Fruit, vegetable, and animal food intake and breast cancer risk by hormone receptor status

The effects of diet on breast cancer are controversial and whether the effects vary with hormone receptor status has not been well investigated. This study evaluated the associations of dietary factors with risk for breast cancer overall and by the hormone receptor status of tumors among Chinese women. The Shanghai Breast Cancer Study, a large, population-based, case-control study, enrolled 3,443 cases and 3,474 controls in 1996-1998 (phase I) and 2002-2005 (phase II); 2676 cases had estrogen receptor (ER) and progesterone receptor (PR) data. Dietary intake was assessed using a validated, quantitative, food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from multivariate, polychotomous, unconditional logistic regression models. Total vegetable intake was inversely related to breast cancer risk, with an adjusted OR for the highest quintile of 0.80 (95% CI = 0.67-0.95; P trend = 0.02). Reduced risk was also related to high intake of allium vegetables (P trend = 0.01) and fresh legumes (P trend = 0.0008). High intake of citrus fruits and rosaceae fruits were inversely associated with breast cancer risk (P trend = 0.003 and 0.004, respectively), although no consistent association was seen for total fruit intake. Elevated risk was observed for all types of meat and fish intake (all P trend < 0.05), whereas intakes of eggs and milk were associated with a decreased risk of breast cancer (both P trend <0.05). There was little evidence that associations with dietary intakes varied across the 4 tumor subtypes or between ER+/PR+ and ER-/PR- tumors (P for heterogeneity >0.05). Our results suggest that high intake of total vegetables, certain fruits, milk, and eggs may reduce the risk of breast cancer, whereas high consumption of animal-source foods may increase risk. The dietary associations did not appear to vary by ER/PR status.

Association of hormone-related characteristics and breast cancer risk by estrogen receptor/progesterone receptor status in the shanghai breast cancer study

Etiologic differences between subtypes of breast cancer defined by estrogen receptor (ER) and progesterone receptor (PR) status are not well understood. The authors evaluated associations of hormone-related factors with breast cancer subtypes in a population-based case-control study involving 1,409 ER-positive (ER+)/PR-positive (PR+) cases, 712 ER-negative (ER-)/PR-negative (PR-) cases, 301 ER+/PR- cases, 254 ER-/PR+ cases, and 3,474 controls aged 20-70 years in Shanghai, China (phase I, 1996-1998; phase II, 2002-2005). Polytomous logistic regression and Wald tests for heterogeneity across subtypes were conducted. Breast cancer risks associated with age at menarche, age at menopause, breastfeeding, age at first livebirth, waist-to-hip ratio, and oral contraceptive use did not differ by hormone receptor status. Among postmenopausal women, higher parity (≥2 children vs. 1) was associated with reduced risk (odds ratio (OR) = 0.69, 95% confidence interval (CI): 0.52, 0.91) and higher body mass index (BMI; weight (kg)/height (m)(2)) with increased risk (highest quartile: OR = 2.40, 95% CI: 1.65, 3.47) of the ER+/PR+ subtype but was unrelated to the ER-/PR- subtype (for parity, P(heterogeneity) = 0.02; for BMI, P(heterogeneity) < 0.01). Hormone replacement therapy (OR = 2.25, 95% CI: 1.40, 3.62) and alcohol consumption (OR = 1.59, 95% CI: 1.01, 2.51) appeared to be preferentially associated with the ER+/PR- subtype. These findings indicate that BMI, parity, hormone replacement therapy, and alcohol consumption may play different roles in subtypes of breast cancer. More research is needed to better understand the etiology of 2 relatively rare subtypes, ER+/PR- tumors and ER-/PR+ tumors.

Dietary iron intake and risk of endometrial cancer: a population-based case-control study in Shanghai, China

Dietary red meat and animal fat have been linked to endometrial cancer (EC) risk, but the impact of bioavailable iron in animal-derived foods has been less well studied. Our objective was to investigate the effects of iron and fats on the risk of EC in a large, population-based, case-control study. The Shanghai Endometrial Cancer Study enrolled 1,204 EC cases and 1,212 controls who completed in-person interviews, including a food frequency questionnaire. Animal-derived iron and fat intakes were calculated from dietary intakes and food composition tables. Logistic regression models were used to evaluate independent and joint effects of iron and fat on EC risk. Animal-derived iron intake was positively associated with EC risk [adjusted OR = 1.9; 95% CI = 1.4-2.7, P(trend) < 0.01, highest vs. lowest quartile], predominantly after menopause (OR = 2.2; 95%CI = 1.4-3.4, P(trend) < 0.01) and in women with BMI >or= 25 kg/m(2)(OR = 3.2; 95% CI = 1.4-7.5 in postmenopausal obese women, P(trend) < 0.01). Animal-derived fat was also associated with postmenopausal EC risk (OR = 1.7; 95% CI = 1.2-2.5, P(trend) < 0.01). Multiplicative interactions between animal-derived iron and BMI or animal-derived fat intake were not observed. Animal-derived iron intake is associated with increased risk of EC after menopause and among obese women. Avoidance of animal-derived (heme) iron may reduce the risk of EC in these women.

Association of the progesterone receptor gene with endometrial cancer risk in a Chinese population

BACKGROUND

Single nucleotide polymorphisms (SNPs) in the progesterone receptor (PGR) gene have been associated with the risk of endometrial cancer. However, to the authors' knowledge, no study to date has systematically evaluated the role of the PGR gene in endometrial carcinogenesis.

METHODS

Exposure information and DNA samples collected in the Shanghai Endometrial Cancer Study, a population-based case-control study of 1,204 incident cases and 1,212 age- and frequency-matched population controls, were used in this study. Seven tag SNPs were identified for the PGR gene plus the 5-kilobase (kb) flanking regions using the Han Chinese data from the HapMap project with a pairwise correlation coefficient (r(2)) >or= 0.90. These 7 SNPs captured 92% of SNPs in the region with a pairwise r(2) >or= 0.90 or 100% of SNPs with a pairwise r(2) >or= 0.80. Genotyping of polymorphisms was performed by using the Affymetrix MegAllele Targeted Genotyping System. A logistic regression model was used to compute adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Of 7 tag SNPs that were assessed, 2 polymorphisms in the 3' flanking region of the PGR gene, reference SNP identification number (rs) 11224561 (rs11224561) and rs471767, were associated with the risk of endometrial cancer. The cytosine/cytosine (CC) genotype of SNP rs11224561 was associated with decreased risk (OR, 0.68; 95% CI, 0.50-0.92) compared with the thymine/thymine (TT) genotype. Carrying the guanine (G) allele of the rs471767 SNP also was associated with decreased risk, although the association was not statistically significant (OR, 0.78, 95%CI, 0.59-1.04 and OR, 0.32, 95%CI, 0.03-3.05 for the adenine [A]G and GG genotypes, respectively, compared with the homozygote AA).

CONCLUSIONS

The current findings suggested that polymorphisms in the 3' flanking region of the PGR gene may be associated with the risk of endometrial cancer.

Association of thymidylate synthase gene with endometrial cancer risk in a Chinese population

We comprehensively evaluated genetic variants in the thymidylate synthase (TYMS) gene in association with endometrial cancer risk in a population-based case-control study of 1,199 incident endometrial cancer cases and 1,212 age frequency-matched population controls. Exposure information was obtained via in-person interview, and DNA samples (blood or buccal cell) were collected. Genotyping of 11 haplotype-tagging single nucleotide polymorphisms (SNP) for the TYMS gene plus the 5-kb flanking regions was done for 1,028 cases and 1,003 controls by using the Affymetrix MegAllele Targeted Genotyping System. Of 11 haplotype-tagging SNPs identified, 7 that are located in flanking regions of the TYMS gene are also in the ENOSF1 (rTS) gene. The SNP rs3819102, located in the 3'-flanking region of the TYMS gene and in an intron of the ENOSF1 gene, was associated with risk of endometrial cancer. The odds ratio (95% confidence interval) for the CC genotype was 1.5 (1.0-2.2) compared with the TT genotype. Haplotype TTG in block 2 of the TYMS gene, which includes SNPs rs10502289, rs2298583, and rs2298581 (located in introns of the ENOSF1 gene), was associated with a marginally significant decrease in risk of endometrial cancer under the dominant model (odds ratio, 0.8; 95% confidence interval, 0.6-1.0). This study suggests that genetic polymorphisms in the TYMS or ENOSF1 genes may play a role in the development of endometrial cancer among Chinese women.

Common MMP-7 polymorphisms and breast cancer susceptibility: a multistage study of association and functionality

Matrix metalloproteinase-7 (MMP-7) is a small secreted proteolytic enzyme with broad substrate specificity against ECM and non-ECM components. Known to be vital for tumor invasion and metastasis, accumulating evidence also implicates MMP-7 in cancer development. Using data from the Shanghai Breast Cancer Study, we conducted a two-stage study to evaluate the association of MMP-7 single nucleotide polymorphisms (SNPs) with breast cancer risk. Additionally, associated SNPs were characterized by laboratory assays. In stage 1, 11 SNPs were genotyped among 1,079 incident cases and 1,082 community controls using an Affymetrix Genotyping System. Promising SNPs were selected for stage 2 evaluation and genotyped by TaqMan allelic discrimination assays in an independent set of 1,911 cases and 1,811 controls. Three SNPs were selected for stage 2 validation (rs880197, rs10895304, and rs12184413); one had highly consistent results between the two stages of the study. In combined analysis, homozygosity for the variant T allele for rs12184413 was associated with an odds ratio (OR) of 0.7 [95% confidence interval (95% CI), 0.6-0.9] compared with the common C allele. This effect was slightly more pronounced in postmenopausal women (OR, 0.6; 95% CI, 0.4-0.8) than in premenopausal women (OR, 0.8; 95% CI, 0.6-1.1). This SNP is located 3' of the MMP-7 gene, in an area enriched with CTCF binding sites. In silico analysis suggested a regulatory role for this region, and our in vitro assays showed an allelic difference in nuclear protein binding capacity. Results from our study suggest that common MMP-7 genetic polymorphisms may contribute to breast cancer susceptibility.

Nutritional factors in relation to endometrial cancer: a report from a population-based case-control study in Shanghai, China

We evaluated the role of dietary nutrients in the etiology of endometrial cancer in a population-based case-control study of 1,204 newly diagnosed endometrial cancer cases and 1,212 age frequency-matched controls. Information on usual dietary habits was collected during an in-person interview using a validated, quantitative food frequency questionnaire. Logistic regression analysis was conducted to evaluate the association of nutrients with endometrial cancer risk using an energy density method (e.g., nutrient intake/1,000 kilocalories of intake). Higher energy intake was associated with increased risk, which was attributable to animal source energy and a high proportion of energy from protein and fat. Odds ratios comparing highest versus lowest quintiles of intake were elevated for intake of animal protein (Odds ratio (OR) = 2.0, 95% confidential interval: 1.5-2.7) and fat (OR = 1.5, 1.2-2.0), but reduced for plant sources of these nutrients (OR = 0.7, 0.5-0.9 for protein and OR = 0.6, 0.5-0.8 for fat). Further analysis showed that saturated and monounsaturated fat intake was associated with elevated risk, while polyunsaturated fat intake was unrelated to risk. Dietary retinol, beta-carotene, vitamin C, vitamin E, fiber, and vitamin supplements were inversely associated with risk. No significant association was observed for dietary vitamin B1 or vitamin B2. Our findings suggest that associations of dietary macronutrients with endometrial cancer risk may depend on their sources, with intake of animal origin nutrients being related to higher risk and intake of plant origin nutrients related to lower risk. Dietary fiber, retinol, beta-carotene, vitamin C, vitamin E, and vitamin supplementation may decrease the risk of endometrial cancer.

Nutritional factors in relation to endometrial cancer: a report from a population-based case-control study in Shanghai, China

We evaluated the role of dietary nutrients in the etiology of endometrial cancer in a population-based case-control study of 1,204 newly diagnosed endometrial cancer cases and 1,212 age frequency-matched controls. Information on usual dietary habits was collected during an in-person interview using a validated, quantitative food frequency questionnaire. Logistic regression analysis was conducted to evaluate the association of nutrients with endometrial cancer risk using an energy density method (e.g., nutrient intake/1,000 kilocalories of intake). Higher energy intake was associated with increased risk, which was attributable to animal source energy and a high proportion of energy from protein and fat. Odds ratios comparing highest versus lowest quintiles of intake were elevated for intake of animal protein (Odds ratio (OR) = 2.0, 95% confidential interval: 1.5-2.7) and fat (OR = 1.5, 1.2-2.0), but reduced for plant sources of these nutrients (OR = 0.7, 0.5-0.9 for protein and OR = 0.6, 0.5-0.8 for fat). Further analysis showed that saturated and monounsaturated fat intake was associated with elevated risk, while polyunsaturated fat intake was unrelated to risk. Dietary retinol, beta-carotene, vitamin C, vitamin E, fiber, and vitamin supplements were inversely associated with risk. No significant association was observed for dietary vitamin B1 or vitamin B2. Our findings suggest that associations of dietary macronutrients with endometrial cancer risk may depend on their sources, with intake of animal origin nutrients being related to higher risk and intake of plant origin nutrients related to lower risk. Dietary fiber, retinol, beta-carotene, vitamin C, vitamin E, and vitamin supplementation may decrease the risk of endometrial cancer.

Dietary animal-derived iron and fat intake and breast cancer risk in the Shanghai Breast Cancer Study

BACKGROUND

Dietary fats and other constituents have been studied extensively in relation to breast cancer risk. Iron, an essential micronutrient with pro-oxidant properties, has received little attention, and specific fats may augment its toxicity. We investigated the effects of iron and fats from various food sources on the risk of breast cancer.

METHODS

Participants in a population-based case-control study, 3,452 breast cancer cases, and 3,474 age-frequency-matched controls, completed in-person interviews, including a detailed food-frequency questionnaire. Plant- and animal-derived iron and fat intakes were derived from dietary intake data and food composition tables. Unconditional logistic regression models were used to study the independent and interactive effects of different forms of iron and fats on breast cancer risk.

RESULTS

Animal-derived (largely heme) iron intake was positively associated with breast cancer risk (P (trend) < 0.01; OR = 1.49 in the highest vs. lowest quartile, 95% confidence interval [CI] 1.25-1.78) after adjustment for known risk factors, antioxidant vitamin and isoflavone intake, and vitamin supplement use. The effect of animal-derived iron was similar in pre- and postmenopausal women. Intake of animal-derived fats was also associated with increased risk (adjusted OR = 1.34, 95% CI 1.14-1.58), particularly after menopause. A significant interaction between iron and fat from animal sources was observed (P < 0.01).

CONCLUSIONS

A high intake of animal-derived (heme) iron may be associated with an increased risk of primary breast cancer in Chinese women, and saturated and mono-unsaturated fats that are also derived from animal sources may augment this effect. Combined reductions in animal-derived iron and fat consumption have the potential to reduce breast cancer risk.

Functional Plasminogen Activator Inhibitor-1 Gene Variants and Breast Cancer Survival

PURPOSE

Plasminogen activator inhibitor-1 (PAI-1) plays an important role in cancer invasion and metastasis. A common polymorphism (4G/5G) in the promoter region of the PAI-1 gene has been reported to influence transcription and plasma levels of PAI-1. We evaluated the association between PAI-1 4G/5G polymorphism and breast cancer survival in a population-based cohort of breast cancer patients.

EXPERIMENTAL DESIGN

Included in this analysis were 1,083 Chinese women diagnosed with stage 0 to III primary breast cancer at age 25 to 64 years who were recruited between 1996 and 1998 for the Shanghai Breast Cancer Study and followed for a median of 5.2 years. The Kaplan-Meier method and Cox model were used to evaluate the genotype and survival association.

RESULTS

After adjustment for known prognostic factors for breast cancer, patients homozygous for the 4G allele had significantly poorer disease-free survival [hazard ratio (HR), 1.7; 95% confidence interval (95% CI), 1.1-2.4] and overall survival (HR, 1.5; 95% CI, 1.0-2.3) than those homozygous for the 5G allele. The association was more evident in patients with advanced disease. The HRs (95% CI) were 3.5 (1.4-9.0) for disease-free survival and 3.1 (1.1-8.3) for overall survival in stage III patients.

CONCLUSIONS

The PAI-1 4G/5G polymorphism may be a prognostic marker for young and middle-aged Chinese breast cancer patients.

Association of genetic polymorphisms in the VEGF gene with breast cancer survival

The vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis and vascular permeability. VEGF overexpression has been associated with advanced stage and poor survival of several cancers. We evaluated the association of functional polymorphisms in the VEGF gene with breast cancer survival in a cohort of 1,193 breast cancer patients who were recruited as part of a population-based case-control study in Shanghai, China from 1996 to 1998 and followed for cancer recurrence and mortality between March 2000 and December 2002. Included in the study were three functional polymorphisms (C-460T, G+405C, and C+936T) in the VEGF gene. Carrying the -460C or +405G allele was associated with decreased overall survival. The age-adjusted hazard ratios (HR) were 1.5 [95% confidence interval (95% CI), 0.9-2.5] for -460CC genotype carriers and 1.6 (95% CI, 1.0-2.5) for +405GG genotype carriers compared with noncarriers. Further analyses showed that the -460T/+450C/+936C haplotype was related to increased survival (HR, 0.57; 95% CI, 0.4-0.9), whereas the -460C/+405G/+936T haplotype was associated with nonsignificantly decreased survival (HR, 2.1; 95% CI, -0.9 to 4.7). The C+936T polymorphism alone was not related to overall or disease-free survival. This study suggests that VEGF polymorphisms may be a significant genetic marker for breast cancer prognosis.

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.

Genetic polymorphisms in glutathione-S-transferase genes (GSTM1, GSTT1, GSTP1) and survival after chemotherapy for invasive breast carcinoma

BACKGROUND

It has been suggested that genetic polymorphisms in certain glutathione-S-transferase (GST) genes reduce the effectiveness of detoxifying cytotoxins generated by chemotherapeutic agents, potentially resulting in enhanced clinical responses to chemotherapy.

METHODS

The authors evaluated common polymorphisms in the GSTM1, GSTT1, and GSTP1 genes for associations with overall survival in 1034 patients with invasive breast carcinoma who were recruited into the Shanghai Breast Cancer Study between 1996 and 1998, treated with chemotherapy, and followed for a median of 5.3 years.

RESULTS

After adjusting for age, tumor stage, and the use of radiotherapy and tamoxifen, women who were homozygous for the variant GSTP1 105Val allele had a 60% reduction in mortality risk compared with women who were homozygous for the Ile allele (hazard ratio, 0.4; 95% confidence interval, 0.2-0.8). No association was found with respect to any of the GSTM1 or GSTT1 genotypes.

CONCLUSIONS

The results of the current study indicate a potential role for GSTP1 polymorphism in predicting the clinical outcomes of patients with breast carcinoma who are treated with chemotherapy.

The Long-Term Impact of Medical and Socio-Demographic Factors on the Quality of Life of Breast Cancer Survivors Among Chinese Women

Quality of life (QOL) has become an integral part of the modern assessment of cancer treatment in Western society. However, little is known about the QOL of Chinese breast cancer survivors. To evaluate the long-term impact of medical and socio-demographic factors on survivors' QOL, we conducted a population-based study of 1065 breast cancer survivors in Shanghai, China. The mean age at diagnosis was 48.1 years and the median survival time was 4.3 years for the study participants. The Generic Quality of Life Inventory was used to assess survivors' QOL. Multiple linear regression models were employed to analyze the associations of QOL outcomes with socio-demographic and medical factors. The results revealed that recurrence status, time since diagnosis, marital status, income and education all had an independent, significant association with overall QOL and differential domains of QOL. Age at diagnosis exhibited a dual effect on QOL, positively associated with material well-being and negatively associated with physical well-being. Stage of disease was only associated with social well-being, while the type of surgery was related to material well-being alone. No associations between QOL and chemotherapy or radiotherapy were found. Further, analyses by survival intervals suggested a domain-specific order of recovery of QOL after cancer treatment. These results fill gaps in the limited literature, and provide valuable information for physicians to target the specific needs of Chinese women with breast cancer, choose appropriate interventions at the optimal time, and develop strategies accordingly in terms of improvement of patient's QOL.

Use of complementary and alternative medicine by chinese women with breast cancer

The use of complementary and alternative medicine (CAM) has been rapidly increasing among cancer patients. The aim of this study is to evaluate the prevalence and patterns of CAM use, particularly patients' intentions and their perceived effectiveness of using Chinese herbal medicine (CHM), as well as the relations between the herbal medicine use and demographic and clinical factors among Chinese women with breast cancer. We analyzed the data from a population-based sample of 1065 breast cancer women in urban Shanghai. Patients' average age at diagnosis was 48.1 years and the median time from the initial diagnosis to the follow-up survey was 4.3 years. Overall, 98% of patients had used at least one form of CAM therapy after diagnosis of breast cancer. The most popular CAM modality was traditional Chinese medicine (86.7%), followed by the use of supplements (84.8%), physical exercises (65.5%), and support group attendance (16.6%). CHM was used by 86.4% of patients, while acupuncture was used only by 4.9% of patients. Treating cancer (81.5%) was the most common intentions of using CHM. Other cited intentions included enhancing the immune system (12%), preventing metastasis of cancer or managing other discomforts (7.9%), and lessening menopausal symptoms (4.7%). The majority of patients reported that they had benefited from the use of CHM. Patients who were younger, married, had higher education or income, received chemotherapy or radiotherapy, or had recurrence/metastasis of cancer tended to use CHM more frequently than other patients. The relations between patient characteristics and use of CHMs varied with users' intentions. Given the high prevalence of CAM use among breast cancer patients, research is urgently needed to systematically evaluate the efficacy and safety of CAM use, particularly use of herbal medicines.

[Trends analysis of common urologic neoplasm incidence of elderly people in Shanghai, 1973-1999]

BACKGROUND & OBJECTIVE

Few studies on trend analysis in cancer incidence of the elderly people in China. The purpose of this study was to analyze time trends in urologic cancer incidence of the elderly people during the period 1973-1999 in Shanghai.

METHODS

The registered cancer cases were coded according to the 3-digit rubrics of the ninth revision of the International Classification of Diseases (ICD-9). Population estimates were based on periodic censuses, with age- and sex-specific annual estimates derived by linear inter- and extrapolation for the remaining years. The age-standardized rates adjusted to the world population were calculated for nine 3-year periods. Annual percent changes in incidence were estimated by means of a linear regression of the respective rates on the mid-point of calendar years, weighted by the number of cases.

RESULTS

During the 27-year period, cancers of prostate, bladder, and kidney have risen substantially among elderly male residents in Shanghai. The annual percent changes were 6.60%, 1.15%, and 5.30%, respectively. Among the elderly women, the rate of kidney cancer increased rapidly, with the annual percent change of 4.87%. The 75 years and older age group in women had substantial increases in incidence rates of bladder cancer.

CONCLUSION

From 1973 to 1999, the incidence rates of the commonly urologic cancers increased substantially among the elderly residents in Shanghai, except for female bladder cancer.

Genetic Polymorphisms in the TGF-β1 Gene and Breast Cancer Survival

The effect of genetic polymorphisms in the TGF-beta1 gene at codon 10 (T+29C), codon 25 (G+74C), and the promoter region [C --> T at -509 from the transcription site, (C-509T)] on breast cancer survival was evaluated among a cohort of 1111 patients. The median follow-up time for the cohort was 5.17 years after cancer diagnosis. No DNA sequence variation at codon 25 of the TGF-beta1 gene was found, whereas polymorphisms in C-509T and T+29C were in strong linkage disequilibrium. Patients who carried the C allele of T+29C polymorphism had a reduced 5-year disease-free survival rate (75.6% for T/C, and 78.2% for C/C) compared with the T/T genotype (85.1%; P, 0.04); the age-adjusted hazard ratio was 1.5 (95% confidence interval, 1.1-2.2). Adjustment for clinical prognostic factors slightly attenuated the association (hazard ratio, 1.4, 95% confidence interval, 1.0-1.9). Our study suggests that genetic polymorphisms in the TGF-beta1 gene may play a role in breast cancer progression.

Menstrual and reproductive factors and endometrial cancer risk: Results from a population-based case-control study in urban Shanghai

The purpose of our study was to evaluate the association of menstrual and reproductive factors with the risk of endometrial cancer. In a population-based case-control study conducted in urban Shanghai, in-person interviews were completed for 833 women aged 30-69 years and an equal number of controls frequency-matched to cases by age. All cases were newly diagnosed with endometrial cancer between January 1, 1997 and December 31, 2001. The unconditional logistic regression model was employed to derive the adjusted odds ratios (ORs) of endometrial cancer and 95% confidence intervals (CIs) in relation to menstrual and reproductive factors. Earlier menarche age, particularly among premenopausal women, and later menopausal age were associated with an elevated risk of endometrial cancer. A clear dose-response relation between endometrial cancer risk and years of menstruation was observed (p for trend < 0.01). Compared to women ever having a pregnancy and women ever having had a live birth, respectively, nulligravity and nulliparity were both associated with a more than one-fold elevated risk of endometrial cancer. Both completed (OR = 3.02, 95% CI 1.10-8.32 for women never having a complete pregnancy) and incomplete pregnancy (OR = 0.69, 95%CI 0.55-0.87) conferred a protective effect against endometrial cancer, and the protective effect appeared to increase with total number of pregnancies (p for trend = 0.01). The effect of pregnancy on endometrial cancer remained unchanged with increasing time since the last pregnancy. Stillbirth and age at first pregnancy was unrelated to endometrial cancer risk. Our study suggests that prolonged menstruation was related to an increased risk of endometrial cancer while pregnancy, including induced abortion, reduced the risk of endometrial cancer.

Consumption of animal foods, cooking methods, and risk of breast cancer

Cumulative evidence suggests a possible interaction of cooking methods with diet in the pathogenesis of breast cancer. Studies, however, are few and inconsistent. We evaluated the association of animal food intake and degree of browning by deep-frying with breast cancer risk in a population-based case-control study conducted during 1996-1998 among Chinese women in Shanghai, a population with a traditionally low risk of breast cancer. Included in the study were 1459 cases and 1556 age-frequency-matched controls with response rates of 91.1 and 90.3%, respectively. A validated food frequency questionnaire was used to obtain information on usual intake of animal foods and cooking oils and usual cooking methods. Increasing intake of red meat and freshwater fish was related to a moderately elevated risk of breast cancer risk. Stratified analyses showed that the positive association with red meat intake was primarily restricted to those who used deep-frying cooking method, particularly among those who deep-fried foods to well-done (odds ratio, 1.92; 95% confidence interval, 1.30-2.83 for the highest versus the lowest quintile; P for trend, 0.002). On the other hand, high intake of nonhydrogenated soybean cooking oil was related to a reduced risk of breast cancer among women who never deep-fried animal foods (odds ratio, 0.48; 95% confidence interval, 0.28-0.82 for the highest versus the lowest quintile; P for trend, 0.02). The positive association of breast cancer risk with red meat intake, especially well-done red meat, was more pronounced among women with a high body mass index than those without this risk factor, and the test for multiplicative interaction was statistically significant. This study suggests that high intake of deep-fried, well-done red meat may be associated with an increased risk of breast cancer, and the positive association may be modified by body weight. This study also suggests that nonhydrogenated soybean oil, if not used in high-temperature cooking, may be associated with a reduced risk of breast cancer.

Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study

Overall physical activity in adolescence and adulthood, and changes in activity over the lifespan were analysed by in-person interviews among 1459 women newly diagnosed with breast cancer and 1556 age-matched controls in urban Shanghai. Physical activity from exercise and sports, household, and transportation (walking and cycling) was assessed in adolescence (13-19 y) and adulthood (last 10 y), as was lifetime occupational activity. Logistic regression was used to estimate odds ratios (OR) and 95% confidence limits (OR (95% CL)) while controlling for confounders. Risk was reduced for exercise only in adolescence (OR = 0.84 (0.70-1.00)); exercise only in adulthood (OR = 0.68 (0.53-0.88)), and was further reduced for exercise in both adolescence and adulthood (OR = 0.47 (0.36-0.62)). Graded reductions in risk were noted with increasing years of exercise participation (OR(1-5 yrs)= 0.81 (0.67-0.94); OR(6-10 yrs)= 0.74 (0.59-0.93); OR(11-15 yrs)= 0.55 (0.38-0.79); OR(16 + yrs)= 0.40 (0.27-0.60);P(trend,)< 0.01). Lifetime occupational activity also was inversely related to risk (P(trend)< 0.01). These findings demonstrate that consistently high activity levels throughout life reduce breast cancer risk. Furthermore, they suggest that women may reduce their risk by increasing their activity levels in adulthood.