effectiveness plane from all three perspectives. Based on the 2-year data, TKR gained more QALYs at higher costs compared to UKA. A long-term prospective study is necessary to determine cost-effectiveness of TKR and UKA.

BMI and diabetes risk in Singaporean Chinese.

OBJECTIVE: Increased BMI is a robust risk factor for type 2 diabetes. Paradoxically, South Asians have relatively low BMIs despite their high prevalence of type 2 diabetes. We examined the association between BMI and incident type 2 diabetes because detailed prospective cohort data on this topic in Asians are scarce. RESEARCH DESIGN AND METHODS: This study was a prospective analysis of 37,091 men and women aged 45-74 years in the Singapore Chinese Health Study, using Cox regression analysis. RESULTS: Risk of incident type 2 diabetes significantly increased beginning with BMIs 18.5-23.0 kg/m(2)(relative risk 2.47 [95% CI 1.75-3.48]) and continued in a monotonic fashion across the spectrum of BMI. Results were stronger for younger than for older adults. CONCLUSIONS: BMIs considered lean and normal in Singaporean Chinese are strongly associated with increased risk of incident type 2 diabetes. This association weakened with advanced age but remained significant.

Reproductive variables, soy intake, and lung cancer risk among nonsmoking women in the Singapore Chinese Health Study.

Lung cancer among nonsmokers has emerged as a distinct clinicopathologic entity for which the etiology is still poorly understood, but which accounts for a significant proportion of the lung cancers among women. Although estrogens have been shown to have mitogenic effects in lung cells and interact with growth factor pathways in tumorigenesis, epidemiologic evidence for a link between reproductive hormones and lung cancer is sparse and inconsistent. We examined the effect of parity, age at menarche/menopause, cycle length and use of exogenous hormones, and dietary soy and soy isoflavonoid intake on lung cancer risk in a prospective cohort of middle-aged and elderly Chinese women in Singapore among whom 91% were lifetime nonsmokers. Among 35,298 women (mean follow-up time, 9.6 years), 298 cases of incident lung cancer were recorded, of which 189 (63.4%) occurred in nonsmokers. Compared with nulliparous women, those with one to two, three to four, and more than five livebirths had relative risks of between 0.49 and 0.59 (P for trend<0.01) for all lung cancers, and between 0.32 and 0.42 (P for trend<0.001) for adenocarcinomas. This relationship was observed in both smokers and nonsmokers. Age at menarche and menopause did not seem to influence risk. Dietary soy isoflavonoid intake was associated with a statistically significant inverse trend among nonsmokers only (relative risks, 0.59 for highest versus lower quartile; P for trend, 0.021). These findings add support for the role of hormonal factors in the etiology of lung cancer among nonsmoking women, and are consistent with emerging experimental evidence in this regard.

New ISSCR guidelines underscore major principles for responsible translational stem cell research.

The International Society for Stem Cell Research (ISSCR) task force that developed new Guidelines for the Clinical Translation of Stem Cells discusses core principles that should guide the responsible transition of basic stem cell research into appropriate clinical applications.

Coffee, tea, and incident type 2 diabetes: the Singapore Chinese Health Study.

BACKGROUND: Increasing coffee intake was inversely associated with risk of type 2 diabetes in populations of European descent; however, data from high-risk Asian populations are lacking as are data on tea intake in general. OBJECTIVE: We investigated the prospective associations between intakes of coffee, black tea, and green tea with the risk of type 2 diabetes in Singaporean Chinese men and women. DESIGN: We analyzed data from 36 908 female and male participants in the Singapore Chinese Health Study aged 45-74 y in 1993-1998 who had multiple diet and lifestyle measures assessed and then were followed up between 1999 and 2004. We used Cox regression models to investigate the association of baseline coffee and tea intakes with incident type 2 diabetes during follow-up, with adjustment for a number of possible confounding or mediating variables. RESULTS: In multivariate models participants reporting > or =4 cups of coffee/d had a 30% reduction in risk of diabetes [relative risk (RR): 0.70; 95% CI: 0.53, 0.93] compared with participants who reported nondaily consumption. Participants reporting > or =1 cup of black tea/d had a suggestive 14% reduction in risk of diabetes (RR: 0.86; 95% CI: 0.74, 1.00) compared with participants who reported 0 cups/d, and we observed no association with green tea. CONCLUSION: Regular consumption of coffee and potentially black tea, but not green tea, is associated with lower risk of type 2 diabetes in Asian men and women in Singapore.

Sleep duration and coronary heart disease mortality among Chinese adults in Singapore: a population-based cohort study.

While some studies have found a positive association between both short and long sleep durations and cardiovascular disease (CVD), others have found an association only with a long or short sleep duration. In addition, there are limited data from non-Western populations on this topic. The authors examined the association between sleep duration and coronary heart disease (CHD) mortality among Chinese adults in Singapore (1993-2006), performing a prospective cohort study among 58,044 participants aged > or =45 years (55.9% women) without preexisting CVD. The main outcome of interest was CHD mortality (n = 1,416). The authors found both short and long sleep durations to be positively associated with CHD mortality, independent of smoking, alcohol intake, and body mass index. Compared with persons with a sleep duration of 7 hours (referent), the multivariable relative risk of CHD mortality for a sleep duration of < or =5 hours was 1.57 (95% confidence interval: 1.32, 1.88); for a sleep duration of > or =9 hours, it was 1.79 (95% confidence interval: 1.48, 2.17). This association persisted in subgroup analyses by sex and body mass index. In a population-based cohort of Chinese adults from Singapore, sleep durations of < or =5 hours and > or =9 hours (versus 7 hours) were modestly associated with CHD mortality. These results suggest that sleep duration may be an important marker for CVD.

Incense use and respiratory tract carcinomas: a prospective cohort study.

BACKGROUND: Incense use is an integral part of daily life in large parts of Asia. The burning of incense is a powerful producer of particulate matter and the smoke contains a multitude of well-characterized carcinogens. However, to the authors' knowledge, no convincing association has been reported between exposure to incense smoke and the development of cancer. Therefore, the relation between incense use and the risk of respiratory tract carcinomas was analyzed in a prospective cohort study. METHODS: Between 1993 and 1998, a population-based cohort of 61,320 Singapore Chinese who were free of cancer and ages 45 to 74 years completed a comprehensive interview regarding living conditions and dietary and lifestyle factors. Through linkage to population-based registries, the cohort was followed through 2005 and cancer occurrence determined. The relative risk for these cancers associated with incense use was estimated using a Cox proportional hazards model. RESULTS: A total of 325 upper respiratory tract (UPT) carcinomas and 821 lung carcinomas were observed during follow-up. Incense use was associated with a significantly increased risk of UPT carcinomas other than nasopharyngeal, whereas no overall effect was observed on lung cancer. The duration and intensity of incense use were associated with an increased risk of squamous cell carcinomas in the entire respiratory tract (P for trend = .004), whereas there was no significant association noted between incense use and nonsquamous cell carcinomas. The relative risk of squamous cell carcinomas among long-term incense users was 1.8 (95% confidence interval [95% CI], 1.2-2.6; P = .004) in the entire respiratory tract. CONCLUSIONS: The results of the current study indicate that long-term use of incense is associated with an increased risk of squamous cell carcinoma of the respiratory tract.

Chronic rhinosinusitis and risk of lung cancer in the Singapore Chinese Health Study.

Epidemiologic evidence suggests that chronic inflammatory conditions of the lung may increase lung cancer risk. These chronic conditions, such as chronic obstructive pulmonary disease and asthma, commonly coexist with chronic rhinosinusitis. We prospectively examined if chronic rhinitis or sinusitis was associated with lung cancer risk in the Singapore Chinese Health Study, a population-based cohort of 63,257 Singapore Chinese, who were aged 45-74 years when recruited between 1993 and 1998. Each subject completed a comprehensive interview on medical conditions, dietary and lifestyle factors at recruitment, and cancer occurrence and survival status were determined via linkage to population-based registries. As of 31 December, 2005, 954 cohort participants had developed lung cancer. Compared with subjects without such history, subjects who reported a history of physician-diagnosed rhinitis or sinusitis at baseline, whether allergic or nonallergic, had a statistically significant 59% increase in risk of lung cancer (hazard ratio [HR] = 1.59; confidence interval [CI] = 1.06-2.37). This association was significant and stronger in women (HR = 2.32; 95% CI = 1.23-4.39) compared to men, and for the adenocarcinoma cell type (HR = 1.91; 95% CI = 1.07-3.42) compared to other histologies. Overall, a history of asthma, hay fever, allergic dermatitis, food allergy or any other allergic conditions asked in a single question was not related to lung cancer risk (HR = 1.11; 95% CI = 0.90-1.36). Chronic rhinosinusitis may be a marker of pan-airway inflammation and its association with lung cancer risk provides evidence linking inflammation to lung carcinogenesis, especially among women.

Cost effectiveness analysis of population-based serology screening and (13)C-Urea breath test for Helicobacter pylori to prevent gastric cancer: a markov model.

AIM: To compare the costs and effectiveness of no screening and no eradication therapy, the population-based Helicobacter pylori (H pylori) serology screening with eradication therapy and (13)C-Urea breath test (UBT) with eradication therapy. METHODS: A Markov model simulation was carried out in all 237900 Chinese males with age between 35 and 44 from the perspective of the public healthcare provider in Singapore. The main outcome measures were the costs, number of gastric cancer cases prevented, life years saved, and quality-adjusted life years (QALYs) gained from screening age to death. The uncertainty surrounding the cost-effectiveness ratio was addressed by one-way sensitivity analyses. RESULTS: Compared to no screening, the incremental cost-effectiveness ratio (ICER) was $16166 per life year saved or $13571 per QALY gained for the serology screening, and $38792 per life year saved and $32525 per QALY gained for the UBT. The ICER was $477079 per life year saved or $390337 per QALY gained for the UBT compared to the serology screening. The cost-effectiveness of serology screening over the UBT was robust to most parameters in the model. CONCLUSION: The population-based serology screening for H pylori was more cost-effective than the UBT in prevention of gastric cancer in Singapore Chinese males.

Sleep duration, melatonin and breast cancer among Chinese women in Singapore.

BACKGROUND: Sleep duration has been hypothesized to be inversely associated with breast cancer risk, possibly due to greater overall melatonin production in longer sleepers. However, data are inconclusive from the three studies conducted in Western populations on sleep duration and breast cancer risk. METHODS: We investigated the relationship between self-reported usual sleep duration determined at baseline and subsequent risk of breast cancer in the prospective, population-based cohort of the Singapore Chinese Health Study. We excluded from the study women with <2 years of follow-up due to possible change in sleep pattern among breast cancer cases close to the time of diagnosis. Five hundred and twenty-five incident cases of breast cancer were identified among the remaining 33 528 women after up to 11 years of follow-up. RESULTS: Among women postmenopausal at baseline, breast cancer risk decreased with increasing sleep duration (P trend = 0.047); those who reported 9+ h of sleep showed a relative risk of 0.67 (95% confidence interval = 0.4-1.1) compared with women who reported < or =6 h of sleep. This inverse association was observed primarily in lean women [i.e. body mass index below the median value (23.2 kg/m(2))] (P = 0.024). In this study population, irrespective of gender, urinary 6-sulfatoxymelatonin levels increased with increasing self-reported hours of sleep (P trend = 0.035) after adjustment for age and time of day of urine collection. Melatonin levels were 42% higher in those with 9+ versus those with < or =6 h of sleep. CONCLUSION: Sleep duration may influence breast cancer risk, possibly via its effect on melatonin levels.

Cost-effectiveness analysis of Helicobacter pylori screening in prevention of gastric cancer in Chinese.

OBJECTIVES: The aim of this study was to evaluate the costs and effectiveness associated with no screening, Helicobacter pylori serology screening, and the 13C-urea breath test (UBT) for gastric cancer in the Chinese population. METHODS: A Markov model simulation was carried out in Singaporean Chinese at 40 years of age (n = 478,500) from the perspective of public healthcare providers. The main outcome measures were costs, number of gastric cancer cases prevented, life-years saved, quality-adjusted life-years (QALYs) gained from the screening age to death, and incremental cost-effectiveness ratios (ICERs), which were compared among the three strategies. The uncertainty surrounding ICERs was addressed by scenario analyses and probabilistic sensitivity analysis using Monte Carlo simulation. RESULTS: The ICER of serology screening versus no screening was $25,881 per QALY gained (95 percent confidence interval (95 percent CI), $5,700 to $120,000). The ICER of UBT versus no screening was $53,602 per QALY gained (95 percent CI, $16,000 to $230,000). ICER of UBT versus serology screening was $470,000 per QALY gained, for which almost all random samples of the ICERs distributed above $50,000 per QALY. CONCLUSIONS: It cannot be confidently concluded that either H pylori screening was a cost-effective strategy compared with no screening in all Chinese at the age of 40 years. Nevertheless, serology screening has demonstrated much more potential to be a cost-effective strategy, especially in the population with higher gastric cancer prevalence.

Graduate public health education--Singapore's contribution to strengthening capacity in the region and beyond.

The year 2008 marks the 55th anniversary of the graduate public health programme in Singapore. This article traces the evolution of the programme-from the Diploma in Public Health in 1953 to the Master of Public Health in 2007--in response to changing challenges and needs. It also discusses the role Singapore can continue to play in addressing global inequities in access to public health education and in strengthening public health capacity in the region and beyond.

Morbidity and mortality in relation to smoking among women and men of Chinese ethnicity: the Singapore Chinese Health Study.

OBJECTIVES: We examined the association among cigarette smoking, smoking cessation and a broad range of cancer incidence and all cause and cause-specific mortality in a population-based cohort of adults of Chinese ethnicity in Singapore. METHODS: Subjects were 61,320 participants of the Singapore Chinese Health Study (44.5% men, aged 45-74 years, recruitment from 1993-1998) who were free of cancer at the baseline examination. Main outcomes-of-interest included cancer incidence, all cause and cause-specific mortality as of December 31, 2005. RESULTS: Cigarette smoking was positively associated with overall cancer incidence, including cancers at the following specific sites: head and neck region, upper gastrointestinal tract, hepatobiliary and pancreas cancer, lung, and bladder/renal pelvis cancer. Compared to never smokers, the relative risk (RR) (95% confidence interval [CI]) of cancer incidence (all cancer sites) among current smokers smoking >22 cigarettes/day was 1.9 (1.7-2.1), p-trend<0.0001. Similarly, cigarette smoking was associated with all cause and cause-specific mortality, including deaths due to cancer, ischemic heart disease, other heart diseases, and chronic obstructive pulmonary disease. Compared to never smokers, RR (95%CI) of all cause mortality among current smokers smoking >22 cigarettes/day was 1.8 (1.6-2.0), p-trend<0.0001. Also, relative to current smokers, ex-smokers experienced reduced cancer incidence and total mortality. The population attributable risk of smoking in men for cancer incidence as well as all-cause mortality was 23%, whereas in women it ranged from 4-5%. CONCLUSIONS: Cigarette smoking is an important risk factor for cancer incidence and major causes of mortality in Chinese men and women of Singapore.

Validation of the Comprehensive ICF Core Set for Osteoarthritis (OA) in patients with knee OA: a Singaporean perspective.

OBJECTIVE: To evaluate content validity and construct validity of the International Classification of Functioning, Disability and Health (ICF) Comprehensive Core Set for Osteoarthritis (OA) in Singapore. METHODS: Patients with knee OA completed case report forms, which included the SF-36, Self-administered Comorbidity Questionnaire (SCQ), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Health professionals completed the ICF Comprehensive Core Set for OA. Content validity was evaluated using frequency and percentage of patients with a reported problem for each ICF category, while construct validity was evaluated using Spearman correlation between the ICF categories and SF-36 and the WOMAC. RESULTS: A consecutive sample of 122 patients completed this study. In body functions, 12 categories were documented as a problem by more than 10% of the patients, of which 7, 12, and 10 categories correlated significantly with the SF-36 Physical Component Summary (PCS), WOMAC pain, and physical function, respectively. Only s750 (Structure of lower extremity) in body structures was reported as a problem and correlated significantly with SF-36 and WOMAC. In activities and participation, 12 categories were reported as a problem by more than 10% of the patients, of which, 11, 11, and 12 correlated significantly with SF-36 PCS, WOMAC pain, and physical function, respectively. In environmental factors, 2 and 14 categories were documented as barrier and facilitator, respectively, by more than 10% of the patients, but none correlated significantly with SF-36 and WOMAC. CONCLUSION: The content and construct validity of the Comprehensive Core Set for OA could be supported. Some categories, especially in environmental factors, need to be studied further in different sociocultural contexts.

Green tea and black tea consumption in relation to colorectal cancer risk: the Singapore Chinese Health Study.

The relationships between green tea and black tea consumption and colorectal cancer risk were examined within the Singapore Chinese Health Study, a prospective cohort study of diet and cancer involving >60,000 men and women. Intake of green tea and black tea was assessed through in-person interviews. Incident cancer cases and deaths among cohort members were identified through record linkage of the cohort database with respective databases from the nationwide Singapore Cancer Registry and the Singapore Registry of Births and Deaths. The proportional hazard regression method was used to examine the associations between intake of green and black tea separately and colorectal cancer risk with adjustment for potential confounders. After an average of 8.9 years of follow-up, 845 colorectal cancer cases were identified. Subjects who drank green tea exhibited a statistically non-significant increase in risk [relative risk (RR) = 1.12, 95% confidence interval (CI) = 0.97-1.29] relative to non-drinkers of green tea. This risk increase was mainly confined to men (RR = 1.31, 95% CI = 1.08-1.58); the comparable RR in women was 0.89 (95% CI = 0.71-1.12). In men, the green tea-colorectal cancer association was noted mainly in those with advanced disease (Duke C or D) (RR = 1.53, 95% CI = 1.19-1.97), and the association was dose dependent (P for trend = 0.0002). This latter association was especially strong within the colon subsite (RR = 1.75, 95% CI = 1.24-2.46; P for trend < 0.0001). Irrespective of gender, intake of black tea was not associated with risk of colorectal cancer (RR = 0.92, 95% CI = 0.79-1.07) in this Asian population.