[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.

A prospective cohort study of cigarette smoking, alcohol drinking and liver cancer incidence in Chinese men

OBJECTIVES

Population-based prospective studies on the associations of cigarette smoking, alcohol drinking, and primary liver cancer remain limited in Mainland China. Our study was designed to evaluate such relationships in middle-aged Chinese men.

METHODS

Self-reported habits of cigarette smoking and alcohol drinking were obtained from all cohort members at the baseline survey. The outcomes were identified through in-person follow-up and annual record linkage to multiple statistics of vital and cancer registration. Age-adjusted and multivariable-adjusted hazard ratio (HR) and their corresponding 95% confidence interval (CI) were estimated utilizing the Cox regression model.

RESULTS

After a median follow-up of 12.31 years, 329 cases of incident primary liver cancer occurred among 45 266 male participants. Compared with never smoker, former smoker was positively associated with liver cancer risk, with a multivariable-adjusted HR of 1.42 (95% CI 1.02-1.98). Individuals who had smoked for more than 40 years had a 49% increased risk of liver cancer (HR≥40 years  1.49, 95% CI 1.04-2.14). The association of alcohol drinking with liver cancer showed no statistical significance.

CONCLUSIONS

Our study provided evidence that cigarette smoking was positively associated with an increased liver cancer risk among Chinese men. Attention to such non-viral modifiable risk factors to prevent liver cancer effectively is needed.

[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.

Trends of stomach cancer survival: A systematic review of survival rates from population-based cancer registration

OBJECTIVES

We aimed to describe the pattern and time trends of survival from stomach cancer worldwide from population-based cancer registers.

METHODS

A systematic search of PubMed, Web of Science, EMBASE, SEER and SinoMed for articles published up to 31 December 2020 was conducted. All eligible survival analyses of stomach cancer were collected and evaluated by countries or regions, periods, sex and age groups.

RESULTS

Our review included 76 articles on stomach cancer survival rates and found that these rates had improved globally with time, although this increase was unremarkable. The highest 5-year survival rate of 72.1% was observed in Japan (2004-2007). The 5-year relative and net survival, rates were relatively high in Korea and Japan, while they were fairly poor in Africa and India. Sex-specific survival rates were higher in women than in men in America, Europe and Oceania, whereas they were relatively low in Asia. The poorest age-specific 5-year relative and net survival rates were observed in patients aged over 75 years.

CONCLUSIONS

Over the past decades, patient prognosis of stomach cancer has gradually improved worldwide and survival rates in developed regions were higher than those in developing regions. White men and Asian women had a poorer survival than white women and Asian men. Younger patients had better survival rates than those aged over 75 years globally.

Long-term liver cancer incidence and mortality trends in the Changning District of Shanghai, China

OBJECTIVE

To evaluate the trends and estimate the long-term effects of age, period and birth cohort on the incidence and mortality rates of liver cancer (LC) in an urban district of Shanghai, China.

METHODS

Crude and age-standardized rates of the incidence and mortality of LC were calculated from 1973 to 2013 annually by sex, and the direction and magnitude of the trends were estimated by the average annual percentage change (AAPC) using the Joinpoint Regression Model. An age-period-cohort (APC) model was also used to evaluate the non-linear effects of calendar time and birth cohort on LC incidence and mortality.

RESULTS

In 1973-1977 and 2008-2013 the age-standardized rates of LC incidence and mortality (per 100 000) were 24.27 and 22.60 in men, and 7.50 and 7.26 in women, respectively. Declining trends of LC incidence and mortality rates were observed for both sexes (AAPC; P < 0.05 for both). The APC models indicated that the rates of LC incidence and mortality were significantly influenced both by calendar time and birth cohort effects.

CONCLUSIONS

The incidence and mortality rates of LC have decreased in both sexes in the Changning District of Shanghai over the past four decades. Although obvious descending trends of LC incidence and mortality were detected, attention should also be paid to the LC burden for a long time in the future because of huge population size in China and the continuity of population aging.

Time trends of incidence and mortality in colorectal cancer in Changning District, Shanghai, 1975-2013

OBJECTIVE

To evaluate the incidence and mortality of colorectal cancer (CRC) and the estimated patient's age, diagnostic duration and birth cohort effects in patients of Changning District, Shanghai.

METHODS

Age-standardized rates (ASRs) of CRC over eight intervals of 5 years from 1975 to 2013 were determined. Joinpoint regression analysis was used to determine the changes in annual incidence and mortality trends. Age-period-cohort analysis was performed to investigate their effects on the incidence and mortality trends of CRC.

RESULTS

For incidence, the ASRs of 14.14 per 100 000 and 11.81 per 100 000 during 1975-1979 increased to 32.11 per 100 000 and 26.25 per 100 000 in men and women during 2008-2013. For mortality, ASRs of 9.40 per 100 000 and 8.76 per 100 000 increased to 14.80 per 100 000 and 11.92 per 100 000 in men and women, respectively, from 1975-1979 to 2010-2013. Joinpoint regression analysis found an increasing incidence (average annual percentage change [AAPC] 2.18% for men and 1.65% for women) and mortality (AAPC 1.47% for men and 0.97% for women) of CRC throughout the entire period. The incidence and mortality trends of CRC were significantly affected by birth cohorts.

CONCLUSIONS

The increasing incidence and mortality of CRC are largely affected by the effects of birth cohorts. The increased incidence of CRC may be attributed to changes in lifestyle and diet, while that in mortality trends may be resulted from increasing incidence, an aging population and changing lifestyles.

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.

Human metabolic correlates of body mass index

BACKGROUND

A high body mass index (BMI) is a major risk factor for several chronic diseases, but the biology underlying these associations is not well-understood. Dyslipidemia, inflammation, and elevated levels of growth factors and sex steroid hormones explain some of the increased disease risk, but other metabolic factors not yet identified may also play a role.

DESIGN

In order to discover novel metabolic biomarkers of BMI, we used non-targeted metabolomics to assay 317 metabolites in blood samples from 947 participants and examined the cross-sectional associations between metabolite levels and BMI. Participants were from three studies in the United States and China. Height, weight, and potential confounders were ascertained by questionnaire (US studies) or direct measurement (Chinese study). Metabolite levels were measured using liquid-phase chromatography and gas chromatography coupled with mass spectrometry. We evaluated study-specific associations using linear regression, adjusted for age, gender, and smoking, and we estimated combined associations using random effects meta-analysis.

RESULTS

The meta-analysis revealed 37 metabolites significantly associated with BMI, including 19 lipids, 12 amino acids, and 6 others, at the Bonferroni significance threshold (p<0.00016). Eighteen of these associations had not been previously reported, including histidine, an amino acid neurotransmitter, and butyrylcarnitine, a lipid marker of whole-body fatty acid oxidation. Heterogeneity by study was minimal (all P_{heterogeneity} >0.05). In total, 110 metabolites were associated with BMI at the p<0.05 level.

CONCLUSION

These findings establish a baseline for the BMI metabolome, and suggest new targets for researchers attempting to clarify mechanistic links between high BMIs and disease risk.

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.

Metabolomics in epidemiology: sources of variability in metabolite measurements and implications

BACKGROUND

Metabolite levels within an individual vary over time. This within-individual variability, coupled with technical variability, reduces the power for epidemiologic studies to detect associations with disease. Here, the authors assess the variability of a large subset of metabolites and evaluate the implications for epidemiologic studies.

METHODS

Using liquid chromatography/mass spectrometry (LC/MS) and gas chromatography-mass spectroscopy (GC/MS) platforms, 385 metabolites were measured in 60 women at baseline and year-one of the Shanghai Physical Activity Study, and observed patterns were confirmed in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening study.

RESULTS

Although the authors found high technical reliability (median intraclass correlation = 0.8), reliability over time within an individual was low. Taken together, variability in the assay and variability within the individual accounted for the majority of variability for 64% of metabolites. Given this, a metabolite would need, on average, a relative risk of 3 (comparing upper and lower quartiles of "usual" levels) or 2 (comparing quartiles of observed levels) to be detected in 38%, 74%, and 97% of studies including 500, 1,000, and 5,000 individuals. Age, gender, and fasting status factors, which are often of less interest in epidemiologic studies, were associated with 30%, 67%, and 34% of metabolites, respectively, but the associations were weak and explained only a small proportion of the total metabolite variability.

CONCLUSION

Metabolomics will require large, but feasible, sample sizes to detect the moderate effect sizes typical for epidemiologic studies.

IMPACT

We offer guidelines for determining the sample sizes needed to conduct metabolomic studies in epidemiology.

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.

Abstract 626: Dietary glycemic load, glycemic index and risk of primary liver cancer: Results from the Shanghai women's and men's health studies

Introduction Dietary glycemic index (GI) and glycemic load (GL) have been observed to have a positive relationship with obesity and diabetes which are risk factors for liver cancer. However, studies assessing the association between GI, GL and liver cancer have yielded inconsistent results. We evaluated the association of GI and GL with liver cancer using data from two prospective cohort studies, the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS). Methods The study population consisted of 72,906 women from SWHS and 60,203 men from the SMHS who had not been previously diagnosed with cancer, did not have extreme total energy intake as assessed by a food frequency questionnaire (FFQ) and had complete data on all covariates of interest. Subject recruitment for the SWHS began in 1996 and for the SMHS began in 2002. Outcome follow-up data through December 31, 2009 from both cohorts were used in the current analysis. At baseline, a validated FFQ was administered and daily dietary GI and GL were calculated for each cohort member. These values were energy adjusted using the residuals method and categorized into quintiles. Confounders were assessed using data from the baseline questionnaire. Hazard ratios and 95% confidence intervals were calculated for the association between GI/GL and liver cancer incidence with adjustment for potential confounders. Results After a median follow-up of 11.2 and 5.3 years for the SWHS and SMHS, respectively, 346 incident liver cancer (ICD-9: 155) were identified. Women in the upper quintiles of GL intake were more likely to be older, have less education, have lower annual family incomes, be smokers, be post-menopausal, and were less likely to exercise, consume alcohol or have a history of diabetes or hepatitis. Men in the upper quintiles of GL intake were more likely to have less education, have lower annual per capita family incomes, and were less likely to exercise, to consume alcohol or have a history of diabetes. After adjustment for all confounders, no statistically significant trends were observed for men or women for the quintile of intake of GI or GL with the incidence of liver cancer (SWHS: GL p trend = 0.67, GI p trend = 0.11; SMHS: GL p trend = 0.64, GI p trend = 0.29). Similarly, no statistically significant trends were observed when the models were stratified by chronic hepatitis status (yes or no). Conclusions There is little evidence that GI or GL affect the incidence of liver cancer in this population. Further research about other modifiable risk factors for liver cancer is warranted.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 626. doi:1538-7445.AM2012-626

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.

Validity of a physical activity questionnaire in Shanghai

PURPOSE

In large epidemiologic studies, physical activity (PA) is often assessed using PA questionnaires (PAQ). Because available PAQ may not capture the full range of PA in which urban Chinese adults engage, a PAQ was developed for this purpose. We examined the validity of this PAQ and the 1-yr stability of PA in 545 urban Shanghai adults.

METHODS

The PAQ was interview-administered twice, approximately 1 yr apart, and participants also wore an accelerometer and completed a PA-log for seven consecutive days every 3 months during the same year. The intraclass correlation coefficient (ICC) was used to evaluate the stability of PA across questionnaire administrations, and Spearman correlation coefficients (ρ) and mean differences and 95% limits of agreement were used to examine the validity of the questionnaire compared against accelerometry and the PA-log.

RESULTS

When measured by accelerometry, estimates of time spent in moderate-to-vigorous PA were lower and estimates of time spent sedentary were higher than when self-reported on the PAQ (P < 0.001). Total PA (ICC = 0.65) and PA domains (ICC = 0.45-0.85) showed moderate to high stability across PAQ administrations. Total PA (ρ = 0.30), moderate-to-vigorous activity (ρ = 0.17), light activity (ρ = 0.36), and sedentary behavior (ρ = 0.16) assessed by PAQ and by accelerometry were significantly and positively correlated, and correlations of the PAQ with the PA-log (ρ = 0.36-0.85) were stronger than those observed with accelerometry.

CONCLUSIONS

The PAQ significantly overestimated time spent in moderate-to-vigorous activity and underestimated time spent in light activity and sedentary behavior compared with accelerometry, but it performed well at ranking participants according to PA level.

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.

Accelerometer-measured physical activity in Chinese adults

BACKGROUND

Following adoption of a Western lifestyle, China is experiencing a decline in physical activity levels, which is projected to contribute to future increases in the burden of chronic diseases.

PURPOSE

This study aims to target public health interventions and identify personal characteristics associated with physical activity and sedentary behavior in urban Chinese adults.

METHODS

In a sample of 576 men and women aged 40-74 years from Shanghai, multiple logistic regression was used to examine demographic, anthropometric, and lifestyle factors in relation to levels of physical activity and sedentary behavior assessed by Actigraph accelerometers.

RESULTS

Participants spent 317 minutes/day in physical activity and 509 minutes/day sedentary. In multivariate models, people aged > or =60 years were significantly less likely than those aged <50 years to engage in physical activity (OR=0.29, 95% CI=0.17, 0.49) and more likely to spend time sedentary (OR=2.77, 95% CI=1.53, 5.05). Similarly, obese individuals were less likely to be physically active (OR=0.34, 95% CI=0.17, 0.66) and they were suggestively more likely to be sedentary (OR=1.87, 95% CI=0.94, 3.71) than normal-weight individuals. Furthermore, current cigarette smokers were less physically active than those who formerly or never smoked (OR=0.47, 95% CI=0.28, 0.78).

CONCLUSIONS

Physical activity promotion programs in urban China should target older people, obese individuals, and cigarette smokers, as these population subgroups exhibited low levels of physical activity.

Interaction of soy food and tea consumption with CYP19A1 genetic polymorphisms in the development of endometrial cancer

Certain polyphenols inhibit the activity of aromatase, a critical enzyme in estrogen synthesis that is coded by the CYP19A1 gene. Consumption of polyphenol-rich foods and beverages, thus, may interact with CYP19A1 genetic polymorphisms in the development of endometrial cancer. The authors tested this hypothesis in the Shanghai Endometrial Cancer Study (1997-2003), a population-based case-control study of 1,204 endometrial cancer cases and 1,212 controls. Dietary information was obtained by use of a validated food frequency questionnaire. Genotypes of CYP19A1 at rs28566535, rs1065779, rs752760, rs700519, and rs1870050 were available for 1,042 cases and 1,035 controls. Unconditional logistic regression models were used to calculate odds ratios and their 95% confidence intervals after adjustment for potential confounding factors. Higher intake of soy foods and tea consumption were both inversely associated with the risk of endometrial cancer, with odds ratios of 0.8 (95% confidence interval: 0.6, 1.0) for the highest versus the lowest tertiles of intake of soy and 0.8 (95% confidence interval: 06, 0.9) for ever tea consumption. The association of single nucleotide polymorphisms rs1065779, rs752760, and rs1870050 with endometrial cancer was modified by tea consumption (p(interaction) < 0.05) but not by soy isoflavone intake. The authors' findings suggest that tea polyphenols may modify the effect of CYP19A1 genetic polymorphisms on the development of endometrial cancer.

Oral contraceptive and IUD use and endometrial cancer: a population-based case-control study in Shanghai, China

Oral contraceptive (OC) and intrauterine device (IUD) use have been shown to be protective factors for endometrial cancer in several epidemiological studies; however, few studies have been conducted in Chinese populations. We evaluated the association between OC and IUD use and endometrial cancer risk in a population-based case-control study among Chinese women in Shanghai, China. The study included 1,204 newly diagnosed endometrial cancer cases and 1,212 age frequency-matched healthy controls. Logistic regression models were used to estimate adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). In our study population, 18.5% cases and 24.9% controls reported having ever used OCs with an OR of 0.75 (95% CI, 0.60-0.93), after adjusting for known risk or protective factors for endometrial cancer. The risk of endometrial cancer decreased with long-term use of OCs with the OR for more than 72 months of use being 0.50 (95% CI, 0.30-0.85). The effect of OC use remained 25 or more years after cessation of use; the associated OR was 0.57 (95% CI = 0.42-0.78) as compared to nonusers. Similarly, fewer cases than controls had ever used IUD, with the multivariable adjusted OR being 0.53 (95% CI = 0.43-0.65). A reduction in risk was observed regardless the duration of use or age at first and last use. These results suggest that OC and IUD use may confer long-term protection against endometrial cancer.

Weight history and risk of endometrial cancer among Chinese women

BACKGROUND

Adult obesity is a well-established risk factor for endometrial cancer. However, little is known about the association of endometrial cancer risk with body size early in life and weight change during adulthood. We investigated whether women with greater early-age body size or with greater weight change during adulthood have an increased risk of endometrial cancer.

METHODS

We analysed data from a population-based case-control study of endometrial cancer conducted between 1997 and 2001 in Shanghai, China. Included in this analysis were 832 endometrial cancer cases aged 30-69 years and 846 population controls. Information on weight and height history from adolescence through adulthood was obtained via structured in-person interviews. A logistic regression model was used to derive odds ratios (ORs) and 95% confidence intervals (CIs) for endometrial cancer in association with adolescent and adult adiposity, as well as adult body weight change. All ORs were adjusted for age, education, menstrual status, duration of menstruation, number of pregnancies, oral contraceptive use, and family history of cancer.

RESULTS

Perceived weights and heights during puberty that were greater than average were associated with a modestly increased risk of cancer. The association for perceived weight was substantially weakened after adjustment for current body mass index (BMI). High BMI at all adult ages significantly predicted endometrial cancer risk, with recent BMI being the strongest predictor. Further analyses disclosed that weight gain during adulthood, particularly during the peri-menopausal period (age 40-50 years), was associated with a significantly elevated risk of endometrial cancer, even among currently non-obese women. Gaining >5 kg between age 40 and 50 was related to ORs of 2.3 (95% CI 1.4-3.9) for women with a BMI<25 kg/m2 and 2.0 (95% CI 1.3-3.0) for women with BMI>or=25 kg/m2.

CONCLUSIONS

Adult weight gain, particularly during the peri-menopausal period, plays a significant role in the development of endometrial cancer risk.

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.

Physical activity and risk of endometrial cancer: a report from the Shanghai endometrial cancer study

We evaluated the type and amount of physical activity associated with risk of endometrial cancer. In this population-based case-control study, in-person interviews were completed among 832 incident endometrial cancer cases and 846 age-matched controls. Physical activity from exercise, household activities, and transportation was assessed in adolescence and adulthood, as was lifetime occupational activity. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence limits (95% CL). Women reporting exercise participation in both adolescence and adulthood were at nearly a 40% reduced risk (OR, 0.63; 95% CL, 0.42-0.95), compared with women reporting no exercise in either life period. Postmenopausal women who initiated exercise in adulthood were also at reduced risk (OR, 0.76; 95% CL, 0.56-1.02). Reductions in risk were also observed for common lifestyle activities, including household activity (both life periods) and walking for transportation (adulthood). Examination of the independent and combined effect of exercise and lifestyle activities revealed that women with less active lifestyles but who reported exercise were at 35% reduced risk (OR, 0.65; 95% CL, 0.41-1.02), whereas nonexercisers with more active lifestyles were at 40% to 45% reduced risk. These findings suggest that both lifestyle activities of lower intensity (e.g., walking and doing household chores) and intentional exercise can reduce endometrial cancer risk.

Effect of adiposity and fat distribution on endometrial cancer risk in Shanghai women

The authors conducted a population-based case-control study of 832 endometrial cancer cases and 846 frequency-matched controls in Shanghai, China (1997-2001), to examine the association of overall adiposity and body fat distribution with disease risk. Overall adiposity was estimated using weight and body mass index (BMI); upper body fat distribution was evaluated using waist circumference and waist:hip ratio. Overall and upper-body obesity were both associated with an elevated risk of endometrial cancer. Adjusted odds ratios and 95% confidence intervals for highest-versus-lowest quartile comparisons were 2.6 (95% confidence interval (CI): 2.0, 3.5) for weight, 2.9 (95% CI: 2.2, 3.9) for BMI, 4.7 (95% CI: 3.4, 6.4) for waist circumference, and 3.5 (95% CI: 2.6, 4.8) for waist:hip ratio. The positive associations with weight and BMI vanished after results were controlled for waist circumference, while associations with waist circumference and waist:hip ratio persisted after adjustment for BMI. The positive association with upper-body obesity was more pronounced among younger women, women who had never used oral contraceptives, and women with a history of diabetes mellitus (p for multiplicative interaction < 0.05). Upper-body obesity was related to increased risk among women with low BMI. These results suggest that obesity, particularly upper-body fat deposition, is associated with an increased risk of endometrial cancer.

Association of passive smoking by husbands with prevalence of stroke among Chinese women nonsmokers

Growing evidence suggests that exposure to environmental tobacco smoke may have deleterious cardiovascular effects. Few studies have investigated environmental tobacco smoke exposure in relation to stroke. The authors examined the association between smoking by husbands and stroke prevalence among women nonsmokers in Shanghai, China, where two thirds of men but few women smoke. They analyzed baseline survey data (1997-2000) from a population-based cohort study, the Shanghai Women's Health Study. A total of 60,377 eligible women (aged 40-70 years) were included in the analysis. Information on husbands' smoking status and history of physician-diagnosed stroke was obtained through in-person interviews. Logistic regression was used to compute odds ratios for the associations. There were 526 prevalent cases of stroke reported. The adjusted odds ratios of stroke in women associated with husbands' current smoking of 1-9, 10-19, and > or =20 cigarettes per day were 1.28 (95% confidence interval: 0.92, 1.77), 1.32 (95% confidence interval: 1.01, 1.72), and 1.62 (95% confidence interval: 1.28, 2.05), respectively (p for trend = 0.0002). Prevalence of stroke also increased with increasing duration of husbands' smoking. The authors found that women nonsmokers who lived with husbands who smoked had an elevated prevalence of stroke, and prevalence increased with increasing intensity and duration of husbands' smoking.

Soya food intake and risk of endometrial cancer among Chinese women in Shanghai: population based case-control study

OBJECTIVE

To evaluate the association of intake of soya food, a rich source of phytoestrogens, with the risk of endometrial cancer.

DESIGN

Population based case-control study, with detailed information on usual soya food intake over the past five years collected by face to face interview using a food frequency questionnaire.

SETTING

Urban Shanghai, China.

PARTICIPANTS

832 incident cases of endometrial cancer in women aged of 30 to 69 years diagnosed during 1997-2001 and identified from the Shanghai Cancer Registry; 846 control women frequency matched to cases on age and randomly selected from the Shanghai Residential Registry.

MAIN OUTCOME MEASURES

Odds ratios for risk of endometrial cancer in women with different intakes of soya foods.

RESULTS

Regular consumption of soya foods, measured as amount of either soya protein or soya isoflavones, was inversely associated with the risk of endometrial cancer. Compared with women with the lowest quarter of intake, the adjusted odds ratio of endometrial cancer was reduced from 0.93 to 0.85 and 0.67 with increasing quarter of soya protein intake (P for trend 0.01). A similar inverse association was observed for soya isoflavones and soya fibre intake. The inverse association seemed to be more pronounced among women with high body mass index and waist:hip ratio.

CONCLUSION

Regular intake of soya foods is associated with a reduced 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.