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1.  Residential Levels of Polybrominated Diphenyl Ethers and Risk of Childhood Acute Lymphoblastic Leukemia in California 
Environmental Health Perspectives  2014;122(10):1110-1116.
Background: House dust is a major source of exposure to polybrominated diphenyl ethers (PBDEs), which are found at high levels in U.S. homes.
Methods: We studied 167 acute lymphoblastic leukemia (ALL) cases 0–7 years of age and 214 birth certificate controls matched on date of birth, sex, and race/ethnicity from the Northern California Childhood Leukemia Study. In 2001–2007, we sampled carpets in the room where the child spent the most time while awake; we used a high-volume small-surface sampler or we took dust from the home vacuum. We measured concentrations of 14 PBDE congeners including penta (28, 47, 99, 100, 153, 154), octa (183, 196, 197, 203), and decaBDEs (206–209). Odds ratios (ORs) were calculated using logistic regression, adjusting for demographics, income, year of dust collection, and sampling method.
Results: BDE-47, BDE-99, and BDE-209 were found at the highest concentrations (medians, 1,173, 1,579, and 938 ng/g, respectively). Comparing the highest to lowest quartile, we found no association with ALL for summed pentaBDEs (OR = 0.7; 95% CI: 0.4, 1.3), octaBDEs (OR = 1.3; 95% CI: 0.7, 2.3), or decaBDEs (OR = 1.0; 95% CI: 0.6, 1.8). Comparing homes in the highest concentration (nanograms per gram) tertile to those with no detections, we observed significantly increased ALL risk for BDE-196 (OR = 2.1; 95% CI: 1.1, 3.8), BDE-203 (OR = 2.0; 95% CI: 1.1, 3.6), BDE-206 (OR = 2.1; 95% CI: 1.1, 3.9), and BDE-207 (OR = 2.0; 95% CI: 1.03, 3.8).
Conclusion: We found no association with ALL for common PBDEs, but we observed positive associations for specific octa and nonaBDEs. Additional studies with repeated sampling and biological measures would be informative.
Citation: Ward MH, Colt JS, Deziel NC, Whitehead TP, Reynolds P, Gunier RB, Nishioka M, Dahl GV, Rappaport SM, Buffler PA, Metayer C. 2014. Residential levels of polybrominated diphenyl ethers and risk of childhood acute lymphoblastic leukemia in California. Environ Health Perspect 122:1110–1116; http://dx.doi.org/10.1289/ehp.1307602
doi:10.1289/ehp.1307602
PMCID: PMC4181922  PMID: 24911217
2.  Case-control study of birth characteristics and the risk of hepatoblastoma 
Cancer epidemiology  2013;37(4):390-395.
Background
Hepatoblastoma is a malignant embryonal tumor typically diagnosed in children younger than five years of age. Little is known on hepatoblastoma etiology.
Methods
We matched California Cancer Registry records of hepatoblastomas diagnosed in children younger than age 6 from 1988–2007 to birth records using a probabilistic record linkage program, yielding 261 cases. Controls (n=218,277), frequency matched by birth year to all cancer cases in California for the same time period, were randomly selected from California birth records. We examined demographic and socioeconomic information, birth characteristics, pregnancy history, complications in pregnancy, labor and delivery, and abnormal conditions and clinical procedures relating to the newborn, with study data taken from birth certificates.
Results
We observed increased risks for hepatoblastoma among children with low [1500–2499 g, Odds Ratio (OR)=2.02, 95% confidence interval (CI) 1.29–3.15] and very low birthweight (<1500 g, OR=15.4, 95% CI 10.7–22.3), preterm birth <33 weeks (OR=7.27, 95% CI 5.00, 10.6), small size for gestational age (OR=1.75, 95% CI 1.25–2.45), and with multiple birth pregnancies (OR=2.52, 95% CI 1.54–4.14). We observed a number of pregnancy and labor complications to be related to hepatoblastoma, including preeclampsia, premature labor, fetal distress, and congenital anomalies.
Conclusions
These findings confirm previously reported associations with low birthweight and preeclampsia. The relation with multiple birth pregnancies has been previously reported and may indicate a relation to infertility treatments.
doi:10.1016/j.canep.2013.03.004
PMCID: PMC3679264  PMID: 23558166
hepatoblastoma; birth weight; preterm labor; fetal distress; gestational age; pre-eclampsia; multiple birth offspring; risk factors; epidemiology; etiology
3.  Menopausal Hormone Therapy and Lung Cancer-Specific Mortality Following Diagnosis: The California Teachers Study 
PLoS ONE  2014;9(7):e103735.
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.
doi:10.1371/journal.pone.0103735
PMCID: PMC4117568  PMID: 25079077
4.  Risk of colorectal cancer associated with active smoking among female teachers 
Cancer causes & control : CCC  2013;24(7):1291-1304.
Purpose
The objective of this study was to examine the risk of colorectal cancer associated with active smoking among members of the California Teachers Study (CTS), a large cohort of female public school employees for whom highly detailed smoking information is available.
Methods
The analysis was conducted among the 122,264 CTS participants who lived in California at cohort entry in 1995/1996, had no prior history of colorectal cancer, and provided detailed smoking information. 1,205 cases of invasive colorectal cancer prospectively diagnosed in 1995–2009 were identified from the California Cancer Registry, including 650 in the proximal colon, 267 in the distal colon, and 288 in the rectum. Hazard ratios and 95 % confidence intervals were estimated using Cox proportional hazards models, stratified by age at cohort entry, and adjusted for race/ethnicity.
Results
Compared to never smokers, current smokers had an approximately 30 % increased risk of colorectal cancer. Overall, a slightly elevated risk was also noted for former smokers. Among former smokers, risks appeared to remain elevated for up to 20 years following cessation. Risks among former and current smokers increased with greater intensity and duration of smoking. Little evidence for heterogeneity in risk was noted for colon versus rectal cancer or for different subsites within the colon.
Conclusions
These results provide convincing evidence that heavy and/or long-term smoking is a risk factor for cancers of the colon and rectum. Such evidence should be considered when updating screening guidelines to include targeting people with long active smoking histories.
doi:10.1007/s10552-013-0207-z
PMCID: PMC3733091  PMID: 23572327
Smoking; Colorectal cancer; Colon cancer; Rectal cancer; Risk; Women
5.  Common non-synonymous SNPs associated with breast cancer susceptibility: findings from the Breast Cancer Association Consortium 
Milne, Roger L. | Burwinkel, Barbara | Michailidou, Kyriaki | Arias-Perez, Jose-Ignacio | Zamora, M. Pilar | Menéndez-Rodríguez, Primitiva | Hardisson, David | Mendiola, Marta | González-Neira, Anna | Pita, Guillermo | Alonso, M. Rosario | Dennis, Joe | Wang, Qin | Bolla, Manjeet K. | Swerdlow, Anthony | Ashworth, Alan | Orr, Nick | Schoemaker, Minouk | Ko, Yon-Dschun | Brauch, Hiltrud | Hamann, Ute | Andrulis, Irene L. | Knight, Julia A. | Glendon, Gord | Tchatchou, Sandrine | Matsuo, Keitaro | Ito, Hidemi | Iwata, Hiroji | Tajima, Kazuo | Li, Jingmei | Brand, Judith S. | Brenner, Hermann | Dieffenbach, Aida Karina | Arndt, Volker | Stegmaier, Christa | Lambrechts, Diether | Peuteman, Gilian | Christiaens, Marie-Rose | Smeets, Ann | Jakubowska, Anna | Lubinski, Jan | Jaworska-Bieniek, Katarzyna | Durda, Katazyna | Hartman, Mikael | Hui, Miao | Yen Lim, Wei | Wan Chan, Ching | Marme, Federick | Yang, Rongxi | Bugert, Peter | Lindblom, Annika | Margolin, Sara | García-Closas, Montserrat | Chanock, Stephen J. | Lissowska, Jolanta | Figueroa, Jonine D. | Bojesen, Stig E. | Nordestgaard, Børge G. | Flyger, Henrik | Hooning, Maartje J. | Kriege, Mieke | van den Ouweland, Ans M.W. | Koppert, Linetta B. | Fletcher, Olivia | Johnson, Nichola | dos-Santos-Silva, Isabel | Peto, Julian | Zheng, Wei | Deming-Halverson, Sandra | Shrubsole, Martha J. | Long, Jirong | Chang-Claude, Jenny | Rudolph, Anja | Seibold, Petra | Flesch-Janys, Dieter | Winqvist, Robert | Pylkäs, Katri | Jukkola-Vuorinen, Arja | Grip, Mervi | Cox, Angela | Cross, Simon S. | Reed, Malcolm W.R. | Schmidt, Marjanka K. | Broeks, Annegien | Cornelissen, Sten | Braaf, Linde | Kang, Daehee | Choi, Ji-Yeob | Park, Sue K. | Noh, Dong-Young | Simard, Jacques | Dumont, Martine | Goldberg, Mark S. | Labrèche, France | Fasching, Peter A. | Hein, Alexander | Ekici, Arif B. | Beckmann, Matthias W. | Radice, Paolo | Peterlongo, Paolo | Azzollini, Jacopo | Barile, Monica | Sawyer, Elinor | Tomlinson, Ian | Kerin, Michael | Miller, Nicola | Hopper, John L. | Schmidt, Daniel F. | Makalic, Enes | Southey, Melissa C. | Hwang Teo, Soo | Har Yip, Cheng | Sivanandan, Kavitta | Tay, Wan-Ting | Shen, Chen-Yang | Hsiung, Chia-Ni | Yu, Jyh-Cherng | Hou, Ming-Feng | Guénel, Pascal | Truong, Therese | Sanchez, Marie | Mulot, Claire | Blot, William | Cai, Qiuyin | Nevanlinna, Heli | Muranen, Taru A. | Aittomäki, Kristiina | Blomqvist, Carl | Wu, Anna H. | Tseng, Chiu-Chen | Van Den Berg, David | Stram, Daniel O. | Bogdanova, Natalia | Dörk, Thilo | Muir, Kenneth | Lophatananon, Artitaya | Stewart-Brown, Sarah | Siriwanarangsan, Pornthep | Mannermaa, Arto | Kataja, Vesa | Kosma, Veli-Matti | Hartikainen, Jaana M. | Shu, Xiao-Ou | Lu, Wei | Gao, Yu-Tang | Zhang, Ben | Couch, Fergus J. | Toland, Amanda E. | Yannoukakos, Drakoulis | Sangrajrang, Suleeporn | McKay, James | Wang, Xianshu | Olson, Janet E. | Vachon, Celine | Purrington, Kristen | Severi, Gianluca | Baglietto, Laura | Haiman, Christopher A. | Henderson, Brian E. | Schumacher, Fredrick | Le Marchand, Loic | Devilee, Peter | Tollenaar, Robert A.E.M. | Seynaeve, Caroline | Czene, Kamila | Eriksson, Mikael | Humphreys, Keith | Darabi, Hatef | Ahmed, Shahana | Shah, Mitul | Pharoah, Paul D.P. | Hall, Per | Giles, Graham G. | Benítez, Javier | Dunning, Alison M. | Chenevix-Trench, Georgia | Easton, Douglas F. | Berchuck, Andrew | Eeles, Rosalind A. | Olama, Ali Amin Al | Kote-Jarai, Zsofia | Benlloch, Sara | Antoniou, Antonis | McGuffog, Lesley | Offit, Ken | Lee, Andrew | Dicks, Ed | Luccarini, Craig | Tessier, Daniel C. | Bacot, Francois | Vincent, Daniel | LaBoissière, Sylvie | Robidoux, Frederic | Nielsen, Sune F. | Cunningham, Julie M. | Windebank, Sharon A. | Hilker, Christopher A. | Meyer, Jeffrey | Angelakos, Maggie | Maskiell, Judi | van der Schoot, Ellen | Rutgers, Emiel | Verhoef, Senno | Hogervorst, Frans | Boonyawongviroj, Prat | Siriwanarungsan, Pornthep | Schrauder, Michael | Rübner, Matthias | Oeser, Sonja | Landrith, Silke | Williams, Eileen | Ryder-Mills, Elaine | Sargus, Kara | McInerney, Niall | Colleran, Gabrielle | Rowan, Andrew | Jones, Angela | Sohn, Christof | Schneeweiß, Andeas | Bugert, Peter | Álvarez, Núria | Lacey, James | Wang, Sophia | Ma, Huiyan | Lu, Yani | Deapen, Dennis | Pinder, Rich | Lee, Eunjung | Schumacher, Fred | Horn-Ross, Pam | Reynolds, Peggy | Nelson, David | Ziegler, Hartwig | Wolf, Sonja | Hermann, Volker | Lo, Wing-Yee | Justenhoven, Christina | Baisch, Christian | Fischer, Hans-Peter | Brüning, Thomas | Pesch, Beate | Rabstein, Sylvia | Lotz, Anne | Harth, Volker | Heikkinen, Tuomas | Erkkilä, Irja | Aaltonen, Kirsimari | von Smitten, Karl | Antonenkova, Natalia | Hillemanns, Peter | Christiansen, Hans | Myöhänen, Eija | Kemiläinen, Helena | Thorne, Heather | Niedermayr, Eveline | Bowtell, D | Chenevix-Trench, G | deFazio, A | Gertig, D | Green, A | Webb, P | Green, A. | Parsons, P. | Hayward, N. | Webb, P. | Whiteman, D. | Fung, Annie | Yashiki, June | Peuteman, Gilian | Smeets, Dominiek | Brussel, Thomas Van | Corthouts, Kathleen | Obi, Nadia | Heinz, Judith | Behrens, Sabine | Eilber, Ursula | Celik, Muhabbet | Olchers, Til | Manoukian, Siranoush | Peissel, Bernard | Scuvera, Giulietta | Zaffaroni, Daniela | Bonanni, Bernardo | Feroce, Irene | Maniscalco, Angela | Rossi, Alessandra | Bernard, Loris | Tranchant, Martine | Valois, Marie-France | Turgeon, Annie | Heguy, Lea | Sze Yee, Phuah | Kang, Peter | Nee, Kang In | Mariapun, Shivaani | Sook-Yee, Yoon | Lee, Daphne | Ching, Teh Yew | Taib, Nur Aishah Mohd | Otsukka, Meeri | Mononen, Kari | Selander, Teresa | Weerasooriya, Nayana | staff, OFBCR | Krol-Warmerdam, E. | Molenaar, J. | Blom, J. | Brinton, Louise | Szeszenia-Dabrowska, Neonila | Peplonska, Beata | Zatonski, Witold | Chao, Pei | Stagner, Michael | Bos, Petra | Blom, Jannet | Crepin, Ellen | Nieuwlaat, Anja | Heemskerk, Annette | Higham, Sue | Cross, Simon | Cramp, Helen | Connley, Dan | Balasubramanian, Sabapathy | Brock, Ian | Luccarini, Craig | Conroy, Don | Baynes, Caroline | Chua, Kimberley
Human Molecular Genetics  2014;23(22):6096-6111.
Candidate variant association studies have been largely unsuccessful in identifying common breast cancer susceptibility variants, although most studies have been underpowered to detect associations of a realistic magnitude. We assessed 41 common non-synonymous single-nucleotide polymorphisms (nsSNPs) for which evidence of association with breast cancer risk had been previously reported. Case-control data were combined from 38 studies of white European women (46 450 cases and 42 600 controls) and analyzed using unconditional logistic regression. Strong evidence of association was observed for three nsSNPs: ATXN7-K264R at 3p21 [rs1053338, per allele OR = 1.07, 95% confidence interval (CI) = 1.04–1.10, P = 2.9 × 10−6], AKAP9-M463I at 7q21 (rs6964587, OR = 1.05, 95% CI = 1.03–1.07, P = 1.7 × 10−6) and NEK10-L513S at 3p24 (rs10510592, OR = 1.10, 95% CI = 1.07–1.12, P = 5.1 × 10−17). The first two associations reached genome-wide statistical significance in a combined analysis of available data, including independent data from nine genome-wide association studies (GWASs): for ATXN7-K264R, OR = 1.07 (95% CI = 1.05–1.10, P = 1.0 × 10−8); for AKAP9-M463I, OR = 1.05 (95% CI = 1.04–1.07, P = 2.0 × 10−10). Further analysis of other common variants in these two regions suggested that intronic SNPs nearby are more strongly associated with disease risk. We have thus identified a novel susceptibility locus at 3p21, and confirmed previous suggestive evidence that rs6964587 at 7q21 is associated with risk. The third locus, rs10510592, is located in an established breast cancer susceptibility region; the association was substantially attenuated after adjustment for the known GWAS hit. Thus, each of the associated nsSNPs is likely to be a marker for another, non-coding, variant causally related to breast cancer risk. Further fine-mapping and functional studies are required to identify the underlying risk-modifying variants and the genes through which they act.
doi:10.1093/hmg/ddu311
PMCID: PMC4204770  PMID: 24943594
6.  Increased long-term recreational physical activity is associated with older age at natural menopause among heavy smokers: the California Teachers Study 
Menopause (New York, N.Y.)  2013;20(3):282-290.
Objective
Although physical activity modulates the hypothalamic-ovarian-pituitary axis, the few studies investigating whether physical activity is associated with age at natural menopause have had mixed results. We set out to determine whether physical activity is associated with the timing of natural menopause in a large cohort of California women, overall, and by smoking history.
Methods
We investigated the association between long-term physical activity (hours/week/year) and age at natural menopause among 97,945 women in the California Teachers Study. Multivariable Cox proportional hazards regression methods were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). The impact of cigarette smoking (never smoker, former-light smoker, former-heavy smoker, current-light smoker, current-heavy smoker) as an effect modifier was evaluated.
Results
In a multivariable model adjusting for body mass index at age 18, age at menarche, race/ethnicity, and age at first full-term pregnancy, increased physical activity was statistically significantly associated with older age at natural menopause (ptrend=0.005). Higher body mass index at age 18 (ptrend=0.0003) and older age at menarche (ptrend=0.0003) were also associated with older age at natural menopause. Hispanic ethnicity (vs. non-Hispanic whites, HR 1.17, 95% CI 1.09–1.26), current smokers (vs. never smokers, HR 1.68, 95% CI 1.60–1.75 for current-light smokers; HR 1.38, 95% CI 1.33–1.44 for current-heavy smokers) and older age at first full-term pregnancy (HR≥29, 2+ full-term pregnancies vs. <29, 2+ full-term pregnancies 1.10, 95% CI 1.06–1.14) were associated with earlier age at natural menopause. Upon stratification by smoking history, increased physical activity was statistically significantly associated with older natural menopause among heavy smokers only (HRHighest vs. Lowest quartile 0.88, 95% CI 0.81–0.97, ptrend=0.02 for former-heavy smokers; HRHighest vs. Lowest quartile 0.89, 95% CI 0.80–0.99, ptrend=0.04 for current-heavy smokers).
Conclusion
Age at natural menopause is a complex trait; the determinants of age at natural menopause, including physical activity, may differ by smoking status.
doi:10.1097/GME.0b013e31826ce3d4
PMCID: PMC3580010  PMID: 23435025
Physical activity; smoking status; age at natural menopause; reproductive factors; cohort studies
7.  Recreational physical activity and risk of papillary thyroid cancer among women in the California Teachers Study 
Cancer epidemiology  2012;37(1):46-53.
Purpose
Little is known about the relationship between physical activity and thyroid cancer risk, and few cohort data on this association exist. Thus, the present study aimed to prospectively examine long-term activity and risk of papillary thyroid cancer among women.
Methods
116,939 women in the California Teachers Study, aged 22 to 79 years with no history of thyroid cancer at cohort entry, were followed from 1995-1996 through 2009; 275 were diagnosed with invasive papillary thyroid cancer. Cox proportional-hazards regression provided relative risk (RR) estimates and 95% confidence intervals (CI) for associations between thyroid cancer and combined strenuous and moderate recreational physical activity both in the long-term (high school through age 54 years or current age if younger than 54 years) and recently (during the three years prior to joining the cohort).
Results
Overall, women whose long-term recreational physical activity averaged at least 5.5 MET-hours/week (i.e. were active) had a non-significant 23% lower risk of papillary thyroid cancer than inactive women (RR=0.77, 95% CI: 0.57, 1.04). RR estimates were stronger among normal weight or underweight women (body mass index, BMI<25.0 kg/m2, trend p=0.03) than among overweight or obese women (trend p=0.35; homogeneity-of-trends p=0.03). A similar pattern of risk was observed for recent activity (BMI<25 kg/m2, trend p=0.11; BMI≥25 kg/m2, trend p=0.16; homogeneity-of-trends p=0.04). Associations for long-term activity did not appear to be driven by activity in any particular life period (e.g. youth, adulthood).
Conclusions
Long-term physical activity may reduce papillary thyroid cancer risk among normal weight and underweight women.
doi:10.1016/j.canep.2012.09.003
PMCID: PMC3543486  PMID: 23116823
Physical activity; thyroid cancer; cancer prevention; women; overweight/obesity; Body Mass Index
8.  Alcohol consumption and breast cancer risk among postmenopausal women following the cessation of hormone therapy use: the California Teachers Study 
Background
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.
Methods
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).
Results
Increased breast cancer risk associated with alcohol consumption was observed among postmenopausal women who were current HT users (RR=1.60, 95% 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 3–4 years before completing the follow-up questionnaire or in the more distant past. Results were similar for ER+ and ER+PR+ tumors; while power was limited, no increase in risk was observed for ER- tumors.
Conclusions
Following the cessation of HT use, alcohol consumption is not significantly associated with breast cancer risk, although a non-significant increased risk was observed among women who never used HT.
Impact
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.
doi:10.1158/1055-9965.EPI-12-0418
PMCID: PMC3721729  PMID: 22832206
breast cancer; alcohol; hormone therapy; cessation; epidemiology
10.  A cross-sectional analysis of light at night, neighborhood sociodemographics and urinary 6-sulfatoxymelatonin concentrations: implications for the conduct of health studies 
Background
There is accumulating evidence that circadian disruption, mediated by alterations in melatonin levels, may play an etiologic role in a wide variety of diseases. The degree to which light-at-night (LAN) and other factors can alter melatonin levels is not well-documented. Our primary objective was to evaluate the degree to which estimates of outdoor environmental LAN predict 6-sulftoxymelatonin (aMT6s), the primary urinary metabolite of melatonin. We also evaluated other potential behavioral, sociodemographic, and anthropomorphic predictors of aMT6s.
Methods
Study participants consisted of 303 members of the California Teachers Study who provided a 24-hour urine specimen and completed a self-administered questionnaire in 2000. Urinary aMT6s was measured using the Bühlmann ELISA. Outdoor LAN levels were estimated from satellite imagery data obtained from the U.S. Defense Meteorological Satellite Program’s (DMSP) Operational Linescan System and assigned to study participants’ geocoded residential address. Information on other potential predictors of aMT6s was derived from self-administered surveys. Neighborhood socioeconomic status (SES) was based on U.S. Census block group data.
Results
Lower aMT6s levels were significantly associated with older age, shorter nights, and residential locations in lower SES neighborhoods. Outdoor sources of LAN estimated using low-dynamic range DMSP data had insufficient variability across urban neighborhoods to evaluate. While high-dynamic range DMSP offered much better variability, it was not significantly associated with urinary aMT6s.
Conclusions
Future health studies should utilize the high-dynamic range DMSP data and should consider other potential sources of circadian disruption associated with living in lower SES neighborhoods.
doi:10.1186/1476-072X-12-39
PMCID: PMC3766028  PMID: 24127816
Circadian disruption; Light at night; Melatonin; aMT6s; Socioeconomic status; Women
11.  Determinants and Within-Person Variability of Urinary Cadmium Concentrations among Women in Northern California 
Environmental Health Perspectives  2013;121(6):643-649.
Background: Cadmium (Cd) is a toxic metal associated with increased morbidity and mortality. Urinary Cd (U-Cd) concentration is considered a biomarker of long-term exposure.
Objectives: Our objectives were to evaluate the within-person correlation among repeat samples and to identify predictors of U-Cd concentrations.
Methods: U-Cd concentrations (micrograms per liter) were measured in 24-hr urine samples collected from 296 women enrolled in the California Teachers Study in 2000 and a second 24-hr sample collected 3–9 months later from 141 of the participants. Lifestyle and sociodemographic characteristics were obtained via questionnaires. The Total Diet Study database was used to quantify dietary cadmium intake based on a food frequency questionnaire. We estimated environmental cadmium emissions near participants’ residences using a geographic information system.
Results: The geometric mean U-Cd concentration was 0.27 µg/L and the range was 0.1–3.6 µg/L. The intraclass correlation among repeat samples from an individual was 0.50. The use of a single 24-hr urine specimen to characterize Cd exposure in a case–control study would result in an observed odds ratio of 1.4 for a true odds ratio of 2.0. U-Cd concentration increased with creatinine, age, and lifetime pack-years of smoking among ever smokers or lifetime intensity-years of passive smoking among nonsmokers, whereas it decreased with greater alcohol consumption and number of previous pregnancies. These factors explained 42–44% of the variability in U-Cd concentrations.
Conclusion: U-Cd levels varied with several individual characteristics, and a single measurement of U-Cd in a 24-hr sample did not accurately reflect medium- to long-term body burden.
doi:10.1289/ehp.1205524
PMCID: PMC3672909  PMID: 23552363
cadmium; biomarkers; diet; exposure science; GIS
12.  The Association Between Neighborhood Characteristics and Body Size and Physical Activity in the California Teachers Study Cohort 
American journal of public health  2011;102(4):689-697.
Objectives
We considered interactions between physical activity and body mass index (BMI) and neighborhood factors.
Methods
We used recursive partitioning to identify predictors of low recreational physical activity (<2.5 hours/week) and overweight and obesity (BMI≥25.0 kg/m2) among 118 315 women in the California Teachers Study. Neighborhood characteristics were based on 2000 US Census data and Reference US business listings.
Results
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).
Conclusions
Associations between physical activity, overweight and obesity, and the built environment varied by sociodemographic characteristics in this educated population.
doi:10.2105/AJPH.2011.300150
PMCID: PMC3410673  PMID: 21852626
13.  Long-Term Exposure to Air Pollution and Cardiorespiratory Disease in the California Teachers Study Cohort 
Rationale: Several studies have linked long-term exposure to particulate air pollution with increased cardiopulmonary mortality; only two have also examined incident circulatory disease.
Objectives: 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.
Methods: 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.
Measurements and Main Results: 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.
Conclusions: 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.
doi:10.1164/rccm.201012-2082OC
PMCID: PMC3208653  PMID: 21700913
particulate matter; cardiovascular diseases; air pollutants; epidemiology
14.  Birth Anomalies and Obstetric History as Risks for Childhood Tumors of the Central Nervous System 
Pediatrics  2011;128(3):e652-e657.
OBJECTIVE:
The causes of childhood central nervous system (CNS) tumors are largely unknown. Birth characteristics have been examined as possible risk factors for childhood CNS tumors, although the studies have been underpowered and inconclusive. We hypothesized that birth anomalies and a mother's history of previous pregnancy losses, as a proxy for genetic defects, increase the risk for CNS tumors.
METHODS:
From the California Cancer Registry, we identified 3733 patients aged 0 to 14 years with CNS tumors, diagnosed from 1988 through 2006 and linked to a California birth certificate. Four controls were matched to each patient. We calculated odds ratios (ORs) for the reported presence of a birth defect and for history of pregnancy losses by using logistic regression, adjusted for race, Hispanic ethnicity, maternal age, birth weight, and birth order.
RESULTS:
Offspring from mothers who had ≥2 fetal losses after 20 weeks' gestation had a threefold risk for CNS tumors (OR: 3.13 [95% confidence interval (CI): 1.32–7.41]) and a 14-fold risk for high-grade glioma (OR: 14.28 [95% CI: 1.56–130.65]). Birth defects increased risk for the CNS cancers medulloblastoma (OR: 1.70 [95% CI: 1.12–2.57]), primitive neuroectodermal tumor (OR: 3.64 [95% CI: 1.54–8.56]), and germ cell tumors (OR: 6.40 [95% CI: 2.09–19.56]).
CONCLUSIONS:
Multiple pregnancy losses after 20 weeks' gestation and birth defects increase the risk of a childhood CNS tumor. Previous pregnancy losses and birth defects may be surrogate markers for gene defects in developmental pathways that lead to CNS tumorigenesis.
doi:10.1542/peds.2010-3637
PMCID: PMC3164097  PMID: 21824884
childhood brain tumors; congenital anomalies; birth defects; central nervous system tumors
15.  Cigarette Smoking, Passive Smoking, and Non-Hodgkin Lymphoma Risk: Evidence From the California Teachers Study 
American Journal of Epidemiology  2011;174(5):563-573.
Epidemiologic studies conducted to date have shown evidence of a causal relation between smoking and non-Hodgkin lymphoma (NHL) risk. However, previous studies did not account for passive smoking exposure in the never-smoking reference group. The California Teachers Study collected information about lifetime smoking and household passive smoking exposure in 1995 and about lifetime exposure to passive smoking in 3 settings (household, workplace, and social settings) in 1997–1998. Multivariable-adjusted relative risks and 95% confidence intervals were estimated by fitting Cox proportional hazards models with follow-up through 2007. Compared with never smokers, ever smokers had a 1.11-fold (95% confidence interval (CI): 0.94, 1.30) higher NHL risk that increased to a 1.22-fold (95% CI: 0.95, 1.57) higher risk when women with household passive smoking were excluded from the reference category. Statistically significant dose responses were observed for lifetime cumulative smoking exposure (intensity and pack-years; both P ’s for trend = 0.02) when women with household passive smoking were excluded from the reference category. Among never smokers, NHL risk increased with increasing lifetime exposure to passive smoking (relative risk = 1.51 (95% CI: 1.03, 2.22) for >40 years vs. ≤5 years of passive smoking; P for trend = 0.03), particularly for follicular lymphoma (relative risk = 2.89 (95% CI: 1.23, 6.80); P for trend = 0.01). The present study provides evidence that smoking and passive smoking may influence NHL etiology, particularly for follicular lymphoma.
doi:10.1093/aje/kwr127
PMCID: PMC3202153  PMID: 21768403
cohort studies; lymphoma, non-Hodgkin; smoking; tobacco smoke pollution
16.  Hormonal Factors and the Risk of Papillary Thyroid Cancer in the California Teachers Study Cohort 
Background
Despite the increasing incidence of thyroid cancer, there is limited information on its etiology. The strikingly higher rates in young women, compared to men, suggest that sex steroid hormones may be involved in the development of this disease.
Methods
We investigated the effects of menstrual, reproductive, and other hormonal factors on papillary thyroid cancer risk in the prospective California Teachers Study (CTS) 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% confidence intervals (CI) were estimated using Cox proportional hazards regression models.
Results
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; pinteraction 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 non-significant increase in risk (RR=1.69, 95% CI: 0.95–2.98).
Conclusions
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.
Impact
These results suggest the importance of future research into the role of progesterone and the estrogen-to-progesterone ratio.
doi:10.1158/1055-9965.EPI-11-0381
PMCID: PMC3288117  PMID: 21791618
papillary thyroid cancer; menstrual factors; reproductive factors; exogenous hormone use; epidemiology
17.  Birth order and Risk of Childhood Cancer: A Pooled Analysis from Five U.S. States 
The causes of childhood cancers are largely unknown. Birth order has been used as a proxy for prenatal and postnatal exposures, such as frequency of infections and in utero hormone exposures. We investigated the association between birth order and childhood cancers in a pooled case-control dataset. The subjects were drawn from population-based registries of cancers and births in California, Minnesota, New York, Texas, and Washington. We included 17,672 cases less than 15 years of age who were diagnosed from1980-2004 and 57,966 randomly selected controls born 1970-2004, excluding children with Down syndrome. We calculated odds ratios and 95% confidence intervals using logistic regression, adjusted for sex, birth year, maternal race, maternal age, multiple birth, gestational age, and birth weight. Overall, we found an inverse relationship between childhood cancer risk and birth order. For children in the fourth or higher birth order category compared to first-born children, the adjusted OR was 0.87 (95% CI: 0.81, 0.93) for all cancers combined. When we examined risks by cancer type, a decreasing risk with increasing birth order was seen in the central nervous system (CNS) tumors, neuroblastoma, bilateral retinoblastoma, Wilms tumor, and rhabdomyosarcoma. We observed increased risks with increasing birth order for acute myeloid leukemia but a slight decrease in risk for acute lymphoid leukemia. These risk estimates were based on a very large sample size which allowed us to examine rare cancer types with greater statistical power than in most previous studies, however the biologic mechanisms remain to be elucidated.
doi:10.1002/ijc.25593
PMCID: PMC3008504  PMID: 20715170
birth order; case-control studies; child; epidemiology; neoplasms
18.  MENOPAUSAL HORMONE THERAPY DOES NOT INFLUENCE LUNG CANCER RISK: RESULTS FROM THE CALIFORNIA TEACHERS STUDY 
Background
Results from studies examining the association between hormone therapy (HT) and lung cancer risk disagree.
Methods
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, 727 women were diagnosed with lung cancer. Multivariable Cox proportional hazards regression models were fit using age as the time metric.
Results
No measure of HT use was associated with lung cancer risk (all p-values for trend≥0.4). In addition, no variations in risk by smoking status (never, ever, former, current), type of HT (E-alone, E+P use), type of menopause, or lung cancer histology were observed.
Conclusions
Our findings do not support an association between HT and lung cancer.
Impact
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.
doi:10.1158/1055-9965.EPI-10-1182
PMCID: PMC3065239  PMID: 21266521
19.  Survival following non-small cell lung cancer among Asian/Pacific Islander, Latina, and non-Hispanic White women who have never smoked 
BACKGROUND
Lung cancer is the leading cause of cancer death among US Asian/Pacific Islander (API) and Latina women, despite low smoking prevalence. This study examined survival patterns following non-small cell lung cancer in a population-based sample of lung cancer cases from the San Francisco Bay Area Lung Cancer Study (SFBALCS).
METHODS
Women diagnosed with lung cancer from 1998–2003 and 2005–2008 and identified through the Greater Bay Area Cancer Registry were telephone-screened for eligibility for the SFBALCS. The screener data were linked to the cancer registry data to determine follow-up. This analysis included 187 non-Hispanic White, 23 US-born Latina, 32 foreign-born Latina, 30 US-born API, and 190 foreign-born API never smokers diagnosed with lung cancer and followed through 2008.
RESULTS
All-cause survival was poorer among APIs (hazard ratio (HR) and 95% confidence interval (CI) = 1.7 (1.0–2.8) among US-born APIs; 1.2 (0.9–1.5) among foreign-born APIs), and Latinas (HR (95% CI) = 2.1 (1.2–3.6) among US-born Latinas; 1.4 (0.9–2.3) among foreign-born Latinas), relative to non-Hispanic Whites. These survival differences were not explained by differences in selected sociodemographic or clinical factors.
CONCLUSIONS
Further research should focus on factors such as cultural behaviors, access to or attitudes toward health care, and genetic variations, as possible explanations for these striking racial/ethnic differences.
IMPACT
Latina and API female never smokers diagnosed with lung cancer were up to two-times more likely to die than non-Hispanic Whites, highlighting the need for additional research to identify the underlying reasons for the disparities, as well as heightened clinical awareness.
doi:10.1158/1055-9965.EPI-10-0965
PMCID: PMC3070404  PMID: 21239685
lung cancer survival; Asian; Latina; Hispanic; never smokers; nativity
20.  Age-specific effects of hormone therapy use on overall mortality and ischemic heart disease mortality among women in the California Teachers Study 
Menopause (New York, N.y.)  2011;18(3):253-261.
Objective
Although the Women’s Health Initiative trial (WHI) suggested that menopausal hormone therapy (HT) does not reduce coronary heart disease mortality overall, subsequent results have suggested that there may be a benefit in younger women. The California Teachers Cohort Study (CTS) questionnaire and mortality data was used to examine whether age modified the association between HT and the relative risk of overall mortality and ischemic heart disease (IHD) deaths.
Methods
Participants from the CTS were 71,237 postmenopausal women (mean age = 63, range 36 to 94 years) followed prospectively for mortality and other outcomes from 1995–1996 through 2004.
Results
Age at baseline was a much more important modifier of HT effects than age at start of therapy. Risks for all-cause mortality (n=8,399) were lower for younger current HT users at baseline than for never users (for women ≤60 years: HR=0.54, 95% CI=0.46–0.62). These risk reductions greatly diminished, in a roughly linear fashion, with increasing baseline age (for women 85–94 years HR=0.94, 95% CI=0.81–1.10 for all-cause mortality). Similar results were seen for IHD deaths (n=1,464). No additional significant modifying effects of age at first use, duration of use, or formulation were apparent.
Conclusions
These results provide evidence that reduced risks of mortality associated with HT use are observed among younger users but not for older postmenopausal women even those starting therapy close to their time of menopause.
doi:10.1097/gme.0b013e3181f0839a
PMCID: PMC3253313  PMID: 20881652
Overall mortality; heart disease; menopausal hormone therapy; risk; survival; age
21.  Body size and the risk of ovarian cancer by hormone therapy use in the California Teachers Study cohort 
Cancer causes & control : CCC  2010;21(12):2241-2248.
Objective
To investigate whether obesity and hormone therapy (HT) are associated with ovarian cancer risk among women in the California Teachers Study cohort.
Methods
Of 56,091 women age ≥45 years, 277 developed epithelial ovarian cancer between 1995 and 2007. Multivariate Cox regression was performed.
Results
Among women who never used HT, greater adult weight gain, waist circumference and waist-to-height ratio, but not adult BMI, increased risk of ovarian cancer. Compared to women who never used HT and had a stable adult weight, risk of ovarian cancer was increased in women who gained ≥40 lb (relative risk (RR) 1.8, 95% confidence interval (CI): 1.0–3.0) or used HT for >5 years (RR 2.3 95% CI: 1.3–4.1). Having both exposures (RR 1.9, 95% CI: 0.99–3.5), however, did not increase risk more than having either alone. Results were similar for waist circumference and weight-to-height ratio; however, differences across HT groups were not statistically significant.
Conclusions
This study suggests that abdominal adiposity and weight gain, but not overall obesity, increase ovarian cancer risk and that there may be a threshold level beyond which additional hormones, whether exogenous or endogenous, do not result in additional elevation in risk. However, large pooled analyses are needed to confirm these findings.
doi:10.1007/s10552-010-9647-x
PMCID: PMC3120052  PMID: 20924664
Ovarian cancer; Obesity; Abdominal adiposity; Hormone therapy
22.  Body size and the risk of endometrial cancer by hormone therapy use in postmenopausal women in the California Teachers Study cohort 
Cancer causes & control : CCC  2010;21(9):1407-1416.
Objective
To investigate whether hormone therapy (HT) and obesity are associated with endometrial cancer risk among postmenopausal women in the California Teachers Study cohort.
Methods
Of 28,418 postmenopausal women, 395 developed type 1 endometrial cancer between 1995 and 2006. Multivariate Cox regression was performed to estimate relative risks (RR), stratified by HT use (never used, ever estrogen-alone (ET), or exclusively estrogen-plus-progestin (EPT)).
Results
Among women who never used HT, overall and abdominal adiposity were associated with increased risk; when evaluated simultaneously, abdominal adiposity was more strongly associated (RR 2.2, 95% confidence interval (CI): 1.1–4.5 for waist ≥35 vs. <35 inches). Among women who ever used ET, risk was increased in women with BMI ≥25 kg/m2 (RR 1.6, 95% CI: 1.1–2.3 vs. <25 kg/m2). Neither overall nor abdominal obesity was associated with risk in women who exclusively used EPT (P-interaction<0.001 for BMI by HT use).
Conclusions
Among women who never used HT, risk was strongly positively related to obesity and may have been influenced more by abdominal than overall adiposity; however, due to small numbers, this latter finding requires replication. Among women who ever used ET, being overweight at baseline predicted higher risk, whereas use of EPT mitigated any effect of obesity.
doi:10.1007/s10552-010-9568-8
PMCID: PMC2925506  PMID: 20431936
endometrial cancer; obesity; abdominal adiposity; hormone therapy
23.  Determinants of Agricultural Pesticide Concentrations in Carpet Dust 
Environmental Health Perspectives  2011;119(7):970-976.
Background: Residential proximity to agricultural pesticide applications has been used as a surrogate for exposure in epidemiologic studies, although little is known about the relationship with levels of pesticides in homes.
Objective: We identified determinants of concentrations of agricultural pesticides in dust.
Methods: We collected samples of carpet dust and mapped crops within 1,250 m of 89 residences in California. We measured concentrations of seven pesticides used extensively in agriculture (carbaryl, chlorpyrifos, chlorthal-dimethyl, diazinon, iprodione, phosmet, and simazine). We estimated use of agricultural pesticides near residences from a statewide database alone and by linking the database with crop maps. We calculated the density of pesticide use within 500 and 1,250 m of residences for 180, 365, and 730 days before collection of dust and evaluated relationships between agricultural pesticide use estimates and pesticide concentrations in carpet dust.
Results: For five of the seven pesticides evaluated, residences with use of agricultural pesticides within 1,250 m during the previous 365 days had significantly higher concentrations of pesticides than did residences with no nearby use. The highest correlation with concentrations of pesticides was generally for use reported within 1,250 m of the residence and 730 days before sample collection. Regression models that also accounted for occupational and home use of pesticides explained only a modest amount of the variability in pesticide concentrations (4–28%).
Conclusions: Agricultural pesticide use near residences was a significant determinant of concentrations of pesticides in carpet dust for five of seven pesticides evaluated.
doi:10.1289/ehp.1002532
PMCID: PMC3222988  PMID: 21330232
agriculture; dust; exposure; GIS; pesticides
24.  Childhood cancer in relation to parental race and ethnicity: a five-state pooled analysis 
Cancer  2010;116(12):3045-3053.
Background
Children of different racial/ethnic backgrounds have varying risks of cancer. However, few studies have examined cancer occurrence in mixed ancestry children.
Methods
Population-based case-control study examining cancer among children age <15 years using linked cancer and birth-registry data from 5 U.S. states from 1978 to 2004. Data were available for 13,249 cancer cases and 36,996 controls selected from birth records. Parental race/ethnicity was determined from birth records. Logistic regression was used to examine the association of cancer with different racial/ethnic groups.
Results
Relative to Whites, Blacks had a 28% decreased risk of cancer (odds ratio (OR) 0.72, 95% CI 0.65–0.80), while both Asians and Hispanics had an approximate 15% decrease. Children of mixed White/Black ancestry also were at decreased risk (OR 0.71, 95% CI 0.56–0.90), but estimates for mixed White/Asian and White/Hispanic children did not differ from those of Whites. Relative to Whites: 1.) Black and mixed White/Black children had decreased ORs for acute lymphoblastic leukemia, (0.39, 95% CI 0.31–0.49) and (0.58, 95% CI 0.37–0.91), respectively; 2.) Asian and mixed White/Asian children had decreased ORs for brain tumors, (0.51, 95% CI 0.39–0.68) and (0.79, 95% CI 0.54–1.16), respectively; and 3.) Hispanic and mixed White/Hispanic children had decreased ORs for neuroblastoma (0.51, 95% CI 0.42–0.61) and (0.67, 95% CI 0.50–0.90), respectively.
Conclusion
The tendency of mixed ancestry children to have risks more similar to racial/ethnic minority children than the White majority group may help formulate etiologic studies designed to more directly study possible genetic and environmental differences.
doi:10.1002/cncr.25099
PMCID: PMC2903004  PMID: 20564410
child; ethnicity; neoplasms/epidemiology; race; risk factors

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