Phytoestrogens and risk of prostate cancer: an updated meta-analysis of epidemiologic studies

This updated meta-analysis was performed to clarify the relationship between phytoestrogens and prostate cancer risk. Twenty one case–control and two cohort studies were finally selected for this meta-analysis, totaling 11,346 cases and 140,177 controls. Analytical results showed that daidzein (OR?=?0.85; 95% CI: 0.75–0.96), genistein (OR?=?0.87; 95% CI: 0.78–0.98), and glycitein (OR?=?0.89; 95% CI: 0.81–0.98) were associated with a reduction of prostate cancer risk, but total isoflavones (OR?=?0.93; 95% CI: 0.84–1.04), equol (OR?=?0.86; 95% CI: 0.66–1.14), total lignans (OROgna.05; 95% CI: 0.54–2.04), secoisolariciresinol (OR?=?1.02; 95% CI: 0.83–1.24), matairesinol (OR?=?0.91; 95% CI: 0.75–1.11), enterolactone (OR?=?0.94; 95% CI: 0.73–1.20), and coumestrol (OR?=?0.89; 95% CI: 0.76–1.06) were not. Sensitivity and publication bias analyses demonstrated that the pooled estimates were stable and reliable. The results support the notion that some phytoestrogens may have a role in decreasing the risk of prostate cancer. Additional large and well-designed cohort studies are needed to confirm these relationships.     

Tumour stage and gender predict recurrence and second primary malignancies in head and neck cancer: a multicentre study within the INHANCE consortium

Recurrence and second primary cancer (SPC) continue to represent major obstacles to long-term survival in head and neck cancer (HNC). Our aim was to evaluate whether established demographics, lifestyle-related risk factors for HNC and clinical data are associated with recurrence and SPC in HNC. We conducted a multicentre study by using data from five studies members of the International Head and Neck Cancer Epidemiology consortium—Milan, Rome, Western Europe, Sao Paulo, and Japan, totalling 4005 HNC cases with a median age of 59 (interquartile range 52–67). Multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for recurrence and SPC. During follow-up, 1161 (29%) patients had recurrence and 343 (8.6%) developed SPC. Advanced tumour stage was associated with increased risk of recurrence in HNC overall (HR?=?1.76, 95% CI 1.41–2.19). Women with laryngeal cancer had a reduced risk of recurrence compared to men (HR?=?0.39, 95% CI: 0.24–0.74). Concerning predictors of SPC, advanced age (HR?=?1.02; 95% CI: 1.00–1.04) and alcohol consumption (>?1 drink per day, HR?=?2.11; 95% CI: 1.13–3.94) increased the risk of SPC among patients with laryngeal cancer. Additionally, women were at higher risk of SPC, in HNC overall group (HR?=?1.68; 95% CI: 1.13–2.51) and oropharyngeal cancer group (HR?=?1.74; 95% CI: 1.02–2.98). Tumour stage and male gender (larynx only) were positive predictors of cancer recurrence in HNC patients. Predictors of SPC were advanced age and alcohol use among laryngeal cancer cases, and female gender for oropharyngeal and HNC overall.     

Body mass index and risk of head and neck cancer by race: the Carolina Head and Neck Cancer Epidemiology Study

PurposeMost studies, primarily conducted in populations of European ancestry, reported increased risk of head and neck cancer (HNC) associated with leanness (body mass index [BMI] <18.5 kg/m²) and decreased for overweight or obesity (25.0 to <30.0 and >30 kg/m², respectively), compared with normal weight (18.5 to <25.0 kg/m²).MethodsThe Carolina Head and Neck Cancer Epidemiology Study is a population-based, racially diverse case-control study of 1289 incident HNC cases (330 African Americans) and 1361 controls (261 African Americans). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for associations between BMI 1 year prediagnosis and HNC risk stratified by race and adjusted for age, sex, smoking, alcohol, and education.ResultsMultiplicative interaction between BMI and race was evident (P_int = .00007). Compared with normal weight, ORs for leanness were increased for African Americans (OR, 3.91; 95% CI, 0.72–21.17) and whites (OR, 1.48; 95% CI, 0.60–3.65). For overweight and obesity, ORs were decreased in African Americans (OR, 0.51; 95% CI, 0.32–0.83 and OR, 0.47; 95% CI, 0.28–0.79, respectively) but in not whites. The increased risk associated with leanness was greater for smokers than nonsmokers (P_int = .02).ConclusionsThese data, which require replication, suggest that leanness is associated with increased HNC risk among African Americans to a greater extent than whites and overweight and obesity is associated with decreased HNC risk only among African Americans.     

Plant foods, antioxidants, and prostate cancer risk: findings from case-control studies in Canada

Epidemiological data on most cancer sites suggest that consumption of plant foods, which contain high levels of antioxidants, might slow or prevent the appearance of cancer. We used data from three case-control studies to test this hypothesis. The total study population consisted of 617 incident cases of prostate cancer and 636 population controls from Ontario, Quebec, and British Columbia. Dietary information was collected by an in-person interview with a detailed quantitative dietary history. Unconditional logistic regression analyses were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). A decreasing, statistically significant association was found with increasing intakes of green vegetables (OR = 0.54, 95% CI = 0.40-0.71 for 4th quartile), tomatoes (OR = 0.64, 95% CI = 0.45-0.91), beans/lentils/nuts (OR = 0.69, 95% CI = 0.53-0.91), and cruciferous vegetables (OR = 0.69, 95% CI = 0.52-0.91 for 3rd quartile). Higher intakes of fruit were associated with higher ORs (OR = 1.51, 95% CI = 1.14-2.01 for 4th quartile), an effect that was seen for total fruit and citrus fruit, as well as for all other noncitrus fruits. Among the grains, refined-grain bread intake was associated with a decrease in risk (OR = 0.65 for 4th quartile), whereas whole-grain breakfast cereals were associated with a higher risk for prostate cancer. Of all the antioxidant nutrients studied, the ORs were higher with higher intakes of cryptoxanthin (OR = 1.44, 95% CI = 1.09-1.89 for 4th quartile). Exposure to certain dietary components of plant origin, which are potentially modifiable, indicates the theoretical scope for reducing the risk from prostate cancer. Future experimental studies or trials are warranted for further understanding.     

Raw and cooked vegetables, fruits, selected micronutrients, and breast cancer risk: a case-control study in Germany

In 1998-2000, a case-control study of breast cancer was conducted in Heidelberg, Germany. Three hundred ten consecutively recruited cases with primary breast cancer were matched according to 10-yr age groups to 353 controls with conditions unrelated to diet or endocrine disorders. Intake of raw vegetables, total vegetables, and whole-grain products was inversely associated with breast cancer risk (highest vs. lowest quartile adjusted odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31-0.84; OR = 0.62, 95% CI = 0.38-1.02; and OR = 0.57; 95% CI = 0.34-0.95, respectively). Also, high intake of some selected vitamins and minerals possessing putative DNA-stabilizing properties displayed significant inverse risk associations. Adjusted ORs were as follows: vitamin C (OR = 0.49, 95% CI = 0.2-0.88), folate equivalents (OR = 0.47, 95% CI = 0.25-0.88), b-carotene (OR = 0.46, 95% CI = 0.27-0.80), zinc (OR = 0.35, 95% CI = 0.15-0.78), and copper (OR = 0.51, 95% CI = 0.31-1.03). In contrast, no significant association with risk was seen for an increased intake of fruits, cooked vegetables, fiber, calcium, manganese, or iron. In this population of German women, components of raw vegetables and some micronutrients appear to decrease breast cancer risk.     

Diet diversity and colorectal cancer

BACKGROUND: Food diversity has been recommended to achieve a healthy diet and prevent cancer. The relation between diet diversity and the risk of colorectal cancer was investigated using data from a multicenter case-control study carried out between 1992 and 1996 in Italy. METHODS: The study included 1225 subjects with cancer of the colon (688 men and 537 women), 728 with cancer of the rectum (437 men and 291 women), and 4154 controls (2073 men and 2081 women) residing in the same geographical areas. Odds ratios (ORs) of colon and rectal cancer and the corresponding 95% confidence intervals (CI) according to food diversity were derived from unconditional multiple logistic regression equations. RESULTS: For colon cancer, an inverse association for total diversity was found in males (adjusted OR of 0.65 for the highest vs the lowest quintile of total diversity; 95% CI: 0.46-0.93) and in females (OR = 0.85; 95% CI: 0.57-1.26). With respect to specific food groups, there was an inverse association only with diversity within vegetables (OR = 0.66; 95% CI: 0.54-0.81 in colon cancer and OR = 0.71; 95% CI: 0.55-0.91 in rectal cancer). CONCLUSIONS: This study suggests that total diversity is moderately related to a decreased risk of colorectal cancer risk. A better understanding of the potential influence of dietary patterns on colorectal cancer is needed.     

Ultraviolet sunlight exposure during adolescence and adulthood and breast cancer risk: a population-based case-control study among Ontario women

Recent studies suggest that vitamin D may be associated with reduced breast cancer risk, but most studies have evaluated only dietary vitamin D intake. The associations among ultraviolet radiation from sunlight, factors related to cutaneous vitamin D production, and breast cancer risk were evaluated in a population-based case-control study conducted in Ontario, Canada, between 2003 and 2004 (n = 3,101 cases and n = 3,471 controls). Time spent outdoors was associated with reduced breast cancer risk during 4 periods of life (>21 vs. ≤6 hours/week age-adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI): 0.60, 0.85 in the teenage years; OR = 0.64, 95% CI: 0.53, 0.76 in the 20s-30s; OR = 0.74, 95% CI: 0.61, 0.88 in the 40s-50s; and OR = 0.50, 95% CI: 0.37, 0.66 in the 60s-74 years). Sun protection practices and ultraviolet radiation were not associated with breast cancer risk. A combined solar vitamin D score, including all the variables related to vitamin D production, was significantly associated with reduced breast cancer risk. These associations were not confounded or modified by menopausal status, dietary vitamin D intake, or physical activity. This study suggests that factors suggestive of increased cutaneous production of vitamin D are associated with reduced breast cancer risk.     

Associations between food insecurity and healthy behaviors among Korean adults

BACKGROUND/OBJECTIVESFood insecurity has been suggested as being negatively associated with healthy behaviors and health status. This study was performed to identify the associations between food insecurity and healthy behaviors among Korean adults.SUBJECTS/METHODSThe data used were the 2011 Community Health Survey, cross-sectional representative samples of 253 communities in Korea. Food insecurity was defined as when participants reported that their family sometimes or often did not get enough food to eat in the past year. Healthy behaviors were considered as non-smoking, non-high risk drinking, participation in physical activities, eating a regular breakfast, and maintaining a normal weight. Multiple logistic regression and multinomial logistic regression analyses were used to identify the association between food insecurity and healthy behaviors.RESULTSThe prevalence of food insecurity was 4.4% (men 3.9%, women 4.9%). Men with food insecurity had lower odds ratios (ORs) for non-smoking, 0.75 (95% CI: 0.68-0.82), participation in physical activities, 0.82 (95% CI: 0.76-0.90), and eating a regular breakfast, 0.66 (95% CI: 0.59-0.74), whereas they had a higher OR for maintaining a normal weight, 1.19 (95% CI: 1.09-1.30), than men with food security. Women with food insecurity had lower ORs for non-smoking, 0.77 (95% CI: 0.66-0.89), and eating a regular breakfast, 0.79 (95% CI: 0.72-0.88). For men, ORs for obesity were 0.78 (95% CI: 0.70-0.87) for overweight and 0.56 (95% CI: 0.39-0.82) for mild obesity. For women, the OR for moderate obesity was 2.04 (95% CI: 1.14-3.63) as compared with normal weight.CONCLUSIONSFood insecurity has a different impact on healthy behaviors. Provision of coping strategies for food insecurity might be critical to improve healthy behaviors among the population.     

Breast cancer risk and lifetime occupational history: employment in professional and managerial occupations

OBJECTIVE: In this case-control study, occupational histories were used to assess the relation between risk of breast cancer and employment in professional and managerial occupations while adjusting for reproductive and other risk factors. METHODS: Incident, primary, female cases of breast cancer diagnosed between 1986 and 1991, and randomly selected controls were interviewed to obtain detailed medical, reproductive, and occupational histories. Mantel-Haenszel crude odds ratios (OR) and 95% confidence intervals (95% CIs) were used to estimate risk of breast cancer related to the job of longest duration. Unconditional logistic regression was used to estimate crude and adjusted ORs and 95% CIs associated with having ever been employed and duration of employment in a professional or managerial occupation. RESULTS: A non-significant threefold increase in risk was found among premenopausal women whose major job was in the occupational category of precision production, craft, and repair (95% CI 0.90 to 20.35). No increase in risk was found for premenopausal women whose major job was a managerial or professional occupation. However, an inverse relation between risk of premenopausal breast cancer and having ever held a professional or managerial job was observed (OR 0.53, 95% CI 0.34 to 0.82). This relation was strongest for women who worked one to 10 years (OR 0.47, 95% CI 0.29 to 0.77). Postmenopausal breast cancer was not related to professional and managerial employment. CONCLUSIONS: In this population, employment in professional and managerial occupations is not associated with postmenopausal risk of breast cancer, but seems to be related to a reduction in risk of premenopausal breast cancer. Methodological limitations of this study including response rates are discussed.

 

     

Diabetes Mellitus and Site-specific Colorectal Cancer Risk in Korea: A Case-control Study

Objectives:

Previous large-scale cohort studies conducted in Korea have found a positive association between diabetes mellitus (DM) and colorectal cancer (CRC) in men only, in contrast to studies of other populations that have found significant associations in both men and women.

Methods:

A total of 1070 CRC cases and 2775 controls were recruited from the National Cancer Center, Korea between August 2010 and June 2013. Self-reported DM history and the duration of DM were compared between cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by binary and polytomous logistic regression models.

Results:

DM was associated with an elevated risk of CRC in both men (OR, 1.47; 95% CI, 1.13 to 1.90) and women (OR, 1.92; 95% CI, 1.24 to 2.98). This association remained when we controlled for age, body mass index, alcohol consumption, and physical activity level. In sub-site analyses, DM was associated with distal colon cancer risk in both men (multivariate OR, 2.04; 95% CI, 1.39 to 3.00) and women (multivariate ORs, 1.99; 95% CI, 1.05 to 3.79), while DM was only associated with rectal cancer risk in women (multivariate OR, 2.05; 95% CI, 1.10 to 3.82). No significant association was found between DM and proximal colon cancer risk in either men (multivariate OR, 1.45; 95% CI, 0.88 to 2.41) or women (multivariate OR, 1.79; 95% CI, 0.78 to 4.08).

Conclusions:

Overall, DM was associated with an increased risk of CRC in Koreans. However, potential over-estimation of the ORs should be considered due to potential biases from the case-control design.     

Intakes of selected nutrients, foods, and phytochemicals and prostate cancer risk in western New York

A number of epidemiological studies have suggested that diet may affect the etiology of prostate cancer, but few have investigated the impact of phytochemical intakes on this cancer. We conducted a case-control study of diet and prostate cancer in western New York involving 433 men with primary, histologically confirmed prostate cancer and 538 population-based controls, frequency matched to cases on age and county of residence. Diet was assessed with a detailed food-frequency questionnaire. We calculated daily intakes of nutrients and the phytochemicals beta-sitosterol, campesterol, stigmasterol, total phytosterols, total lignan precursors, quercetin, and kaempferol based on published food composition data. Odds ratios (ORs) and 95% confidence intervals (CIs) describing the association of prostate cancer risk with selected nutrients, phytochemicals, and food groups were estimated with unconditional logistic regression. Compared with men in the lowest quartile of intake, reduced risks were observed for men in the highest quartile of intake of vitamin C (OR = 0.49; 95% CI = 0.33-0.74), beta-carotene (OR = 0.53; 95% CI = 0.36-0.79), alpha-carotene (OR = 0.67; 95% CI = 0.47-0.97), lutein (OR = 0.55; 95% CI = 0.37-0.81), lycopene (OR = 0.62; 95% CI = 0.42-0.92), total lignan precursors (OR = 0.66; 95% CI = 0.47-0.94), quercetin (OR = 0.64; 95% CI = 0.44-0.92), and total vegetables (OR = 0.53; 95% CI = 0.36-0.79), but weak increased risks were observed for snacks and sweets (OR = 1.46; 95% CI = 0.95-2.23). Estimates associated with nutrients and phytochemicals were attenuated after adjustment for total vegetable intake. Nevertheless, our results support the hypothesis that a phytochemical-rich, plant-based diet is of importance in reducing risks of hormone-related neoplasms.     

Carotenoid intake and head and neck cancer: a pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

Food and nutrition play an important role in head and neck cancer (HNC) etiology; however, the role of carotenoids remains largely undefined. We explored the relation of HNC risk with the intake of carotenoids within the International Head and Neck Cancer Epidemiology Consortium. We pooled individual-level data from 10 case–control studies conducted in Europe, North America, and Japan. The analysis included 18,207 subjects (4414 with oral and pharyngeal cancer, 1545 with laryngeal cancer, and 12,248 controls), categorized by quintiles of carotenoid intake from natural sources. Comparing the highest with the lowest quintile, the risk reduction associated with total carotenoid intake was 39 % (95 % CI 29–47 %) for oral/pharyngeal cancer and 39 % (95 % CI 24–50 %) for laryngeal cancer. Intakes of β-carotene equivalents, β-cryptoxanthin, lycopene, and lutein plus zeaxanthin were associated with at least 18 % reduction in the rate of oral and pharyngeal cancer (95 % CI 6–29 %) and 17 % reduction in the rate of laryngeal cancer (95 % CI 0–32 %). The overall protective effect of carotenoids on HNC was stronger for subjects reporting greater alcohol consumption (p < 0.05). The odds ratio for the combined effect of low carotenoid intake and high alcohol or tobacco consumption versus high carotenoid intake and low alcohol or tobacco consumption ranged from 7 (95 % CI 5–9) to 33 (95 % CI 23–49). A diet rich in carotenoids may protect against HNC. Persons with both low carotenoid intake and high tobacco or alcohol are at substantially higher risk of HNC.     

Case-control study of lifetime total physical activity and prostate cancer risk

A population-based case-control study of physical activity and prostate cancer risk was conducted in Alberta, Canada, between 1997 and 2000. A total of 988 incident, histologically confirmed cases of stage T2 or greater prostate cancer were frequency matched to 1,063 population controls. The Lifetime Total Physical Activity Questionnaire was used to measure occupational, household, and recreational activity levels from childhood until diagnosis. Multivariable logistic regression analyses were conducted. No association for total lifetime physical activity and prostate cancer risk was found (odds ratio (OR) for > or =203 vs. <115 metabolic equivalent-hours/week/year=0.87, 95% confidence interval (CI): 0.65, 1.17). By type of activity, the risks were decreased for occupational (OR=0.90, 95% CI: 0.66, 1.22) and recreational (OR=0.80, 95% CI: 0.61, 1.05) activity but were increased for household (OR=1.36, 95% CI: 1.05, 1.76) activity when comparing the highest and lowest quartiles. For activity performed at different age periods throughout life, activity done during the first 18 years of life (OR=0.78, 95% CI: 0.59, 1.04) decreased risk. When activity was examined by intensity of activity (i.e., low, <3; moderate, 3-6; and vigorous, >6 metabolic equivalents), vigorous activity decreased prostate cancer risk (OR=0.70, 95% CI: 0.54, 0.92). This study provides inconsistent evidence for the association between physical activity and prostate cancer risk.     

Black tea consumption and risk of rectal cancer in Moscow population

PURPOSE: This population-based case-control study (663 cases and 323 controls) examined the effect of black tea intake on the risk of rectal cancer in Moscow residents. The Moscow population was selected for its wide range of black tea consumption. METHODS: This study used three measures of tea consumption: the volume of beverage (l/month), zavarka (tea concentrate, l/month), and dry tea (g/month). We calculated the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for these three parameters of tea intake using logistic regression. RESULTS: Greater use of dry tea was associated with lower risk of rectal cancer in women (high vs. low: OR = 0.40; 95% CI, 0.23-0.70) and in men (high vs. low: OR = 0.77; 95% CI, 0.42-1.43). The observed effect was weaker when tea was measured as zavarka (high vs. low in women: OR = 0.47; 95% CI, 0.26-0.83; in men: OR = 0.99; 95% CI, 0.52-1.96) and as beverage volume (high vs. low in women: OR = 0.68; 95% CI, 0.39-1.19; in men: OR = 1.03; 95% CI, 0.53-2.09). CONCLUSIONS: These findings support the hypothesis that black tea consumption reduces the risk of rectal cancer. The attenuation of the effect across the three measures of tea intake can be explained by an increasing degree of exposure misclassification from dry tea to zavarka and beverage volume.     

Analgesic drug use and risk of ovarian cancer

BACKGROUND: Previous epidemiologic research suggests that analgesic use may reduce the risk of ovarian cancer, although results are not consistent. METHODS: In a population-based, case-control study, we analyzed data from 586 ovarian cancer cases and 627 matched controls in North Carolina for the relationship between analgesic use and ovarian cancer risk. Logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) while adjusting for potential confounders. RESULTS: Use of any nonsteroidal antiinflammatory drugs, including aspirin, within 5 years of diagnosis/interview was found to be associated with a reduction in the risk of ovarian cancer (adjusted OR = 0.72; 95% CI = 0.56-0.92). For use of acetaminophen, the OR was 0.78 (95% CI = 0.56-1.08). CONCLUSIONS: These data support an inverse relationship between the use of both nonsteroidal antiinflammatory drugs and acetaminophen and the risk of ovarian cancer.     

Physical activity and colorectal cancer

Physical activity has been inconsistently associated with rectal cancer despite the consistent association between physical activity and colon cancer. In this study, the authors evaluated the association between physical activity and rectal cancer using the same questionnaire used to evaluate the previously reported association with colon cancer. A population-based study of 952 incident cases of cancer in the rectum and rectosigmoid junction and 1,205 age- and sex-matched controls was conducted in Utah and northern California at the Kaiser Permanente Medical Care Program between 1997 and 2002. Vigorous physical activity was associated with reduced risk of rectal cancer in both men and women (odds ratio (OR) = 0.60, 95% confidence interval (CI): 0.44, 0.81 for men; OR = 0.59, 95% CI: 0.40, 0.86 for women). Among men, moderate levels of physical activity also were associated with reduced risk of rectal cancer (OR = 0.70, 95% CI: 0.51, 0.97). Participation in vigorous activity over the past 20 years conferred the greatest protection for both men and women (OR = 0.55, 95% CI: 0.39, 0.78 for men; OR = 0.44, 95% CI: 0.30, 0.67 for women). In summary, physical activity was associated with reduced risk of rectal cancer in these data. The reduced risk was similar to that previously observed for colon cancer.     

Some life-style factors and the risk of invasive epithelial ovarian cancer in Swedish women

The objective of this nationwide case-control study was to examine body mass index (BMI), alcohol use, coffee consumption, cigarette smoking, and leisure-time physical activity in relation to epithelial ovarian cancer (EOC) risk. Subjects were 655 newly diagnosed EOC cases and 3899 population controls, all 50-74 years of age at recruitment between 1993 and 1995. Data were collected through mailed questionnaires. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. Women with a BMI 30 kg/m² compared with those with a BMI < 22 kg/m² appeared to have an elevated EOC risk (OR = 1.37, 95% CI: 1.01-1.85), particularly of mucinous (OR = 2.76, 95% CI: 1.15-6.61) and clear-cell histologies (OR = 2.68, 95% CI: 0.96-7.48). The OR for EOC among coffee users reporting 6 daily cups compared with non-users was 0.68 (95% CI: 0.42-1.10). Alcohol consumption was unrelated to EOC risk. Compared to non-smokers the ORs of EOC among current smokers were 0.70 (95% CI: 0.52-0.94) for those who smoked 1-10 cigarettes/day and 0.74 (95% CI: 0.53-1.02) for heavier smokers, while former smokers were at an unaltered risk (OR = 0.83, 95% CI: 0.66-1.04). Reduced EOC risks were observed among women in the highest compared with the lowest physical activity levels both at age 18-30 years (OR = 0.67, 95% CI: 0.52-0.87) and during the last years preceding study enrollment (OR = 0.68, 95% CI: 0.53-0.87). We conclude that women may avoid an excess risk of EOC through maintaining a normal BMI and reduce their risk by participation in leisure-time physical activity. The use of coffee, alcohol, or cigarette smoking does not appearto increase the risk of EOC.     

Opposing effects of emphysema, hay fever, and select genetic variants on lung cancer risk

The authors compared histories of nonmalignant respiratory diseases (asthma, bronchitis, emphysema, hay fever, and pneumonia) in 1,553 lung cancer patients and 1,375 healthy controls enrolled in a Texas case-control study from 1995 to 2003. They incorporated data on two biologically relevant polymorphic genes, matrix metalloproteinase-1 and myeloperoxidase. Emphysema was associated with a statistically significant increased lung cancer risk (odds ratio (OR) = 2.87, 95% confidence interval (CI): 2.20, 3.76), while hay fever had a significant protective effect (OR = 0.58, 95% CI: 0.48, 0.70). Odds ratios were consistent after exclusion of respiratory disease diagnoses made up to 10 years before interview. There was little association between other respiratory diseases and lung cancer risk. Among carriers of "protective" genotypes, emphysema was associated with a 1.7-fold increased risk (95% CI: 0.84, 3.50), as compared with the substantially higher risk for persons possessing one (OR = 4.98, 95% CI: 2.94, 8.44) or two (OR = 4.23, 95% CI: 1.84, 9.73) "adverse" genotypes. For hay fever, significantly decreased risks were evident with one (OR = 0.32, 95% CI: 0.21, 0.50) or two (OR = 0.35, 95% CI: 0.19, 0.66) protective genotypes as compared with none (OR = 0.69, 95% CI: 0.30, 1.59). The biologic role of respiratory disease in lung cancer is unclear. Further study may yield new insights for identification of susceptible subgroups.     

女性激素替代治疗、口服避孕药与女性肺癌关系的Meta分析

目的探讨女性激素替代治疗(HRT)与口服避孕药(OCs)对女性肺癌的影响。方法搜索Medline等计算机数据库,系统收集相关文献。采用固定模型或随机效应模型(研究结果存在异质性)计算合并OR。结果纳入Meta分析的文献共12篇,其中3篇为队列研究,9篇为病例对照研究。Meta分析HRT与肺癌合并OR值为0.88(95%CI:0.77～1.01)。按是否吸烟进行分层分析,吸烟者与非吸烟者中HRT的合并OR值分别为0.76(95%CI:0.61～0.95)和0.78(95%CI:0.64～0.95)。口服避孕药与女性肺癌无统计学关联(OR=0.95;95%CI:0.83～1.20)。结论HRT可能降低女性肺癌发生的危险度,其结果还需要进一步深入研究来验证。     

Dietary Factors and Thyroid Cancer Risk: A Meta-Analysis of Observational Studies

To better understand the relationship between dietary factors and thyroid cancer risk, we summarized the published evidence on relationship between dietary factors and thyroid cancer incidence. Searching several databases for relevant studies published by March 2014 included a total of 19 studies. We calculated summary odds ratios (ORs) for each risk factor. Based on the highest level of total consumption vs. the lowest level, the summary OR [95% (confidence interval) CI] of thyroid cancer was 0.79 (0.66, 0.94) for fish; 0.95 (0.74, 1.23) for salt water fish; 0.86 (0.63, 1.16) for fresh water fish; 0.76 (0.58, 1.00) for vegetables; 0.88 (0.72, 1.08) for shellfish; 0.93 (0.66, 1.29) for cruciferous vegetables; 0.97 (0.78, 1.21) for fruits; 0.96 (0.70, 1.34) for meat; and 1.11 (0.86, 1.42) for grains. Subgroup analysis showed that fish (OR 0.74, 95%CI: 0.59, 0.92) and shellfish (OR 0.46, 95%CI: 0.27, 0.75) consumption have a protective effect in iodine deficiency areas, whereas the ORs were not statistically significant in iodine-rich areas. Our findings indicated that fish and shellfish consumption may decrease the risk of thyroid cancer in iodine deficiency areas, although no such effect was observed in iodine-rich areas.