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.

Pancreatitis and pancreatic cancer risk: a pooled analysis in the International Pancreatic Cancer Case-Control Consortium (PanC4)

BACKGROUND

Pancreatitis is a known risk factor for pancreatic cancer; however, an unknown fraction of the disease is thought to be a consequence of tumor-related duct obstruction.

PATIENTS AND METHODS

A pooled analysis of a history of pancreatitis and risk of pancreatic cancer was carried out considering the time interval between diagnoses and potential modification by covariates. Adjusted pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from 10 case-control studies (5048 cases of ductal pancreatic adenocarcinoma and 10,947 controls) taking part in the International Pancreatic Cancer Case-Control Consortium (PanC4).

RESULTS

The association between pancreatitis and pancreatic cancer was nearly three-fold at intervals of >2 years between diagnoses (OR: 2.71, 95% CI: 1.96-3.74) and much stronger at intervals of ≤2 years (OR: 13.56, 95% CI: 8.72-21.90) probably reflecting a combination of reverse causation and antecedent misdiagnosis of pancreas cancer as pancreatitis. The younger (<65 years) pancreatic cancer cases showed stronger associations with previous (>2 years) pancreatitis (OR: 3.91, 95% CI: 2.53-6.04) than the older (≥65 years) cases (OR: 1.68, 95% CI: 1.02-2.76; P value for interaction: 0.006).

CONCLUSIONS

Despite a moderately strong association between pancreatitis (diagnosed before >2 years) and pancreatic cancer, the population attributable fraction was estimated at 1.34% (95% CI: 0.612-2.07%), suggesting that a relatively small proportion of pancreatic cancer might be avoided if pancreatitis could be prevented.

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.

Cigarette smoking and pancreatic cancer: an analysis from the International Pancreatic Cancer Case-Control Consortium (Panc4)

BACKGROUND

To evaluate the dose-response relationship between cigarette smoking and pancreatic cancer and to examine the effects of temporal variables.

METHODS

We analyzed data from 12 case-control studies within the International Pancreatic Cancer Case-Control Consortium (PanC4), including 6507 pancreatic cases and 12 890 controls. We estimated summary odds ratios (ORs) by pooling study-specific ORs using random-effects models.

RESULTS

Compared with never smokers, the OR was 1.2 (95% confidence interval [CI] 1.0-1.3) for former smokers and 2.2 (95% CI 1.7-2.8) for current cigarette smokers, with a significant increasing trend in risk with increasing number of cigarettes among current smokers (OR=3.4 for ≥35 cigarettes per day, P for trend<0.0001). Risk increased in relation to duration of cigarette smoking up to 40 years of smoking (OR=2.4). No trend in risk was observed for age at starting cigarette smoking, whereas risk decreased with increasing time since cigarette cessation, the OR being 0.98 after 20 years.

CONCLUSIONS

This uniquely large pooled analysis confirms that current cigarette smoking is associated with a twofold increased risk of pancreatic cancer and that the risk increases with the number of cigarettes smoked and duration of smoking. Risk of pancreatic cancer reaches the level of never smokers ∼20 years after quitting.

Alcohol consumption and pancreatic cancer: a pooled analysis in the International Pancreatic Cancer Case-Control Consortium (PanC4)

BACKGROUND

Heavy alcohol drinking has been related to pancreatic cancer, but the issue is still unsolved.

METHODS

To evaluate the role of alcohol consumption in relation to pancreatic cancer, we conducted a pooled analysis of 10 case-control studies (5585 cases and 11,827 controls) participating in the International Pancreatic Cancer Case-Control Consortium. We computed pooled odds ratios (ORs) by estimating study-specific ORs adjusted for selected covariates and pooling them using random effects models.

RESULTS

Compared with abstainers and occasional drinkers (< 1 drink per day), we observed no association for light-to-moderate alcohol consumption (≤ 4 drinks per day) and pancreatic cancer risk; however, associations were above unity for higher consumption levels (OR = 1.6, 95% confidence interval 1.2-2.2 for subjects drinking ≥ 9 drinks per day). Results did not change substantially when we evaluated associations by tobacco smoking status, or when we excluded participants who reported a history of pancreatitis, or participants whose data were based upon proxy responses. Further, no notable differences in pooled risk estimates emerged across strata of sex, age, race, study type, and study area.

CONCLUSION

This collaborative-pooled analysis provides additional evidence for a positive association between heavy alcohol consumption and the risk of pancreatic cancer.

A biomarker survey of urinary deoxynivalenol in China: the Shanghai Women's Health Study

Deoxynivalenol (DON) is a trichothecene mycotoxin found on wheat, maize and barley. In ecological surveys in China, DON and other trichothecenes have been implicated in acute poisoning episodes and linked with the incidence of esophageal cancer. In order to better understand exposure patterns, this pilot survey provided a combined measure of urinary un-metabolised or free DON (fD) and its glucuronide metabolite (DG) in a subset of 60 samples taken from the Shanghai Women's Health Study cohort, China. Samples were collected in 1997/1998 from women age 40-70 years. Urinary fD+DG combined was detected in 58/60 (96.7%) samples (mean 5.9 ng DON/mg creatinine; range nd-30.5); a similar frequency, and a mean level approximately half, of that previously observed for women in the UK. Wheat consumption was approximately 25% of that consumed by western diets; thus DON contamination of wheat may be higher in Shanghai than the UK. The de-epoxy metabolite of DON, a detoxification product observed in animals, was not detected, suggesting that humans may be particularly sensitive to DON due to a more restricted detoxification capacity.

Occupational exposure to pesticides and pancreatic cancer

BACKGROUND

An increased risk of exposure to pesticides for pancreatic cancer has been suggested in a number of epidemiologic studies.

METHODS

Cases (N = 484), aged 30-79 years, were diagnosed in 1986-1989. Controls (N = 2,095) were a random sample of the general population. Information on usual occupation and potential confounding factors was obtained. A job-exposure matrix (JEM) approach was used to estimate the level of occupational exposure to pesticides.

RESULTS

A significant trend in risk with increasing exposure level of pesticides was observed, with ORs of 1.3 and 1.4 for low and moderate/high exposure levels, respectively. Excess risks were found for occupational exposure to fungicides (OR = 1.5) and herbicides (OR = 1.6) in the moderate/high level after adjustment for potential confounding factors. An increased risk for insecticide exposure was disappeared after adjustment for fungicide and herbicide exposures. Results of our occupation-based analysis were consistent with those from the JEM-based analysis.

CONCLUSIONS

Our results suggest that pesticides may increase risk of pancreatic cancer, and indicate the need for investigations that can evaluate risk by specific chemical exposures. Published 2001 Wiley-Liss, Inc.

Cancer incidence trends in urban shanghai, 1972-1994: an update

Incidence rates for a number of cancers in urban Shanghai, China, have been changing markedly. Herein we update the trends using population-based data from the Shanghai Cancer Registry for 1972-1994. During 1993-1994, cancers of the lung, stomach, and liver were the 3 leading forms among men, with age-adjusted (world standard) incidence rates of 50.9, 39.2, and 26.5 per 100,000 person-years, respectively, followed by cancers of the colon (12.4) and esophagus (10.0). Among women, cancers of the breast (27.5), stomach (19.1), and lung (17.7) were the most common tumors, followed by cancers of the colon (11.3) and liver (9.4). Over the 23-year period, the rate for all cancers combined, excluding non-melanoma skin cancer, decreased from 247.5 to 215.2 among men and from 173.6 to 154.0 among women. However, trends for individual forms of cancer varied considerably. Rates doubled for cancers of the colon and biliary tract in both sexes, and they increased substantially for cancers of the brain and nervous system, kidney, pancreas, prostate, corpus uteri, female breast, and ovary, and for non-Hodgkin's lymphoma. Rates for cancers of the lung and rectum changed little. Rates declined by at least one-half for cancers of the esophagus and cervix, with notable decreases also for cancers of the stomach and liver. Some of these trends may reflect variations in diagnostic or screening practices, although changes in lifestyle and other environmental exposures are likely to play important roles. Further epidemiologic research in China is needed to identify risk factors influencing the cancer incidence trends.

Cancer incidence trends in urban shanghai, 1972-1994: an update

Incidence rates for a number of cancers in urban Shanghai, China, have been changing markedly. Herein we update the trends using population-based data from the Shanghai Cancer Registry for 1972-1994. During 1993-1994, cancers of the lung, stomach, and liver were the 3 leading forms among men, with age-adjusted (world standard) incidence rates of 50.9, 39.2, and 26.5 per 100,000 person-years, respectively, followed by cancers of the colon (12.4) and esophagus (10.0). Among women, cancers of the breast (27.5), stomach (19.1), and lung (17.7) were the most common tumors, followed by cancers of the colon (11.3) and liver (9.4). Over the 23-year period, the rate for all cancers combined, excluding non-melanoma skin cancer, decreased from 247.5 to 215.2 among men and from 173.6 to 154.0 among women. However, trends for individual forms of cancer varied considerably. Rates doubled for cancers of the colon and biliary tract in both sexes, and they increased substantially for cancers of the brain and nervous system, kidney, pancreas, prostate, corpus uteri, female breast, and ovary, and for non-Hodgkin's lymphoma. Rates for cancers of the lung and rectum changed little. Rates declined by at least one-half for cancers of the esophagus and cervix, with notable decreases also for cancers of the stomach and liver. Some of these trends may reflect variations in diagnostic or screening practices, although changes in lifestyle and other environmental exposures are likely to play important roles. Further epidemiologic research in China is needed to identify risk factors influencing the cancer incidence trends.

Occupational risk factors for pancreatic cancer: a case-control study based on death certificates from 24 U.S. states

BACKGROUND

The relation between occupational exposure and pancreatic cancer is not well established. A population-based case-control study based on death certificates from 24 U.S. states was conducted to determine if occupations/industries or work-related exposures to solvents were associated with pancreatic cancer death.

METHODS

The cases were 63,097 persons who died from pancreatic cancer occurring in the period 1984-1993. The controls were 252,386 persons who died from causes other than cancer in the same time period.

RESULTS

Industries associated with significantly increased risk of pancreatic cancer included printing and paper manufacturing; chemical, petroleum, and related processing; transport, communication, and public service; wholesale and retail trades; and medical and other health-related services. Occupations associated with significantly increased risk included managerial, administrative, and other professional occupations; technical occupations; and sales, clerical, and other administrative support occupations. Potential exposures to formaldehyde and other solvents were assessed by using a job exposure matrix developed for this study. Occupational exposure to formaldehyde was associated with a moderately increased risk of pancreatic cancer, with ORs of 1.2, 1.2, 1.4 for subjects with low, medium, and high probabilities of exposure and 1.2, 1.2, and 1.1 for subjects with low, medium, and high intensity of exposure, respectively.

CONCLUSIONS

The findings of this study did not suggest that industrial or occupational exposure is a major contributor to the etiology of pancreatic cancer. Further study may be needed to confirm the positive association between formaldehyde exposure and pancreatic cancer. Published 1999 Wiley-Liss, Inc.

Occupation and pancreatic cancer risk in Shanghai, China

BACKGROUND

Any association between occupation and pancreatic cancer risk has not been conclusively demonstrated. A population-based case-control study was conducted to examine occupational risks of pancreatic cancer in Shanghai, China.

METHODS

The study included 451 pancreatic cancer patients newly diagnosed in 1990-1993 and 1,552 controls randomly selected from Shanghai residents. Information on a lifetime job history and other factors was obtained in a face-to-face interview.

RESULTS

Among men, an increased risk of pancreatic cancer was associated with employment as an electrician (OR = 7.5, CI = 2.6-21.8), and a positive trend in risk with increasing duration of employment was apparent (P for trend = 0.0003). Exposure to electric magnetic fields (EMF) as measured by a job exposure matrix also was associated with an increased risk among electricians. Threefold risks were observed for men with the highest level of intensity and for those with the highest probability of EMF exposure, although women with heavy EMF exposure did not experience increased risk. Among men, elevated risks also were found for metal workers (OR = 2.1, CI = 1.0-4.8); toolmakers (OR = 3.4, CI = 14-7.1); plumbers and welders (OR = 3.0, CI = 1.2-7.5); and glass manufacturers, potters, painters, and construction workers (OR = 2.6, CI = 1.1-6.3). Among women, textile workers experienced an increased risk (OR = 1.4, CI = 0.8-2.6).

CONCLUSIONS

Our results suggest that occupations associated with exposures to metal and textile dusts or certain chemicals may increase the risk of pancreatic cancer. The elevated risk among electricians may warrant further study to evaluate the possible role of EMF or other exposures.

Colorectal cancer incidence trends by subsite in urban Shanghai, 1972-1994

Epidemiological characteristics of colorectal cancer may differ by particular anatomical subsite, suggesting that the subsite-specific colorectal cancers may represent different disease entities. This study explored the time trends over a 23-year period in colorectal cancer incidence at various subsites by sex and age group. Data on the incidence of colorectal cancer were obtained from a population-based cancer registry in Shanghai, People's Republic of China. Between 1972 and 1994, 30,693 patients with colorectal cancer were registered at the Shanghai Cancer Registry. The overall age-adjusted colorectal cancer incidence rates increased > 50%, or 2% per year from 1972-1977 to 1990-1994, from 14 to 22 per 100,000 among men and from 12 to 19 per 100,000 among women. The increases in rates were considerably more rapid for colon cancer, with rates approximately doubling, than they were for rectal cancer. Proximal colon cancer was more common than distal colon cancer over the whole study period, whereas rates for both cancers rose with similar annual percentage changes (> 5% per year) and across virtually all age groups. The estimated annual increases rose from 2% at ages 35-44 years to 7% at ages 75-84 years for proximal colon cancer, but they were more uniform for distal colon cancer (5-6% per year). Age-adjusted and age-specific rectal cancer rates changed little. The male:female age-adjusted rate ratio for colorectal cancer was 1.19 in 1990-1994. The ratios increased over time and varied by subsites, with ratios increasing from the proximal colon to the distal colon and to the rectum. Furthermore, men had higher rates than women for distal colon and rectal cancers at ages 55 and older, whereas women had higher rates than men at younger ages for these two cancers. Male:female rate ratios for proximal colon cancer did not vary substantially with age. The findings from this study indicate that subsite-specific incidence rates of colorectal cancer differ by sex and age and in their time trends. Cancers arising in the proximal colon, distal colon, and rectum may have somewhat different disease etiologies.

Dietary habits and stomach cancer in Shanghai, China

Stomach cancer remains the second leading cancer in incidence in Shanghai, China, despite its decline over the past 2 decades. To clarify risk factors for this common malignancy, we conducted a population-based case-control study in Shanghai, China. Included in the study were 1,124 stomach cancer patients (age 20-69) newly diagnosed in 1988-1989 and 1,451 controls randomly selected among Shanghai residents. Usual adult dietary intake was assessed using a comprehensive food frequency questionnaire. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Risks of stomach cancer were inversely associated with high consumption of several food groups, including fresh vegetables and fruits, poultry, eggs, plant oil, and some nutrients, such as protein, fat, fiber and antioxidant vitamins. By contrast, risks increased with increasing consumption of dietary carbohydrates, with odds ratios (ORs) of 1.5 (95% confidence interval [CI] 1.1-2.1) and 1.9 (95% CI 1.3-2.9) in the highest quartile of intake among men (p for trend=0.02) and women (p=0.0007), respectively. Similar increases in risk were associated with frequent intake of noodles and bread in both men (p=0.07) and women (p=0.05) after further adjustment for fiber consumption. In addition, elevated risks were associated with frequent consumption of preserved, salty or fried foods, and hot soup/porridge, and with irregular meals, speed eating and binge eating. No major differences in risk were seen according to subsite (cardia vs. non-cardia). Our findings add to the evidence that diet plays a major role in stomach cancer risk and suggest the need for further evaluation of risks associated with carbohydrates and starchy foods as well as the mechanisms involved.

Dietary habits and stomach cancer in Shanghai, China

Stomach cancer remains the second leading cancer in incidence in Shanghai, China, despite its decline over the past 2 decades. To clarify risk factors for this common malignancy, we conducted a population-based case-control study in Shanghai, China. Included in the study were 1,124 stomach cancer patients (age 20-69) newly diagnosed in 1988-1989 and 1,451 controls randomly selected among Shanghai residents. Usual adult dietary intake was assessed using a comprehensive food frequency questionnaire. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Risks of stomach cancer were inversely associated with high consumption of several food groups, including fresh vegetables and fruits, poultry, eggs, plant oil, and some nutrients, such as protein, fat, fiber and antioxidant vitamins. By contrast, risks increased with increasing consumption of dietary carbohydrates, with odds ratios (ORs) of 1.5 (95% confidence interval [CI] 1.1-2.1) and 1.9 (95% CI 1.3-2.9) in the highest quartile of intake among men (p for trend=0.02) and women (p=0.0007), respectively. Similar increases in risk were associated with frequent intake of noodles and bread in both men (p=0.07) and women (p=0.05) after further adjustment for fiber consumption. In addition, elevated risks were associated with frequent consumption of preserved, salty or fried foods, and hot soup/porridge, and with irregular meals, speed eating and binge eating. No major differences in risk were seen according to subsite (cardia vs. non-cardia). Our findings add to the evidence that diet plays a major role in stomach cancer risk and suggest the need for further evaluation of risks associated with carbohydrates and starchy foods as well as the mechanisms involved.

Dietary habits and stomach cancer in Shanghai, China

Stomach cancer remains the second leading cancer in incidence in Shanghai, China, despite its decline over the past 2 decades. To clarify risk factors for this common malignancy, we conducted a population-based case-control study in Shanghai, China. Included in the study were 1,124 stomach cancer patients (age 20-69) newly diagnosed in 1988-1989 and 1,451 controls randomly selected among Shanghai residents. Usual adult dietary intake was assessed using a comprehensive food frequency questionnaire. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Risks of stomach cancer were inversely associated with high consumption of several food groups, including fresh vegetables and fruits, poultry, eggs, plant oil, and some nutrients, such as protein, fat, fiber and antioxidant vitamins. By contrast, risks increased with increasing consumption of dietary carbohydrates, with odds ratios (ORs) of 1.5 (95% confidence interval [CI] 1.1-2.1) and 1.9 (95% CI 1.3-2.9) in the highest quartile of intake among men (p for trend=0.02) and women (p=0.0007), respectively. Similar increases in risk were associated with frequent intake of noodles and bread in both men (p=0.07) and women (p=0.05) after further adjustment for fiber consumption. In addition, elevated risks were associated with frequent consumption of preserved, salty or fried foods, and hot soup/porridge, and with irregular meals, speed eating and binge eating. No major differences in risk were seen according to subsite (cardia vs. non-cardia). Our findings add to the evidence that diet plays a major role in stomach cancer risk and suggest the need for further evaluation of risks associated with carbohydrates and starchy foods as well as the mechanisms involved.

Do standing, lifting, climbing, or long hours of work during pregnancy have an effect on fetal growth?

We assessed prospectively the impact of length of the work week and job activity on fetal growth. Among 575 women who worked during pregnancy, neither prolonged standing, frequent lifting, or climbing at work, nor a high composite activity score showed an association with fetal growth, as measured by birthweight for gestational age. Long hours of work, however, did reduce fetal growth. Infants of women working long hours late in pregnancy showed decreases in gestation-adjusted birthweight of about 80 gm (95% confidence limits = -238, +74 gm), compared with women working 20 hours or less. When long hours (> 40 hours per week) were combined with job activity, the estimated reductions ranged up to 350 gm. At lower weights (< or = 3,000 gm), categorical analyses showed elevated odds ratios (1.1-1.8) for climbing, lifting, and long hours and for the combination of prolonged standing with a lengthy work week. These results indicate that long weeks of physically demanding work could lead to fetal growth reductions that may be clinically significant. Consistent with this suggestion, infants of women who worked part-time had the highest mean birthweights. Hours of work, not only job tasks, may be important for pregnant workers.

Body mass index and the risk of cancers of the gastric cardia and distal stomach in Shanghai, China

The divergent incidence patterns of gastric cardia and distal stomach cancers suggest different etiologies. Although obesity has recently been linked to cardia cancer in Western populations, its association with distal stomach cancer remains unclear. This study examined the relation of anthropometric measurements to risk by subsites of stomach cancer in a Chinese population. We identified 1124 population-based cases of stomach cancer, ages 20-69 years, newly diagnosed between December 1988 and November 1989 in Shanghai, China. Controls (n = 1451) were randomly selected from permanent Shanghai residents and frequency-matched to cases by age and sex. Information on demographic characteristics, height and weight, diet, smoking, and other exposures was obtained by trained interviewers in person. The body mass index (BMI) was calculated as weight in kilograms divided by height in square meters and categorized into quartiles based on the distribution among controls. Odds ratios and 95% confidence intervals were estimated using logistic regression models, simultaneously adjusting for age, education, income, cigarette smoking (men only), alcohol drinking (men only), intake of total calories, and chronic gastric diseases. For gastric cardia cancer, the odds ratios among men were 1.4, 1.5, and 3.0 in the second, third, and fourth quartiles of usual BMI (P for trend, < 0.01). Among women, elevated risks also were associated with excess weight, but the gradient in risk was not smooth. Risk patterns for usual body weight, maximum BMI, and minimum BMI were similar to those found for usual BMI. For distal stomach cancer, no association with usual BMI was observed among men, but a slightly elevated risk was seen among women. Our observations in China support recent findings in Western populations that obesity contributes to the risk of gastric cardia cancer, especially among men.

Prior immunity-related medical conditions and oesophageal cancer risk: a population-based case-control study in Shanghai

To investigate the role of immunity-related medical conditions in the aetiology of oesophageal cancer, data were analysed from a population-based case-control study, conducted in Shanghai during 1992-93. Information on histories of selected autoimmune diseases and allergic conditions was obtained from 163 incident cases of oesophageal cancer and 275 age- and sex-matched controls through personal interviews using a structured questionnaire. A significant 2.4-fold excess risk (95% CI, 1.3-4.4) of oesophageal cancer was associated with a history of autoimmune diseases after adjustment for age and sex. In contrast, a history of allergy was associated with a reduced risk (adjusted OR = 0.6, 95% CI = 0.4-0.9). The risk was also reduced 30-40% among individuals who reported having a moderate or strong skin reaction to mosquito bites. This study suggests that host immune function may be involved in the aetiology of oesophageal cancer. Further investigations into the mechanism of these observed associations are warranted.

Paternal cigarette smoking and the risk of childhood cancer among offspring of nonsmoking mothers

BACKGROUND

Cigarette smoking has been shown to increase oxidative DNA damage in human sperm cells. Assessment of the role of cigarette smoking in the etiology of childhood cancer has focused primarily on the effect of maternal smoking. Similar studies in relation to paternal smoking, however, have been inconclusive. Few studies have evaluated the effect of paternal smoking in the preconception period, and most of these could not disentangle the effects of paternal from maternal smoking.

PURPOSE

We investigated the relationship of paternal smoking, particularly in the preconception period, with childhood cancer among offspring of the nonsmoking mothers.

METHODS

We conducted a population-based, case-control study in Shanghai, People's Republic of China, where the prevalence of smoking is high among men but extremely low among women. The study included 642 childhood cancer case patients (<15 years of age) and their individually matched control subjects. Information concerning parental smoking, alcohol drinking, and other exposures of the index child was obtained by direct interview of both parents of the study subjects. Odds ratios (ORs), derived from conditional logistic regression models, were used to measure the association between paternal smoking and risk of childhood cancers.

RESULTS AND CONCLUSIONS

Paternal preconception smoking was related to a significantly elevated risk of childhood cancers, particularly acute leukemia and lymphoma. The risks rose with increasing pack-years of paternal preconception smoking for acute lymphocytic leukemia (ALL) (P for trend = .01), lymphoma (P for trend = .07), and total cancer (P for trend = .006). Compared with children whose fathers had never smoked cigarettes, children whose fathers smoked more than five pack-years prior to their conception had adjusted ORs of 3.8 (95% confidence interval [CI] = 1.3-12.3) for ALL, 4.5 (95% CI = 1.2-16.8) for lymphoma, 2.7 (95% CI = 0.8-9.9) for brain tumors, and 1.7 (95% CI = 1.2-2.5) for all cancers combined. Statistically significant increased risks of cancer were restricted to children under the age of 5 years at diagnosis or those whose fathers had smoked during all of the 5 years prior to conception.

IMPLICATIONS

Further studies are needed to confirm the association of paternal smoking with increased risk of cancer in offspring, to clarify the pattern of risks in relation to the timing of cigarette smoking, and to elucidate the biologic mechanism involved in predisposing the offspring to cancer. For example, it may be that paternal smoking induces prezygotic genetic damage that, in turn, acts as the predisposing factor.

Green tea consumption and the risk of pancreatic and colorectal cancers

The effect of green tea drinking in reducing human cancer risk is unclear, though a protective effect has been reported in numerous animal studies and several epidemiologic investigations. Herein the hypothesis that green tea consumption may reduce the risk of cancers of the colon, rectum and pancreas is examined in a large population-based case-control study conducted in Shanghai, China. Newly diagnosed cancer cases (931 colon, 884 rectum and 451 pancreas) during 1990-1993 among residents 30-74 years of age were included. Controls (n = 1,552) were selected among Shanghai residents and frequency-matched to cases by gender and age. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of each cancer associated with green tea consumption were derived after adjustment for age, income, education and cigarette smoking. Additional adjustment for dietary items and body size was found to have minimal impact. An inverse association with each cancer was observed with increasing amount of green tea consumption, with the strongest trends for rectal and pancreatic cancers. For men, compared with non-regular tea drinkers, ORs among those in the highest tea consumption category (> or = 300 g/month) were 0.82 for colon cancer, 0.72 for rectal cancer and 0.63 for pancreatic cancer, with p values for trend being 0.38, 0.04 and 0.04, respectively. For women, the respective ORs for the highest consumption category (> or = 200 g/month) were 0.67, 0.57 and 0.53, with the respective p values for trend being 0.07, 0.001 and 0.008. Our findings provide further evidence that green tea drinking may lower the risk of colorectal and pancreatic cancers.

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China

BACKGROUND

The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach.

METHODS

Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers.

CONCLUSIONS

Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

Diet and other risk factors for cancer of the salivary glands:a population-based case-control study

A population-based case-control study of cancer of the salivary glands, involving interviews of 41 incident cases and 414 controls, was conducted in Shanghai. After adjustment for other risk factors, occupational exposure to silica dust was linked to a 2.5-fold increased risk of salivary-gland cancer. The risk was also significantly elevated among individuals who reported ever using kerosene as cooking fuel or having a prior history of head X-ray examinations. Dietary analyses revealed a significant protective effect of consumption of dark-yellow vegetables or liver, with about 70% reduced risk of salivary-gland cancer among individuals in the highest intake group of these foods. Our findings are consistent with previous observations on a possible role of environmental exposure and radiation in the etiology of salivary-gland cancer, and suggest that dietary factors may contribute to the development of this malignancy.

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China

BACKGROUND

The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach.

METHODS

Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers.

CONCLUSIONS

Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

Anthropometric and reproductive factors and the risk of pancreatic cancer: a case-control study in Shanghai, China

To examine the possible role of body size and reproductive factors in pancreatic cancer, data were analyzed from a population-based case-control study conducted in Shanghai, China. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990, and June 30, 1993. Deceased cases (19%) were excluded from the study. Controls (n = 1,552) were randomly selected from permanent Shanghai residents and frequency-matched to cases by gender and age. Information on body size and reproductive and other possible risk factors was collected through personal interviews. After adjustment for age, income, smoking and other confounders, a positive dose-response relation between body mass index and risk of pancreatic cancer was observed in both sexes. Among women, the risk of pancreatic cancer was significantly associated with number of pregnancies and live births. Compared with 0-2 pregnancies or live births, the odds ratio (OR) for 8 or more pregnancies was 1.90, while that for 5 or more births was 1.88. A modest elevation in risk, independent of parity, was associated with early age at first birth. Risk increased over 40% among women with a first birth at or before age 19 years relative to those at age 26 years or older. Ever use of oral contraceptives was associated with excess risk, though based on small numbers of users. Our findings suggest that, in Shanghai, obesity, gravidity, parity and perhaps use of oral contraceptives are associated with moderate increases in risk of pancreatic cancer, indicating that hormonal determinants deserve further investigation.

Biliary tract cancers among textile and other workers in Shanghai, China

Using occupational data for more than 500 patients with cancers of the biliary tract (CBT) diagnosed between 1980 and 1984 in Shanghai, and employment information from the 1982 census for the Shanghai population, the associations between CBT and occupational categories were examined by standardized incidence ratios (SIR). Compared to the general population, risk was elevated by nearly 40% among textile workers (SIR for women = 137, 95% CI = 106-175 and SIR for men = 137, 95% CI = 76-217), consistent with other investigations linking CBT to textile work. Increased risks were observed also among waiters/ waitresses, male sanitation personnel and chemical workers, and female janitor and similar workers. Although causal inferences cannot be firmly drawn, our findings add to the limited evidence linking CBT to occupational exposures, especially in the textile industry.

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China

BACKGROUND

The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach.

METHODS

Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers.

CONCLUSIONS

Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

Anthropometric and reproductive factors and the risk of pancreatic cancer: a case-control study in Shanghai, China

To examine the possible role of body size and reproductive factors in pancreatic cancer, data were analyzed from a population-based case-control study conducted in Shanghai, China. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990, and June 30, 1993. Deceased cases (19%) were excluded from the study. Controls (n = 1,552) were randomly selected from permanent Shanghai residents and frequency-matched to cases by gender and age. Information on body size and reproductive and other possible risk factors was collected through personal interviews. After adjustment for age, income, smoking and other confounders, a positive dose-response relation between body mass index and risk of pancreatic cancer was observed in both sexes. Among women, the risk of pancreatic cancer was significantly associated with number of pregnancies and live births. Compared with 0-2 pregnancies or live births, the odds ratio (OR) for 8 or more pregnancies was 1.90, while that for 5 or more births was 1.88. A modest elevation in risk, independent of parity, was associated with early age at first birth. Risk increased over 40% among women with a first birth at or before age 19 years relative to those at age 26 years or older. Ever use of oral contraceptives was associated with excess risk, though based on small numbers of users. Our findings suggest that, in Shanghai, obesity, gravidity, parity and perhaps use of oral contraceptives are associated with moderate increases in risk of pancreatic cancer, indicating that hormonal determinants deserve further investigation.

Dietary factors and the risk of pancreatic cancer: a case-control study in Shanghai China

In Shanghai, China, age-adjusted incidence rates for pancreatic cancer have increased steadily, beginning in the early 1970s. To examine the effects of diet on this cancer, a population-based case-control study was conduct. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990 and June 30, 1993. Decreased cases (19%) were excluded from the study. Controls (n = 1552) were selected among Shanghai residents, frequency matched to cases by gender and age. Information on usual adult dietary intake was obtained by trained interviewers in person, using a food frequency questionnaire. Dietary associations were measured by odds ratios and 95% confidence intervals. Risks of pancreatic cancer were inversely associated with consumption of vegetables (P for trend among men = 0.03; among women = 0.15) and fruits (P among men = 0.02; among women = 0.08). Reductions in risk were related also to intake of dietary fiber and micronutrients abundant in plant sources, such as vitamins C and E and carotene. There was also an inverse association with egg consumption (P for trend among men = 0.08; among women = 0.001). No consistent positive associations were observed with intake of other food groups, including preserved animal foods, fresh red meat, organ meat, poultry, and staple foods. On the other hand, risks increased with frequency of consumption of preserved vegetables and foods that were deep fried, grilled, cured, or smoked, providing clues to the possible role of nitrosamines, polycyclic aromatic hydrocarbons, and heterocyclic aromatic amines. The inverse associations observed with intake of dietary fat and protein in our study were unexpected, although these findings were based on consumptions well below the average intake in Western countries, where most previous studies on pancreatic cancer were conducted. Our results suggest that dietary variations have contributed little to the rising trends of pancreatic cancer in Shanghai. However, given the improving food availability and changing dietary patterns in China, further study of dietary and nutritional risk factors for pancreatic cancer appears warranted.

Prior immunity-related medical conditions and pancreatic-cancer risk in Shanghai

To investigate the role of immunity-related medical conditions in the etiology of pancreatic cancer, we analyzed data from a population-based case-control study of pancreatic cancer conducted in Shanghai during 1992 and 1993. Information on prior histories of selected auto-immune diseases and allergic conditions was obtained from 108 incident pancreatic-cancer cases and 275 age- and gender-frequency matched controls by face-to-face interviews using a structured questionnaire. A prior history of auto-immune diseases was associated with a 2-fold elevated risk of pancreatic cancer (95% CI = 1.0-4.2), with an indication of a dose-response relation for the number of reported diseases. In contrast, a prior history of allergic condition was related to reduced risk (OR = 0.6, 95% CI = 0.4-1.1). With the possible exception of drug allergy, such an inverse association was seen for virtually all allergic conditions., although none of the OR was statistically significant. This study suggests that host immune function may be involved in the etiology of pancreatic cancer. Further investigations into the mechanism of these observed associations are warranted.

Cigarette smoking and alcohol consumption and the risk of pancreatic cancer: a case-control study in Shanghai, China

Cancer of the pancreas has been rising in incidence in Shanghai, China since the early 1970s. In 1987-89, this malignancy ranked eighth in cancer incidence among men and ninth among women in Shanghai. To examine risk factors for this tumor in urban Shanghai, a population-based case-control study was conducted. Cases (n = 451) were permanent residents of Shanghai, 30 to 74 years of age, newly diagnosed with pancreatic cancer between 1 October 1990 and 30 June 1993. Deceased cases (19 percent) were excluded from the study. Controls (n = 1,552) were selected among Shanghai residents, frequency-matched to cases by gender and age. Cases and controls were interviewed about their demographic background and potential risk factors, including tobacco, alcohol and beverage consumption, diet, and medical history. Adjusted odds ratios (OR) and 95 percent confidence intervals (CI) were estimated using logistic regression models. Current cigarette smoking was associated with excess risk of pancreatic cancer in both men (OR = 1.6, CI = 1.1-2.2) and women (OR = 1.4, CI = 0.9-2.4). ORs increased significantly with number of cigarettes smoked per day, and with duration and pack-years of smoking. Risk increased three- to sixfold among those in the highest categories of cigarette consumption, while risk decreased with increasing years since smoking cessation. Former smokers who stopped smoking for 10 or more years had risks comparable to nonsmokers.

Infant breastfeeding and the risk of childhood lymphoma and leukaemia

BACKGROUND

A protective effect of breastfeeding on childhood lymphoma has been indicated but supportive evidence is limited.

METHOD

Data from a population-based case-control study of childhood cancer in Shanghai, including 82 lymphoma cases and 159 acute leukaemia cases and their age- and sex-matched community controls, were analysed.

RESULTS

After adjustment for potentially confounding variables, a slight, although non-significant, reduction in risk of lymphoma was observed among children who were breastfed as infants versus those who were not (odds ratio [OR] = 0.69; 95% CI: 0.3-1.7). The reduction was somewhat greater for children who had been breastfed longer and appeared to pertain primarily to Hodgkin's disease and to cases diagnosed before the age of 6 years. As expected, there was no reduction in risk of acute leukaemia associated with breastfeeding.

CONCLUSIONS

Although providing neither strong support for nor refuting the study hypothesis, these data suggest that if breastfeeding does reduce the risk of lymphoma, its protective effect among Chinese children is likely modest in magnitude and concentrated in certain subgroups defined by length of breastfeeding, age at diagnosis and histological subtype of cancer.

Risk factors for esophageal cancer in Shanghai, China. I. Role of cigarette smoking and alcohol drinking

A population-based case-control study of esophageal cancer was conducted in urban Shanghai involving interviews with 902 cases and 1,552 controls. Risk of esophageal cancer was increased among tobacco smokers and alcohol drinkers. Odds ratios (OR) for smoking were 2.1 and 1.6 for men and women, respectively, and increased with number of cigarettes smoked per day, duration of smoking, number of pack-years and decreasing age at start of smoking. For men who were current alcohol drinkers OR was 1.4, with the excess risk primarily among heavy drinkers. Few women drank alcoholic beverages. The combined effect of heavy smoking and drinking among men was pronounced: OR was 12.0 for those who smoked more than 1 pack per day and drank more than 750 g of ethanol per week. The relation with smoking appeared stronger for cancers of the middle and lower thirds of the esophagus than for the upper third, while patterns of risk for squamous cell carcinoma and adenocarcinoma were similar. Heavy drinking affected all 3 subsites, with increased risks mainly limited to squamous cell carcinoma. Cigarette smoking and alcohol drinking combined accounted for almost 50% of all esophageal cancers among men in Shanghai; among women, 14% of cases were attributed to smoking. Our study confirms that smoking and drinking are important risk factors for esophageal cancer in China, thereby paralleling findings from developed countries.

Risk factors for esophageal cancer in Shanghai, China. II. Role of diet and nutrients

A population-based case-control study of esophageal cancer (902 cases, 1,552 controls) in Shanghai, China, investigated the etiologic role of diet. After adjustment for cigarette smoking, alcohol consumption and other risk factors, increasing consumption of fruits, dark orange vegetables and beef or mutton was associated with statistically significant decreasing trends in risk for esophageal cancer. In general, risks were about 40% lower among those in the upper vs. lower quartiles of intake of these foods. Fivefold increases in risk were observed among those who consumed burning hot soup or porridge, with smaller excesses for preserved vegetables, salty and deep fried foods. Nutrient analysis revealed that increased dietary intake of protein, carotene, vitamins C and E and riboflavin was associated with reduced esophageal cancer risk. Our findings support the notion that the reported temporal increases in the per capita consumption of fruits, vegetables and animal products contribute to the substantial reduction in the incidence of esophageal cancer in Shanghai, particularly since cigarette and alcohol use has not decreased.

[A case-control study on colorectal cancer and dietary fiber and calcium of various sources]

A population-based case-control study was conducted in 726 incident cases with colorectal cancer and 1400 controls matched on age and sex in Shanghai, to explore the possible difference in associations between colorectal cancer and dietary fiber and calcium of various sources. The results showed reverse correlation between intake of vegetable fiber and ascending and descending colon cancer and rectal cancer, and between intake of fruit fiber and ascending colon cancer only. Dietary intake of calcium from animal sources could reduce the relative risk of ascending and descending colon cancer. These associations still existed after adjustment of the effects of the factors such as age, sex, intakes of total calorie, vitamin C, saturated fatty acid, etc. with logistic regression model, which indicated all of those variables were independent of other ones. Intake of dietary fiber from grains and calcium from plant sources had no significant protection from colorectal cancer. This study also showed the protective effects of dietary fiber and calcium on colorectal cancer not only correlated to their intake, but also closely to their sorts and sources.

Reduced risk of esophageal cancer associated with green tea consumption

BACKGROUND

Studies in laboratory animals have suggested inhibitory effects of green tea on the induction of some cancers, notably, esophageal cancer. However, only a few epidemiologic studies have evaluated green tea as a potential inhibitor of human esophageal cancer.

PURPOSE

Our purpose was to evaluate the relationship between green tea consumption and the risk of esophageal cancer.

METHODS

This esophageal cancer study was part of a larger multicenter, case-control study that included three other gastrointestinal sites (pancreas, colon, and rectum). Medical records of patients aged 30-74 years old who were diagnosed with esophageal cancer from October 1, 1990, through January 31, 1993, were identified from the Shanghai Cancer Registry, which covers 6.8 million people in the urban area of Shanghai, People's Republic of China. During the ascertainment period, records of 1016 eligible cases of esophageal cancer were identified. Control subject records were selected by frequency matching in accordance with the age-sex distribution of the four gastrointestinal cancers ascertained by the cancer registry during 1986-1987. Patient interviews were then conducted using a structured, standardized questionnaire to obtain information on demographic characteristics, residential history, height and weight, diet, smoking, alcohol and tea drinking, medical history, family history of cancer, occupation, physical activity, and reproductive history.

RESULTS

Of the 902 patients interviewed, 734 (81.4%) had their disease pathologically confirmed. There were 1552 control subjects interviewed, including 240 alternates. All analyses of tea effects were conducted separately among men and women and all were adjusted for age. After further adjustment for other known confounders, a protective effect of green tea drinking on esophageal cancer was observed among women (odds ratio [OR] = 0.50; 95% confidence interval [CI] = 0.30-0.83), and this risk decreased (P for trend < or = .01) as tea consumption increased. Among men, the ORs were also below 1.00, although not statistically significant. ORs for green tea intake were estimated among those persons who neither smoked nor drank alcohol. In this subset, statistically significant decreases in risk among tea drinkers were observed for both men (OR = 0.43; 95% CI = 0.22-0.86; P for trend = .05) and women (OR = 0.40; 95% CI = 0.20-0.77; P for trend < .001).

CONCLUSIONS

This population-based, case-control study of esophageal cancer in urban Shanghai suggests a protective effect of green tea consumption. Although these findings are consistent with studies in laboratory animals, indicating that green tea can inhibit esophageal carcinogenesis, further investigations are definitely needed.

Urinary aflatoxin levels, hepatitis-B virus infection and hepatocellular carcinoma in Taiwan

Using a urinary immunoassay to measure aflatoxin metabolites, we examined the associations between exposure to aflatoxin, chronic infection with the hepatitis-B virus (HBV) and background rates of hepatocellular carcinoma (HCC) mortality in a cross-sectional survey of 250 residents from 8 areas of Taiwan with a 4-fold variation in age-adjusted HCC mortality. Specimens of fasting blood and overnight urines were used to determine HBV carrier status and excretion of aflatoxin in the subjects surveyed. While the prevalence of hepatitis-B virus carriers showed moderate variability, there was a 500-fold range in urinary aflatoxin levels. Mean log-transformed levels of aflatoxin metabolites were similar in males and females and in HBV carriers and non-carriers. In the 8 townships, HCC mortality correlated positively with both area HBV carrier prevalence and mean aflatoxin levels. The primary analyses, however, were conducted at the individual level. Each subject's aflatoxin level was treated as the response variable in a multiple regression model, and the corresponding sex-specific area HCC rate was included as a predictor along with the individual's carrier status, age and sex; alcohol consumption and cigarette smoking were also considered. In these analyses, a significant association was again observed between the marker of aflatoxin exposure and the background rate of HCC mortality. In females, the slope of the regression line was somewhat steeper in HBV carriers, but this pattern was not seen in males and formal testing yielded no statistically significant evidence of an interaction. Our findings are consistent with the hypothesis that aflatoxin plays an independent role in hepatocellular carcinoma in Taiwan.

A population-based case-control study of cancers of the nasal cavity and paranasal sinuses in Shanghai

A population-based case-control study of cancer of the nasal cavity and sinuses, involving interviews of 60 incident cases and 414 controls, was conducted in Shanghai. Cigarette smoking was associated with a mild elevation in risk of squamous-cell carcinoma but not cancers of other cell types. Occupational exposures to wood and silica dusts and to petroleum products, and the use of wood and straw as cooking fuel, were linked to moderate increases in risk, while 4-fold or greater increases were associated with a history of chronic nasal diseases, including those occurring 10 or more years prior to cancer diagnosis. Dietary analyses revealed a significant protective effect of consumption of allium vegetables, oranges and tangerines, with a 50% reduced risk of nasal cancer among individuals in the highest intake group of these foods. Consumption of salt-preserved vegetables, meat and fish was associated with a significantly increased risk of nasal cancer in a dose-response fashion, with a 5-fold excess observed for the heaviest intake of these salted foods. These findings suggest that dietary factors may contribute to the development of nasal cancer.

Risk factors for renal-cell cancer in Shanghai, China

A population-based case-control study of 154 histologically verified renal-cell cancer patients and 157 controls was performed in Shanghai, China, an area with low rates for this tumor. Elevated risks were observed for cigarette smoking (odds ratio (OR) = 2.3; 95% confidence interval (CI): 1.1 to 4.9), and for increasing categories of body weight and meat consumption, while reduced risks were seen for increasing categories of fruit and vegetable intake. An increased risk was also observed for regular use of phenacetin-containing analgesics (OR = 2.3; 95% CI:0.7 to 7.0). These findings are consistent with earlier studies in Western countries, and indicate that many of the same etiologic factors for renal-cell cancer operate in low- and high-risk societies.

Risk factors for oral and pharyngeal cancer in Shanghai, with emphasis on diet

A population-based case-control study of oral and pharyngeal cancer was conducted in Shanghai, China, from 1988 to 1990, in which 204 (115 male, 89 female) incident cases and 414 (269 male, 145 female) controls were interviewed. Cigarette smoking and alcohol consumption, as well as occupational exposures to asbestos and to petroleum products and the use of kerosene stoves in cooking, were associated with increased risk of oral and pharyngeal cancer. In addition, more cases than controls reported having chronic oral diseases and false teeth. Dietary intakes of 42 major foods and selected salt-preserved or deep-fried foods during the past 10 years, ignoring any recent changes, were measured by a structured quantitative food questionnaire. After adjusting for known etiological factors, risks decreased with increasing intake of fruits, particularly oranges and tangerines, and some vegetables, including dark yellow vegetables and Chinese white radish. Men in the highest tertile of intake of these fruits and vegetables had about 30-50% the risk of those in the lowest tertile, with a less pronounced effect among women. A new finding was an excess risk associated with high consumption of salt-preserved meat and fish. The findings from this study provide further evidence that dietary factors play an important role in the development of oral and pharyngeal cancer.

Diet and other risk factors for laryngeal cancer in Shanghai, China

A population-based, case-control study of laryngeal cancer was conducted in Shanghai, China, during 1988-1990, in which 201 incident cases (177 males, 24 females) and 414 controls (269 males, 145 females) were interviewed. Cigarette smoking was the major risk factor, accounting for 86% of the male and 54% of the female cases. After adjusting for smoking, there was little increase in risk associated with drinking alcoholic beverages. Among men, cases more often reported occupational exposures to asbestos and coal dust. A protective effect was associated with the intake of fruits (particularly oranges and tangerines), certain dark green/yellow vegetables, and garlic, but there was an increased risk with the intake of salt-preserved meat and fish. The findings suggest that risk factors for laryngeal cancer in Shanghai resemble those in Western countries, and they provide further evidence that dietary factors play an important etiologic role.