Fat intake and its relationship with pre- and post-menopausal breast cancer risk: a case-control study in Malaysia

Background: Fat intake has been shown to play a role in the etiology of breast cancer, but the findings have been inconsistent. Objective: To assess the association of premenopausal and postmenopausal breast cancer risk with fat and fat subtypes intake. Methodology: This is a population based case-control study conducted in Kuala Lumpur, Malaysia from January 2006 to December 2007. Food intake pattern was collected from 382 breast cancer patients and 382 control group via an interviewer-administered food frequency questionnaire. Logistic regression was used to compute odds ratios (OR) with 95% confidence intervals (CI) and a broad range of potential confounders was included in analysis. Results: This study showed that both premenopausal and postmenopausal breast cancer risk did not increase significantly with greater intake of total fat [quartile (Q) 4 versus Q1 OR=0.76, 95% CI, 0.23-2.45 and OR=1.36, 95% CI, 0.30-3.12], saturated fat (ORQ4 to Q1=1.43, 95% CI, 0.51-3.98 and ORQ4 to Q1=1.75, 95% CI, 0.62-3.40), monounsaturated fat (ORQ4 to Q1=0.96, 95% CI, 0.34-1.72 and ORQ4 to Q1=1.74, 95% CI, 0.22-2.79), polyunsaturated fat (ORQ4 to Q1=0.64, 95% CI, 0.23-1.73 and ORQ4 to Q1=0.74, 95% CI, 0.39-1.81), n-3 polyunsaturated fat (ORQ4 to Q1=1.10, 95% CI, 0.49-2.48 and ORQ4 to Q1=0.78, 95% CI, 0.28-2.18), n-6 polyunsaturated fat (ORQ4 to Q1=0.67, 95% CI, 0.24-1.84 and ORQ4 to Q1=0.71, 95% CI, 0.29-1.04) or energy intake (ORQ4 to Q1=1.52, 95% CI, 0.68-3.38 and ORQ4 to Q1=2.21, 95% CI, 0.93-3.36). Conclusion: Total fat and fat subtypes were not associated with pre- and postmenopausal breast cancer risk after controlling for age, other breast cancer risk factors and energy intake. Despite the lack of association, the effects of total fat and fat subtypes intake during premenopausal years towards postmenopausal breast cancer risk still warrant investigation.     

Adolescent diet and breast cancer in Utah

A population-based case-control study was conducted to assess the association between breast cancer risk, body mass index (BMI) and adolescent dietary fat and fiber consumption. Data were collected in Utah from white female cases (N = 172) and controls (N = 190) between the ages of 20 and 54 years. Odds ratios (OR) and 95% test-based confidence intervals (CI) were determined by multiple-logistic regression analysis controlling for age, education, age at menarche, and age at first pregnancy. Menopausal status was identified as an effect modifier, therefore, separate analyses were performed for pre and postmenopausal groups. An elevated risk (OR = 2.9 for highest quartile versus lowest, CI = 1.1-8.1) was associated with a larger BMI at age 12 in premenopausal women; a larger adult BMI lowered the odds ratio (OR = 0.4, CI = 0.2-1.0 for highest quartile versus lowest) in premenopausal women; BMI did not alter risk in postmenopausal women. Although not statistically significant, high fat intake consistently lowered the odds ratios below 1.0 in premenopausal women in the upper three quartiles compared to the lowest fat intake referent quartile (OR = 0.7, CI = 0.2-2.1 for highest versus lowest quartile) but was inconsistent in postmenopausal women (OR = 0.7, CI = 0.2-2.7 for highest versus lowest quartile). When fat intake was assessed by its component parts, fat from milk, cheese and yogurt reduced the odds ratios in both premenopausal (OR = 0.4, CI = 0.1-1.1 for highest versus lowest quartile) and postmenopausal women (OR = 0.2, CI = 0.0-0.8). In postmenopausal women, high fiber intake produced elevated odds ratios in all three upper quartiles (OR = 6.6, CI = 1.5-29.6 for highest versus lowest quartile), while fiber from grains resulted in a decreased risk in both premenopausal (OR = 0.2, 95% CI = 0.2-0.7 for highest versus lowest quartile) and postmenopausal women (OR = 0.7, 95% CI = 0.3-2.0). The possibility of biased estimates from low response rates (cases = 60%, controls = 61%), potential recall bias, and some lack of precision in the dietary instrument should be considered. It appears from these analyses that the relation of breast cancer to dietary intake, especially during adolescent years, is not clear, and that risk associated with fat or fiber intake may be affected by the nutrient source.     

Obesity,Diet and Physical Inactivity and Risk of Breast Cancer in Thai Women

To evaluate the relationship between obesity, diet, physical activity and breast cancer in Thai women, weconducted a case control study with 1,130 cases and 1,142 controls. Informed consent was obtained from allparticipants and a structured questionnaire was performed by trained interviewers to collect information ondemographic and anthropometric data, reproductive and medical history, residential history, physical activityand occupation as well as dietary habits. A significant positive association with an increased risk of breast cancerwas observed in women body mass index (BMI) of ≥25 mg/m2 (OR=1.33, 95%CI 1.07-1.65), the risk beinghigher in postmenopausal women (OR=1.67, 95%CI 1.24-2.25). In addition, underweight BMI at ages 10 and 20years showed an inverse association in all women (OR=0.70, 95%CI 0.56-0.88 and OR=0.74, 95%CI 0.59-0.93,respectively) and in those with a premenopausal status (OR=0.69, 95%CI 0.51-0.93 and OR=0.76, 95%CI 0.56-0.99, respectively). Regular exercise was associated with a decreased risk of breast cancer (OR=0.78, 95%CI0.68-0.98). Interestingly, analysis by type of activity revealed significant protective effects for women who reportedthe highest levels of walking for shopping (OR=0.58, 95%CI 0.38-0.88). High consumption of vegetables andfruit were associated with a decreased risk of breast cancer, while high consumption of animal fat showed anincreased risk in postmenopausal women. In conclusion, our results indicate that obesity and high consumptionof animal fat are associated with breast cancer risk, particularly in postmenopausal women, while recreationalphysical activity has protective effects. It seems that primary prevention of breast cancer should be promotedin an integrated manner. Effective strategies need to be identified to engage women in healthy lifestyles.     

Association between Vegetable,Fruit and Carbohydrate Intake and Breast Cancer Risk in Relation to Physical Activity

Background: Although the nutritional may exert effect on the breast cancer risk, it is not clear whetherthe role diet is the same in sedentary and physically active women. The aim of this study was to evaluate theassociation between fruit, vegetable and carbohydrate intake and the risk of breast cancer among Polish womenconsidering their physical activity level. Materials and Methods: A case-control study was conducted that included858 women with histological confirmed breast cancer and 1,085 controls, free of any cancer diagnosis, aged28-78 years. The study was based on a self-administered questionnaire to ascertain physical activity, dietaryintake, sociodemographic characteristics, reproductive factors, family history of breast cancer, current weightand high, and other lifestyle factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimatedin unconditional logistic regression analyses including a broad range of potential confounders. Results: Withcomparison of the highest vs lowest quartile of intake, strong significant associations were observed for totalvegetables (OR=0.37, 95%CI=0.20-0.69 P for trend <0.01 and OR=0.53, 95%CI=0.29-0.96, P for trend <0.02),and total fruits (OR=0.47, 95%CI=0.25-0.87, P for trend <0.05 and OR=0.47, 95%CI=0.24-0.90, P for trend<0.02) among women characterized by the lowest and the highest quartile of physical activity. No associationswere observed for total carbohydrate intake. Additional analysis showed a positive association for sweets anddesert intake among women in the lowest quartile of physical activity (OR=3.49, 95%CI=1.67-7.30, P for trend<0.009) for extreme quartiles of intake comparing to the referent group. Conclusions: The results suggest thata higher consumption of vegetable and fruit may be associated with a decreased risk of breast cancer, especiallyamong women who were low or most physically active throughout their lifetimes. These findings do not supportan association between diet high in carbohydrate and breast cancer. However, a higher intake of sweets anddeserts may by associated with an increased risk of breast cancer among women who were less physically active.     

血清睾酮水平与乳腺癌雌、孕激素受体表达的相关性研究

目的:回顾性研究血清睾酮（testosterone,T）水平与乳腺癌雌激素受体（estrogen receptor,ER）,孕激素受体（progesterone receptor,PR）表达的相关性。方法:回顾性分析2016年1月至2018年12月在南京市妇幼保健院进行体检和治疗的63例健康女性,99例良性肿瘤,204例乳腺癌的临床病理资料,比较三组之间的血清睾酮水平的差异。将所有204例乳腺癌患者根据睾酮水平由低到高排序,按四分位数分为4组,采用Logistic回归比较不同睾酮水平下4组乳腺癌患者ER、PR、Her2表达状态的比值比（OR）。结果:乳腺癌组血清睾酮水平与乳腺良性肿瘤组、健康对照组相比差异均无统计学意义（P＞0.05）。ER+和PR+乳腺癌患者中血清睾酮水平分别高于ER-和PR-患者,而Her2+乳腺癌患者中血清睾酮水平低于Her2-患者,差异均有统计学意义（P＜0.05）。采用Logistic回归计算OR值,根据绝经与否进一步分层,其中T≥0.44 ng/mL组相对于T≤0.22 ng/mL组ER阳性表达的总体OR值为2.46（95%CI=1.04~5.86,P=0.042）,绝经前OR值为3.77（95%CI=1.11~12.80,P=0.034）,绝经后OR值为1.05（95%CI=0.28~3.92,P=0.945）;T≥0.44 ng/mL组相对于T≤0.22 ng/mL组PR阳性表达的总体OR值为3.69（95%CI=1.60~8.49,P=0.002）,绝经前OR值为4.80（95%CI=1.51~15.23,P=0.008）,绝经后OR值为1.78（95%CI=0.47~6.71,P=0.396）,结果显示绝经前乳腺癌患者中ER、PR的阳性表达与血清睾酮水平呈现出明显的正相关性;而Her2阳性表达与血清睾酮水平在总体、绝经前、绝经后乳腺癌患者中均未表现出明显的负相关性。结论:高血清睾酮水平与乳腺癌ER、PR的阳性表达呈正相关,在绝经前乳腺癌患者中表现尤为显著。血清睾酮水平可以作为预测绝经前激素受体状态的标志物之一。     

Carbohydrates and the risk of breast cancer among Mexican women.

OBJECTIVE: High carbohydrate intake has been hypothesized to be a risk factor for breast cancer, possibly mediated by elevated levels of free insulin, estrogens, and insulin-like growth factor-1. Therefore, we conducted a population-based case-control study among a Mexican population characterized by relatively low fat and high carbohydrate intakes. METHODS: Women ages 20 to 75 years, identified through six hospitals in Mexico City (n = 475), were interviewed to obtain data relating to diet (using a food frequency questionnaire) and breast cancer risk factors. Controls (n = 1,391) were selected from the Mexico City population using a national sampling frame. RESULTS: Carbohydrate intake was positively associated with breast cancer risk. Compared with women in the lowest quartile of total carbohydrate intake, the relative risk of breast cancer for women in the highest quartile was 2.22 [95% confidence interval (95% CI) 1.63-3.04], adjusting for total energy and potential confounding variables (P for trend < 0.0001). This association was present in premenopausal and postmenopausal women (for highest versus lowest quartile, odds ratio 2.31, 95% CI 1.36-3.91 in premenopausal women and odds ratio 2.22, 95% CI 1.49-3.30 in postmenopausal women). Among carbohydrate components, the strongest associations were observed for sucrose and fructose. No association was observed with total fat intake. DISCUSSION: In this population, a high percentage of calories from carbohydrate, but not from fat, was associated with increased breast cancer risk. This relation deserves to be investigated further, particularly in populations highly susceptible to insulin resistance.     

A case-control study on the dietary intake of mushrooms and breast cancer risk among Korean women

To evaluate the association between dietary mushroom intake and breast cancer risk, a total of 362 women between the ages of 30 and 65 years who were histologically confirmed to have breast cancer were matched to controls by age (+/-2 years) and menopausal status. Mushroom intake was measured via a food frequency questionnaire that was administered by well-trained interviewers. The associations between the daily intake and the average consumption frequency of mushrooms with breast cancer risk were evaluated using matched data analysis. Both the daily intake (5th vs. 1st quintile, OR = 0.48, 95% CI = 0.30-0.78, p for trend 0.030) and the average consumption frequency of mushrooms (4th vs. 1st quartile, OR = 0.54, 95% CI = 0.35-0.82, p for trend 0.008) were inversely associated with breast cancer risk after adjustment for education, family history of breast cancer, regular exercise [>or=22.5 MET (metabolic equivalent)-hr/week], BMI (body mass index, Kg/m(2)), number of children and whether they are currently smoking, drinking or using multivitamin supplements. Further adjustments were made for energy-adjusted carbohydrate, soy protein, folate and vitamin E levels, which tended to attenuate these results. After a stratification was performed according to menopausal status, a strong inverse association was found in postmenopausal women (OR = 0.16, 95% CI = 0.04-0.54, p for trend = 0.0058 for daily intake; OR = 0.17, 95% CI = 0.05-0.54, p for trend = 0.0037 for average frequency), but not in premenopausal women. In conclusion, the consumption of dietary mushrooms may decrease breast cancer risk in postmenopausal women.     

Heme iron from meat and risk of adenocarcinoma of the esophagus and stomach

Iron can cause oxidative stress and DNA damage, and heme iron can catalyze endogenous formation of N-nitroso compounds, which are potent carcinogens. Dietary iron promotes esophageal cancer incidence in animal studies and has been identified as a growth factor for Helicobacter pylori, an established risk factor for stomach cancer. We conducted a population-based case-control study of adenocarcinoma of the esophagus (n=124) and stomach (n=154) and 449 controls in Nebraska. Heme iron and total iron intake were estimated from a food frequency questionnaire and databases of heme and total iron. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for known risk factors. Esophageal cancer was positively associated with higher intakes of heme iron (ORQ4 vs. Q1=3.04, 95% CI: 1.20-7.72; P trend=0.009) and total iron from meat sources (ORQ4 vs. Q1=2.67, 95% CI: 0.99-7.16; P trend=0.050). Risk of stomach cancer was elevated among those with higher intakes of heme iron (ORQ4 vs.Q1=1.99, 95% CI: 1.00-3.95; P trend=0.17) and total iron from meat (OR=2.26, 95% CI: 1.14-4.46; P trend=0.11). Iron intake from all dietary sources was not significantly associated with risk of either cancer. Our results suggest that high intakes of heme and iron from meat may be important dietary risk factors for esophageal and stomach cancer and may partly explain associations with red meat.     

Variation in breast cancer hormone receptor and HER2 levels by etiologic factors: a population-based analysis

Evidence suggests that breast cancer hormone receptor status varies by etiologic factors, but studies have been inconsistent. In a population-based case-control study in Poland that included 2,386 cases and 2,502 controls, we assessed ER-alpha and PR status of tumors based on clinical records according to etiologic exposure data collected via interview. For 842 cancers, we evaluated ER-alpha, ER-beta, PR and HER2 levels by semiquantitative microscopic scoring of immunostained tissue microarrays and a quantitative immunofluorescence method, automated quantitative analysis (AQUAtrade mark). We related marker levels in tumors to etiologic factors, using standard regression models and novel statistical methods, permitting adjustment for both correlated tumor features and exposures. Results obtained with different assays were generally consistent. Receptor levels varied most significantly with body mass index (BMI), a factor that was inversely related to risk among premenopausal women and directly related to risk among postmenopausal women with larger tumors. After adjustment for correlated markers, exposures and pathologic characteristics, PR and HER2 AQUA levels were inversely related to BMI among premenopausal women (p-trend = 0.01, both comparisons), whereas among postmenopausal women, PR levels were associated directly with BMI (p-trend = 0.002). Among postmenopausal women, analyses demonstrated that BMI was related to an interaction of PR and HER2: odds ratio (OR) = 0.86 (95% CI = 0.69-1.07) for low PR and HER2 expression vs. OR = 1.78 (95% CI = 1.25-2.55) for high expression (p-heterogeneity = 0.001). PR and HER2 levels in breast cancer vary by BMI, suggesting a heterogeneous etiology for tumors related to these markers.     

Serum concentrations of estrogens, sex hormone-binding globulin, and androgens and risk of breast cancer in postmenopausal women

We assessed the relationship between serum concentrations of estrogens, androgens, and sex hormone-binding globulin and risk of breast cancer among postmenopausal women. Study participants provided serum prior to breast biopsy or mastectomy in 3 hospitals in Grand Rapids, Michigan between 1977 and 1987. A total of 179 subjects with localized breast cancer were compared to 152 subjects with nonproliferative breast changes that have not been associated with elevated breast cancer risk. Increasing serum concentrations of estrone and estrone sulfate were associated with increases in breast cancer risk; the odds ratios (ORs) in the fourth quartiles compared to the first were 2.3 (95% confidence interval (CI) 1.1-4.6) for both (p-trend = 0.02 and 0.03, respectively). Estradiol and bioavailable estradiol concentrations were associated with nonstatistically significant increases in risk. Androstenediol levels were associated with risk (p-trend = 0.01); the OR in the fourth compared to the first quartile was 2.2 (95% CI 1.0-4.6). Testosterone, dehydroepiandrosterone and androstenedione levels were not associated with increased risk. Sex hormone-binding globulin was associated with a nonsignificant decrease in risk. Associations with estrone and estrone sulfate persisted after adjustment for androstenediol (ORs for fourth compared to first quartiles were 2.0 (95% CI 0.9-4.5) and 2.2 (95% CI 1.0-4.6), respectively (p-trend = 0.16 for both). The association with androstenediol was attenuated after adjustment for estrone (OR for fourth compared to first quartile was 1.6 (95% CI 0.7-3.6); p-trend = 0.13). Higher serum concentrations of estrogens were associated with increased breast cancer risk in postmenopausal women. Androgen levels were not independently associated with substantially increased risk.     

Dietary carotenoids and the risk of invasive breast cancer

Certain classes of vitamins and nutrients found in fruits and vegetables have been of particular interest in relation to cancer prevention, owing to their potential anticarcinogenic properties. We examined the association between certain fruits, vegetables, carotenoids, and vitamin A and breast cancer risk in a large population‐based case‐control study of women residing in the states of Massachusetts, New Hampshire and Wisconsin. The study was comprised of 5,707 women with incident invasive breast cancer (2,363 premenopausal women and 3,516 postmenopausal women) and 6,389 population controls (2,594 premenopausal women and 3,516 postmenopausal women). In an interview, women were asked about their intake of carotenoid rich fruits and vegetables 5 years prior to a referent date. An inverse association observed among premenopausal women was for high levels of vitamin A (OR: 0.82, 95% CI: 0.68–0.98, p for trend = 0.01), β‐carotene (OR: 0.81, 95% CI 0.68–0.98, p for trend = 0.009), α‐carotene (OR: 0.82, 95% CI: 0.68–0.98, p for trend = 0.07) and lutein/zeaxanthin (OR: 0.83, 95% CI 0.68–0.99, p for trend = 0.02). An inverse association was not observed among postmenopausal women. Among premenopausal women who reported ever smoking, these results were stronger than among never smokers, although tests for interaction were not statistically significant. Results from this study are comparable to previous prospective studies, and suggest that a high consumption of carotenoids may reduce the risk of premenopausal but not postmenopausal breast cancer, particularly among smokers. © 2009 UICC     

Effect of family history,obesity and exercise on breast cancer risk among postmenopausal women

We examined effects of obesity and lifetime exercise patterns on postmenopausal breast cancer risk according to family history in a large population-based case control study conducted in Los Angeles County, California, because we hypothesized that both factors would affect risk through similar mechanistic pathways, and that their effects would be stronger among women with a family history. We studied 1883 postmenopausal breast cancer case subjects and 1628 postmenopausal control subjects ranging in age from 55-72 years. Cases were diagnosed with incident breast cancer in the late 1980s and 1990s. Controls were individually matched to case subjects on age, ethnic origin and neighborhood. In-person interviews determined known breast cancer risk factors including: height, weight, lifetime exercise, and family history of breast and other cancers. Breast cancer risk was raised among women who had at least 1 first-degree relative with breast cancer (odds ratio [OR] = 1.68; 95% confidence interval [CI] = 1.36-2.08). Risk increased with increasing levels of body-mass index (wt-kg/ht-m(2)) (p-trend = 0.005). Breast cancer risk was reduced among women who maintained, on average, 17.6 metabolic equivalent of energy expenditure (MET)-hr of activity/week from menarche onward (OR = 0.66; 95% CI = 0.48-0.90). Body-mass index, adjusted for lifetime exercise, was strongly associated with breast cancer risk among women with a positive family history of breast cancer (p-trend < 0.0001), but only weakly associated among women with no family history (p-trend = 0.08; homogeneity of trends p = 0.0005). In contrast, the risk reduction associated with exercise activity, adjusting for body-mass index, was limited to women without a family history of breast cancer (p-trend = 0.001; homogeneity of trends p = 0.005). Body-mass index and exercise activity, both modifiable risk factors for breast cancer, seem to have differential effects depending on a woman's family history of breast cancer, and may impact risk through different biological mechanisms.     

Risk Factor Analysis for Breast Cancer in Premenopausal and Postmenopausal Women of Punjab,India

Objective: Amritsar, the second largest town of agrarian state of Punjab, India reports high number of breast cancer cases every year. The present study investigated the etiology of breast cancer using various obesity indices and other epidemiological factors among breast cancer patients residing in and around Amritsar city. Methods: In this case control study, risk factors for breast cancer were analyzed in 542 female subjects: 271 females with breast cancer patients and 271 unrelated healthy females matched for age as control females. Results: Bivariate analysis for risk factors in cases and controls showed a lower risk (OR=0.65, 95% CI 0.43-0.99, p=0.04) in obese cases with BMI≥25kg/m2 as compared to subjects with normal BMI. Risk factor analysis showed that parameter which provided risk for cancer in postmenopausal women was obesity and in premenopausal women was parity. Postmenopausal women with BMI (overweight: OR=0.39, 95% CI 0.17-0.92, p=0.03; obese: OR= 0.26, 95% CI 0.13-0.52, p=0.00), WC (OR=0.17, 95% CI 0.05-0.52, p=0.00) and WHtR (p=0.02) had highr risk. Premenopausal women with 3 or less than 3 children had a higher risk (OR=5.54, 95 % CI 2.75-11.19, p=0.00) than postmenopausal women when compared to women with more than 3 children. Binary logistic regression analysis revealed that low parity (≤3) substantially increased the risk for breast cancer (OR=4.80, 95% CI 2.34-9.85, p=0.00) in premenopausal women. Conclusion: Obesity, parity associated breast cancer risk and reduced breastfeeding cumulatively predispose the premenopausal women of this region to higher risk of breast cancer.     

2q35 rs13387042和8q24 rs13281615单核苷酸多态性与中国东北汉族绝经前妇女乳腺癌风险关系

背景与目的：乳腺癌作为中国女性最常见的恶性肿瘤,每年的新发数量和死亡数量分别占全世界的12.2%和9.6%,但与中国乳腺癌患者明显相关的基因多态位点至今尚不清楚。本研究旨在探讨2q35 rs13387042和8q24 rs13281615单核苷酸多态性与中国北方汉族绝经前妇女乳腺癌风险关系,为预防和治疗乳腺癌提供循证依据。方法：采用多重单碱基延伸单核苷酸多态性分型技术(SNaPshot)分析方法,检测了280例绝经前乳腺癌患者和287例绝经前正常对照者2q35 rs13387042和8q24 rs13281615多态性位点基因型,并比较不同基因型和等位基因与乳腺癌风险的关系。结果：2q35 rs13387042多态性位点基因型频率在乳腺癌和对照样本之间差异有统计学意义(P=0.017);8q24 rs13281615多态性位点基因型频率在乳腺癌和对照样本之间差异无统计学意义(P=0.967)。Logistic回归分析结果显示,对于2q35 rs13387042位点,与GG相比,GA和GA+AA基因型携带者显著增加乳腺癌的患病风险(OR=1.793,95%CI：1.177～2.733,P=0.007;OR=1.691,95%CI：1.122～2.550,P=0.012),而AA携带者与乳腺癌的患病风险无关(OR=0.572,95%CI：0.104～3.153,P=0.521);与G等位基因相比,A等位基因显著增加乳腺癌的患病风险(OR=1.505,95%CI：1.033～2.193,P=0.033)。对于8q24rs13281615位点,与AA相比,AG、GG和AG+GG基因型携带者与乳腺癌的患病风险无关(OR=0.992,95%CI：0.660～1.490,P=0.968;OR=1.047,95%CI：0.642～1.708,P=0.853;OR=1.007,95%CI：0.682～1.487,P=0.971);与A等位基因相比,G等位基因不增加乳腺癌患病风险(OR=1.021,95%CI：0.809～1.288,P=0.863)。结论：本实验证实2q35 rs13387042多态性位点能够增加中国北方汉族绝经前妇女乳腺癌易感风险,而8q24 rs13281615多态性位点与中国北方汉族绝经前妇女乳腺癌易感性无明显相关性。     

Glycemic Index and Glycemic Load Dietary Patterns and the Associated Risk of Breast Cancer: A Case-control Study

The glycemic index (GI) and glycemic load (GL) have been considered risk factors for breast cancer, butassociation studies of breast cancer risk using simple GI and GL might be affected by confounding effects of theoverall diet. A total of 357 cases and 357 age-matched controls were enrolled, and dietary intake was assessedusing a validated food frequency questionnaire (FFQ) with 103 food items. GI and GL dietary patterns werederived by reduced rank regression (RRR) method. The GI and GL pattern scores were positively associatedwith breast cancer risk among postmenopausal women [OR (95%CI): 3.31 (1.06-10.39), p for trend=0.031; 9.24(2.93-29.14), p for trend<0.001, respectively], while the GI pattern showed no statistically significant effects onbreast cancer risk, and the GL pattern was only marginally significant, among premenopausal women (p fortrend=0.043). The GI and GL pattern scores were positively associated with the risk of breast cancer in subgroupsdefined by hormone receptor status in postmenopausal women. The GI and GL patterns based on all food itemsconsumed were positively associated with breast cancer.     

Reproductive factors and family history of breast cancer in relation to plasma prolactin levels in premenopausal and postmenopausal women

Many reproductive factors are associated with breast cancer risk, potentially through a hormonal pathway. The peptide hormone prolactin is essential in mammary development and lactation and may be a link between risk factors and breast cancer. While higher prolactin levels are associated with increased breast cancer risk, few determinants of prolactin levels are known. We conducted a cross-sectional analysis among 1,089 premenopausal and 1,311 postmenopausal women within the Nurses' Health Study (NHS) and the NHS II to examine the associations of reproductive factors, benign breast disease and family history of breast cancer with plasma prolactin levels. Parous women had significantly lower prolactin levels than nulliparous women (parous vs. nulliparous multivariate-adjusted geometric means = 14.1 ng/mL vs. 16.6 ng/mL, p<0.001 for premenopausal and 9.1 vs. 10.1, p=0.04 for postmenopausal women), although levels did not decrease with increasing number of children for either premenopausal (p-trend = 0.23) or postmenopausal (p-trend = 0.07) parous women. Age at first birth was not associated with prolactin levels. The reduction in prolactin levels among parous premenopausal women appeared to attenuate with increasing time since first birth, but the trend was not statistically significant (p-trend = 0.12). Age at menarche, duration of lactation and benign breast disease were not associated with prolactin levels. Family history of breast cancer was associated with significantly higher prolactin levels when compared with no family history among premenopausal (15.9 ng/mL vs. 14.3 ng/mL, p=0.04) but not postmenopausal (p=0.73) women. In conclusion, the associations of parity and family history with breast cancer risk may be mediated, at least in part, by prolactin levels.     

Circulating prolactin and breast cancer risk among pre- and postmenopausal women in the EPIC cohort

BackgroundExperimental and epidemiological evidence suggests that prolactin might play a role in the etiology of breast cancer. We analyzed the relationship of prediagnostic circulating prolactin levels with the risk of breast cancer by menopausal status, use of postmenopausal hormone replacement therapy (HRT) at blood donation, and by estrogen and progesterone receptor status of the breast tumors.Patients and methodsConditional logistic regression was used to analyze the data from a case–control study nested within the prospective European EPIC cohort, including 2250 invasive breast cancer and their matched control subjects.ResultsStatistically significant heterogeneity in the association of prolactin levels with breast cancer risk between women who were either pre- or postmenopausal at the time of blood donation was observed (P_het = 0.04). Higher serum levels of prolactin were associated with significant increase in the risk of breast cancer among postmenopausal women [odds ratio (OR)_Q4–Q1 = 1.29 (95% confidence interval, CI, 1.05–1.58), P_trend = 0.09]; however, this increase in risk seemed to be confined to women who used postmenopausal HRT at blood donation [OR_Q4–Q1 = 1.45 (95% CI 1.08–1.95), P_trend = 0.01], whereas no statistically significant association was found for the non-users of HRT [OR_Q4–Q1 = 1.11 (95%CI 0.83–1.49), P_trend = 0.80] (P_het = 0.08). Among premenopausal women, a statistically non-significant inverse association was observed [OR_Q4–Q1 = 0.70 (95% CI 0.48–1.03), P_trend = 0.16]. There was no heterogeneity in the prolactin–breast cancer association by hormone receptor status of the tumor.ConclusionOur study indicates that higher circulating levels of prolactin among the postmenopausal HRT users at baseline may be associated with increased breast cancer risk.     

Lifetime Occupational Physical Activity and the Risk of Breast Cancer: a Case-control Study

Objective: Epidemiological studies have shown that physical activity is a protective factor for breast cancer,although research findings are inconsistent regarding menopausal status. To determine the impact of occupationalphysical activity for breast cancer, a hospital-based case-control study was conducted in Poland in 2003-2007.Methods: In total, data on physical activity of 858 invasive breast cancer cases and 1,085 controls were analyzed.Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression .Separate calculations were performed for premenopausal and postmenopausal women. Occupational physicalactivity was measured by sitting time and job titles. The risk estimates were controlled for potential risk factorsand lifetime household and recreational activities. Results: A significantly decreased breast cancer risk wasfound among postmenopausal women declaring physically active jobs (requiring more than 80% of time spentstanding, walking) compared with those with low activity jobs (more than 80% of the working time spent in asitting position, during workhours) (OR=0.66; 95%CI 0.44-0.98, P trend=0.03). A similar inverse associationbetween occupational physical activity and breast cancer risk was also found when activity was evaluatedaccording to job titles provided by subjects. Postmenopausal women with physically demanding jobs, in particular,had a lower risk compared to those in sedentary occupations (OR=0.57; 95%CI 0.36-0.91, P trend=0.02).Conclusion: These findings support observations from previous studies that sufficiently high occupational physicalactivity may reduce breast cancer risk, particularly among postmenopausal women.     

Dietary carbohydrates and breast cancer risk: a prospective study of the roles of overall glycemic index and glycemic load

We examined breast cancer risk in association with overall glycemic index (GI), glycemic load (GL), and dietary carbohydrate and sugar intake in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. During a mean follow-up of 16.6 years, we observed 1,461 incident breast cancer cases. GI, GL, total carbohydrate and total sugar intake were not associated with breast cancer risk in the total cohort. However, there was evidence of effect modification of the association between GI and breast cancer risk by menopausal status (p = 0.01), the hazard ratio for the highest versus the lowest quintile level of GI being 0.78 (95% CI = 0.52-1.16; ptrend = 0.12) in premenopausal women and 1.87 (95% CI = 1.18-2.97; ptrend = 0.01) in postmenopausal women. The associations between GI and GL were not modified by body mass index (BMI) or by vigorous physical activity among pre- or postmenopausal women. Similarly, the associations between GI/GL and risk in postmenopausal women were not modified by BMI, vigorous physical activity, or ever use of hormone replacement therapy (HRT), although the associations were slightly stronger among those who reported no vigorous physical activity (ptrend = 0.02), among those who reported ever using HRT (ptrend = 0.02) and among normal-weight women (BMI < 25 kg/m2; ptrend = 0.03). Our data suggest that consumption of diets with high GI values may be associated with increased risk of breast cancer among postmenopausal women, possibly more so among subgroups defined by participation in vigorous physical activity, ever use of HRT and those who are not overweight.     

Soybean products and reduction of breast cancer risk: a case-control study in Japan

Components of the Japanese diet, which might contribute to the relatively low breast cancer incidence rates in Japan, have not been clarified in detail. Since soybean products are widely consumed in Japan, a case-control study taking account of the menopausal status was conducted using data from the hospital-based epidemiologic research program at Aichi Cancer Center (HERPACC). In total, 167 breast cancer cases were included and 854 women confirmed as free of cancer were recruited as the control group. Odds ratios (OR) and 95% confidence intervals (95% CI) were determined by multiple logistic regression analysis. There were reductions in risk of breast cancer associated with high intake of soybean products among premenopausal women. Compared with women in the lowest tertile, the adjusted ORs for top tertile intake of tofu (soybean curd) was 0.49 (95% CI, 0.25-0.95). A significant decrease in premenopausal breast cancer risk was also observed for increasing consumption of isoflavones (OR=0.44; 95% CI, 0.22-0.89 for highest vs lowest tertile; P for trend=0.02). The present study found a statistically inverse association between tofu or isoflavone intake and risk of breast cancer in Japanese premenopausal women, while no statistically significant association was evident with the risk among postmenopausal women.