Dietary zinc, copper and selenium, and risk of lung cancer

Zinc, copper and selenium are important cofactors for several enzymes that play a role in maintaining DNA integrity. However, limited epidemiologic research on these dietary trace metals and lung cancer risk is available. In an ongoing study of 1,676 incident lung cancer cases and 1,676 matched healthy controls, we studied the associations between dietary zinc, copper and selenium and lung cancer risk. Using multiple logistic regression analysis, the odds ratios (OR) and 95% confidence intervals (CI) of lung cancer for all subjects by increasing quartiles of dietary zinc intake were 1.0, 0.80 (0.65-0.99), 0.64 (0.51-0.81), 0.57 (0.42-0.75), respectively (p trend = 0.0004); similar results were found for men. For dietary copper, the ORs and 95% CI for all subjects were 1.0, 0.59 (0.49-0.73), 0.51 (0.41-0.64), 0.34 (0.26-0.45), respectively (p trend < 0.0001); similar reductions in risk and trend were observed by gender. Dietary selenium intake was not associated with risk, except for a significant inverse trend (p = 0.04) in men. Protective trends (p < 0.05) against lung cancer with increased dietary zinc intake were also found for all ages, BMI > 25, current smokers, pack-years < or =30, light drinkers and participants without emphysema. Increased dietary copper intake was associated with protective trends (p < 0.05) across all ages, BMI, smoking and vitamin/mineral supplement categories, pack-years < or =30 and 30.1-51.75 and participants without emphysema. Our results suggest that dietary zinc and copper intakes are associated with reduced risk of lung cancer. Given the known limitations of case-control studies, these findings must be interpreted with caution and warrant further investigation.     

Serum tocopherols, selenium and lung cancer risk among tin miners in China

Objective: To evaluate the association of prediagnostic serum antioxidants and lung cancer risk we conducted a case–control study nested in an occupational cohort of tin miners. Methods: Male workers free of cancer enrolled in the cohort. During up to 6 years of follow-up, 339 lung cancer cases were diagnosed and, among these cases, those who donated blood prospectively (n = 108) were eligible for this study. For each case, two controls alive and free of cancer at the time of case diagnosis were matched on age and date of blood collection. Results: Overall, we observed no association between serum alpha-tocopherol, gamma-tocopherol or selenium levels and lung cancer risk. However, a significant gradient of decreasing lung cancer risk with increasing serum alpha-tocopherol was apparent for men less than 60years old (odds ratio by tertile: 1.0, 0.9, 0.2; trend p = 0.002). Alpha-tocopherol was also protective in men who reported no alcohol drinking (OR by tertile: 1.0, 0.6, 0.3; trend p = 0.008). Conclusion: Although there were no significant overall associations between prospectively collected serum alpha-tocopherol, gamma-tocopherol or selenium and incidence of lung cancer, results from this study suggest that higher alpha-tocopherol levels may be protective in men less than 60 years old and in those who do not drink alcohol.     

Vitamin E intake and the lung cancer risk among female nonsmokers: A report from the Shanghai Women's Health Study

Vitamin E includes several tocopherol isoforms, which may reduce lung cancer risk, but past studies evaluating the association between vitamin E intake and lung cancer risk were inconsistent. We prospectively investigated the associations between tocopherol intake from diet and from supplements with lung cancer risk among 72,829 Chinese female nonsmokers aged 40–70 years and participating in the Shanghai Women's Health Study (SWHS). Dietary and supplement tocopherol exposure was assessed by a validated food‐frequency questionnaire at baseline and reassessed for change in intake during follow‐up. Cox proportional hazards models with time‐dependent covariates were used to calculate multivariate‐adjusted hazard ratios (HRs) and 95% confidence interval (CIs) for lung cancer. After 12.02 years of follow‐up, 481 women were diagnosed with lung cancer. Total dietary tocopherol was inversely associated with lung cancer risk among women meeting dietary guidelines for adequate intake (AI) of tocopherol (14 mg/day or more: HR: 0.78; 95% CI 0.60–0.99; compared with the category less than AI). The protective association between dietary tocopherol intake and lung cancer was restricted to women exposed to side‐stream smoke in the home and workplace [HR = 0.53 (0.29–0.97), p‐trend = 0.04]. In contrast, vitamin E supplement use was associated with increased lung cancer risk (HR: 1.33; 95% CI: 1.01–1.73), more so for lung adenocarcinoma risk (HR: 1.79; 95% CI: 1.23–2.60). In summary, dietary tocopherol intake may reduce the risk of lung cancer among female nonsmokers; however, supplements may increase lung adenocarcinoma risk and requires further investigation.     

Dietary patterns and risk of prostate cancer in Ontario, Canada

Dietary patterns reflect combinations of dietary exposures, and here we examine these in relation to prostate cancer risk. In a case-control study, 80 incident primary prostate cancer cases and 334 urology clinic controls were enrolled from 1997 through 1999 in Kingston, Ontario, Canada. Food-frequency questionnaires were completed prior to diagnosis and assessed intake in the 1-year period 2-3 years prior to enrollment. Among controls, dietary intake was used in principal components analyses to identify patterns that were then evaluated with all subjects in relation to prostate cancer risk using unconditional logistic regression, controlling for age. Four dietary patterns were identified: Healthy Living, Traditional Western, Processed and Beverages. Increased prostate cancer risk is apparent in relation to the Processed pattern, composed of processed meats, red meats, organ meats, refined grains, white bread, onions and tomatoes, vegetable oil and juice, soft drinks and bottled water. The OR for the highest tertile compared to baseline is 2.75 (95% CI 1.40-5.39), with a dose-response pattern (trend test p < 0.0035). Our results suggest that a dietary pattern including refined grain products, processed meats and red and organ meats contributes to increased prostate cancer risk. Since dietary information was collected before subjects knew their diagnosis, recall bias was avoided.     

Dietary fiber,vitamins A,C, and E,and risk of breast cancer: a cohort study

Risk of breast cancer was examined in relation to intake of dietary fiber and vitamins A, C, and E, and food groups which are sources of these dietary constituents, in a cohort of 56,837 women enrolled in the Canadian National Breast Screening Study. Between 1982 and 1987, 519 incident, histologically confirmed cases of breast cancer were identified among women who previously had completed self-administered dietary questionnaires. Their nutrient and food intake was compared with that of 1,182 women who had not developed breast cancer during the follow-up period. Women at the uppermost quintile level of dietary fiber intake had a 30 percent reduction in risk of breast cancer relative to that for women at the lowest quintile level (adjusted odds ratio = 0.68,95 percent confidence interval = 0.46–1.00), and the reduction in risk persisted after adjustment (separately) for total vitamin A, -carotene, vitamin C, and -tocopherol. Inverse associations of similar magnitude were observed in association with consumption of pasta, cereals (the trend for which was statistically significant), and vegetables rich in vitamins A and C. Smaller, statistically nonsignificant reductions in risk were observed with increasing intake of dietary retinol, -carotene, and vitamin C, but the magnitude of these associations was reduced after adjustment for other dietary factors. Vitamin E intake was not associated with altered risk of breast cancer.Drs Roban, Howe, and Jain are with the NCIC Epidemiology Unit, University of Toronto, Toronto, Canada. The authors are also affihated teith the Department of Preventive Medicine and Biostatistics, University of Toronto, Toronto, Canada (Drs rohan, Howe, Jain, and Miller), and with the Department of Community Health sciences, University of Calgary, Calgary, Canada (Dr Friedenreich). Address correspondence to Dr Roban, NCIC Epidemiology Unit, University of Toronto, McMurricb Buiding, 3rd Floor, 12 Queen's Park Crescent West, Toronto, Ontario, MSS 1A8, Canada.     

Dietary carotenoids,vegetables, and lung cancer risk in women: the Missouri women's health study (United States)

Objective: To examine the effect of specific dietary carotenoids and their primary plant food sources on lung cancer risk in a population-based case–control study of women. Methods: Data were available for 587 incident primary lung cancer cases and 624 controls frequency matched to cases based on age. A modified version of the 100-item NCI-Block food-frequency questionnaire was used to obtain information concerning usual diet 2–3 years prior to interview. Results: In models adjusted for age, total calorie intake, pack-years of smoking, and education, -carotene, -cryptoxanthin, lutein + zeaxanthin, and total carotenoid intake were each associated with a significantly lower risk of lung cancer. Several vegetable groups were predictive of lower lung cancer risk, particularly the frequency of total vegetable intake. Individual and total carotenoids were no longer significantly associated with lower lung cancer risk in models adjusted for total vegetable intake. However, total vegetable intake remained significantly inversely associated with risk in models adjusted for total carotenoids. Conclusions: These results indicate that consumption of a wide variety of vegetables has a greater bearing on lung cancer risk in a population of smoking and nonsmoking women than intake of any specific carotenoid or total carotenoids.     

Mediterranean dietary pattern and cancer risk in the EPIC cohort

Background:

Although several studies have investigated the association of the Mediterranean diet with overall mortality or risk of specific cancers, data on overall cancer risk are sparse.

Methods:

We examined the association between adherence to Mediterranean dietary pattern and overall cancer risk using data from the European Prospective Investigation Into Cancer and nutrition, a multi-centre prospective cohort study including 142 605 men and 335 873. Adherence to Mediterranean diet was examined using a score (range: 0–9) considering the combined intake of fruits and nuts, vegetables, legumes, cereals, lipids, fish, dairy products, meat products, and alcohol. Association with cancer incidence was assessed through Cox regression modelling, controlling for potential confounders.

Results:

In all, 9669 incident cancers in men and 21 062 in women were identified. A lower overall cancer risk was found among individuals with greater adherence to Mediterranean diet (hazard ratio=0.96, 95% CI 0.95–0.98) for a two-point increment of the Mediterranean diet score. The apparent inverse association was stronger for smoking-related cancers than for cancers not known to be related to tobacco (P (heterogeneity)=0.008). In all, 4.7% of cancers among men and 2.4% in women would be avoided in this population if study subjects had a greater adherence to Mediterranean dietary pattern.

Conclusion:

Greater adherence to a Mediterranean dietary pattern could reduce overall cancer risk.     

Dietary intake of fruit and vegetable and lung cancer risk: a case-control study in Harbin, northeast China.

BACKGROUND: We studied the relationship between dietary intake of vegetables and fruit and lung cancer risk in Harbin, Heilongjiang province, northeast China, an area with a very high baseline risk of lung cancer in both sexes. PATIENTS AND METHODS: We used data from a case-control study, conducted from 1987 to 1990, among 218 cases with incident, histologically confirmed lung cancer and 436 controls admitted to the same hospitals as cases with non-neoplastic, non-lung diseases unrelated to smoking and other potential risk factors for lung cancer. RESULTS: Compared with the lowest tertile of intake of vegetables, fruit or both, the multivariate odds ratios (ORs) for the highest tertile of intake were 0.39 [95% confidence interval (CI) 0.25-0.62], 0.73 (95% CI 0.48-1.11) and 0.40 (95% CI 0.25-0.63), respectively. In particular, high intake of Chinese cabbage (OR = 0.53), chives (OR = 0 .54), carrots (OR = 0.51) and celery (OR = 0.40) was inversely associated with lung cancer. The OR was more than six-fold elevated for smokers reporting low intake of vegetables, and more than four-fold elevated for smokers reporting low intake of fruit, as compared with never smokers reporting high intake of these items. CONCLUSION: In agreement with previous studies, we found an inverse relation between vegetable and fruit intake and lung cancer risk in both strata of current and never smokers.     

A cohort study of dietary carotenoids and lung cancer risk in women (Canada)

Objective: To investigate the association between dietary carotenoid intake and lung cancer risk in women. Methods: A case–cohort study was undertaken in the Canadian National Breast Screening Study dietary cohort, which consists of 56,837 women who completed a self-administered dietary questionnaire. The cohort was recruited between 1980 and 1985, and during follow-up to the end of 1993 a total of 196 cohort members were diagnosed with incident lung cancer. For analysis, a subcohort consisting of a random sample of 5681 women was selected from the full dietary cohort. After exclusions for various reasons, the analyses were based on 155 cases and 5361 non-cases. Results: When compared to those in the lowest quartile level of intake, the adjusted incidence rate ratios (95% confidence intervals) for those in the highest quartile levels of -carotene, -carotene, -cryptoxanthin, lycopene, and lutein intake were 0.90 (0.51–1.58), 1.40 (0.76–2.59), 0.66 (0.33–1.32), 1.04 (0.61–1.76), and 1.26 (0.70–2.24), respectively; none of the associated tests for trend was statistically significant. Conclusion: These results suggest that there is no association between dietary carotenoid intake and lung cancer risk, at least for the range of intakes observed here.     

Fibre intake and prostate cancer risk

Dietary fibre has been reported to protect from several neoplasms, but the issue remains controversial. No previous study considered in depth the topic of fibres and prostate cancer. A multicentre case-control study was conducted in Italy from 1991 to 2002, including 1,294 men with incident, histologically confirmed prostate cancer and 1,451 controls admitted to the same network of hospitals as cases with acute nonmalignant conditions. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were obtained after allowance for major identified confounding factors, including total energy intake. Compared to the lowest quintile, the OR of prostate cancer for the highest quintile of total fibre intake was 0.93 (95% CI 0.71-1.22). The risk was inversely related with soluble fibre (OR = 0.89, 95% CI 0.78-1.02, for a difference between 80th and 20th percentile), cellulose (OR = 0.88, 95% CI 0.78-1.01) and vegetable fibre (OR = 0.82, 95% CI 0.73-0.93). These relationships were consistent across strata of age, family history of prostate cancer, body mass index and education. Vegetable fibres appear, therefore, to have a favourable association with prostate cancer risk.     

Dietary inflammatory index and risk of epithelial ovarian cancer in African American women

Chronic inflammation has been implicated in the development of epithelial ovarian cancer (EOC); yet the contribution of inflammatory foods and nutrients to EOC risk has been understudied. We investigated the association between the dietary inflammatory index (DII), a novel literature‐derived tool to assess the inflammatory potential of one's diet, and EOC risk in African American (AA) women in the African American Cancer Epidemiology Study, the largest population‐based case–control study of EOC in AA women to date. The energy‐adjusted DII (E‐DII) was computed per 1,000 kilocalories from dietary intake data collected through a food frequency questionnaire, which measured usual dietary intake in the year prior to diagnosis for cases or interview for controls. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable logistic regression for the association between the E‐DII and EOC risk. 493 cases and 662 controls were included in the analyses. We observed a 10% increase in EOC risk per a one‐unit change in the E‐DII (OR = 1.10, 95% CI = 1.03–1.17). Similarly, women consuming the most pro‐inflammatory diet had a statistically significant increased EOC risk in comparison to the most anti‐inflammatory diet (OR_{Quartile4/Quartile1} = 1.72; 95% CI = 1.18–2.51). We also observed effect modification by age (p < 0.05), where a strong, significant association between the E‐DII and EOC risk was observed among women older than 60 years, but no association was observed in women aged 60 years or younger. Our findings suggest that a more pro‐inflammatory diet was associated with an increased EOC risk, especially among women older than 60 years.     

Dietary acrylamide and risk of prostate cancer

Acrylamide has been designated by IARC as a "probable human carcinogen." High levels are formed during cooking of many commonly consumed foods including French fries, potato chips, breakfast cereal and coffee. Two prospective cohort studies and two case-control studies in Europe found no association between acrylamide intake and prostate cancer. We examined this association in a large prospective cohort of 47,896 US men in the Health Professionals' Follow-up Study, using updated dietary acrylamide intake from food frequency questionnaires in 1986, 1990, 1994, 1998 and 2002. From 1986 through 2006, we documented 5025 cases of prostate cancer, and 642 lethal cancers. We used Cox proportional hazards models to assess the association between acrylamide intake from diet and prostate cancer risk overall as well as risk of advanced or lethal cancer. Acrylamide intake ranged from a mean of 10.5 mcg/day in the lowest quintile to 40.1 mcg/day in the highest quintile; coffee and potato products were largest contributors to intake. The multivariate-adjusted relative risk of prostate cancer was 1.02 (95% confidence interval: 0.92-1.13) for the highest versus lowest quintile of acrylamide intake (p-value for trend = 0.90). Results were similar when restricted to never smokers and to men who had prostate-specific antigen (PSA) tests. There was no significant association for dietary acrylamide and risk of lethal, advanced or high-grade disease, or for different latency periods ranging from 0-4 years to 12-16 years. We found no evidence that acrylamide intake, within the range of US diets, is associated with increased risk of prostate cancer.     

Comparison of discriminatory power and accuracy of three lung cancer risk models

Background:

Three lung cancer (LC) models have recently been constructed to predict an individual''s absolute risk of LC within a defined period. Given their potential application in prevention strategies, a comparison of their accuracy in an independent population is important.

Methods:

We used data for 3197 patients with LC and 1703 cancer-free controls recruited to an ongoing case–control study at the Harvard School of Public Health and Massachusetts General Hospital. We estimated the 5-year LC risk for each risk model and compared the discriminatory power, accuracy, and clinical utility of these models.

Results:

Overall, the Liverpool Lung Project (LLP) and Spitz models had comparable discriminatory power (0.69), whereas the Bach model had significantly lower power (0.66; P=0.02). Positive predictive values were highest with the Spitz models, whereas negative predictive values were highest with the LLP model. The Spitz and Bach models had lower sensitivity but better specificity than did the LLP model.

Conclusion:

We observed modest differences in discriminatory power among the three LC risk models, but discriminatory powers were moderate at best, highlighting the difficulty in developing effective risk models.     

Vitamin E and cancer prevention: Studies with different forms of tocopherols and tocotrienols

α-Tocopherol (α-T) is the major form of vitamin E (VE) in animals and has the highest activity in carrying out the essential antioxidant functions of VE. Because of the involvement of oxidative stress in carcinogenesis, the cancer prevention activity of α-T has been studied extensively. Lower VE intake or nutritional status has been shown to be associated with increased cancer risk, and supplementation of α-T to populations with VE insufficiency has shown beneficial effects in lowering the cancer risk in some intervention studies. However, several large intervention studies with α-T conducted in North America have not demonstrated a cancer prevention effect. More recent studies have centered on the γ- and δ-forms of tocopherols and tocotrienols (T3). In comparison with α-T, these forms have much lower systemic bioavailability but have shown stronger cancer-preventive activities in many studies in animal models and cell lines. γ-T3 and δ-T3 generally have even higher activities than γ-T and δ-T. In this article, we review recent results from human and laboratory studies on the cancer-preventive activities of different forms of tocopherols and tocotrienols, at nutritional and pharmacological levels. We aim to elucidate the possible mechanisms of the preventive actions and discuss the possible application of the available information for human cancer prevention by different VE forms.     

Atributable risk of breast,prostate, and lung cancer in Hawaii due to saturated fat

The dietary data from case-control studies of breast, prostate, and lung cancer in Hawaii revealed that saturated fat was a risk factor for these malignancies. The dietary intakes from the three studies were used to calculate the attributable risk (AR) due to saturated fat. For all ethnic groups combined, the ARs for the highest quartiles of intake were 14.9 percent for female breast cancer, 13.0 percent for prostate cancer, and 23.1 percent for male lung cancer. Our results suggested that a reduction of saturated fat to the lowest quartiles of intake could result in a 10 to 20 percent decrease in risk for these three cancers in Hawaii. We also examined the ethnic-specific risks associated with saturated fat consumption among the Japanese and the Caucasians in the three studies. The ARs for the highest quartiles of intake were notably higher among the Caucasians than the Japanese, primarily due to the difference in their dietary patterns. Although the calculated AR due to saturated fat was higher among the Caucasians than among the Japanese, all persons in the population would derive considerable benefit by reducing their intake of this nutrient.Authors are with the Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, 1236 Lauhala Street, Honolulu, HI 96813, USA. Address correspondence to Dr Hankin. This study was supported in part by NIH Grant PO1 CA 33619.     

Dietary acrylamide and human cancer

Low levels of acrylamide have been found in several foods cooked at high temperatures. While there is sufficient evidence for the carcinogenicity of acrylamide in experimental animals, the few epidemiologic studies conducted to date on occupational and dietary exposure to acrylamide have found no consistent evidence of association with human cancer risk. Using data from an integrated network of Italian and Swiss hospital-based case-control studies, we analyzed the relation between dietary acrylamide intake and cancers of the oral cavity and pharynx (749 cases, 1,772 controls), esophagus (395 cases, 1,066 controls), large bowel (1,394 cases of colon, 886 cases of rectal cancer, 4,765 controls), larynx (527 cases, 1,297 controls), breast (2,900 cases, 3,122 controls), ovary (1,031 cases, 2,411 controls) and prostate (1,294 cases, 1,451 controls). All the studies included incident, histologically confirmed cancer cases and controls admitted to the same network of hospitals for acute nonneoplastic conditions. We calculated odds ratios (ORs) using multivariate logistic regression models, adjusted for energy intake and other major covariates of interest. The ORs for the highest versus the lowest quintile of acrylamide intake were 1.12 (95% CI = 0.76-1.66) for cancer of the oral cavity/pharynx, 1.10 (95% CI = 0.65-1.86) for esophageal, 0.97 (95% CI = 0.80-1.18) for colorectal, 1.23 (95% CI = 0.80-1.90) for laryngeal, 1.06 (95% CI = 0.88-1.28) for breast, 0.97 (95% CI = 0.73-1.31) for ovarian and 0.92 (95% CI = 0.69-1.23) for prostate cancer. None of the trend in risk was significant. This uniquely large and comprehensive data set does not show any consistent association between intake of acrylamide and the risk of breast and several other common cancers.     

Dietary patterns and breast cancer risk: results from three cohort studies in the DIETSCAN project

Objective: Only a few consistent findings on individual foods or nutrients that influence breast cancer risk have emerged thus far. Since people do not consume individual foods but certain combinations of them, the analysis of dietary patterns may offer an additional aspect for assessing associations between diet and diseases such as breast cancer. It is also important to examine whether the relationships between dietary patterns and breast cancer risk are consistent across populations.Methods: We examined the risk of breast cancer with two dietary patterns, identified as “Vegetables” (VEG) and “Pork, Processed Meat, Potatoes” (PPP), common to all cohorts of the DIETSCAN project. During 7 to 13 years of follow-up, three of the cohorts – the Netherlands Cohort Study on diet and cancer (NLCS), the Swedish Mammography Cohort (SMC), and the Ormoni e Dieta nella Eziologia dei Tumori (Italy-ORDET) – provided data on 3271 breast cancer cases with complete information on their baseline diet measured by a validated food frequency questionnaire.Results: After adjustment for potential confounders, VEG was not associated with the risk of breast cancer across all cohorts. PPP was also not associated with the risk of breast cancer in SMC and ORDET, but a high PPP score tended to be inversely associated with breast cancer in the NLCS study (RR = 0.69; 95% CI, 0.52–0.92, highest versus lowest quartile). PPP differed in one aspect between the cohorts: butter loaded positively on the pattern in all cohorts except NLCS, in which butter loaded negatively and appeared to be substituted by low-fat margarine loading positively.Conclusion: In general, the dietary patterns showed consistent results across the three cohorts except for the possible protective effect of PPP in the NLCS cohort, which could be explained by a difference in that pattern for NLCS. The results supported the suggestion derived from traditional epidemiology that relatively recent diet may not have an important role in the etiology of breast cancer.     

Dietary nitrate and nitrite intake and risk of colorectal cancer in the Shanghai Women's Health Study

Nitrate and nitrite are precursors of endogenously formed N‐nitroso compounds (NOC), known animal carcinogens. Nitrosation reactions forming NOCs can be inhibited by vitamin C and other antioxidants. We prospectively investigated the association between dietary nitrate and nitrite intake and risk of colorectal cancer in the Shanghai Women's Health Study, a cohort of 73,118 women ages 40–70 residing in Shanghai. We evaluated effect modification by factors that affect endogenous formation of NOCs: vitamin C (at or above/below median) and red meat intake (at or above/below median). Nitrate, nitrite and other dietary intakes were estimated from a 77‐item food frequency questionnaire administered at baseline. Over a mean of 11 years of follow‐up, we identified 619 colorectal cancer cases (n = 383, colon; n = 236, rectum). Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazard regression. Overall, nitrate intake was not associated with colorectal cancer risk (HR = 1.08; 95% CI: 0.73–1.59). However, among women with vitamin C intake below the median (83.9 mg day^?1) and hence higher potential exposure to NOCs, risk of colorectal cancer increased with increasing quintiles of nitrate intake (highest vs. lowest quintile HR = 2.45; 95% CI: 1.15–5.18; p trend = 0.02). There was no association among women with higher vitamin C intake. We found no association between nitrite intake and risk of colorectal cancer overall or by intake level of vitamin C. Our findings suggest that high dietary nitrate intake among subgroups expected to have higher exposure to endogenously formed NOCs increases risk of colorectal cancer.     

Hormone replacement therapy and lung cancer risk in Chinese

BACKGROUND: The association between hormone replacement therapy (HRT) and a reduced lung cancer risk has been reported in previous studies. There is a high female to male ratio in Chinese lung cancer patients, and female patients have different clinicopathological characteristics compared with Western patient populations. The authors investigated whether HRT may reduce lung cancer risk in Taiwan. METHODS: The authors used a case-control study design to investigate 826 women with lung cancer and 531 healthy controls. Personal interviews based on a structured questionnaire were performed to collect information on HRT use of at least 3 months, age, ethnicity, active and passive smoking, exposure to air pollution, cooking or incense fumes, body mass index (BMI), menopause, and family history of cancers. RESULTS: HRT use was associated with reduced lung cancer risk with a multivariate, adjusted odds ratio of 0.70 (95% CI, 0.53-0.94; P = .019). HRT use was associated with reduced odds ratio of lung cancer in all subset analyses stratified by histology, active and passive cigarette smoking, BMI, history of incense burning, cooking, and motorcycle riding, as well as family history of certain cancers. CONCLUSIONS: This study confirmed that HRT is associated with a reduced lung cancer risk. The results appeared to be applicable to Chinese female population groups.