California Teachers Study Cohort Research Articles

Dietary patterns and endometrial cancer risk in the California Teachers Study cohort.

Information on the role of dietary patterns and endometrial cancer risk is limited. We investigated whether dietary patterns are associated with endometrial cancer risk among women in the California Teachers Study cohort. Among 75,093 eligible women, 937 developed invasive endometrial cancer between 1995 and 2011. Multivariate Cox regression was performed to estimate relative risks (RR) and 95% confidence intervals (CI) associated with five dietary patterns identified by principal components factor analysis: "plant-based," "high protein/high fat," "high carbohydrates," "ethnic," and "salad and wine." These dietary patterns were not associated with endometrial cancer risk overall (RR = 0.91, 95% CI: 0.72, 1.15 for the highest vs. lowest quintile of the "plant-based" dietary pattern) or by menopausal status and hormone therapy use. Dietary patterns do not seem to be associated with endometrial cancer risk.

Associations of mortality with long-term exposures to fine and ultrafine particles, species and sources: results from the California Teachers Study Cohort.

BackgroundAlthough several cohort studies report associations between chronic exposure to fine particles (PM2.5) and mortality, few have studied the effects of chronic exposure to ultrafine (UF) particles. In addition, few studies have estimated the effects of the constituents of either PM2.5 or UF particles.MethodsWe used a statewide cohort of > 100,000 women from the California Teachers Study who were followed from 2001 through 2007. Exposure data at the residential level were provided by a chemical transport model that computed pollutant concentrations from > 900 sources in California. Besides particle mass, monthly concentrations of 11 species and 8 sources or primary particles were generated at 4-km grids. We used a Cox proportional hazards model to estimate the association between the pollutants and all-cause, cardiovascular, ischemic heart disease (IHD), and respiratory mortality.ResultsWe observed statistically significant (p < 0.05) associations of IHD with PM2.5 mass, nitrate, elemental carbon (EC), copper (Cu), and secondary organics and the sources gas- and diesel-fueled vehicles, meat cooking, and high-sulfur fuel combustion. The hazard ratio estimate of 1.19 (95% CI: 1.08, 1.31) for IHD in association with a 10-μg/m3 increase in PM2.5 is consistent with findings from the American Cancer Society cohort. We also observed significant positive associations between IHD and several UF components including EC, Cu, metals, and mobile sources.ConclusionsUsing an emissions-based model with a 4-km spatial scale, we observed significant positive associations between IHD mortality and both fine and ultrafine particle species and sources. Our results suggest that the exposure model effectively measured local exposures and facilitated the examination of the relative toxicity of particle species.CitationOstro B, Hu J, Goldberg D, Reynolds P, Hertz A, Bernstein L, Kleeman MJ. 2015. Associations of mortality with long-term exposures to fine and ultrafine particles, species and sources: results from the California Teachers Study cohort. Environ Health Perspect 123:549–556; http://dx.doi.org/10.1289/ehp.1408565

Abstract 2165: Parents' ages at birth and risk of hormone-related cancer among women in the California Teachers Study

Abstract Childbearing age has increased in Western countries over the last several decades. The immediate effects of advanced parental age on the health of offspring have been extensively studied. However, few studies have examined the effect of parental age at birth on the risk of adult-onset cancer. We explored the association between parental age at birth and the risk of adult-onset hormone-related cancers (i.e., breast cancer, ovarian cancer and endometrial cancer) in the prospective California Teachers Study cohort of 133,479 female teachers and administrators. Between 1995 and 2010, 5359 women were diagnosed with breast cancer, 515 women were diagnosed with ovarian cancer, and 1110 women were diagnosed with endometrial cancer. Multivariate adjusted relative risks (RR) and 95% confidence intervals (CI) were estimated by fitting Cox proportional hazards models. After mutual adjustment for paternal age/maternal age at birth, no association was observed for maternal age at birth for any of the three types of cancer. However, compared to those born to a father whose age at his daughter's birth was 25-29 years, women born to a father under age 20 years had 35% greater risk of breast cancer (RR=1.35, 95% CI=1.03-1.76) and more than 2 times greater risk of ovarian cancer (RR=2.26, 95% CI=1.14-4.50); women born to a father whose age at childbirth was 30-34 years had 25% greater risk of endometrial cancer (RR=1.25, 95% CI=1.05-1.48) than women whose father was 25-29 years. In an interaction model, relative to daughters born to a mother younger than 25 year and a father between 25-29 years, relative risk was elevated for those born to a mother younger than 25 and a father younger than 20 years (RR=1.37, 95% CI=1.07-1.76), or to a father older than 34 years old regardless of mother's age (mother &amp;lt;25 or ≥25 years old; RR=1.31 and 1.12 respectively). Lower ovarian cancer risk was observed among women born to a mother ≥25 years and a father between 25-29 years (RR=0.66, 95% CI=0.48-0.90); no association was observed for endometrial cancer. These findings indicate that parental age at birth, especially paternal age at birth, may affect the adult-onset cancer risk of daughters, especially breast cancer. Citation Format: Yani Lu, Jianning Luo, Sophia Wang, Huiyan Ma, Jane Sullivan-Halley, Peggy Reynolds, Leslie Bernstein. Parents' ages at birth and risk of hormone-related cancer among women in the California Teachers Study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2165. doi:10.1158/1538-7445.AM2014-2165

Menopausal hormone therapy and lung cancer-specific mortality following diagnosis: the California Teachers Study.

Previous results from research on menopausal hormone therapy (MHT) and lung cancer survival have been mixed and most have not studied women who used estrogen therapy (ET) exclusively. We examined the associations between MHT use reported at baseline and lung cancer-specific mortality in the prospective California Teachers Study cohort. Among 727 postmenopausal women diagnosed with lung cancer from 1995 through 2007, 441 women died before January 1, 2008. Hazard Ratios (HR) and 95% Confidence Intervals (CI) for lung-cancer-specific mortality were obtained by fitting multivariable Cox proportional hazards regression models using age in days as the timescale. Among women who used ET exclusively, decreases in lung cancer mortality were observed (HR, 0.69; 95% CI, 0.52–0.93). No association was observed for estrogen plus progestin therapy use. Among former users, shorter duration (<5 years) of exclusive ET use was associated with a decreased risk of lung cancer mortality (HR, 0.56; 95% CI, 0.35–0.89), whereas among recent users, longer duration (>15 years) was associated with a decreased risk (HR, 0.60; 95% CI, 0.38–0.95). Smoking status modified the associations with deceases in lung cancer mortality observed only among current smokers. Exclusive ET use was associated with decreased lung cancer mortality.

Abstract T MP67: Physical Activity Reduces Stroke Risk Among Women in the California Teachers Study Cohort

Background: Major modifiable stroke risk factors are well-established, yet strategies for effective prevention remain challenging. Developing stroke prevention strategies for women is critical due to: (i) the higher fatality and disability rate that women suffer compared to men, (ii) the unique risks to women such as from post-menopausal hormone therapy use, and (iiii) the aging female population. We evaluated three important modifiable stroke risk factors- obesity, hormone therapy, and physical activity, in the California Teachers Study cohort to identify potential stroke prevention strategies. Methods: The California Teachers Study comprises 133,479 women who enrolled in 1995 and have since been continuously followed. Using linked California state hospitalization data from 1996-2010, 3126 stroke events were defined as ischemic (N=2416; ICD-9 433, 434, 436) or hemorrhagic (N=710; ICD-9 430-432, excluding 432.1) and were validated by medical record review. Information about obesity, physical activity, hormone therapy, and medical history was collected at baseline and in follow-up questionnaires. Multivariable-adjusted hazards ratios and 95% confidence intervals were estimated by fitting Cox proportional hazards models with follow-up through 2010. Results: Consistent with previous reports, current post-menopausal hormone therapy use was associated with a 1.3-fold increased risk for stroke (95% CI=1.03-4.85). Moderate to strenuous physical activity in the 3 years before enrollment (but not lifetime activity) decreased stroke risk by 20% (HR=0.79, 95% CI=0.71-0.98). This decreased risk among physically active women was similar among current hormone therapy users, and appears to counteract the increased risk observed with current hormone therapy use. We found no association between obesity and stroke that was independent of diabetes. Conclusions: Recent physical activity reduces stroke risk and appears to counteract the increased risk associated with post-menopausal hormone therapy use.

Dietary patterns and breast cancer risk in the California Teachers Study cohort

Evidence that diet is associated with breast cancer risk is inconsistent. Most studies have examined risks associated with specific foods and nutrients, rather than measures of overall diet. This study aimed to evaluate dietary patterns and their relation to breast cancer risk in a large cohort of women. Data from 91,779 women in the California Teachers Study cohort were analyzed, including data from 4140 women with a diagnosis of invasive breast cancer made between 1995 and 2009. Five predominant dietary patterns were identified by using principal components factor analysis: a plant-based diet, high in fruit and vegetables; a high-protein, high-fat diet, high in meats, eggs, fried foods, and high-fat condiments; a high-carbohydrate diet, high in convenience foods, pasta, and bread products; an ethnic diet, high in legumes, soy-based foods, rice, and dark-green leafy vegetables; and a salad and wine diet, high in lettuce, fish, wine, low-fat salad dressing, and coffee and tea. The plant-based pattern was associated with a reduction in breast cancer risk (RR: 0.85; 95% CI: 0.76, 0.95 for the highest compared with the lowest consumption quintile; P-trend = 0.003); risk reduction was greater for estrogen receptor-negative progesterone receptor-negative (ER-PR-) tumors (RR: 0.66; 95% CI: 0.48, 0.91; P-trend = 0.03). The salad and wine pattern was associated with an increased risk of estrogen receptor-positive progesterone receptor-positive tumors (RR: 1.29; 95% CI: 1.12, 1.49); this effect was only slightly attenuated after adjustment for alcohol consumption. The finding that greater consumption of a plant-based dietary pattern is associated with a reduced breast cancer risk, particularly for ER-PR- tumors, offers a potential avenue for prevention.

Alzheimer's disease prevention research in the California Teachers Study cohort

Alzheimer's disease prevention research in the California Teachers Study cohort

APOE genotype and the risk of dementia in the oldest-old: The Monzino 80-plus study

Background: The risks, prevention and epidemiology of Alzheimer’s disease continue to remain uncertain despite extensive research. A few modifiable risk and preventive factors, such as low education, obesity, smoking, physical inactivity, and certain hormone therapies, have been reported from epidemiological studies. However, many studies have been limited by methodological quality and relatively small sample sizes, typically involving up to a few hundred Alzheimer’s disease cases and a few thousand participants. Studies from large-scale population-based cohorts with extensive exposure assessment and sufficiently long followup are critically needed. We describe the California Teachers Study cohort, established in 1995 primarily for breast cancer research, as a developing resource for large-scale etiologic Alzheimer’s disease research. Methods: The California Teachers Study consists of 133,479 women who have provided extensive exposure data over their life course including most putative risk factors for Alzheimer’s disease. Four waves of questionnaires have been sent since 1995. In the year 2000, we included neuropsychological test items that focused on visuospatial and language function. Results: Active and retired California public school professionals provided information on environmental and lifestyle factors that may be important for Alzheimer’s disease risk, including obesity, physical and social activity, medical history, medications, hormone use, diet, and demographic factors. In 2000-2001, w78,000 participants completeda clock drawing, cube drawing, and picture description task. Of these, w35,000 were 70 years or older in 2010. Assessment of Alzheimer’s disease in the cohort can be done by database linkage to California statewide hos pitalization data, which includes diagnoses after hospitalization, emergency department visits, and outpatient surgery. Conclusions:Large cohorts are needed in order to pursue risk and prevention research in Alzheimer’s disease, as recommended by the 2010 NIH State-ofthe-Science expert consensus conference. The California Teachers Study provides extensive high quality information on mostpotential environmental and lifestyle risk and protective factors, and represents a robust cohort for epidemiologic research, as a resource to conduct timely analyses using accrued cases, and for prospective outcomes research in Alzheimer’s disease.

Alcohol consumption and breast cancer risk among postmenopausal women following the cessation of hormone therapy use: the California Teachers Study.

Alcohol consumption increases breast cancer risk, but its effect may be modified by hormone therapy (HT) use, such that exposure to both may be synergistic. Because many women stopped taking HT after mid-2002, it is important to quantify risks associated with alcohol consumption in the context of HT cessation, as these risks may be more relevant to cancer prevention efforts today. Among 40,680 eligible postmenopausal California Teachers Study cohort participants, 660 were diagnosed with invasive breast cancer before 2010. Multivariate Cox proportional hazards regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI). Increased breast cancer risk associated with alcohol consumption was observed among postmenopausal women who were current HT users [RR, 1.60; 95% confidence interval (CI), 1.13-2.26 and RR, 2.11; 95% CI, 1.41-3.15 for <20 and ≥20 g/d of alcohol], with risks being similar by HT preparation. Alcohol did not increase risk among women who had stopped using HT within 3 years or 3 to 4 years before completing the follow-up questionnaire or in the more distant past. Results were similar for estrogen receptor positive (ER+) and ER+PR+ progesterone receptors positive (PR+) tumors; while power was limited, no increase in risk was observed for ER- tumors. Following the cessation of HT use, alcohol consumption is not significantly associated with breast cancer risk, although a nonsignificant increased risk was observed among women who never used HT. Our findings confirm that concurrent exposure to HT and alcohol has a substantial adverse impact on breast cancer risk. However, after HT cessation, this risk is reduced.

Body size and the risk of postmenopausal breast cancer subtypes in the California Teachers Study cohort.

PURPOSE: To evaluate how the association between body size and breast cancer risk varies by tumor receptor subtype, host factors, and other exposures among women in the California Teachers Study cohort. METHODS: Among 52,642 postmenopausal women, 2,321 developed invasive breast cancer with known estrogen- and progesterone-receptor status (1,652 ER+PR+, 338 ER+PR-, and 312 ER-PR-) between 1995 and 2007. In a subset of 35,529 with waist circumference data, 1,377 developed invasive breast cancer with known ERPR status (991 ER+PR+, 208 ER+PR-, 169 ER-PR-) between 1997 and 2007. Multivariate Cox regression was performed to estimate relative risks (RR) and 95% confidence intervals (CI). RESULTS: Obesity, adult weight gain of ≥40 pounds, greater abdominal adiposity, and greater height increased the risk of ER+PR+ breast cancer. The increased risk associated with postmenopausal obesity was limited to those who did not use hormone therapy (HT) at cohort entry (RR=1.37; 95% CI, 1.05-1.78 for BMI≥30 vs.<25kg/m(2); p-interaction=0.14) and those who were not overweight or obese at age 18 (p-interaction=0.06). The increased risk associated with greater abdominal adiposity was limited to those who were not also overweight or obese (p-interaction=0.01). Neither obesity, abdominal adiposity, nor height was associated with the risk of ER-PR- tumors. CONCLUSIONS: The effects of body size on postmenopausal breast cancer risk differed by hormone receptor subtype, and among women with ER+PR+ tumors, by HT use and early adult body size.

The Association Between Neighborhood Characteristics and Body Size and Physical Activity in the California Teachers Study Cohort

We considered interactions between physical activity and body mass index (BMI) and neighborhood factors. We used recursive partitioning to identify predictors of low recreational physical activity (< 2.5 hours/week) and overweight and obesity (BMI ≥ 25.0 kg/m(2)) among 118,315 women in the California Teachers Study. Neighborhood characteristics were based on 2000 US Census data and Reference US business listings. Low physical activity and being overweight or obese were associated with individual sociodemographic characteristics, including race/ethnicity and age. Among White women aged 36 to 75 years, living in neighborhoods with more household crowding was associated with a higher probability of low physical activity (54% vs 45% to 51%). In less crowded neighborhoods where more people worked outside the home, the existence of fewer neighborhood amenities was associated with a higher probability of low physical activity (51% vs 46%). Among non-African American middle-aged women, living in neighborhoods with a lower socioeconomic status was associated with a higher probability of being overweight or obese (46% to 59% vs 38% in high-socioeconomic status neighborhoods). Associations between physical activity, overweight and obesity, and the built environment varied by sociodemographic characteristics in this educated population.

Long-Term Exposure to Air Pollution and Cardiorespiratory Disease in the California Teachers Study Cohort

Several studies have linked long-term exposure to particulate air pollution with increased cardiopulmonary mortality; only two have also examined incident circulatory disease. To examine associations of individualized long-term exposures to particulate and gaseous air pollution with incident myocardial infarction and stroke, as well as all-cause and cause specific mortality. We estimated long-term residential air pollution exposure for more than 100,000 participants in the California Teachers Study, a prospective cohort of female public school professionals.We linked geocoded residential addresses with inverse distance-weighted monthly pollutant surfaces for two measures of particulate matter and for several gaseous pollutants. We examined associations between exposure to these pollutants and risks of incident myocardial infarction and stroke, and of all-cause and cause-specific mortality, using Cox proportional hazards models. We found elevated hazard ratios linking long-term exposure to particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5), scaled to an increment of 10 μg/m3 with mortality from ischemic heart disease (IHD) (1.20; 95% confidence interval [CI], 1.02-1.41) and, particularly among postmenopausal women, incident stroke (1.19; 95% CI, 1.02-1.38). Long-term exposure to particulate matter less than 10 μm in aerodynamic diameter (PM10) was associated with elevated risks for IHD mortality (1.06; 95% CI, 0.99-1.14) and incident stroke (1.06; 95% CI, 1.00-1.13), while exposure to nitrogen oxides was associated with elevated risks for IHD and all cardiovascular mortality. This study provides evidence linking long-term exposure to PM2.5 and PM10 with increased risks of incident stroke as well as IHD mortality; exposure to nitrogen oxides was also related to death from cardiovascular diseases.

Adulthood residential ultraviolet radiation, sun sensitivity, dietary vitamin D, and risk of lymphoid malignancies in the California Teachers Study

AbstractTo lend clarity to inconsistent prior findings of an inverse association between ultraviolet radiation (UVR) exposure and risk of lymphoid malignancies, we examined the association of prospectively ascertained residential ambient UVR exposure with risk of non-Hodgkin lymphomas (NHLs), multiple myeloma (MM), and classical Hodgkin lymphoma in the California Teachers Study cohort. Among 121 216 eligible women, 629 were diagnosed with NHL, 119 with MM, and 38 with Hodgkin lymphoma between 1995-1996 and 2007. Cox proportional hazards regression was used to estimate incidence rate ratios (RRs) with 95% confidence intervals (CIs). Residential UVR levels within a 20-km radius were associated with reduced risk of overall NHL (RR for highest vs lowest statewide quartile of minimum UVR [≥ 5100 vs < 4915 W-h/m2], 0.58; 95% CI, 0.42-0.80), especially diffuse large B-cell lymphoma (RR, 0.36; 95% CI, 0.17-0.78) and chronic lymphocytic leukemia/small lymphocytic lymphoma (RR, 0.46; 95% CI, 0.21-1.01), and MM (RR for maximum UVR, 0.57; 95% CI, 0.36-0.90). These associations were not modified by skin sensitivity to sunlight, race/ethnicity, body mass index, or neighborhood socioeconomic status. Dietary vitamin D also was not associated with risk of lymphoid malignancies. These results support a protective effect of routine residential UVR exposure against lymphomagenesis through mechanisms possibly independent of vitamin D.

Hormonal factors and the risk of papillary thyroid cancer in the California Teachers Study cohort.

Despite the increasing incidence of thyroid cancer, there is limited information on its etiology. The strikingly higher rates in young women, compared with men, suggest that sex steroid hormones may be involved in the development of this disease. We investigated the effects of menstrual, reproductive, and other hormonal factors on papillary thyroid cancer risk in the prospective California Teachers Study cohort. Among 117,646 women, 233 were diagnosed with invasive histologically confirmed papillary thyroid cancer after cohort enrollment and before January 1, 2008. Relative risks (RR) and 95% CIs were estimated by using Cox proportional hazards regression models. Among younger women (age <45 years at baseline; approximately one-third of the cohort), but not older women, later age at menarche (age ≥14 years) was associated with increased risk (RR = 1.88, 95% CI: 1.13-3.13; p(interaction) by age = 0.06). Risk was also increased among young women who had longer (>30 days) adolescent menstrual cycles (RR = 1.78, 95% CI: 1.01-3.14) and whose last pregnancy had ended within five years of cohort enrollment (RR = 2.21, 95% CI: 1.13-4.34). Among older women (age ≥45 years at baseline), ever use of estrogen-only therapy was associated with a statistically nonsignificant increase in risk (RR = 1.69, 95% CI: 0.95-2.98). The findings from this prospective analysis suggest that several factors related to delayed pubertal development and the transient effects of pregnancy may be particularly important in influencing risk in young women. These results suggest the importance of future research into the role of progesterone and the estrogen-to-progesterone ratio.

Oral contraceptive use and survival in women with invasive breast cancer.

Oral contraceptives (OC) are widely used in the United States. Although the relation between OC use and breast cancer incidence has been widely studied, the few studies examining associations between OC use prior to breast cancer diagnosis and survival are inconsistent. Women with invasive breast cancer participating in the Women's Contraceptive and Reproductive Experiences (CARE) Study, a population-based case-control study (4565 women ages 35-64 years), and the California Teachers Study (CTS) cohort (3929 women ages 28-91 years) were followed for vital status. A total of 1,064 women died in the CARE Study (median follow-up, 8.6 years) and 523 died in the CTS (median follow-up, 6.1 years). Cox proportional hazards regression provided hazard rate ratio estimates [(relative risk, RR)] with 95% confidence intervals (CIs) for risk of death from any cause and from breast cancer. No association was observed for any OC use prior to diagnosis and all-cause mortality [CARE Study: RR = 1.01 (95% CI = 0.86-1.19); CTS: RR = 0.84 (95% CI = 0.67-1.05)]. A decreased risk of all-cause mortality was observed in the CTS among women with more than 10 years of OC use (RR = 0.67, 95% CI = 0.47-0.96); however, no trend of decreasing risk with increasing OC duration was observed (P(trend) = 0.22), and no association was observed in the CARE study. No associations were observed for breast cancer-specific mortality. OC use is not associated with all-cause or breast cancer-specific mortality among women with invasive breast cancer. These 2 independent studies demonstrated no overall association between OC use and survival among women with breast cancer.

Assessing Long-Term Exposure in the California Teachers Study

Assessing Long-Term Exposure in the California Teachers Study

The association of polymorphisms in hormone metabolism pathway genes, menopausal hormone therapy, and breast cancer risk: a nested case-control study in the California Teachers Study cohort

IntroductionThe female sex steroids estrogen and progesterone are important in breast cancer etiology. It therefore seems plausible that variation in genes involved in metabolism of these hormones may affect breast cancer risk, and that these associations may vary depending on menopausal status and use of hormone therapy.MethodsWe conducted a nested case-control study of breast cancer in the California Teachers Study cohort. We analyzed 317 tagging single nucleotide polymorphisms (SNPs) in 24 hormone pathway genes in 2746 non-Hispanic white women: 1351 cases and 1395 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by fitting conditional logistic regression models using all women or subgroups of women defined by menopausal status and hormone therapy use. P values were adjusted for multiple correlated tests (PACT).ResultsThe strongest associations were observed for SNPs in SLCO1B1, a solute carrier organic anion transporter gene, which transports estradiol-17β-glucuronide and estrone-3-sulfate from the blood into hepatocytes. Ten of 38 tagging SNPs of SLCO1B1 showed significant associations with postmenopausal breast cancer risk; 5 SNPs (rs11045777, rs11045773, rs16923519, rs4149057, rs11045884) remained statistically significant after adjusting for multiple testing within this gene (PACT = 0.019-0.046). In postmenopausal women who were using combined estrogen-progestin therapy (EPT) at cohort enrollment, the OR of breast cancer was 2.31 (95% CI = 1.47-3.62) per minor allele of rs4149013 in SLCO1B1 (P = 0.0003; within-gene PACT = 0.002; overall PACT = 0.023). SNPs in other hormone pathway genes evaluated in this study were not associated with breast cancer risk in premenopausal or postmenopausal women.ConclusionsWe found evidence that genetic variation in SLCO1B1 is associated with breast cancer risk in postmenopausal women, particularly among those using EPT.

Menopausal Hormone Therapy Does Not Influence Lung Cancer Risk: Results from the California Teachers Study

Results from studies examining the association between hormone therapy (HT) and lung cancer risk disagree. We examined the associations between HT use and lung cancer risk among 60,592 postmenopausal women enrolled in the prospective California Teachers Study cohort. Between 1995 and 2007, a total of 727 women had a diagnosis of lung cancer. Multivariable Cox proportional hazards regression models were fit using age as the time metric. No measure of HT use was associated with lung cancer risk (all P(trend) values ≥0.4). In addition, no variations in risk by smoking status (never, ever, former, current), type of HT [estrogen (E)-alone, E + progestin (P) use], type of menopause, or lung cancer histology were observed. Our findings do not support an association between HT and lung cancer. This large-scale, prospective study, which capitalizes on the detailed hormone use, smoking history, and type of menopause information available within this unique cohort, was unable to find any association between intake of HT and lung cancer risk.

Abstract B87: Cigarette smoking, lifetime exposure to passive smoking, and the risk of non-Hodgkin lymphoma in the California Teachers Study

Abstract Background: Overall, epidemiological studies conducted to date do not support a causal relationship between smoking and non-Hodgkin lymphoma (NHL) risk. However, previous studies did not account for passive smoking in the referent group of never smokers, which may have masked subtle effects. We therefore examined the effects of cigarette smoking and passive smoking on NHL risk in the prospective California Teachers Study (CTS) cohort. Methods: The CTS collected lifetime smoking and household passive smoking exposures in 1995 and lifetime passive smoking exposures in three settings (household, workplace, and social) in 1997-1998. Multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CI) were estimated by fitting Cox proportional hazards models for NHL risk with follow-up through 2007. Results: Compared to never smokers, ever smokers had a 1.11-fold elevated NHL risk (95% CI=0.94-1.30) which increased to 1.22 (95% CI=0.95-1.57) when women with household passive smoking were excluded from the reference category. Statistically significant dose-response trends were observed for lifetime cumulative smoking exposures (intensity and pack-years) when women with household passive smoking were excluded from the reference category (both p-trend=0.02). Among never smokers, NHL risk increased with increasing lifetime passive smoking exposure [RR=1.51 (95% CI=1.03-2.22) for more than 40 vs. less than or equal to 5 years, p-trend=0.03]. Both smoking and passive smoking were associated with increased risk of follicular lymphoma, but not other NHL subtypes. Conclusion: Our study provides evidence that smoking and passive smoking may play a role in NHL etiology, particularly for follicular lymphoma. Studies evaluating the effect of smoking should consider the effects of passive smoking. Citation Information: Cancer Prev Res 2010;3(12 Suppl):B87.

Dietary phytocompounds and risk of lymphoid malignancies in the California Teachers Study cohort.

We examined whether dietary intake of isoflavones, lignans, isothiocyanates, antioxidants, or specific foods rich in these compounds is associated with reduced risk of B-cell non-Hodgkin lymphoma (NHL), multiple myeloma (MM), or Hodgkin lymphoma (HL) in a large, prospective cohort of women. Between 1995-1996 and 31 December 2007, among 110,215 eligible members of the California Teachers Study cohort, 536 women developed incident B-cell NHL, 104 developed MM, and 34 developed HL. Cox proportional hazards regression, with age as the time scale, was used to estimate adjusted rate ratios (RRs) with 95% confidence intervals (CIs) for risk of lymphoid malignancies. Weak inverse associations with risk of diffuse large B-cell lymphoma were observed for isothiocyanates (RR for ≥12.1 vs. <2.7 mcM/day = 0.67, 95% CI: 0.43-1.05) and an antioxidant index measuring hydroxyl radical absorbance capacity (RR for ≥2.2 vs. <0.9 μM Trolox equiv/g/day = 0.68, 95% CI: 0.42-1.10; p (trend) = 0.08). Risk of other NHL subtypes, overall B-cell NHL, MM, or HL was not generally associated with dietary intake of isoflavones, lignans, isothiocyanates, antioxidants, or major food sources of these compounds. Isoflavones, lignans, isothiocyanates, and antioxidant compounds are not associated with risk of most B-cell malignancies, but some phytocompounds may decrease the risk of selected subtypes.