[Statistical analysis of disability-adjusted life years for stomach and colorectal cancers in Changning District of Shanghai]

Objectives: To analyze the status and temporal changes of disability-adjusted life year (DALY) for stomach and colorectal cancers among registered permanent residents in Changning District of Shanghai Municipality, and provide scientific basis for the prevention and treatment of stomach and colorectal cancers in this district. Methods: Using the cancer registration data of stomach and colorectal cancers from 2002 to 2019, we estimated the indices such as the DALYs, the DALY crude rates, the age-standardized DALY rates, etc. Then we used the Joinpoint regression model to calculate the average annual percent change (AAPC) and annual percent change (APC) to explore the temporal variations in different periods. Results: The DALYs of stomach and colorectal cancers in Changning District from 2002 to 2019 were 55 931 person years and 65 252 person years, respectively. The crude rates of DALY were 512.16/105 and 597.51/105, respectively. We observed a higher disease burden in men than in women, and the peak rate of DALY in stomach cancer was in the 75-79 years age group, while in colorectal cancer the rate was in the 85-years-or-older age group. Joinpoint regression analysis showed that from 2002 to 2019, the age-standardized DALY rate of stomach cancer showed a downward trend (AAPC=-3.86%, P＜0.05), while the trend of colorectal cancer was not statistically significant(AAPC=-0.08%, P＞0.05). However, the trends in the age-standardized DALY rates of colorectal cancer were different between males and females, with males showing an upward trend (AAPC=1.24%, P＜0.05) and females showing a downward trend (AAPC=-1.67%, P＜0.05). Conclusions: The DALY of stomach and colorectal cancers in Changning District of Shanghai showed a decreasing trend. Males and the middle-aged and elderly populations are still the key targets for disease prevention and control in this district.

[Pre- and post-diagnosis body mass index in association with colorectal cancer death in a prospective cohort study]

Objective: To evaluate the association between pre-and post-diagnosis body mass index (BMI) and risk of colorectal cancer (CRC) death. Methods: The cohort consisted of 3, 057 CRC patients from Shanghai who were diagnosed from Jan. 1, 2009 to Dec. 31, 2011 and aged from 20 to 74 years. The pre- and post-diagnosis BMI and clinical and lifestyle factors were collected at baseline. Death information was collected using record linkage with the Shanghai Cancer Registry and telephone confirmation during follow-up by the end of 2019. The Cox proportional regression model was used to estimate HR with 95% CI. Results: Analysis by multivariable Cox model showed no association between pre-diagnosis BMI and death risk in both male and female patients. Male patients with a post-diagnosis underweight BMI had an elevated risk of death compared to those in normal weight (HR=1.69, 95% CI: 1.21-2.37), especially in early stage cases. Overweight patients (HR=0.74, 95% CI: 0.61-0.89) and patients with obesity class Ⅰ (HR=0.63, 95% CI: 0.45-0.89)had better survival with decreased risks of death, especially in advanced stage cases. The decreased death risk in patients with obesity class Ⅱ was not significant (HR=0.57, 95% CI: 0.24-1.39). The P(trend) value for decreased risk of death with increased BMI in female patients was statistically significant (P<0.001), and the overweight and obesity class Ⅰ categories had better survival in advanced stage(HR(overweight)=0.62, 95% CI: 0.42-0.93; HR(obesity class Ⅰ)=0.39, 95% CI: 0.16-0.98). Both male and female patients with post-diagnosis BMI loss >2.0 kg/m(2) had an increased death risk when compared with those with stable BMI (change≤1.0 kg/m(2)) between pre- and post-diagnosis. BMI gain after diagnosis did not change death risk. Conclusions: Post-diagnosis BMI in the overweight or obesity class Ⅰ groups might be conducive to prolonging male CRC patients' survival, while underweight might result in poor prognosis. Keeping weight and avoiding excessive weight loss should be suggested for all CRC patients after diagnosis.

[Progress on development and application of the diet-related inflammatory index in cancer epidemiological studies]

Cancer is a major public health problem worldwide, causing an more serious burden of disease. Inflammation is considered a predisposing factor for cancer with close relationship with its incidence. In recent years, the public and epidemiologists has paid more attention to the association between nutrition and cancer and other chronic diseases in the perspective of inflammation. This paper summarizes the development and application of the diet-related inflammatory index in cancer epidemiological studies based on the literature retrieval of common diet-related inflammatory index. Firstly, we highlight the common diet-related inflammatory indices and their construction methods, such as the Dietary Inflammatory Index, a literature-derived diet-related inflammatory index, and the Empirical Dietary Inflammatory Index, an empirically derived diet-related inflammatory index, and so on. Secondly, the epidemiological research progress on the commonly used diet-related inflammatory indices is briefly introduced. Finally, the advantages and disadvantages of the two types of this inflammatory indices are also briefly described for the purpose of providing reference for nutrition epidemiological studies of cancer and other chronic diseases in China.

[Choice and application of time scale selection for Cox proportional hazards regression model in cohort studies]

Cox proportional hazards regression model (Cox model) is the most commonly used multivariate approach in time-to-event data analysis. A vital issue in fitting Cox model is choosing the appropriate time scale related to the occurrence of the outcome events. However, few domestic studies have focused on selecting and applying time scales for Cox model in the analysis of cohort study data. This study briefly introduced and compared several time scales in the reports from literature; and used data from the Shanghai Women's Health Study to illustrate the impact of different time scales on data analysis results, using the association between central obesity and the risk of liver cancer as an example. On this basis, several suggestions on selecting time scales in Cox model are proposed to provide a reference for the analysis of cohort study data.

[Statistical methods for relative risk estimation and applications in case-cohort study]

Objective: To systematically introduce the design of case-cohort study and the statistical methods of relative risk estimation and their application in the design. Methods: First, we introduced the basic principles of case-cohort study design. Secondly, Prentice's method, Self-Prentice method and Barlow method were described in the weighted Cox proportional hazard regression models in detail, finally, the data from the Shanghai Women's Health Study were used as an example to analyze the association between obesity and liver cancer incidence in the full cohort and case-cohort sample, and the results of parameters from each method were compared. Results: Significant association was observed between obesity and risk for liver cancer incidence in women in both the full cohort and the case-cohort sample. In the Cox proportional hazard regression model, the partial regression coefficients of the full cohort and the case-cohort sample fluctuated with the adjustment of confounding factors, but the hazard ratio estimates of them were close. There was a difference in the standard error of the partial regression coefficient between the full cohort and the case-cohort sample. The standard error of the partial regression coefficient of the case-cohort sample was larger than that of the full cohort, resulting in a wider 95% confidence interval of the relative risk. In the weighted Cox proportional hazard regression model, the standard error of the partial regression coefficient of Prentice's method was closer to the parameter estimates from full cohort than Self-Prentice method and Barlow method, and the 95% confidence interval of hazard ratio was closer to that of the full cohort. Conclusions: Case-cohort design could yield parameter results closer to the full cohort by collecting and analyzing data from sub-cohort members and patients with the disease, and reduce sample size and improve research efficiency. The results suggested that Prentice's method would be preferred in case-cohort design.

No association between circulating concentrations of vitamin D and risk of lung cancer: an analysis in 20 prospective studies in the Lung Cancer Cohort Consortium (LC3)

Background

There is observational evidence suggesting that high vitamin D concentrations may protect against lung cancer. To investigate this hypothesis in detail, we measured circulating vitamin D concentrations in prediagnostic blood from 20 cohorts participating in the Lung Cancer Cohort Consortium (LC3).

Patients and methods

The study included 5313 lung cancer cases and 5313 controls. Blood samples for the cases were collected, on average, 5 years before lung cancer diagnosis. Controls were individually matched to the cases by cohort, sex, age, race/ethnicity, date of blood collection, and smoking status in five categories. Liquid chromatography coupled with tandem mass spectrometry was used to separately analyze 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3] and their concentrations were combined to give an overall measure of 25(OH)D. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for 25(OH)D as both continuous and categorical variables.

Results

Overall, no apparent association between 25(OH)D and risk of lung cancer was observed (multivariable adjusted OR for a doubling in concentration: 0.98, 95% CI: 0.91, 1.06). Similarly, we found no clear evidence of interaction by cohort, sex, age, smoking status, or histology.

Conclusion

This study did not support an association between vitamin D concentrations and lung cancer risk.

[The joint effects of major lifestyle factors on stomach cancer risk among Chinese men: a prospective cohort study]

Objective: To investigate the combined impact of lifestyle factors on stomach cancer risk. Methods: We analyzed the data from the Shanghai Men's Health Study (SMHS) (2002-2013). The SMHS was conducted in eight neighborhood communities of urban Shanghai. From 2002 through June 2006, 61 480 residents aged 40 to 74 years old with no history of cancer were recruited. Failure time was the date of stomach cancer incidence, death or date of the last follow-up (December 31, 2013). The first two in-person follow-up surveys were conducted in 2004-2008, and 2008-2011, respectively. Using data on lifestyle, the healthy lifestyle index (HLI) was developed. The following lifestyle factors were included: smoking, alcohol consumption, diet habit, overweighted and physical activity. Cox proportional hazard models were used to evaluate the association of stomach cancer risk with lifestyle factors and HLI. Results: Over 9.28 years' follow-up, 477 incident cases of stomach cancer were identified from 59 503 study participants. Participants with zero, one, two, three, four, and five favorable lifestyle behaviors accounted for 3.44% (n=2 045), 18.14% (n=10 793), 33.68% (n=20 041), 29.43% (n=17 511), 12.82% (n=7 627), and 2.50% (n=1 486), respectively. Among all the five lifestyle factors, smoking and alcohol use were significantly related to stomach cancer risk. The relative risk of stomach cancer was 0.71 (95%CI: 0.57-0.87) for those who never smoked or quitted smoking for no less than 10 years and 0.70 (95%CI: 0.55-0.90) for those who consumed alcohol no more than 14 drinks per week. For each increment of healthy lifestyle index, the relative risk of stomach cancer was 0.86 (95%CI: 0.79-0.95). Compared to men with none or one healthy lifestyle factor, the relative risk for those with four or five was 0.62 (95%CI: 0.46-0.83). When we rebuilt HLI using more categories of each lifestyle factors, the HLI ranged from 0 to 11. For each point increase, the relative risk of stomach cancer was 0.93 (95%CI: 0.89-0.97). Compared those with 0 to 3 points, the relative risk of those with 8 to 11 points was 0.64 (95%CI: 0.47-0.87). Conclusion: In the SMHS, only a small proportion of men adhered to all the five healthy lifestyle factors. Compared to those with none or one healthy lifestyle behaviors, those with five may prevent about 1/3 stomach cancer incidence and the HLI was inversely associated with stomach cancer risk.

Breast cancer incidence and mortality: trends over 40 years among women in Shanghai, China

BACKGROUND

Breast cancer incidence rates are increasing among Asian women, likely due to the changes in risk factors caused by globalization. Trends in breast cancer rates among Chinese women may differ from other Asian regions due to the implementation of a nationwide family planning program and resulting changes in women's reproductive practices. Appraisal of cancer trends can direct cancer control and public health planning, but relevant studies in China are scarce due to a lack of long-term data. We sought to evaluate secular time trends in breast cancer incidence and mortality using 40 years of cancer registry data for women in urban Shanghai.

MATERIALS AND METHODS

Data on invasive breast cancer incidence and mortality were collected by the Shanghai Cancer Registry. Age-standardized rates (ASRs) for incidence and mortality were calculated using the Segi/Doll 1960 world standard population. Age, period, and birth cohort effects were evaluated using age-period-cohort (APC) Poisson regression models. Overall linear trends, interpreted as the estimated annual percentage change (EAPC), were derived from the net drift in age-drift models.

RESULTS

A total of 53 885 breast cancer cases and 17 235 breast cancer-specific deaths were documented among women in urban Shanghai between 1 January 1973 and 31 December 2012. Breast cancer incidence and mortality ASRs increased by 141.2% and 26.6%, respectively. Significant age, cohort, and period effects were identified in both incidence and mortality APC models; cohort effects were pronounced. Overall, a substantial increase in breast cancer incidence (EAPC = 2.96%/year) and a moderate increase in breast cancer mortality (EAPC = 0.87%/year) was observed. A notable downward trend in mortality was identified among younger women born after 1960.

CONCLUSIONS

Forty years of cancer registry data document a tremendous increase in incidence and a slight increase in mortality for breast cancer among women in Shanghai. Effective, appropriate, and affordable breast cancer prevention and control strategies are urgently needed in China.

Oral health and risk of colorectal cancer: results from three cohort studies and a meta-analysis

BACKGROUND

While studies have shown that poor oral health status may increase the risk of cancer, evidence of a specific association with the risk of colorectal cancer (CRC) is inconclusive. We evaluated the association between oral health and CRC risk using data from three large cohorts: the Shanghai Men's Health Study (SMHS), the Shanghai Women's Health Study (SWHS), and the Southern Community Cohort Study (SCCS), and carried out a meta-analysis of results from other relevant published studies.

PATIENTS AND METHODS

This study applied a nested case-control study design and included 825 cases/3298 controls from the SMHS/SWHS and 238 cases/2258 controls from the SCCS. The association between oral health status (i.e. tooth loss/tooth decay) and CRC risk was assessed using conditional logistic regression models. A meta-analysis was carried out based on results from the present study and three published studies.

RESULTS

We found that tooth loss was not associated with increased risk of CRC. ORs and respective 95% CIs associated with loss of 1-5, 6-10, and >10 teeth compared with those with full teeth are 0.87 (0.69-1.10), 0.93 (0.70-1.24), and 0.85 (0.66-1.11) among SMHS/SWHS participants; and 1.13 (0.72-1.79), 0.87 (0.52-1.43), and 1.00 (0.63-1.58) for those with loss of 1-4, 5-10, and >10 teeth among SCCS participants. Data regarding tooth decay were available in the SCCS, but were not associated with CRC risk. Meta-analysis confirmed the null association between tooth loss/periodontal disease and CRC risk (OR 1.05, 95% CI 0.86-1.29).

CONCLUSION

In this analysis of three cohorts and a meta-analysis, we found no evidence supporting an association between oral health and CRC risk.

Body weight, fat distribution and colorectal cancer risk: a report from cohort studies of 134255 Chinese men and women

OBJECTIVE

To evaluate the association of body size and fat distribution with risk of colorectal cancer (CRC) in Chinese men and women.

DESIGN

Population-based, prospective cohort study.

SUBJECTS

The analysis included 134 255 Chinese adults enrolled in the Shanghai Women’s Health Study and the Shanghai Men’s Health Study, with an average follow-up of 11.0 and 5.5 years, respectively.

MEASUREMENTS

Waist circumference (WC), body mass index (BMI) and waist-to-hip ratio (WHR) were measured by trained interviewers at baseline. Multivariable Cox models were used to calculate adjusted hazard ratios (HRs) for incident CRC.

RESULTS

A total of 935 incident CRC cases were identified. Both measures of general adiposity (measured by BMI) and central adiposity (measured by WHR and WC) were significantly associated with increased risk of colon cancer in men but not in women. Multivariable adjusted HRs for colon cancer in men in the highest compared with the lowest quintiles were 2.15 (95% CI: 1.35-3.43; P for trend = 0.0006) for BMI, 1.97 (95% CI: 1.19-3.24; P for trend = 0.0004) for WHR and 2.00 (95% CI: 1.21-3.29; P for trend = 0.0002) for WC. The BMI-associated risk was attenuated in analyses stratified by WHR, while the WHR-associated risk remained significant in the high BMI stratum (HR for comparison of extreme tertiles of WHR: 3.38, 95% CI: 1.47-7.75; P for trend =0.0002). None of these anthropometric measures were significantly associated with rectal cancer.

CONCLUSION

Obesity, particularly central obesity, was associated with increased risk of colon cancer in men.

Infertility and incident endometrial cancer risk: a pooled analysis from the epidemiology of endometrial cancer consortium (E2C2)

BACKGROUND

Nulliparity is an endometrial cancer risk factor, but whether or not this association is due to infertility is unclear. Although there are many underlying infertility causes, few studies have assessed risk relations by specific causes.

METHODS

We conducted a pooled analysis of 8153 cases and 11 713 controls from 2 cohort and 12 case-control studies. All studies provided self-reported infertility and its causes, except for one study that relied on data from national registries. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Nulliparous women had an elevated endometrial cancer risk compared with parous women, even after adjusting for infertility (OR=1.76; 95% CI: 1.59-1.94). Women who reported infertility had an increased risk compared with those without infertility concerns, even after adjusting for nulliparity (OR=1.22; 95% CI: 1.13-1.33). Among women who reported infertility, none of the individual infertility causes were substantially related to endometrial cancer.

CONCLUSIONS

Based on mainly self-reported infertility data that used study-specific definitions of infertility, nulliparity and infertility appeared to independently contribute to endometrial cancer risk. Understanding residual endometrial cancer risk related to infertility, its causes and its treatments may benefit from large studies involving detailed data on various infertility parameters.

Cruciferous vegetables consumption and the risk of female lung cancer: a prospective study and a meta-analysis

BACKGROUND

Epidemiological studies evaluating the association between cruciferous vegetables (CVs) intake and female lung cancer risk have produced inconsistent results.

PATIENTS AND METHODS

This study followed 74 914 Chinese women aged 40-70 years who participated in the Shanghai Women's Health Study. CV intake was assessed through a validated food-frequency questionnaire (FFQ) at baseline and reassessed during follow-up. Hazard ratios (HRs) and 95% confidence interval (CIs) were estimated by using Cox proportional hazards models. Furthermore, we carried out a meta-analysis of all observational studies until December 2011.

RESULTS

After excluding the first 2 years of follow-up, 417 women developed lung cancer over a mean of 11.1 years of follow-up. An inverse association of borderline statistical significance was observed between CV consumption and female lung cancer risk, with HR for the highest compared with the lowest quartiles of 0.73 (95% CI 0.54-1.00, P trend = 0.1607). The association was strengthened in analyses restricting to never smokers, with the corresponding HR of 0.59 (95% CI 0.40-0.87, P trend = 0.0510). The finding of an inverse association between CV intake and lung cancer risk in women was supported by our meta-analysis of 10 included studies.

CONCLUSIONS

Our study suggests that CV consumption may reduce the risk of lung cancer in women, particularly among never smokers.

Prospective evaluation of type 2 diabetes mellitus on the risk of primary liver cancer in Chinese men and women

BACKGROUND

No prospective study has investigated the relationship between type 2 diabetes mellitus (T2DM) and the risk of primary liver cancer (PLC) in mainland China, and little is known about the effect of diabetes duration on PLC risk.

DESIGN

Data from two population-based cohorts (the Shanghai Men's Health Study, SMHS, 2002-2006 and the Shanghai Women's Health Study, SWHS, 1996-2000) were thus used to assess the associations among T2DM, diabetes duration and PLC risk in Chinese population.

RESULTS

During follow-up through 2009, 344 incident PLC cases were identified among 60 183 men and 73 105 women. T2DM is significantly associated with the increased risk of PLC in both men [hazard ratio (HR) = 1.63, 95% confidence interval (CI) 1.06-2.51] and women (HR = 1.64, 95% CI 1.03-2.61). The highest risk of incident liver cancer was observed in the first 5 years after diabetes diagnosis, and decreased substantially with the prolonged diabetes duration (P(trend) < 0.001). No synergistic interaction in the development of PLC was found between diabetes and other known risk factors.

CONCLUSIONS

T2DM is associated with the increased risk of subsequent liver cancer within 5 years after diagnosis in Chinese population, suggesting that hyperinsulinaemia rather than hyperglycaemia is more likely to be a primary mediator for this association.

Evaluation of GWAS-identified genetic variants for age at menarche among Chinese women

STUDY QUESTION

Do genetic polymorphisms which influence age at menarche in women of European ancestry also influence women of Chinese ancestry?

SUMMARY ANSWER

Many genetic variants influencing age at menarche in European populations appear to impact Chinese populations in a similar manner.

WHAT IS KNOWN AND WHAT THIS PAPER ADDS

Prior genome-wide association studies have uncovered 42 SNPs associated with age at menarche in European populations. This study is the first to demonstrate that many of the genetic determinants of age at menarche are shared between European and Chinese women.

PARTICIPANTS AND SETTING

We evaluated 37 of 42 SNPs identified as associated with age at menarche from a recent, large meta-analysis, consisting primarily of women of European ancestry, in a population of 6929 Chinese women from Shanghai, China. We also constructed weighted genetic risk scores (GRSs) combining the number of effect variants for all 37 SNPs, or only the SNPs associated with age at menarche among our study population, to evaluate their joint influence on age at menarche.

MAIN RESULTS

For 32 of the 37 evaluated variants, the direction of the allele associations were the same between women of European ancestry and women of Chinese ancestry (P = 3.71 × 10(-6), binomial sign test); 9 of these were statistically significant. Subjects in the highest quintile of GRSs began menarche ∼5 months later than those in the lowest quintile. BIAS, LIMITATIONS AND GENERALIZABILITY TO OTHER POPULATIONS: Age at menarche was obtained by self-report, which can be subject to recall errors. The current analysis was restricted to loci which met or approached GWAS significance thresholds and did not evaluate loci which may act predominantly or exclusively in the Chinese population. The smaller sample size for our meta-analysis compared with meta-analyses conducted in European populations reduced the power to detect significant results.

STUDY FUNDING/COMPETING INTERESTS

This study was supported, in part, by grants from US National Institutes of Health (grants R01CA124558, R01CA090899, R01CA070867; R01CA064277 and R01CA092585 and UL1 RR024975), Ingram professorship funds and Allen Foundation funds. There are no competing interests to declare.

The etiology of uterine sarcomas: a pooled analysis of the epidemiology of endometrial cancer consortium

BACKGROUND

Uterine sarcomas are characterised by early age at diagnosis, poor prognosis, and higher incidence among Black compared with White women, but their aetiology is poorly understood. Therefore, we performed a pooled analysis of data collected in the Epidemiology of Endometrial Cancer Consortium. We also examined risk factor associations for malignant mixed mullerian tumours (MMMTs) and endometrioid endometrial carcinomas (EECs) for comparison purposes.

METHODS

We pooled data on 229 uterine sarcomas, 244 MMMTs, 7623 EEC cases, and 28,829 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) for risk factors associated with uterine sarcoma, MMMT, and EEC were estimated with polytomous logistic regression. We also examined associations between epidemiological factors and histological subtypes of uterine sarcoma.

RESULTS

Significant risk factors for uterine sarcoma included obesity (body mass index (BMI)≥30 vs BMI<25 kg m(-2) (OR: 1.73, 95% CI: 1.22-2.46), P-trend=0.008) and history of diabetes (OR: 2.33, 95% CI: 1.41-3.83). Older age at menarche was inversely associated with uterine sarcoma risk (≥15 years vs <11 years (OR: 0.70, 95% CI: 0.34-1.44), P-trend: 0.04). BMI was significantly, but less strongly related to uterine sarcomas compared with EECs (OR: 3.03, 95% CI: 2.82-3.26) or MMMTs (OR: 2.25, 95% CI: 1.60-3.15, P-heterogeneity=0.01).

CONCLUSION

In the largest aetiological study of uterine sarcomas, associations between menstrual, hormonal, and anthropometric risk factors and uterine sarcoma were similar to those identified for EEC. Further exploration of factors that might explain patterns of age- and race-specific incidence rates for uterine sarcoma are needed.

Cruciferous vegetables intake and the risk of colorectal cancer: a meta-analysis of observational studies

BACKGROUND

Epidemiological studies have reported inconsistent associations between cruciferous vegetable (CV) intake and colorectal cancer (CRC) risk. To our knowledge, a comprehensive and quantitative assessment of the association between CV intake and CRC has not been reported.

METHODS

Relevant articles were identified by searching MEDLINE. We pooled the relative risks (RR) from individual studies using a random-effect model and carried out heterogeneity and publication bias analyses.

RESULTS

Twenty-four case-control and 11 prospective studies were included in our analysis. When all studies were pooled, we yielded a significantly inverse association between CV (RR: 0.82; 95% confidence interval 0.75-0.90) intake and CRC risk. Specific analysis for cabbage and broccoli yielded similar result. When separately analyzed, case-control studies of CV intake yield similar results, and the results from the prospective studies showed borderline statistical significance. Moreover, significant inverse associations were also observed in colon cancer and its distal subsite both among prospective and case-control studies.

CONCLUSIONS

Findings from this meta-analysis provide evidence that high intake of CV was inversely associated with the risk of CRC and colon cancer in humans. Further analysis on other specific CV, food preparation methods, stratified results by anatomic cancer site, and subsite of colon cancer should be extended in future study.

Meat consumption and risk of lung cancer: evidence from observational studies

BACKGROUND

A number of epidemiological studies have reported inconsistent findings on the association between meat consumption and lung cancer.

DESIGN

We therefore conducted a systematic review and meta-analysis to investigate the relationship between meat consumption and lung cancer risk in epidemiological studies.

RESULTS

Twenty-three case-control and 11 cohort studies were included. All studies adjusted for smoking or conducted in never smokers. The summary relative risks (RRs) of lung cancer for the highest versus lowest intake categories were 1.35 (95% confidence interval (CI) 1.08-1.69) for total meat, 1.34 (95% CI 1.18-1.52) for red meat, and 1.06 (95% CI 0.90-1.25) for processed meat. An inverse association was found between poultry intake and lung cancer (RR = 0.91, 95% CI 0.85-0.97), but not for total white meat (RR = 1.06, 95% CI 0.82-1.37) or fish (RR = 1.01, 95% CI 0.96-1.07).

CONCLUSIONS

The relationship between meat intake and lung cancer risk appears to depend on the types of meat consumed. A high intake of red meat may increase the risk of lung cancer by about 35%, while a high intake of poultry decreases the risk by about 10%. More well-designed cohort studies on meat mutagens or heme iron, meat cooking preferences, and doneness level are needed to fully characterize this meat-lung cancer association.

Dietary glycemic load, glycemic index, and carbohydrates on the risk of primary liver cancer among Chinese women and men

BACKGROUND

Dietary glycemic index (GI) and glycemic load (GL) typically have a positive relationship with obesity and diabetes, which are risk factors for liver cancer. However, studies on their association with liver cancer have yielded inconsistent results. Therefore, we assessed the association of GI, GL, and carbohydrates with liver cancer risk.

PATIENTS AND METHODS

A total of 72 966 women and 60 207 men from the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS) were included for analysis. Food frequency questionnaire (FFQ) data were used to calculate daily dietary GI, GL, and carbohydrate intake. These values were energy adjusted and categorized into quintiles. The hazard ratios (HRs) and 95% confidence intervals (CI) were calculated with adjustment for potential confounders.

RESULTS

After a median follow-up time of 11.2 years for the SWHS and 5.3 years for the SMHS, 139 and 208 incident liver cancer cases were identified in the SWHS and SMHS, respectively. In multivariable Cox regression models, no statistically significant trends by quintile of GI, GL, or carbohydrate intake were observed. Stratification by chronic liver disease/hepatitis, diabetes, or body mass index (BMI) did not alter the findings.

CONCLUSIONS

There is little evidence that dietary GI, GL, or carbohydrates affect the incidence of liver cancer in this Asian population.

Role of cigarette filter on the risk of oral cancer: a case-control study in a Chinese population

OBJECTIVE

To determine the role of cigarette filter on the incidence risk of oral squamous cell cancer among male smokers in a Chinese population.

SUBJECTS AND METHODS

A multicentric hospital-based case-control study was applied. Three hundred and nineteen male cases and 428 male controls matching for age ( ± 3 years) were identified from January 2008 to December 2010. Detailed smoking histories were obtained by interviews. Logistic regression model was used to compare the influence of filter and non-filter cigarettes on oral cancer risk.

RESULTS

The adjusted odd ratios (ORs) for oral cancer were 1.30 (95% CI 1.15, 1.48) of filter cigarette smokers, 2.06 (95% CI 1.17, 3.62) of non-filter cigarette smokers, and 1.73 (95% CI 1.33, 2.25) of mixed smokers, as compared with non-smokers. When classified current smokers according to smoking pack year, the ORs of mixed smokers were 2.27 (95% CI 1.06, 4.85) in <20 pack year, 0.81 (95% CI 0.57, 1.14) in 20-39 pack year, and 0.86 (95% CI 0.57, 1.29) in ≥ 40 pack year, as compared to filter cigarette smokers.

CONCLUSIONS

The protective effect against oral cancer of cigarette filter was limited, restricted to smokers of small amount of smoking accumulation. For most smokers, the difference was non-significant between filter and non-filter cigarettes on the risk of developing oral cancer.

Purine-rich foods, protein intake, and the prevalence of hyperuricemia: the Shanghai Men's Health Study

BACKGROUND AND AIMS

Diet may play an important role in the development of hyperuricemia and gout. However, the association between dietary factors and hyperuricemia remains unclear, and few studies have investigated direct links between food intake and hyperuricemia. The aim of this study was to investigate associations between high purine-content foods and protein intake with the prevalence of hyperuricemia by using data from a cross-sectional study of 3978 men aged 40-74 yrs living in Shanghai, China.

METHODS AND RESULTS

Hyperuricemia was defined as blood uric acid level >7.0 mg/dl. One quarter of this population had hyperuricemia. Dietary information was collected by using a food frequency questionnaire. We collected information on anthropometric measurements and lifestyle factors and other potential confounding factors and disease history via interviews. Total protein consumption was not associated with hyperuricemia. We found a positive association between protein from animal sources and prevalence of hyperuricemia and an inverse association between protein from plant sources and hyperuricemia. However, these associations failed to reach significance in mutually adjusted analysis. Seafood intake was associated with higher prevalence of hyperuricemia. The ORs for quintiles of seafood intake (including fish and shellfish) were 1.00, 1.49, 1.35, 1.34, and 1.56 (p for trend: 0.01). An inverse association approaching significance between soy food consumption and hyperuricemia was observed (ORs: 1.00, 0.90, 0.70, 0.89, and 0.77 for quintiles of intake; p for trend: 0.07). No associations between consumption of purine-rich vegetables or meat and prevalence of hyperuricemia were observed.

CONCLUSIONS

Our data suggest a direct association between seafood consumption and hyperuricemia and an inverse association between consumption of soy food and hyperuricemia among middle-aged, Chinese men.

Lifestyle determinants of C-reactive protein in middle-aged, urban Chinese men

BACKGROUND AND AIM

Increased levels of C-reactive protein (CRP), common in aging populations, are associated with higher risk for chronic diseases, including diabetes and coronary heart disease. The aim of this study was to investigate associations between lifestyle factors and high CRP among middle-aged men living in Shanghai, China.

METHODS AND RESULTS

In this cross-sectional study, 3978 urban Chinese men aged 40-74 years who were free of type-2 diabetes at baseline provided fasting blood samples, anthropometric measurements and information on lifestyle factors and disease history. Dietary patterns were assessed by factor analysis. Participants were categorised into two groups according to CRP level: normal (≤ 3 mg/L) and high (> 3 mg/L). Associations between CRP categories and lifestyle factors were investigated by using logistic regression. Obesity, weight gain, cigarette smoking and alcohol intake were positively associated with high CRP levels, while physical activity and a dietary pattern with high consumption of fruit were inversely related to high CRP levels. A positive trend of marginal significance between quintiles of a dietary pattern with high consumption of meat and high CRP levels was also observed. No association between tea intake and CRP level was observed.

CONCLUSIONS

Components of an adverse lifestyle were associated with high CRP levels. Obesity, smoking and alcohol intake were associated with high CRP, a biomarker of low-grade inflammation in middle-aged men, while a dietary pattern rich in fruit and high physical activity were inversely associated with the prevalence of high CRP.

Genetic variants in vitamin D metabolism-related genes and body mass index: analysis of genome-wide scan data of approximately 7000 Chinese women

Vitamin D deficiency has been consistently associated with obesity. However, it is unclear whether vitamin D deficiency is the cause or consequence of obesity. We investigated this question by evaluating the association between genetic variants in vitamin D metabolism pathway genes and obesity-related traits. Using directly genotyped and imputed data from a genome-wide association study of 6922 women aged 25-70 years, we examined the association of 198 single-nucleotide polymorphisms (SNPs) in vitamin D pathway genes (CYP27A1, CYP27B1, CYP24A1, CYP2R1, group-specific component (GC) and vitamin D nuclear receptor (VDR)) with body mass index (BMI) and body weight. Per allele beta (β) estimates were calculated for this association using linear regression models, controlling for age, square of age, menopausal status and sample sets. Overall, only two SNPs (rs2248359 in CYP24A1 and rs10832313 in CYP2R1) had a nominally significant association with BMI and weight (P<0.05 for all), with no variation observed by menopausal status, physical activity or dietary energy intake. None of the SNPs examined in the VDR gene were associated with BMI or weight. Our findings suggest that common genetic variants in vitamin D pathway genes do not have a major role in obesity among Chinese women. This comprehensive evaluation of genetic polymorphisms in vitamin D metabolism-related genes and obesity-related traits did not provide strong evidence to support low vitamin D levels as a cause of obesity.

Body mass, tobacco smoking, alcohol drinking and risk of cancer of the small intestine--a pooled analysis of over 500,000 subjects in the Asia Cohort Consortium

BACKGROUND

The evidence for a role of tobacco smoking, alcohol drinking, and body mass index (BMI) in the etiology of small intestine cancer is based mainly on case-control studies from Europe and United States.

SUBJECTS AND METHODS

We harmonized the data across 12 cohort studies from mainland China, Japan, Korea, Singapore, and Taiwan, comprising over 500,000 subjects followed for an average of 10.6 years. We calculated hazard ratios (HRs) for BMI and (only among men) tobacco smoking and alcohol drinking.

RESULTS

A total of 134 incident cases were observed (49 adenocarcinoma, 11 carcinoid, 46 other histologic types, and 28 of unknown histology). There was a statistically non-significant trend toward increased HR in subjects with high BMI [HR for BMI>27.5 kg/m2, compared with 22.6-25.0, 1.50; 95% confidence interval (CI) 0.76-2.96]. No association was suggested for tobacco smoking; men drinking>400 g of ethanol per week had an HR of 1.57 (95% CI 0.66-3.70), compared with abstainers.

CONCLUSIONS

Our study supports the hypothesis that elevated BMI may be a risk factor for small intestine cancer. An etiologic role of alcohol drinking was suggested. Our results reinforce the existing evidence that the epidemiology of small intestine cancer resembles that of colorectal cancer.

Cancer survival in Shanghai, China, 1992-1995

The Shanghai cancer registry, established in 1963, is the oldest one in mainland China; cancer registration is entirely done by passive methods. The registry contributed data on 52 cancer sites or types registered during 1992-1995 for this survival study. The methods of follow-up have been a mixture of both active and passive ones, with median follow-up ranging 3-81 months. The proportion with histologically verified diagnosis for various cancers ranged from 14-95%; death certificates only (DCOs) ranged from 0-2% and 98-100% of total registered cases were included for survival analysis. The top ranking cancers on 5-year age-standardized relative survival (%) were thyroid (90%), non-melanoma skin (86%), penis (84%), corpus uteri (82%) and testis (80%). The corresponding survival rates for common cancers were lung (16%), stomach (30%), liver (9%), breast (78%) and colon (48%). The 5-year relative survival by age group reveals an inverse relationship for most cancers. An increasing trend in the 5-year absolute andrelative survival was noted for all cancers registered in 1992-1995 compared to 1988-1991.

Animal food intake and cooking methods in relation to endometrial cancer risk in Shanghai

We evaluated animal food intake and cooking methods in relation to endometrial cancer risk in a population-based case–control study in Shanghai, China. A validated food frequency questionnaire was used to collect the usual dietary habits of 1204 cases and 1212 controls aged 30–69 years between 1997 and 2003. Statistical analyses were based on an unconditional logistic regression model adjusting for potential confounders. High intake of meat and fish was associated with an increased risk of endometrial cancer, with adjusted odds ratios for the highest vs the lowest quartile groups being 1.7 (95% confidence interval: 1.3–2.2) and 2.4 (1.8–3.1), respectively. The elevated risk was observed for all types of meat and fish intake. Intake of eggs and milk was not related to risk. Cooking methods and doneness levels for meat and fish were not associated with risk, nor did they modify the association with meat and fish consumption. Our study suggests that animal food consumption may play an important role in the aetiology of endometrial cancer, but cooking methods have minimal influence on risk among Chinese women.

Body weight and weight change in relation to blood pressure in normotensive men

We examined blood pressure (BP) in association with weight change since age 20, body mass index (BMI) at different ages and fat distribution in normotensive individuals using baseline survey data collected in the Shanghai Men's Health Study, an ongoing population-based prospective cohort study of Chinese men aged 40-74 years. All anthropometric and BP measurements were performed by medical professionals. Included in this analysis were 25 619 men who had no prior history of hypertension, diabetes or cardiovascular disease, never took any antihypertensive medication and had both normal systolic BP (SBP) and diastolic BP (DBP) (<140/90 mm Hg). Both SBP and DBP increased linearly across the whole range of weight gain since age 20. The adjusted mean differences between the highest and the lowest quintiles of weight gain were 6.0 mm Hg (95% confidence interval (CI): 5.6, 6.5) for SBP and 3.9 (95% CI: 3.6, 4.2) for DBP. When accounting for BMI at age 20, the multivariate-adjusted odds ratio of prehypertension (SBP, 120-139 and/or DBP, 80-89 mm Hg) was 4.1 (95% CI: 3.7, 4.5; P for trend <0.0001) comparing the extreme quintiles of weight gain. Similar positive associations were also observed for BMI at age 40, current BMI, circumferences of the waist and hips and waist-to-hip ratio. In conclusion, these data suggest that weight gain since age 20 and elevated adiposity may contribute significantly to the rise in BP in normotensive individuals, emphasizing the importance of weight control throughout adulthood in preventing high BP.

A case-control study in Shanghai of fruit and vegetable intake and endometrial cancer

In a population-based case–control study of 832 incident endometrial cancer cases and 846 frequency-matched controls among Chinese women in Shanghai, using a validated food-frequency questionnaire, dietary habits were estimated by in-person interviews. Total vegetable consumption was inversely associated with endometrial cancer risk (highest quartile vs lowest: OR=0.69, 95% CI 0.50–0.96). The risk was reduced with increasing intake of dark green/dark yellow vegetables (trend test, P=0.02), fresh legumes (trend test, P<0.01), and allium vegetables (trend test, P=0.04). Fruit consumption was unrelated to risk. These results suggest that high consumption of certain vegetables may reduce the risk of endometrial cancer.

Preserved foods in relation to risk of nasopharyngeal carcinoma in Shanghai, China

A population-based case-control study was conducted in Shanghai, China, to investigate the association between dietary factors and risk of nasopharyngeal carcinoma (NPC). The study included 935 NPC patients aged 15 to 74 years and 1,032 community controls. Exposures to salted fish and other protein-containing preserved food were associated with increased risk of NPC. Individuals who ate salted fish at least once a week had an 80% increase in risk of NPC relative to those who ate salted fish less than once a month (p = 0.07). Compared with those in the lowest quartile of protein-containing preserved foods, subjects in the highest quartile of intake experienced a statistically significant 78% increase in risk of NPC [odds ratio (OR) = 1.78, 95% confidence interval (CI) = 1.37-2.31], with a dose-dependent relationship (p for linear trend < 0.001 ). A similar association between intake of preserved vegetables and NPC risk was observed (OR = 1.39, p for linear trend = 0.003). In contrast, high intake of oranges/tangerines was associated with a statistically significant reduction in risk of NPC (OR = 0.55, p for linear trend < 0.001). When we examined the joint effect of preserved food and oranges/tangerines on risk of NPC, subjects in the highest tertile of preserved food and the lowest tertile of orange/ tangerine intake had a 3-fold increase in risk (95% CI = 2.08-4.91) compared with those in the lowest tertile of preserved food and the highest tertile of orange/tangerine intake.

Non-dietary risk factors for nasopharyngeal carcinoma in Shanghai, China

A population-based case-control study was conducted in Shanghai, China, to investigate the associations between exposures to various non-dietary variables and risk of nasopharyngeal carcinoma (NPC). A total of 935 NPC patients and 1,032 community controls were included. Active cigarette smoking was a moderate risk factor for NPC [odds ratio (OR) = 1.28, 95% confidence interval (CI) 1.02-1.61]. Results were highly consistent between men and women. It is estimated that 12% of NPC cases in Shanghai, China, can be attributable to cigarette smoking. Among lifelong nonsmokers, there was a strong and statistically significant positive association between NPC risk and exposure to substantial secondhand smoke as a child or as an adult in women. However, the associations among lifelong nonsmoking men were weaker and not statistically significant. The gender differences in risk associated with passive smoking were either statistically significant or almost so. There were excess numbers of NPC patients compared with control subjects who had a history of chronic ear and nose disease (OR = 1.96, 95% CI 1.56-2.46) and a family history of NPC (OR = 7.47, 95% CI 2.14-12.88).

Study of prognostic predictors for non-small cell lung cancer

BACKGROUND

The outcome of treatment in non-small cell lung cancer (NSCLC) remains poor. One of the reasons is that in many patients its biological behavior does not follow a definite pattern, and can not be accurately predicted prior to treatment. In the present study we have examined the significant prognostic predictors.

METHODS

One hundred and fifty-eight patients with NSCLC entered this study. They received surgery alone (95 cases) or combined therapy with postoperative irradiation (63 cases). Three types of data have been collected: (1) clinical characteristics: age, sex, Karnofsky performance status, weight loss, T stage, and N stage; (2) histopathology studies: histological types, tumor differentiation, status of vascular and lymphatic vessel invasions; (3) laboratory measurements by immunohistochemistry assay: oncoprotein overexpression, including pan-ras, c-myc, neu, epidermal growth factor receptor (EGFR) and p53, and tumor cell proliferation by proliferating cell nuclear antigen (PCNA).

RESULTS

For the entire group, 5-year actuarial survival, local control and distant metastasis rates were 44, 63 and 40%, respectively. In the univariate analyses, T stage, N stage and lymphatic vessel invasion correlated to survival; T stage and N stage to local control; N stage, lymphatic vessel invasion and pan-ras protein positive stain to distant metastasis. When the index of oncoprotein positive stains was used, the higher index was associated with a higher distant metastasis rate. In the multivariate analyses, T stage, N stage and lymphatic vessel invasion could be independent predictors for survival; T stage for local control; N stage, lymphatic vessel invasion and index of positive oncoprotein stains for distant metastasis.

CONCLUSIONS

Late T and N stages, lymphatic vessel invasion and multi-oncoprotein positive stains would predict poor prognoses for NSCLC.

[Five methods for the estimation of confidence intervals on survival rate]

Descriptive analysis on medical follow-up data often involves estimation of survival rates, such as Kaplan-Meier product limit estimator or life table survival rate for small or large scale data sets, respectively. Five methods for estimating the confidence intervals (CI) of survival rates were described. These methods for estimation of intervals were the classic (based on Greenwood's formula), correctness, arcsine transformation, log (-log) transformation and logit transformation. Two examples were described in detailed for the calculation of 95% confidence intervals.