Obesity and survival among women with ovarian cancer: results from the Ovarian Cancer Association Consortium.

BACKGROUND: Observational studies have reported a modest association between obesity and risk of ovarian cancer; however, whether it is also associated with survival and whether this association varies for the different histologic subtypes are not clear. We undertook an international collaborative analysis to assess the association between body mass index (BMI), assessed shortly before diagnosis, progression-free survival (PFS), ovarian cancer-specific survival and overall survival (OS) among women with invasive ovarian cancer. METHODS: We used original data from 21 studies, which included 12 390 women with ovarian carcinoma. We combined study-specific adjusted hazard ratios (HRs) using random-effects models to estimate pooled HRs (pHR). We further explored associations by histologic subtype. RESULTS: Overall, 6715 (54%) deaths occurred during follow-up. A significant OS disadvantage was observed for women who were obese (BMI: 30-34.9, pHR: 1.10 (95% confidence intervals (CIs): 0.99-1.23); BMI: ⩾35, pHR: 1.12 (95% CI: 1.01-1.25)). Results were similar for PFS and ovarian cancer-specific survival. In analyses stratified by histologic subtype, associations were strongest for women with low-grade serous (pHR: 1.12 per 5 kg m(-2)) and endometrioid subtypes (pHR: 1.08 per 5 kg m(-2)), and more modest for the high-grade serous (pHR: 1.04 per 5 kg m(-2)) subtype, but only the association with high-grade serous cancers was significant. CONCLUSIONS: Higher BMI is associated with adverse survival among the majority of women with ovarian cancer.

Evidence for a time-dependent association between FOLR1 expression and survival from ovarian carcinoma: implications for clinical testing. An Ovarian Tumour Tissue Analysis consortium study.

BACKGROUND: Folate receptor 1 (FOLR1) is expressed in the majority of ovarian carcinomas (OvCa), making it an attractive target for therapy. However, clinical trials testing anti-FOLR1 therapies in OvCa show mixed results and require better understanding of the prognostic relevance of FOLR1 expression. We conducted a large study evaluating FOLR1 expression with survival in different histological types of OvCa. METHODS: Tissue microarrays composed of tumour samples from 2801 patients in the Ovarian Tumour Tissue Analysis (OTTA) consortium were assessed for FOLR1 expression by centralised immunohistochemistry. We estimated associations for overall (OS) and progression-free (PFS) survival using adjusted Cox regression models. High-grade serous ovarian carcinomas (HGSC) from The Cancer Genome Atlas (TCGA) were evaluated independently for association between FOLR1 mRNA upregulation and survival. RESULTS: FOLR1 expression ranged from 76% in HGSC to 11% in mucinous carcinomas in OTTA. For HGSC, the association between FOLR1 expression and OS changed significantly during the years following diagnosis in OTTA (Pinteraction=0.01, N=1422) and TCGA (Pinteraction=0.01, N=485). In OTTA, particularly for FIGO stage I/II tumours, patients with FOLR1-positive HGSC showed increased OS during the first 2 years only (hazard ratio=0.44, 95% confidence interval=0.20-0.96) and patients with FOLR1-positive clear cell carcinomas (CCC) showed decreased PFS independent of follow-up time (HR=1.89, 95% CI=1.10-3.25, N=259). In TCGA, FOLR1 mRNA upregulation in HGSC was also associated with increased OS during the first 2 years following diagnosis irrespective of tumour stage (HR: 0.48, 95% CI: 0.25-0.94). CONCLUSIONS: FOLR1-positive HGSC tumours were associated with an increased OS in the first 2 years following diagnosis. Patients with FOLR1-negative, poor prognosis HGSC would be unlikely to benefit from anti-FOLR1 therapies. In contrast, a decreased PFS interval was observed for FOLR1-positive CCC. The clinical efficacy of FOLR1-targeted interventions should therefore be evaluated according to histology, stage and time following diagnosis.

Intake of coffee, caffeine and other methylxanthines and risk of Type I vs Type II endometrial cancer.

BACKGROUND: Coffee and other sources of methylxanthines and risk of Type I vs Type II endometrial cancer (EC) have not been evaluated previously. METHODS: Prospective cohort of 23,356 postmenopausal women with 471 Type I and 71 Type II EC cases. RESULTS: Type I EC was statistically significantly associated with caffeinated (relative risk (RR)=0.65 for 4+ cups per day vs ≤1 cup per month: 95% confidence interval (CI): 0.47-0.89) but not decaffeinated (RR=0.76; 95% CI: 0.50-1.15) coffee intake; there were no associations with tea, cola or chocolate, or for Type II EC. The inverse association with caffeinated coffee intake was specific to women with a body mass index 30+ kg m(-2) (RR=0.56; 95% CI: 0.36-0.89). CONCLUSION: Coffee may protect against Type I EC in obese postmenopausal women.

Dietary and supplemental intake of one-carbon nutrients and the risk of type I and type II endometrial cancer: a prospective cohort study.

BACKGROUND: Type I and II endometrial cancer are biologically and clinically distinct, with type II cancers having a high frequency of p53 mutations and an association with chromosomal instability. This raises the hypothesis that one-carbon nutrients (folate, methionine, and the enzymic cofactors vitamins B2, B6, and B12), which mediate chromosomal stability and DNA methylation, may be protective for type II but not type I endometrial cancer. METHODS: Using a prospective cohort of 23 356 postmenopausal women followed 20 years, we estimated the relative risks (RRs) of type I (N = 471) and II (N = 71) endometrial cancers according to intake of one-carbon nutrients, adjusting for confounders. RESULTS: No associations were observed between dietary or supplemental intake of any one-carbon nutrient and risk of type I cancer. For type II cancer, positive associations were due to supplemental, rather than dietary, intake of these nutrients: supplemental folate (RR = 1.80 for >228.6 versus 0 µg/day; P trend = 0.027) and vitamins B2 (RR = 1.94 for >1.70 versus 0 mg/day; P trend = 0.011), B6 (RR = 2.08 for >2.00 versus 0 mg/day; P trend = 0.012), and B12 (RR = 2.10 for >3.43 versus 0 µg/day; P trend = 0.0060). CONCLUSION: Contrary to our hypothesis, use of supplements containing folate and vitamins B2, B6, and B12 was associated with an increased risk of type II endometrial cancer.

Centrosome-related genes, genetic variation, and risk of breast cancer.

Centrosome amplification has been detected in premalignant lesions and in situ tumors in the breast and in over 70% of invasive breast tumors, and has been associated with aneuploidy and tumor development. Based on these observations, the contribution of commonly inherited genetic variation in candidate genes related to centrosome structure and function to breast cancer risk was evaluated in an association study. Seven-hundred and 82 single nucleotide polymorphisms (SNPs) from 101 centrosomal genes were analyzed in 798 breast cancer cases and 843 controls from the Mayo Clinic Breast Cancer Study to assess the association between these SNPs (both individually and combined) and risk of breast cancer in this population. Eleven SNPs out of 782 from six genes displayed associations with breast cancer risk (P < 0.01). Haplotypes in five genes also displayed significant associations with risk. A two SNP combination of rs10145182 in NIN and rs2134808 in the TUBG1 locus (P-interaction = 0.00001), suggested SNPs in mediators of microtubule nucleation from the centrosome contribute to breast cancer. Evaluation of the simultaneous significance of all SNPs in the centrosome pathway suggested that the centrosome pathway is highly enriched (P = 4.76 × 10(-50)) for SNPs that are associated with breast cancer risk. Collections of weakly associated genetic variants in the centrosome pathway, rather than individual highly significantly associated SNPs, may account for a putative role for the centrosome pathway in predisposition to breast cancer.

Variation in genes required for normal mitosis and risk of breast cancer.

The down-regulation of genes involved in normal cell division can cause aberrant mitoses and increased cell death. Surviving cells exhibit aneuploidy and/or polyploidy. Since mitotic disruption has been linked with tumor development and progression, alterations in the expression or activity of these mitotic regulators may contribute to breast tumor formation. We evaluated associations between common inherited variation in these genes and breast cancer risk. Two hundred and five tagging and candidate functional single nucleotide polymorphisms in 30 genes required for normal cell division were genotyped in 798 breast cancer cases and 843 controls from the Mayo Clinic breast cancer study. Two variants in EIF3A (rs10787899 and rs3824830; P < 0.01) and four variants in SART1 (rs660118, rs679581, rs754532, and rs735942; P(trend) < or = 0.02) were significantly associated with an altered risk of breast cancer along with single variants in RRM2, PSCD3, C11orf51, CDC16, SNW1, MFAP1, and CDC2 (P < 0.05). Variation in both SART1 (P = 0.009) and EIF3A (P = 0.02) was also significant at the gene level. Analyses suggested that SART1 SNPs rs660118 and rs679581 accounted for the majority of the association of that gene with breast cancer. The observed associations between breast cancer risk and genetic variation in the SART1 and EIF3A genes that are required for maintenance of normal mitosis suggest a direct role for these genes in the development of breast cancer.

Cell cycle genes and ovarian cancer susceptibility: a tagSNP analysis.

BACKGROUND: Dysregulation of the cell cycle is a hallmark of many cancers including ovarian cancer, a leading cause of gynaecologic cancer mortality worldwide. METHODS: We examined single nucleotide polymorphisms (SNPs) (n=288) from 39 cell cycle regulation genes, including cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors, in a two-stage study. White, non-Hispanic cases (n=829) and ovarian cancer-free controls (n=941) were genotyped using an Illumina assay. RESULTS: Eleven variants in nine genes (ABL1, CCNB2, CDKN1A, CCND3, E2F2, CDK2, E2F3, CDC2, and CDK7) were associated with risk of ovarian cancer in at least one genetic model. Seven SNPs were then assessed in four additional studies with 1689 cases and 3398 controls. Association between risk of ovarian cancer and ABL1 rs2855192 found in the original population [odds ratio, OR(BB vs AA) 2.81 (1.29-6.09), P=0.01] was also observed in a replication population, and the association remained suggestive in the combined analysis [OR(BB vs AA) 1.59 (1.08-2.34), P=0.02]. No other SNP associations remained suggestive in the replication populations. CONCLUSION: ABL1 has been implicated in multiple processes including cell division, cell adhesion and cellular stress response. These results suggest that characterization of the function of genetic variation in this gene in other ovarian cancer populations is warranted.

Validating genetic risk associations for ovarian cancer through the international Ovarian Cancer Association Consortium.

The search for genetic variants associated with ovarian cancer risk has focused on pathways including sex steroid hormones, DNA repair, and cell cycle control. The Ovarian Cancer Association Consortium (OCAC) identified 10 single-nucleotide polymorphisms (SNPs) in genes in these pathways, which had been genotyped by Consortium members and a pooled analysis of these data was conducted. Three of the 10 SNPs showed evidence of an association with ovarian cancer at P< or =0.10 in a log-additive model: rs2740574 in CYP3A4 (P=0.011), rs1805386 in LIG4 (P=0.007), and rs3218536 in XRCC2 (P=0.095). Additional genotyping in other OCAC studies was undertaken and only the variant in CYP3A4, rs2740574, continued to show an association in the replication data among homozygous carriers: OR(homozygous(hom))=2.50 (95% CI 0.54-11.57, P=0.24) with 1406 cases and 2827 controls. Overall, in the combined data the odds ratio was 2.81 among carriers of two copies of the minor allele (95% CI 1.20-6.56, P=0.017, p(het) across studies=0.42) with 1969 cases and 3491 controls. There was no association among heterozygous carriers. CYP3A4 encodes a key enzyme in oestrogen metabolism and our finding between rs2740574 and risk of ovarian cancer suggests that this pathway may be involved in ovarian carcinogenesis. Additional follow-up is warranted.

Associations between cytokine/cytokine receptor single nucleotide polymorphisms and humoral immunity to measles, mumps and rubella in a Somali population.

We genotyped a Somali population (n = 85; age < or =30 years) for 617 cytokine and cytokine receptor single nucleotide polymorphisms (SNPs) using Illumina GoldenGate genotyping to determine associations with measles, mumps and rubella immunity. Overall, 61 significant associations (P < or = 0.01) were found between SNPs belonging to cytokine receptor genes regulating T helper (Th)1 (IL12RB2, IL2RA and B) and Th2 (IL4R and IL10RB) immunity, and cytokine (IL1B, TNFA, IL6 and IFNB1) and cytokine receptor (IL1RA, IFNAR2, IL18R1, TNFRSF1A and B) genes regulating innate immunity and variations in antibody levels to measles, mumps and/or rubella. SNPs within two major inflammatory cytokine genes, TNFA and interleukin (IL) 6, showed associations with measles-specific antibodies. Specifically, the minor allele variant of rs1799964 (TNFA -1211 C>T) was associated with primarily seronegative values (median enzyme immunoassay index values < or =0.87; P = 0.002; q = 0.23) in response to measles disease and/or vaccination. A heterozygous variant CT for rs2069849 (IL6 +4272C>T; Phe201Phe) was also associated with seronegative values and a lower median level of antibody response to measles disease and/or vaccination (P = 0.004; q = 0.36) or measles vaccination alone (P = 0.008). Several SNPs within the coding and regulatory regions of cytokine and cytokine receptor genes showed associations with mumps and rubella antibody levels but were less informative as strong linkage disequilibrium patterns and lower frequencies for minor alleles were observed among these SNPs. Our study identifies specific SNPs in innate immune response genes that may play a role in modulating antibody responses to measles vaccination and/or infection in Somali subjects.

Inter-operator variation in ELISPOT analysis of measles virus-specific IFN-gamma-secreting T cells.

The ELISPOT assay is a highly sensitive technique used for the detection of individual cytokine releasing cells. We have developed an IFN-gamma ELISPOT assay utilizing unfractionated frozen peripheral blood mononuclear cells (PBMC) to quantify the frequency of measles virus (MV)-specific IFN-gamma-secreting T cells in 117 healthy children who had been previously immunized with two doses of the measles-mumps-rubella vaccine. We have also estimated the variability associated with the quantification of ELISPOT plates and compared the number of MV-specific IFN-gamma-secreting T cells for each subject as determined by two different operators of an ELISPOT reader. The median frequency of MV-specific IFN-gamma-producing memory T cells detected by this assay was 0.005 % and 0.01 % as determined by an in-house and commercial operator, respectively. Although we found a significant correlation (r = 0.83, p<0.0001) between the number of spots counted by the commercial and in-house operators of an ELISPOT reader, the median number of spots counted by the commercial operator was twice the number of spots counted by an in-house operator (p<0.001). This demonstrates the importance of using a common ELISPOT reader and operator, among other parameters, to quantify the number of spots when a large volume of plates are being scanned and analyzed.

Correlations among measles virus-specific antibody, lymphoproliferation and Th1/Th2 cytokine responses following measles-mumps-rubella-II (MMR-II) vaccination.

Immunity to measles is conferred by the interplay of humoral and cellular immune responses, the latter being critical in maintaining long-term recall response. Therefore, it is important to evaluate measles-specific humoral and cellular immunity in populations several years after vaccination and understand the correlations among these measures of immunity. We examined measles-specific antibodies, lymphoproliferation and the Th1/Th2 signature cytokines, interferon (IFN)-gamma and interleukin (IL)-4, in a population-based cohort of healthy children from Olmsted County, Minnesota after two doses of measles-mumps-rubella-II (MMR-II) vaccine. We detected positive measures of measles-specific cellular and humoral immunity in the majority of our study population. However, a small proportion of subjects demonstrated an immune response skewed towards the Th2 type, characterized by the presence of either IL-4 and/or measles-specific antibodies and a lack of IFN-gamma production. Further, we observed a significant positive correlation between lymphoproliferation and secretion of IFN-gamma (r = 0.20, P = 0.0002) and IL-4 (r = 0.15, P = 0.005). Measles antibody levels were correlated with lymphoproliferation (r = 0.12, P = 0.03), but lacked correlation to either cytokine type. In conclusion, we demonstrated the presence of both long-term cellular and humoral responses after MMR-II vaccination in a significant proportion of study subjects. Further, a positive correlation between lymphoproliferation and IL-4 and IFN-gamma suggests that immunity to measles may be maintained by both Th1 and Th2 cells. We speculate that the Th2 biased response observed in a subset of our subjects may be insufficient to provide long-term immunity against measles. Further examination of the determinants of Th1 versus Th2 skewing of the immune response and long-term follow-up is needed.

Lack of association between transporter associated with antigen processing (TAP) and HLA-DM gene polymorphisms and antibody levels following measles vaccination.

The transporter associated with antigen processing (TAP) and human leukocyte antigen-DM (HLA-DM) genes are involved in the antigen-processing pathway of both HLA class I and class II-restricted antigen presentation. We hypothesized that polymorphisms within the TAP and DM genes may influence antibody levels following measles vaccination. We examined TAP and DM polymorphisms in 242 school children from Olmsted County, Minnesota, USA who received one dose of measles-mumps-rubella-II (MMR-II) vaccine at the age of 15 months. Based on the level of serum measles-specific immunoglobulin G (IgG) antibodies, subjects were classified as seronegatives (n = 72) or seropositives (n = 170). We determined TAP1 and TAP2 allele types by polymerase chain reaction (PCR) amplification of specific alleles (PASA) and determined DM allele type by PCR amplification followed by direct sequencing of the polymorphic sites. We analysed the data for any TAP or DM allelic association with antibody levels post measles vaccination using the chi-square test and univariate linear regression analysis. We found no trend in the overall distribution of TAP and DM genotype frequencies between seronegative and seropositive subjects, suggesting that TAP and DM polymorphism and antibody levels following measles vaccination are not directly associated. In addition, we did not find an association between TAP (TAP1, P = 0.71; TAP2, P = 0.87) or DM (DMA, P = 0.42; DMB, P = 0.71) homozygosity and seronegativity to measles vaccine in this study group. Our study suggests that TAP and DM gene polymorphisms do not influence antibody levels post measles vaccination.

Lung cancer risk reduction after smoking cessation: observations from a prospective cohort of women.

PURPOSE: We conducted this study because the duration of excess lung cancer risk among former smokers has been inconsistently reported, doubt has been raised regarding the population impact of smoking cessation, and differential risk reduction by histologic cell type after smoking cessation needs to be confirmed. METHODS: The Iowa Women's Health Study is a prospective cohort study of 41,836 Iowa women aged 55 to 69 years. In 1986, mailed questionnaires were used to collect detailed smoking history. Age-adjusted lung cancer incidence through 1999 was analyzed according to years of smoking abstinence. Relative risks were estimated using Cox regression analysis. RESULTS: There were 37,078 women in the analytic cohort. Compared with the never smokers, former smokers had an elevated lung cancer risk (relative risk, 6.6; 95% confidence interval, 5.0 to 8.7) up to 30 years after smoking cessation for all former smokers. However, a beneficial effect of smoking cessation was observed among recent and distant former smokers. The risk of adenocarcinoma remained elevated up to 30 years for both former heavier and former lighter smokers. CONCLUSION: The risk for lung cancer is increased for both current and former smokers compared with never smokers and declines for former smokers with increasing duration of abstinence. The decline in excess lung cancer risk among former smokers is prolonged compared with other studies, especially for adenocarcinoma and for heavy smokers, suggesting that more emphasis should be placed on smoking prevention and lung cancer chemoprevention.

Adenocarcinoma of the lung is strongly associated with cigarette smoking: further evidence from a prospective study of women.

In a prospective cohort of 41,836 Iowa women aged 55-69 years with 13 years of follow-up from 1986 through 1998, the authors examined the association between cigarette smoking history and three common histologic subtypes of lung cancer (123 small cell, 115 squamous cell, and 234 adenocarcinoma). Using Cox proportional hazards and additive Poisson regression analysis, they estimated four epidemiologic measures of effect: age-adjusted incidence rate, relative risk, excess risk (or risk difference), and population attributable risk. Of the three major lung cancer subtypes, the excess risk for heavy smokers compared with never smokers was higher for adenocarcinoma (excess risk = 206) than for squamous cell (excess risk = 122) and small cell (excess risk = 104) carcinomas. Adenocarcinoma of the lung is more strongly associated with tobacco smoke exposure than previously recognized.

Differential association of body mass index and fat distribution with three major histologic types of lung cancer: evidence from a cohort of older women.

The Iowa Women's Health Study, a prospective cohort study of 41,836 Iowa women aged 55-69 years at baseline in 1986, reported that lung cancer was inversely associated with body mass index (BMI) and waist/hip ratio. Risk by histologic subtype was not examined. Through 1998, 596 cases of lung cancer were identified. After adjustment for established risk factors, women in the upper BMI quintile were at decreased risk of all lung cancer subtypes, especially squamous cell carcinoma; the highest versus the lowest quintile of BMI was associated with a relative risk of 0.22 (p-trend = 0.005). Conversely, the highest quintile of waist circumference was positively associated with small cell and squamous cell lung cancer (relative risks = 3.31 and 3.05, respectively). No association of waist circumference with risk of adenocarcinoma of the lung was found. There were too few cases of squamous cell and small cell carcinoma in never smokers to eliminate the possibility that these results are due to the residual effects of smoking. Alternatively, these results may reflect increased activation of chemicals from cigarette smoke among women with an increased waist circumference. Results suggest that waist circumference may be differentially associated with histologic subtypes of lung cancer.

Women's Health Alliance Intervention Study: increasing community breast and cervical cancer screening.

The Women's Health Alliance Intervention Study is a quasi-experimental intervention designed to test if county-based coalitions can increase breast and cervical cancer screening compliance among women aged 40 years and older living in rural communities. A number of interventions were designed and implemented by coalitions in four counties in north-central Wisconsin during a 2-year period. Four control counties in southwestern Wisconsin were identified for comparison. Judging from the results of this study, community-based intervention efforts can increase breast and cervical cancer screening compliance significantly among women living in rural communities.

Identification of an association between HLA class II alleles and low antibody levels after measles immunization.

This is the first large cohort study to report a genetic association between humoral antibody level after measles vaccine and the HLA class II genes. The WHO goal to eradicate measles world-wide magnifies the importance of data relating to the influence of immunogenetics on measles vaccine-induced antibody responses. We present here the analysis of 242 individuals who received one dose of measles-mumps-rubella-II (MMR-II) vaccine at the age of 15 months and were genotyped for HLA class II alleles. These subjects fit into one of three categories; 72 were classified as seronegative, 93 were seropositive and 77 were serohyperpositive. HLA-DRB1*03 (odds ratio (OR), 2.22) and HLA-DPA1*0201 (OR, 1.71) were significantly associated with measles vaccine seronegativity, while additional alleles provided suggestive evidence of association with seronegativity: DQA1*0201, DQB1*0201, and DQA1*0501. The alleles DRB1*03 and DQA1*0201 remained statistically significant after accounting for the effects of other alleles. These findings are crucial in designing both measles eradication by the use of vaccine, and future vaccines to be used in genetically heterozygous populations.

Investigation of an interaction of alcohol intake and family history on breast cancer risk in the Minnesota Breast Cancer Family Study.

BACKGROUND: One explanation for the variability in results in studies of alcohol consumption and breast cancer could be the presence of effect modifiers, such as genetic susceptibility. The authors examined the interaction of alcohol and family history of breast cancer on breast cancer risk in a population-based family study of 426 multigenerational breast cancer families. The authors evaluated whether alcohol use was a stronger risk factor for breast cancer among sisters, daughters, nieces, and granddaughters of breast cancer probands than among women who married into these families. METHODS: Analyses were performed on surrogate and self-reported data combined and on self-reported data alone. To evaluate the interaction of alcohol and breast cancer risk among women with a family history of breast cancer, the authors performed analyses on all 426 families and on a subset of 132 families that had 3 or more breast and/or ovarian cancers in their family. RESULTS: A total of 9032 blood relatives and marry-ins and 558 breast cancer cases were available for analysis. In the entire 426 families, there was a suggestion of an interaction of relationship to the proband and frequency of alcohol consumption on breast cancer risk (P(interaction) = 0.14) for surrogate and self-reported information combined. Among first-degree relatives of the proband, daily drinkers had a significantly increased risk of breast cancer compared with never drinkers (RR = 2.45 [1.20, 5.02]), but this increase was less evident among second-degree relatives who reported daily alcohol intake (RR = 1.27 [0.73, 2.22]) and was not evident in marry-ins who reported daily use of alcohol (RR = 0.90 [0.42, 1.90]). The findings based on the subset of 132 high-risk families with 3 or more breast and/or ovarian cancers were similar to findings based on all 426 families (P(interaction) = 0.07). An interaction of family history with alcohol use was also suggested when the analyses were restricted to self-respondents, although the interaction test P-value was no longer of borderline significance. CONCLUSION: An increased risk of breast cancer due to an increased frequency of alcohol consumption may be limited to women with a family history of breast cancer.

Dietary folate intake, alcohol, and risk of breast cancer in a prospective study of postmenopausal women.

Low B-vitamin intake may increase risk of breast cancer through decreased DNA repair capacity. Alcohol intake increases risk for breast cancer, with evidence from prospective studies of an interaction between alcohol and folate. We explored dietary intake of folate and other B vitamins with risk of breast cancer in a cohort study of 34,387 postmenopausal women. To measure diet, we mailed a food frequency questionnaire; we estimated nutrient intakes and categorized them into four levels: <10th, 11th-30th, 31st-50th, and >50th percentiles. Through 12 years of follow-up, we identified 1,586 cases of breast cancer in the cohort at risk. We estimated relative risks (RRs) and 95% confidence intervals (CIs) through Cox regression models adjusted for age, energy, and other risk factors. Women in the lowest 10th percentile of folate intake from diet alone were at modestly increased risk of breast cancer relative to those above the 50th percentile: RR = 1.21 (95% CI = 0.91--1.61). We examined the joint association of folate intake and alcohol use on risk of breast cancer, with the reference group defined as women with high folate (>50th percentile) and no alcohol use. The RRs of breast cancer associated with low dietary folate intake were 1.08 (95% CI = 0.78--1.49) among nondrinkers, 1.33 (95% CI = 0.86--2.05) among drinkers of < or = 4 gm per day, and 1.59 (95% CI = 1.05--2.41) among drinkers of > 4 gm per day. These results suggest that the risks of postmenopausal breast cancer may be increased among women with low intakes of folate if they consume alcohol-containing beverages.

Cigarette smoking increases risk for breast cancer in high-risk breast cancer families.

Most epidemiological studies of cigarette smoking and breast cancer have failed to demonstrate a strong association. Only one study has been performed on women at high genetic risk, and smoking was reported to be a protective factor. To further explore this observation, we examined the association of cigarette smoking with the risk of breast cancer in a historical cohort study of high-risk breast cancer families. A total of 426 families ascertained through a consecutive series of breast cancer patients (probands) between 1944 and 1952 were followed through 1996. Occurrence of breast cancer and detailed smoking histories for sisters, daughters, granddaughters, nieces, and marry-ins were obtained through telephone interviews between 1991 and 1996. Cox proportional hazards regression, accounting for age, birth cohort, and other risk factors, was used to calculate relative risks and 95% confidence intervals (CIs) of breast cancer. All of the models were constructed within strata defined by relationship to the index case (proband), with nonsmokers designated as the referent group. Of the 426 families in the cohort, 132 had at least three incident breast and/or ovarian cancers in the biological relatives at the end of the follow-up period. Among sisters and daughters in these 132 high-risk families, those who ever smoked were at 2.4-fold increased risk of breast cancer (95% CI, 1.2-5.1) relative to never-smokers. No association between breast cancer and smoking was observed among nieces and granddaughters of probands or among marry-ins. When the analysis was restricted to 35 families at highest genetic risk (each containing five breast and/or ovarian cancers), smoking became an even stronger risk factor. Among sisters and daughters, ever-smokers were at 5.8-fold greater risk than nonsmokers (95% CI, 1.4-23.9). Among nieces and granddaughters, the risk of breast cancer associated with smoking was increased 60% (95% CI, 0.8-3.2). These results suggest that smoking may increase risk for breast cancer in families with multiple cases of breast or ovarian cancer, especially those with the strongest apparent familial predisposition.