Self-Reported Disability Type and Risk of Alcohol-Induced Death - A Longitudinal Study Using Nationally Representative Data

BACKGROUND

Disability is associated with alcohol misuse and drug overdose death, however, its association with alcohol-induced death remains understudied.

OBJECTIVE

To quantify the risk of alcohol-induced death among adults with different types of disabilities in a nationally representative longitudinal sample of US adults.

METHODS

Persons with disabilities were identified among participants ages 18 or older in the Mortality Disparities in American Communities (MDAC) study (n = 3,324,000). Baseline data were collected in 2008 and mortality outcomes were ascertained through 2019 using the National Death Index. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were estimated for the association between disability type and alcohol-induced death, controlling for demographic and socioeconomic covariates.

RESULTS

During a maximum of 12 years of follow-up, 4000 alcohol-induced deaths occurred in the study population. In descending order, the following disability types displayed the greatest risk of alcohol-induced death (compared to adults without disability): complex activity limitation (aHR = 1.7; 95% CI = 1.3-2.3), vision limitation (aHR = 1.6; 95% CI = 1.2-2.0), mobility limitation (aHR = 1.4; 95% CI = 1.3-1.7), ≥2 limitations (aHR = 1.4; 95% CI = 1.3-1.6), cognitive limitation (aHR = 1.2; 95% CI = 1.0-1.4), and hearing limitation (aHR = 1.0; 95% CI = 0.9-1.3).

CONCLUSIONS

The risk of alcohol-induced death varies considerably by disability type. Efforts to prevent alcohol-induced deaths should be tailored to meet the needs of the highest-risk groups, including adults with complex activity (i.e., activities of daily living - "ALDs"), vision, mobility, and ≥2 limitations. Early diagnosis and treatment of alcohol use disorder within these populations, and improved access to educational and occupational opportunities, should be considered as prevention strategies for alcohol-induced deaths.

Untargeted serum metabolomic profiles and breast density in young women

PURPOSE OF THE STUDY

Breast density is an established risk factor for breast cancer. However, little is known about metabolic influences on breast density phenotypes. We conducted untargeted serum metabolomics analyses to identify metabolic signatures associated with breast density phenotypes among young women.

METHODS

In a cross-sectional study of 173 young women aged 25-29 who participated in the Dietary Intervention Study in Children 2006 Follow-up Study, 449 metabolites were measured in fasting serum samples using ultra-high-performance liquid chromatography-tandem mass spectrometry. Multivariable-adjusted mixed-effects linear regression identified metabolites associated with magnetic resonance imaging measured breast density phenotypes: percent dense breast volume (%DBV), absolute dense breast volume (ADBV), and absolute non-dense breast volume (ANDBV). Metabolite results were corrected for multiple comparisons using a false discovery rate adjusted p-value (q).

RESULTS

The amino acids valine and leucine were significantly inversely associated with %DBV. For each 1 SD increase in valine and leucine, %DBV decreased by 20.9% (q = 0.02) and 18.4% (q = 0.04), respectively. ANDBV was significantly positively associated with 16 lipid and one amino acid metabolites, whereas no metabolites were associated with ADBV. Metabolite set enrichment analysis also revealed associations of distinct metabolic signatures with %DBV, ADBV, and ANDBV; branched chain amino acids had the strongest inverse association with %DBV (p = 0.002); whereas, diacylglycerols and phospholipids were positively associated with ANDBV (p ≤ 0.002), no significant associations were observed for ADBV.

CONCLUSION

Our results suggest an inverse association of branched chain amino acids with %DBV. Larger studies in diverse populations are needed.

The risk of drug overdose death among adults with select types of disabilities in the United States - A longitudinal study using nationally representative data

BACKGROUND

Disability is associated with increased risk of drug overdose mortality, but previous studies use coarse and inconsistent methods to identify adults with disabilities. This investigation makes use of the U.S. Department of Health and Human Services disability questions to estimate the risk of drug overdose death among U.S. adults using seven established disability categories.

METHODS

The longitudinal Mortality Disparities in American Communities study was used to determine disability status among a nationally representative sample of adults age ≥18 in 2008 (n = 3,324,000). Through linkage to the National Death Index, drug overdose deaths were identified through 2019. Adults in mutually-exclusive disability categories (hearing, vision, cognitive, mobility, complex activity, ≥2 limitations) were compared to adults with no reported disabilities using adjusted hazard ratios (aHRs) and controlling for demographic and socioeconomic covariates.

RESULTS

The risk of drug overdose death varied considerably by disability type, as adults in some disability categories displayed only marginally significant risk, while adults in other disability categories displayed substantially elevated risk. Compared to non-disabled adults, the risk of drug overdose death was highest among adults with ≥2 limitations (aHR = 3.0, 95% CI = 2.8-3.3), cognitive limitation (aHR = 2.6, 95% CI = 2.3-2.9), mobility limitation (aHR = 2.6, 95% CI = 2.3-2.9), complex activity limitation (aHR = 2.3, 95% CI = 1.8-2.9), hearing limitation (aHR = 1.6, 95% CI = 1.3-1.9), and vision limitation (aHR = 1.3, 95% CI = 1.0-1.7).

CONCLUSIONS

The examination of specific disability categories revealed unique associations that were not apparent in previous research. These findings can be used to focus overdose prevention efforts on the populations at greatest risk for drug-related mortality.

Drug and alcohol use disorders among adults with select disabilities: The national survey on drug use and health

BACKGROUND

Deaths caused by drugs and alcohol have reached high levels in the US, and prior research shows a consistent association between disability status and substance misuse.

OBJECTIVE

Using national data, this study quantifies the association between disability status and drug and alcohol use disorders among US adults.

METHODS

The most recent pre-pandemic years (2018-2019) of the cross-sectional National Survey on Drug Use and Health (n = 83,439) were used to examine how the presence of any disability, and specific disabilities, were associated with past year drug and alcohol use disorders. Logistic regression was used to estimate adjusted odds ratios (aORs) controlling for potential sociodemographic confounders.

RESULTS

Adults with any disability had increased odds of drug (aOR = 2.7; 95% CI = 2.5-3.0), and alcohol use disorder (aOR = 1.8; 95% CI = 1.6-2.0), compared to adults without disability. Examining specific types of disabilities, adults with cognitive limitations only had increased odds of drug (aOR = 3.1; 95% CI = 2.6-3.6), and alcohol use disorders (aOR = 2.2; 95% CI = 1.9-2.5), compared to adults without disability. Smaller associations were observed between vision and complex activity limitations and drug use disorder. Adults with two or more types of limitations had increased odds of drug (aOR = 3.7; 95% CI = 3.3-4.3), and alcohol use disorders (aOR = 2.3; 95% CI = 2.0-2.6).

CONCLUSIONS

The presence of disability, especially cognitive limitation only, or two or more types of limitations, is associated with elevated odds of drug and alcohol use disorder among US adults. Additional research should examine the temporal relationship between and mechanisms linking disability and substance misuse.

A comparison of associations of body mass index and dual-energy x-ray absorptiometry measured percentage fat and total fat with global serum metabolites in young women

OBJECTIVE

Body mass index (BMI) does not directly measure adiposity, whereas dual-energy x-ray absorptiometry (DXA) provides valid direct estimates of adiposity. Therefore, this study evaluated usefulness of BMI as a measure of adiposity in serum metabolomics studies.

METHODS

A cross-sectional analysis was conducted of 202 women aged 25 to 29 years in the Dietary Intervention Study in Children Follow-Up Study. Heights and weights were measured, and body composition was quantified using clinical DXA protocols. Serum metabolomic profiling was performed by liquid chromatography-tandem mass spectrometry. Partial correlations of BMI, percentage fat (%FAT), and total fat (TOTFAT) with log transformed serum metabolites were calculated.

RESULTS

There was significant overlap in the 93 metabolites that correlated with BMI, %FAT, and/or TOTFAT; 9 differently correlated with BMI and %FAT, whereas 15 differently correlated with BMI and TOTFAT. Even for these metabolites, absolute differences were modest. Metabolite set enrichment analysis identified diacylglycerol and sphingolipid metabolism as overrepresented among metabolites significantly correlated with all three measures of adiposity.

CONCLUSIONS

BMI can be a good proxy for DXA measured %FAT and TOTFAT in descriptive metabolomic studies of healthy, young White women. Larger studies in more diverse populations are needed to endorse more generalized conclusions.

Association of Endogenous Pregnenolone, Progesterone, and Related Metabolites with Risk of Endometrial and Ovarian Cancers in Postmenopausal Women: The BFIT Cohort

BACKGROUND

Postmenopausal pregnenolone and/or progesterone levels in relation to endometrial and ovarian cancer risks have been infrequently evaluated. To address this, we utilized a sensitive and reliable assay to quantify prediagnostic levels of seven markers related to endogenous hormone metabolism.

METHODS

Hormones were quantified in baseline serum collected from postmenopausal women in a cohort study nested within the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT). Women using exogenous hormones at baseline (1992-1993) were excluded. Incident endometrial (n = 65) and ovarian (n = 67) cancers were diagnosed during 12 follow-up years and compared with a subcohort of 345 women (no hysterectomy) and 413 women (no oophorectomy), respectively. Cox models with robust variance were used to estimate cancer risk.

RESULTS

Circulating progesterone levels were not associated with endometrial [tertile (T)3 vs. T1 HR (95% confidence interval): 1.87 (0.85-4.11); P _trend = 0.17] or ovarian cancer risk [1.16 (0.58-2.33); 0.73]. Increasing levels of the progesterone-to-estradiol ratio were inversely associated with endometrial cancer risk [T3 vs. T1: 0.29 (0.09-0.95); 0.03]. Increasing levels of 17-hydroxypregnenolone were inversely associated with endometrial cancer risk [0.40 (0.18-0.91); 0.03] and positively associated with ovarian cancer risk [3.11 (1.39-6.93); 0.01].

CONCLUSIONS

Using sensitive and reliable assays, this study provides novel data that endogenous progesterone levels are not strongly associated with incident endometrial or ovarian cancer risks. 17-hydroxypregnenolone was positively associated with ovarian cancer and inversely associated with endometrial cancer.

IMPACT

While our results require replication in large studies, they provide further support of the hormonal etiology of endometrial and ovarian cancers.

Racial and Sex Differences between Urinary Phthalates and Metabolic Syndrome among U.S. Adults: NHANES 2005-2014

Phthalates, plasticizers ubiquitous in household and personal care products, have been associated with metabolic disturbances. Despite the noted racial differences in phthalate exposure and the prevalence of metabolic syndrome (MetS), it remains unclear whether associations between phthalate metabolites and MetS vary by race and sex. A cross-sectional analysis was conducted among 10,017 adults from the National Health and Nutritional Examination Survey (2005–2014). Prevalence odds ratios (POR) and 95% confidence intervals (CIs) were estimated for the association between 11 urinary phthalate metabolites and MetS using weighted sex and race stratified multivariable logistic regression. Higher MCOP levels were significantly associated with increased odds of MetS among women but not men, and only remained significant among White women (POR _{Q4 vs. Q1} = 1.68, 95% CI: 1.24, 2.29; p-trend = 0.001). Similarly, the inverse association observed with MEHP among women, persisted among White women only (POR _{Q4 vs. Q1} = 0.53, 95% CI: 0.35, 0.80; p-trend = 0.003). However, ΣDEHP metabolites were associated with increased odds of MetS only among men, and this finding was limited to White men (POR _{Q4 vs. Q1} = 1.54, 95% CI: 1.01, 2.35; p-trend = 0.06). Among Black men, an inverse association was observed with higher MEP levels (POR _{Q4 vs. Q1} = 0.43, 95% CI: 0.24, 0.77; p-trend = 0.01). The findings suggest differential associations between phthalate metabolites and MetS by sex and race/ethnicity.

Endogenous Progestogens and Colorectal Cancer Risk among Postmenopausal Women

BACKGROUND

The role of progestogens in colorectal cancer development is poorly characterized. To address this, our group developed a highly sensitive assay to measure concentrations of seven markers of endogenous progestogen metabolism among postmenopausal women.

METHODS

The markers were measured in baseline serum collected from postmenopausal women in a case-cohort study within the breast and bone follow-up to the fracture intervention trial (B∼FIT). We followed women not using exogenous hormones at baseline (1992-1993) for up to 12 years: 187 women with incident colorectal cancer diagnosed during follow-up and a subcohort of 495 women selected on strata of age and clinical center. We used adjusted Cox regression models with robust variance to estimate risk for colorectal cancer [hazard ratios (HR), 95% confidence intervals (CI)].

RESULTS

High concentrations of pregnenolone and progesterone were not associated with colorectal cancer [quintile(Q)5 versus Q1: pregnenolone HR, 0.71, 95% CI, 0.40-1.25; progesterone HR, 1.25; 95% CI, 0.71-2.22]. A trend of increasing risk was suggested, but statistically imprecise across quintiles of 17-hydroxypregnenolone (Q2 to Q5 HRs, 0.75-1.44; P _trend, 0.06).

CONCLUSIONS

We used sensitive and reliable assays to measure multiple circulating markers of progestogen metabolism. Progestogens were generally unassociated with colorectal cancer risk in postmenopausal women.

IMPACT

Our findings are consistent with most prior research on circulating endogenous sex hormones, which taken together suggest that sex hormones may not be major drivers of colorectal carcinogenesis in postmenopausal women.

Social Relationships and Functional Impairment in Aging Cancer Survivors: A Longitudinal Social Network Study

BACKGROUND AND OBJECTIVES

The intersection of cancer, treatment, and aging accelerates functional decline. Social networks, through the provision of social support and resources, may slow the progression of functional deterioration. Socioemotional selectivity theory posits that aging and major life events, like cancer, cause an intentional social network pruning to procure and maintain emotionally fulfilling bonds, while shedding weaker, less supportive relationships. However, it is relatively unknown if such network changes impact functional impairment in cancer survivors. This study examined the relationships between changes in the egocentric social network and functional impairment in older adult cancer survivors and a similarly aged group without cancer (older adults).

RESEARCH DESIGN AND METHODS

Data were analyzed from 1,481 community dwelling older adults (n = 201 cancer survivors) aged 57-85 years, from Waves 1 and 2 (2005-2006 and 2010-2011) of the National Social Life, Health and Aging Project. Associations were analyzed with multiple logistic regression.

RESULTS

Cancer survivors and older adults reported similar levels of functional impairment and social network change. Adding 2 new relationships exhibited protective effects against functional impairment, irrespective of cancer status (odds ratio [OR]: 0.64, 95% confidence interval [CI]: 0.41-0.99). Declines in frequent contact were associated with higher odds of functional impairment among cancer survivors (OR: 1.92, 95% CI: 1.15-3.20). Social network components were not significantly associated with functional impairment in older adults.

DISCUSSION AND IMPLICATIONS

Adding new relationships may reduce disability in older adults and increasing network contact may help cancer survivors remain independent. Social network interventions may improve quality of life for older adults.

Abstract 2359: Endogenous progestogens and colorectal cancer risk among postmenopausal women

Progestogens are sex steroid hormones that serve as precursors to androgens, estrogens, and corticosteroids. While known to influence breast and endometrial cancer risk, the exact roles progestogens play in cancer development are poorly characterized–especially for colorectal cancer. Nor have we been able to determine the utility of measuring circulating progestogens for cancer risk prediction in epidemiologic studies and clinical settings. These gaps in knowledge are largely attributable to the difficulty in measuring hormones among postmenopausal women, when concentrations are low. To address this problem, we developed a highly sensitive and reliable liquid chromatography-tandem mass spectrometry assay to measure concentrations of seven markers of endogenous progestogen metabolism: pregnenolone (a progestogen precursor), progesterone, the two 17-alpha-hydroxy (17OH) forms of these hormones (which are androgen precursors), and three progesterone metabolites. These markers were measured in prediagnostic serum collected from women in a case-cohort study within the Breast and Bone Follow-up to the Fracture Intervention Trial (B~FIT). From the 15,595 postmenopausal women in B~FIT, we followed women not using exogenous hormones at baseline (1992-1993) for up to twelve years: 187 women with incident colorectal cancer diagnosed during follow-up and a subcohort of 495 women selected on strata of age (10-year windows) and clinical center. We used Cox regression models to estimate risk for colorectal cancer (hazard ratios [HR], 95% confidence intervals [CI]); models were adjusted for age, body mass index, clinic site, and enrollment arm from the original clinical trial. High concentrations of progestogens were not associated with colorectal cancer risk (quintile(Q)5 vs. Q1: pregnenolone HR 0.71, CI 0.40-1.25; progesterone HR 1.25, CI 0.71, 2.22). A trend of increasing risk was suggested, but imprecise across quintiles of 17OH-pregnenolone (Q2 to Q5 HRs 0.75 to 1.44, p-trend 0.06), but no association was noted with 17OH-progesterone. Using 5-knot splines, we identified non-linear risk relationships with several of the progestogens–indicating that biologic mechanisms unique to each hormone may exist. However, circulating progestogens were generally unrelated to colorectal cancer risk in postmenopausal women, which is in line with prior work indicating that circulating estrogen metabolites are also not associated with risk.

Citation Format: Kara A. Michels, Roni T. Falk, Ashley M. Geczik, Doug C. Bauer, Diana S. Buist, Jane A. Cauley, Cher M. Dallal, Trisha F. Hue, James V. Lacey, Andrea Z. LaCroix, Jeffrey A. Tice, Xia Xu, Louise A. Brinton, Britton Trabert. Endogenous progestogens and colorectal cancer risk among postmenopausal women [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2359.

The Association Between Perceived Stress and Hypertension Among Asian Americans: Does Social Support and Social Network Make a Difference?

Prior research suggests that stress plays role in the etiology and progression of hypertension. To lend a more accurate depiction of the underlying mechanisms between stress and hypertension, this study aims to assess the associations between perceived stress and hypertension across varying levels of social support and social network among Asian Americans. We conducted a cross-sectional study using data on 530 Chinese, Korean and Vietnamese Americans recruited from a liver cancer prevention program in the Washington D.C.-Baltimore metropolitan area. Hypertension prevalence was 29.1%. Individuals with high perceived stress were 61% more likely to have hypertension compared to those with low levels of perceived stress (odds ratio 1.61, 95% confidence interval 1.15, 2.46). There was no evidence that social support and social network acted as effect modifiers. Social support had a direct beneficial effect on hypertension, irrespective of whether individuals were under stress. The relationship between perceived stress and hypertension was modified by gender and ethnicity whereby a significant positive association was only observed among male or Chinese participants. Our study highlights the importance of understanding the associations between stress, social support, and hypertension among Asian American subgroups. Findings from the study can be used to develop future stress management interventions, and incorporate culturally and linguistically appropriate strategies into community outreach and education to decrease hypertension risk within the Asian population.

Association of Circulating Progesterone With Breast Cancer Risk Among Postmenopausal Women

IMPORTANCE

The role of endogenous progesterone in the development of breast cancer remains largely unexplored to date, primarily owing to assay sensitivity limitations and low progesterone concentrations in postmenopausal women. Recently identified progesterone metabolites may provide insights as experimental data suggest that 5α-dihydroprogesterone (5αP) concentrations reflect cancer-promoting properties and 3α-dihydroprogesterone (3αHP) concentrations reflect cancer-inhibiting properties.

OBJECTIVE

To evaluate the association between circulating progesterone and progesterone metabolite levels and breast cancer risk.

DESIGN, SETTING, AND PARTICIPANTS

Using a sensitive liquid chromatography-tandem mass spectrometry assay, prediagnostic serum levels of progesterone and progesterone metabolites were quantified in a case-cohort study nested within the Breast and Bone Follow-up to the Fracture Intervention Trial (n = 15 595). Participation was limited to women not receiving exogenous hormone therapy at the time of blood sampling (1992-1993). Incident breast cancer cases (n = 405) were diagnosed during 12 follow-up years and a subcohort of 495 postmenopausal women were randomly selected within 10-year age and clinical center strata. Progesterone assays were completed in July 2017; subsequent data analyses were conducted between July 15, 2017, and December 20, 2018.

EXPOSURES

Circulating concentrations of pregnenolone, progesterone, and their major metabolites.

MAIN OUTCOMES AND MEASURES

Development of breast cancer, with hazard ratios (HRs) and 95% CIs was estimated using Cox proportional hazards regression adjusted for key confounders, including estradiol. Evaluation of hormone ratios and effect modification were planned a priori.

RESULTS

The present study included 405 incident breast cancer cases and a subcohort of 495 postmenopausal women; the mean (SD) age at the time of the blood draw was 67.2 (6.2) years. Progesterone concentrations were a mean (SD) of 4.6 (1.7) ng/dL. Women with higher circulating progesterone levels were at an increased risk for breast cancer per SD increase in progesterone levels (HR, 1.16; 95% CI, 1.00-1.35; P = .048). The association with progesterone was linear in a 5-knot spline and stronger for invasive breast cancers (n = 267) (HR, 1.24; 95% CI, 1.07-1.43; P = .004). Among women in the lowest quintile (Q1) of circulating estradiol (<6.30 pg/mL) elevated progesterone concentrations were associated with reduced breast cancer risk per SD increase in progesterone levels (HR, 0.38; 95% CI, 0.15-0.95; P = .04) and increased risk among women in higher quintiles of estradiol (Q2-Q5; ≥6.30 pg/mL) (HR, 1.18; 95% CI, 1.04-1.35; P = .01; P = .04 for interaction).

CONCLUSIONS AND RELEVANCE

In this case-cohort study of postmenopausal women, elevated circulating progesterone levels were associated with a 16% increase in the risk of breast cancer. Additional research should be undertaken to assess how postmenopausal breast cancer risk is associated with both endogenous progesterone and progesterone metabolites and their interactions with estradiol.

Parental caregiving trajectories and Metabolic Syndrome: A longitudinal study among Chinese women

Caregiving stress may play a role in the pathogenesis of Metabolic Syndrome (MetS). However, few studies have investigated the consequences of caregiving on this objectively measured health outcome. This study used population based longitudinal data to examine the causal relationship between caregiving trajectory and MetS among Chinese women. This is a retrospective analysis of 741 women using three waves of data from the Ever-Married Women Survey component of the China Health and Nutrition Survey (2004, 2006, and 2009). Group-based trajectory analysis was used to examine the caregiving trajectories among women in China. Three caregiving trajectories were identified. In multivariate analyses adjusting for potential covariates, 'rising to high-intense' caregivers (Odds Ratio (OR) = 3.78; 95% Confidence Interval (CI): 1.10, 12.93) and 'stable low-intense' caregivers (OR = 2.07; 95% CI: 1.09, 3.92) were associated with higher risk of MetS compared with non-caregivers. Moreover, caregivers who provided 'stable low-intense' parental care were found to be associated with hypertension, high glucose and high triglycerides than those awho did not provide caregiving for their parents. Our results demonstrate that the caregiving trajectories were significantly associated with the risk of MetS. Findings from the study can be used to develop future stress management interventions to decrease MetS risk among women who provide care to their parents.

Abstract 589: Circulating progesterone is associated with increased postmenopausal breast cancer risk: B~FIT cohort

BACKGROUND: Epidemiologic data provide compelling evidence of the association between elevated endogenous estrogens and androgens and increased postmenopausal breast cancer risk. However, the role of progesterone remains largely unexplored, primarily due to limitations in assay sensitivity and precision of progesterone measurements at low concentrations in postmenopausal women. Recently identified progesterone metabolites may provide etiologic insights as experimental data suggest that relative changes in concentrations of 5-α dihydroprogesterone (5αP) and 3-α dihydroprogesterone (3αHP) reflect cancer promoting and cancer inhibiting properties, respectively.

METHODS: We developed a sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay and quantified prediagnostic levels of progesterone/progesterone metabolites in a case-cohort study within the Breast and Bone Follow-up to the Fracture Intervention Trial (B~FIT) including 405 breast cancer cases diagnosed during follow-up and a subcohort of 495 postmenopausal women not using exogenous hormones at blood draw. Multivariable adjusted hazard ratios (HR) and 95% confidence intervals (CIs) were estimated using Cox regression and linearity was assessed using splines.

RESULTS: Hormone concentrations among women in the subcohort were on average 4.6 pg/mL (range 2.3-21.6) for progesterone; all measured values were above the assay detection limit. Women with higher circulating progesterone levels had an elevated postmenopausal breast cancer risk [HR (95% CI) per 10 pg/mL increase in progesterone: 1.18 (0.99-1.41)]. This association was linear in a 5-knot spline and strengthened [1.24 (1.03-1.49)] in models excluding women who reported current use of tamoxifen/raloxifene. Higher levels of 5αP relative to 3αHP were associated with a 4% increased postmenopausal breast cancer risk [per unit increase in ratio: 1.04 (1.00-1.07)]. For the individual metabolites, higher levels of both 5αP [per 10 pg/mL increase: 1.04 (0.93-1.18) and 3αHP [per 3 pg/mL increase: 1.11 (0.999-1.24)] were associated with elevated risk. All associations remained after adjustment for circulating estrogen levels.

CONCLUSIONS: Our prospective data suggest that postmenopausal women with increased serum progesterone concentrations, measured using a highly sensitive LC-MS/MS assay, are at increased risk of breast cancer. Consistent with experimental studies, higher levels of 5αP relative to 3αHP were indicative of increased breast cancer risk. Unlike experimental studies, our data do not suggest that endogenous concentrations of 3αHP are associated with reduced breast cancer risk; instead both metabolites were associated with elevated risk. The identification of these risk-related progesterone metabolites supports the need for additional research regarding their role in the etiology of breast cancer.

Citation Format: Britton Trabert, Doug C. Bauer, Louise A. Brinton, Diane S. Buist, Jane A. Cauley, Cher M. Dallal, Gretchen L. Gierach, Roni T. Falk, Trisha F. Hue, James V. Lacey, Andrea Z. LaCroix, Jeffrey A. Tice, Xia Xu. Circulating progesterone is associated with increased postmenopausal breast cancer risk: B~FIT cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 589.

Reproductive and Hormonal Factors in Relation to Lung Cancer Among Nepali Women

Background: Of the 1.8 million global incident lung cancer cases estimated in 2012, approximately 60% occurred in less developed regions. Prior studies suggest sex differences in lung cancer risk and a potential role for reproductive and hormonal factors in lung cancer among women. However, the majority of these studies were conducted in developed regions. No prior study has assessed these relationships among Nepali women.

Methods: Using data from a hospital-based case-control study conducted in B. P. Koirala Memorial Cancer Hospital (Nepal, 2009–2012), relationships between reproductive and hormonal factors and lung cancer were examined among women aged 23–85 years. Lung cancer cases (n = 268) were frequency-matched to controls (n = 226) based on age (±5 years), ethnicity and residential area. The main exposures in this analysis included menopausal status, age at menarche, age at menopause, menstrual duration, gravidity, and age at first live-birth. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression.

Results: Among postmenopausal women, those with a younger age at menopause (<45 years; 45–49 years) had an increased odds of lung cancer compared to those with an older (≥50 years) age at menopause [OR (95%CI): 2.14 (1.09, 4.17); OR (95% CI): 1.93 (1.07, 3.51)], after adjusting for age and cumulative active smoking years. No statistically significant associations were observed with the other reproductive and hormonal factors examined.

Conclusion: These results suggest that Nepali women with prolonged exposure to endogenous ovarian hormones, via later age at menopause, may have a lower odds of lung cancer.

Abstract P1-08-04: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Trabert B, Bauer DC, Brinton LA, Buist DS, Cauley JA, Dallal CM, Gierach GL, Falk RT, Hue TF, Lacey, Jr. JV, LaCroix AZ, Tice JA, Xu X. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-04.

Epidemiologic Risk Factors for In Situ and Invasive Breast Cancers Among Postmenopausal Women in the National Institutes of Health-AARP Diet and Health Study

Comparing risk factor associations between invasive breast cancers and possible precursors may further our understanding of factors related to initiation versus progression. Accordingly, among 190,325 postmenopausal participants in the National Institutes of Health-AARP Diet and Health Study (1995-2011), we compared the association between risk factors and incident ductal carcinoma in situ (DCIS; n = 1,453) with that of risk factors and invasive ductal carcinomas (n = 7,525); in addition, we compared the association between risk factors and lobular carcinoma in situ (LCIS; n = 186) with that of risk factors and invasive lobular carcinomas (n = 1,191). Hazard ratios and 95% confidence intervals were estimated from multivariable Cox proportional hazards regression models. We used case-only multivariable logistic regression to test for heterogeneity in associations. Younger age at menopause was associated with a higher risk of DCIS but lower risks of LCIS and invasive ductal carcinomas (P for heterogeneity < 0.01). Prior breast biopsy was more strongly associated with the risk of LCIS than the risk of DCIS (P for heterogeneity = 0.04). Increased risks associated with use of menopausal hormone therapy were stronger for LCIS than DCIS (P for heterogeneity = 0.03) and invasive lobular carcinomas (P for heterogeneity < 0.01). Associations were similar for race, age at menarche, age at first birth, family history, alcohol consumption, and smoking status, which suggests that most risk factor associations are similar for in situ and invasive cancers and may influence early stages of tumorigenesis. The differential associations observed for various factors may provide important clues for understanding the etiology of certain breast cancers.

Association of Estrogen Metabolism with Breast Cancer Risk in Different Cohorts of Postmenopausal Women

Endogenous estradiol and estrone are linked causally to increased risks of breast cancer. In this study, we evaluated multiple competing hypotheses for how metabolism of these parent estrogens may influence risk. Prediagnostic concentrations of estradiol, estrone, and 13 metabolites were measured in 1,298 postmenopausal cases of breast cancer and 1,524 matched controls in four separate patient cohorts. The median time between sample collection and diagnosis was 4.4 to 12.7 years across the cohorts. Estrogen analytes were measured in serum or urine by liquid chromatography-tandem mass spectrometry. Total estrogen levels (summing all 15 estrogens/estrogen metabolites) were associated strongly and positively with breast cancer risk. Normalizing total estrogen levels, we also found that a relative increase in levels of 2-hydroxylation pathway metabolites, or in the ratio of 2-hydroxylation:16-hydroxylation pathway metabolites, were associated inversely with breast cancer risk. These associations varied by total estrogen levels, with the largest risk reductions occurring in women in the highest tertile. With appropriate validation, these findings suggest opportunities for breast cancer prevention by modifying individual estrogen metabolism profiles through either lifestyle alterations or chemopreventive strategies. Cancer Res; 77(4); 918-25. ©2017 AACR.

Association of Active and Sedentary Behaviors with Postmenopausal Estrogen Metabolism

PURPOSE

Physical activity may reduce endogenous estrogens, but few studies have assessed effects on estrogen metabolism and none have evaluated sedentary behavior in relation to estrogen metabolism. We assessed relationships between accelerometer-measured physical activity and sedentary behavior and 15 urinary estrogens and estrogen metabolites (EM) among postmenopausal controls from a population-based breast cancer case-control study conducted in Poland (2000-2003).

METHODS

Postmenopausal women (N = 542) were ages 40 to 72 yr and not currently using hormone therapy. Accelerometers, worn for 7 d, were used to derive measures of average activity (counts per day) and sedentary behavior (<100 counts per minute per day). Estrogen metabolites were measured in 12-h urine samples using liquid chromatography-tandem mass spectrometry. Estrogen metabolites were analyzed individually, in metabolic pathways (C-2, -4, or -16), and as ratios relative to parent estrogens. Geometric means of estrogen metabolites by tertiles of accelerometer-measures, adjusted for age and body mass, were computed using linear models.

RESULTS

High activity was associated with lower levels of estrone and estradiol (P trend = 0.01), whereas increased sedentary time was positively associated with these parent estrogens (P trend = 0.04). Inverse associations were observed between high activity and 2-methoxyestradiol, 4-methoxyestradiol, 17-epiestriol, and 16-epiestriol (P trend = 0.03). Sedentary time was positively associated with methylated catechols in the 2- and 4-hydroxylation pathways (P trend ≤ 0.04). Women in the highest tertile of activity had increased hydroxylation at the C-2, -4, and -16 sites relative to parent estrogens (P trend ≤ 0.02), whereas increased sedentary time was associated with a lower 16-pathway/parent estrogen ratio (P trend = 0.01).

CONCLUSIONS

Higher activity was associated with lower urinary estrogens, possibly through increased estrogen hydroxylation and subsequent metabolism, whereas sedentary behavior may reduce metabolism.

Abstract 1737: Reproductive and hormonal factors in relation to lung cancer among Nepali women

Of the 1.8 million global incident lung cancer cases estimated in 2012, approximately 58% occurred in less developed regions (LDRs). Studies conducted in more developed regions suggest potential gender differences in lung cancer risk, whereby women may be more susceptible to the carcinogenic effects of tobacco. However, studies of reproductive and hormonal factors and lung cancer among women have been inconsistent and to date, no prior study has assessed these relationships among Nepali women. Using data from a hospital-based case-control study conducted in B. P. Koirala Memorial Cancer Hospital (Nepal, 2009-2012), relationships between reproductive and hormonal factors and lung cancer were examined among women aged 23-85 years. Lung cancer cases (n = 268) were frequency-matched to controls (n = 226), on the basis of age (±5 years), ethnicity and residential area. Controls were selected from visitors of non-lung cancer patients within the same hospital. Participants completed an interviewer-administered questionnaire and provided detailed information on demographics, medical history, smoking history, and reproductive and hormonal factors. The main exposures in this analysis included menopausal status, age at menarche, age at menopause, menstrual duration, gravidity, and age at first live-birth. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression. Final models include adjustment for key confounders including age and smoking status. Among postmenopausal women, those with a younger age at menopause (&lt;45years; 45-49years) had an increased odds of lung cancer compared to those with an older (≥50years, referent) age at menopause (OR = 2.14, 95%CI = 1.09, 4.17; OR = 1.93, 95%CI = 1.07, 3.51, respectively), after adjusting for age and cumulative active smoking (CAS). No statistically significant associations were observed with the other exposures examined. Ongoing analyses include stratification by key factors including CAS years. Further research is needed to corroborate and expand on these findings in order to better understand hormonal risk factors for lung cancer among Nepali women.

Citation Format: Sanah N. Vohra, Amir Sapkota, Mei-Ling T. Lee, Mia Hashibe, Bhola Siwakoti, Chin B. Pun, Cher M. Dallal. Reproductive and hormonal factors in relation to lung cancer among Nepali women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1737.

Assay reproducibility and interindividual variation for 15 serum estrogens and estrogen metabolites measured by liquid chromatography-tandem mass spectrometry

BACKGROUND

Interindividual differences in estrogen metabolism may partially account for differences in risks of estrogen-responsive cancers. We conducted a proof-of-performance study to assess the reproducibility of a LC/MS-MS method for measurement of 15 serum estrogens and metabolites (all 15 termed EM) in total (conjugated+unconjugated) and unconjugated forms and describe interindividual variation.

METHODS

Interindividual variation in serum EM profiles was evaluated for 20 premenopausal women, 15 postmenopausal women, and 10 men. Replicate aliquots from 10 premenopausal women, 5 postmenopausal women, and 5 men were assayed eight times over 4 weeks. Components of variance were used to calculate coefficients of variation (CV) and intraclass correlation coefficients (ICC).

RESULTS

In postmenopausal women and men, median EM concentrations were similar and substantially lower than that in premenopausal women. Within each sex/menopausal group, the sum of all EM varied 5- to 7-fold across extreme deciles. Some EM had greater variation; total estrone varied approximately 12-fold in premenopausal and postmenopausal women. Unconjugated estradiol varied 17-fold in postmenopausal women but only 5-fold in premenopausal women and men. CVs reflecting variation across replicate measures for individuals were <5% for most EM, but higher in some individuals with a low EM concentration. Overall laboratory CVs for all but one EM were <2% and ICCs were >99% for all EM in each group.

CONCLUSIONS

The serum EM assay has excellent laboratory reproducibility. In premenopausal women, postmenopausal women, and men, interindividual variation in EM measures is substantially greater than laboratory variation.

IMPACT

The serum EM assay is suitable for epidemiologic application. See all the articles in this CEBP Focus section, "Biomarkers, Biospecimens, and New Technologies in Molecular Epidemiology."

Estrogen Metabolites Are Not Associated with Colorectal Cancer Risk in Postmenopausal Women

BACKGROUND

A potential protective role for estrogen in colon carcinogenesis has been suggested based on exogenous hormone use, but it is unclear from previous studies whether endogenous estrogens are related to colorectal cancer risk. These few prior studies focused on parent estrogens; none evaluated effects of estrogen metabolism in postmenopausal women.

METHODS

We followed 15,595 women (ages 55-80 years) enrolled in the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT) who donated blood between 1992 and 1993 for cancer through December 2004. A panel of 15 estrogen metabolites (EM), including estradiol and estrone, were measured in serum from 187 colorectal cancer cases and a subcohort of 501 women not using exogenous hormones at blood draw. We examined EM individually, grouped by pathway (hydroxylation at the C-2, C-4, or C-16 position) and by ratios of the groupings using Cox proportional hazards regression models.

RESULTS

No significant associations were seen for estrone (HRQ4 vs. Q1 = 1.15; 95% CI, 0.69-1.93; Ptrend = 0.54), estradiol (HRQ4 vs. Q1 = 0.98; 95% CI, 0.58-1.64; Ptrend > 0.99), or total EM (the sum of all EM; HRQ4 vs. Q1 = 1.35; 95% CI, 0.81-2.24; Ptrend = 0.33). Most metabolites in the 2-, 4-, or 16-pathway were unrelated to risk, although a borderline trend in risk was associated with high levels of 17-epiestriol.

CONCLUSION

Circulating estrogens and their metabolites were generally unrelated to colorectal cancer risk in postmenopausal women.

IMPACT

Additional studies are needed to understand how exogenous estrogen may prevent colorectal cancer.

Abstract 1603: Estrogen metabolites and colorectal cancer risk in postmenopausal women in the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT)

Background: A role for estrogen in colon carcinogenesis is suggested by the lower incidence of colorectal cancer (CRC) in women than men; the protective effect of exogenous hormones on risk; and reduced levels of estrogen receptor beta (ERβ) expression, the predominant ER in the colon, in cancerous compared to healthy colonic tissue. Nonetheless, the few cohort studies of endogenous hormones have not found reduced risks associated with circulating estradiol or estrone levels in postmenopausal women. We hypothesized that specific metabolites in the estrogen metabolic pathway may preferentially bind to and activate colonic ERβ, and analyzed a panel of 15 estrogen metabolites (EM), including estradiol and estrone, in a case-cohort study of CRC.

Methods: We prospectively followed 15,595 women enrolled in B∼FIT (Breast and Bone Follow-up to the Fracture Intervention Trial (FIT)) who had completed questionnaires and donated blood between 1992 and 1993 for incident CRC through December 2004. Using liquid chromatography-tandem mass spectrometry, EM were measured in serum from 197 CRC cases and a subcohort of 491 women who were not using exogenous hormones at the time of blood draw. EM were examined individually, grouped by pathway (hydroxylation at the C-2, C-4, or C-16 positions of the steroid ring), and by ratios of the groupings. Cox proportional hazard regression models adjusted for clinical site and age (grouped in ten year intervals) were used to calculate quartile-specific hazard ratios (HRs) and 95% confidence intervals (CIs).

Results: Significant risks were not observed for individual EM, and HR for quartiles of total EM (sum of all EM) were elevated but not significant (HRQ4 v Q1=1.23, 95% CI=0.8-2.0, ptrend=0.53). No associations were seen for estrone (HRQ4 v Q1=1.05, 95% CI=0.6-1.7) or estradiol (HRQ4 v Q1=0.90. 95% CI=0.5-1.5). When represented as a ratio to the parent estrogens (estrone and estradiol), risks of CRC for women with higher levels of 2-pathway EM or 4-pathway EM were reduced in each quartile, but neither HR nor trends were significant (ratio 2-pathway: parent, HRQ4 v Q1=0.88, 95 CI=0.6-1.4 ptrend=0.56; ratio 4-pathway: parent, HRQ4 v Q1=0.92, 95% CI=0.6, 1.5 ptrend=0.46).

Conclusions: Levels of circulating estrone and estradiol and their metabolites are not associated with CRC risk in the B∼FIT cohort.

Citation Format: Roni T. Falk, Cher M. Dallal, James V. Lacey, Douglas C. Bauer, Diana SM Buist, Jane A. Cauley, Trisha F. Hue, Andrea LaCroix, Jeffrey A. Tice, Ruth M. Pfeiffer, Xia Xu, Timothy D. Veenstra, Louise A. Brinton. Estrogen metabolites and colorectal cancer risk in postmenopausal women in the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT). [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 1603. doi:10.1158/1538-7445.AM2014-1603

Breast cancer risk in older women: results from the NIH-AARP Diet and Health Study

BACKGROUND

Divergent risk factors exist for premenopausal and postmenopausal breast cancers, but it is unclear whether differences by age exist among postmenopausal women.

METHODS

We examined relationships among 190,872 postmenopausal women, ages 50-71 years recruited during 1995-1996 for the NIH-AARP Diet and Health Study, in whom 7,384 incident invasive breast carcinomas were identified through 2006. Multivariable Cox regression hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for breast cancer risk factors by age (50-59, 60-69, ≥70 years).

RESULTS

The only factor showing significant statistical heterogeneity by age (p(het) = 0.001) was menopausal hormone therapy duration, but trends were apparent across all ages and the strongest association prevailed among women 60-69 years. Although other risk factors did not show statistically significant heterogeneity by age, we did observe attenuated relations for parity and late age at first birth among older women [e.g., HR for age at first birth ≥30 vs. 20-24 = 1.62 (95% CI 1.23-2.14) for women 50-59 years vs. 1.12 (0.96-1.31) for ≥70 years]. In contrast, risk estimates associated with alcohol consumption and BMI tended to be slightly stronger among the oldest subjects [e.g., HR for BMI ≥35 vs. 18.5-24.9 = 1.24 (95% CI 0.97-1.58) for 50-59 years vs. 1.46 (1.26-1.70) for ≥70 years]. These differences were somewhat more pronounced for estrogen receptor positive and ductal cancers, tumors predominating among older women. Breast cancer family history, physical activity, and previous breast biopsies did not show divergent associations by age.

CONCLUSION

Although breast cancer risk factor differences among older women were not large, they may merit further consideration with respect to individualized risk prediction.

Estrogen metabolism and breast cancer risk among postmenopausal women: a case-cohort study within B~FIT

Although elevated circulating estrogens are associated with increased postmenopausal breast cancer risk, less is known regarding the role of estrogen metabolism in breast carcinogenesis. We conducted a case-cohort study within the Breast and Bone Follow-up to the Fracture Intervention Trial to assess serum estrogens and estrogen metabolites (EMs) in 407 incident breast cancer cases diagnosed during follow-up and a subcohort of 496 women. In 1992-93, women completed a baseline questionnaire and provided blood samples. Hazard ratios (HRs) and 95% confidence intervals (CIs), adjusted for geography and trial participation status, were estimated using Cox proportional hazard regression. Serum concentrations of EMs were measured by liquid chromatography-tandem mass spectrometry. EMs (quintiles, Q) were analyzed individually, as metabolic pathways (C-2, -4 or -16) and as ratios. Elevated circulating estradiol was associated with increased breast cancer risk (HRQ5vsQ1 = 1.86; 95% CI: 1.19-2.90; P trend = 0.04). An elevated ratio of the 2-hydroxylation pathway (HRQ5vsQ1 = 0.69; 95% CI: 0.46-1.05; P trend = 0.01) and 4-hydroxylation pathway (HRQ5vsQ1 = 0.61; 95% CI: 0.40-0.93; P trend = 0.004) to parent estrogens (estradiol and estrone) was inversely associated with risk. A higher ratio of the 2/16-hydroxylation pathways was associated with reduced risk (HRQ5vsQ1 = 0.60; 95% CI: 0.40-0.90; P trend = 0.002). Increased 2- or 4-hydroxylation of parent estrogens may lower risk of postmenopausal breast cancer. Analyses of metabolic pathways may help elucidate the role of estrogen metabolism in breast carcinogenesis.

Risk factors for specific histopathological types of postmenopausal breast cancer in the NIH-AARP Diet and Health Study

Risk factor associations for rare breast cancer variants are often imprecise, obscuring differences between tumor types. To clarify differences, we examined risk factors for 5 histological types of breast cancer in the National Institutes of Health-AARP Diet and Health Study. Risk factor information was self-reported. We followed 192,076 postmenopausal women aged 50-71 years from 1995-1996 through 2006. During that time period, 5,334 ductal, 836 lobular, 639 mixed ductal-lobular, 216 mucinous, and 132 tubular breast cancers were diagnosed. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards regression. Heterogeneity was evaluated using case-only logistic regression. The strongest differences were for menopausal hormone therapy (Pheterogeneity < 0.01) and age at first birth (Pheterogeneity < 0.01). Risk of tubular cancer in relation to current menopausal hormone therapy (for current use vs. never use, hazard ratio (HR) = 4.39, 95% confidence interval (CI): 2.77, 6.96) was several times stronger than risk of other histological types (range of HRs, 1.39-1.75). Older age at first birth was unassociated with risk of mucinous (for ≥30 years vs. 20-24 years, HR = 0.62, 95% CI: 0.27, 1.42) or tubular (HR = 1.08, 95% CI: 0.51, 2.29) tumors, in contrast to clear positive associations with lobular (HR = 1.82, 95% CI: 1.39, 2.37) and mixed ductal-lobular (HR = 1.87, 95% CI: 1.39, 2.51) tumors. Differing associations for hormonal factors and mucinous and tubular cancers suggest etiologies distinct from those of common breast cancers.

Circulating adipokine levels and endometrial cancer risk in the prostate, lung, colorectal, and ovarian cancer screening trial

BACKGROUND

Circulating adipokine levels may be associated with endometrial cancer risk, yet few studies have evaluated these markers prospectively.

METHODS

We conducted a nested case-control study of postmenopausal women in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (n = 78,216), including 167 incident endometrial cancer cases and 327 controls that were matched on age, study center, race, study year of diagnosis, year of blood draw, time of day of blood draw, and menopausal hormone therapy (MHT) use. Adipokine and estradiol levels were categorized into tertiles (T). ORs and 95% confidence intervals (CIs) for the associations of adiponectin, leptin, and visfatin with endometrial cancer risk were estimated by conditional logistic regression, adjusting for known endometrial cancer risk factors, including body mass index (BMI) and circulating estradiol levels.

RESULTS

Adiponectin levels were inversely associated with risk of endometrial cancer [ORT3vsT1 = 0.48; 95% CI, 0.29-0.80); Ptrend < 0.01], whereas elevated leptin levels showed a positive association [2.77 (1.60-4.79); Ptrend < 0.01]. These results remained significant after adjustment for estradiol, but not after further adjustment for BMI. When analyses were restricted to non-MHT users, associations of adiponectin and leptin were stronger and remained significant after adjustment for estradiol and BMI [0.25 (0.08-0.75); Ptrend = 0.01 and 4.72 (1.15-19.38); Ptrend = 0.02, respectively]. Nonsignificant positive associations were observed for visfatin.

CONCLUSION

Adipokines may influence endometrial cancer risk through pathways other than estrogen-mediated cell growth in postmenopausal women not currently on MHT.

IMPACT

Understanding how adipokines influence endometrial cancer risk may help to elucidate biological mechanisms important for the observed obesity-endometrial cancer association.

Obesity-related hormones and endometrial cancer among postmenopausal women: a nested case-control study within the B~FIT cohort

Endometrial cancer risk is strongly influenced by obesity, but the mechanisms of action remain unclear. Leptin and adiponectin, secreted from adipose tissue, reportedly play a role in such carcinogenic processes as cell proliferation, angiogenesis, and insulin regulation. In this case-control study, nested within the Breast and Bone Follow-up of the Fracture Intervention Trial (n=15,595), we assessed pre-diagnostic serum leptin, total adiponectin, and high-molecular-weight (HMW) adiponectin in relation to endometrial cancer among postmenopausal women. During the 10-year follow-up, 62 incident endometrial cases were identified and matched to 124 controls on age, geographical site, time of fasting blood draw at baseline (1992-1993), and trial participation status. Adipokines and C-peptide were measured by ELISA. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated via conditional logistic regression, with exposures categorized in tertiles (T). Multivariable models considered C-peptide, BMI (kg/m(2)), and estradiol (E2) as potential confounders. Endometrial cancer risk was significantly associated with higher leptin levels, adjusted for E2 and C-peptide (OR(T3 vs T1)=2.96; 95% CI, 1.21-7.25; P trend <0.01). After further adjustment for BMI, the estimates were attenuated and the positive trend was no longer statistically significant (OR(T3 vs T1)=2.11; 95% CI, 0.69-6.44; P trend=0.18). No significant associations were observed with adiponectin or HMW adiponectin and endometrial cancer. Our findings with leptin suggest that the leptin-BMI axis might increase endometrial cancer risk through mechanisms other than estrogen-driven proliferation. Continued exploration of these pathways in larger prospective studies may help elucidate mechanisms underlying observed obesity-endometrial cancer associations.

Abstract P3-07-04: Cigarette smoking and postmenopausal breast cancer risk: results from the NIH-AARP Diet and Health Study

Epidemiologic evidence regarding the relationship between smoking and breast cancer risk is inconsistent. Some studies suggest that the relationship depends on interaction with other factors, such as alcohol use, body mass index (BMI), and menopausal hormone therapy (MHT). We investigated the relationship between smoking and breast cancer risk and interactions with breast cancer risk factors in the NIH-AARP Diet and Health Study, a large prospective cohort. Postmenopausal women ages 50–71 years (N = 192,076) in six US states and two metropolitan areas were followed from 1995–1996 through 2006. Risk factor information was self-reported at baseline. Smoking status was based on whether participants smoked ≥ 100 cigarettes in their lifetime and whether they currently smoked (current −15%, former −40%, never −45%). Alcohol use was estimated from a dietary questionnaire, and categorized based on drinking ≤ 5 or &gt; 5 g/day. BMI was calculated from reported height and weight and categorized as ≥ 30 or &lt; 30 kg/m2. MHT use was categorized as current, former, or never use of any estrogen or progestin preparation. Cancer diagnosis, estrogen receptor (ER), and progesterone receptor (PR) data were reported by state registries. After a mean 9.6 years of follow-up, 7,698 women were diagnosed with primary invasive breast cancer. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Multiplicative interactions between smoking and covariates were evaluated using the likelihood ratio test (LRT). Overall, smokers were at an increased risk of breast cancer compared to women who never smoked (current HR 1.19, 95% CI 1.10, 1.28; former HR 1.08, 95% CI 1.02, 1.13). Excess risk diminished as time since quitting increased and was close to null for women who quit smoking ≥ 10 years prior to study enrollment compared to never smokers (HR 1.04, 95% CI 0.98, 1.11). Relative risks differed significantly based on alcohol use (P-LRT &lt; 0.01), but not BMI or MHT use (P-LRT &gt; 0.05). The HR associated with current smoking was 1.15 (95% CI 1.05, 1.25) among women who drank ≤ 5 g/day, but was higher among women who drank &gt; 5 g/day (HR 1.41, 95% CI 1.22, 1.61). The relationship for those who drank &gt; 5 g/day persisted after adjustment for the amount of alcohol (5–10, 10–20, 20–35, &gt;35 g/day) consumed (HR 1.36, 95% CI 1.18, 1.56). Among women who drank &gt; 5 g/day, current smoking was associated with increased risks of hormone receptor-positive tumors (ER+/PR+ HR 1.29, 95% CI 1.01, 1.64; ER+/PR- HR 2.11, 95% CI 1.27, 3.50), but not ER−/PR− tumors (HR 1.07, 95% CI 0.64, 1.79). In summary, we found that smoking was associated with elevated breast cancer risk which was strongest among women who drank &gt; 5 g of alcohol per day. Among these women, smoking-associated increases in breast cancer risk were limited to hormone receptor-positive tumors, consistent with the known relationship between alcohol use and ER+ breast cancer risk. Findings were similar after additional adjustment for the amount of alcohol consumed, suggesting that the increased risks were not due to residual confounding by alcohol dose, although further analyses are needed to fully understand the interaction between these two factors.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-07-04.

Estrogen metabolism and mammographic density in postmenopausal women: a cross-sectional study

BACKGROUND

Prospective studies have consistently found that postmenopausal breast cancer risk increases with circulating estrogens; however, findings from studies of estrogens and mammographic density (MD), an intermediate marker of breast cancer risk, have been inconsistent. We investigated the cross-sectional associations of urinary estrogens, and their 2-, 4-, and 16-hydroxylated metabolites with MD.

METHODS

Postmenopausal women without breast cancer (n = 194), ages 48 to 82 years, and reporting no current menopausal hormone therapy use were enrolled at a clinic in Western NY in 2005. Urinary estrogens and estrogen metabolites were measured using mass spectrometry. Percent MD and dense area (cm(2)) were measured using computer-assisted analyses of digitized films. Linear regression models were used to estimate associations of log-transformed estrogen measures with MD while adjusting for age, body mass index (BMI), parity, and past hormone therapy use.

RESULTS

Urinary concentrations of most individual estrogens and metabolites were not associated with MD; however, across the interdecile range of the ratio of parent estrogens (estrone and estradiol) to their metabolites, MD increased by 6.8 percentage points (P = 0.02) and dense area increased by 10.3 cm(2) (P = 0.03). Across the interdecile ranges of the ratios of 2-, 4-, and 16-hydroxylation pathways to the parent estrogens, MD declined by 6.2 (P = 0.03), 6.4 (P = 0.04), and 5.7 (P = 0.05) percentage points, respectively. All associations remained apparent in models without adjustment for BMI.

CONCLUSION

In this study of postmenopausal women, less extensive hydroxylation of parent estrogens was associated with higher MD.

IMPACT

Hydroxylation of estrogens may modulate postmenopausal breast cancer risk through a pathway involving MD.

P4-10-03: Association between BMI, Physical Activity and Breast Cancer Histologic Types

Background: Previous research indicates that certain breast cancer risk factor associations vary by histologic tumor type. However, most studies have been too small to examine risk factors for uncommon histologic types. We examined the association between body mass index (BMI), physical activity, and the relative risk of breast cancer histologic types in a large prospective cohort study to determine whether associations for these risk factors varied by histology.

Methods: This analysis included women in the NIH-AARP Diet and Health Cohort Study who were 50 to 71 years old, postmenopausal at baseline, and not previously diagnosed with cancer (N=190,348). The study cohort was established in 1995–1996 when participants completed a baseline questionnaire regarding health and nutritional information. BMI (kg/m2) was calculated from self-reported height and weight. Daily routine physical activity at work or home was derived from a question asking women what best described their daily routine at work, or throughout the day if they did not work at a job. Choices were mostly sitting with little walking, sitting with a fair amount of walking, mostly standing or walking, light lifting or climbing stairs/hills, or heavy work/carrying heavy loads. Cancer diagnosis and histology were obtained from state cancer registries. This analysis includes participant follow-up through December 31, 2006. After a median 11.2 years of follow-up, 7,631 invasive breast cancers were diagnosed: 5,278 ductal, 831 lobular, 640 mixed ductal-lobular, 214 mucinous, 132 tubular, and 536 other types. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression.

Results: Compared to women with a BMI of 18.5 to 24.9, obese women had increased risks of ductal (HR and 95% CI for BMI 30 to 34.9: 1.24, 1.14 — 1.36; BMI ≥ 35: 1.45, 1.30 — 1.62) and mucinous (HR and 95% CI for BMI 30 to 34.9: 1.58, 1.04 — 2.39; BMI ≥ 35: 1.93, 1.16 — 3.20) cancers. For both histologic types, the relative risk increased with increasing BMI (P-trend: ductal P&lt;0.01; mucinous P&lt;0.01). Women whose daily activity at work or home consisted of mostly standing or walking were at reduced risk of ductal and mixed ductal-lobular cancers compared with women who reported mostly sitting (HR and 95% CI for ductal: 0.86, 77 — 0.96; mixed-ductal lobular: 0.64, 0.48 — 0.86). Women who performed heavy work or carried heavy loads were also at a decreased risk of ductal and mixed ductal-lobular cancers compared with women reporting mostly sitting (HR and 95% CI for ductal: 0.68, 0.52−0.91; mixed ductal-lobular: 0.18, 0.04−0.72), though there were few mixed ductal-lobular cases who reported heavy activity.

Conclusions: High BMI was associated with increased risk of ductal and mucinous breast cancers. Women who spent their daily routine activity mostly standing or walking or doing heavy work had a reduced risk of ductal and mixed ductal-lobular cancers. These differences suggest that associations of BMI and physical activity vary by breast cancer histologic type in postmenopausal women and may have different roles in the etiology of these cancers.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-10-03.

Long-term Recreational Physical Activity and Risk of Invasive and In Situ Breast Cancer

BACKGROUND

Long-term physical activity may affect breast cancer risk. Few prospective studies have evaluated in situ or invasive breast cancer risk, or breast cancer receptor subtypes, in relation to long-term activity.

METHODS

We examined the association between recreational physical activity and risk of invasive and in situ breast cancer in the California Teachers Study, a cohort of women established in 1995-1996. Of 110 599 women aged 20 to 79 years with no history of breast cancer followed up through December 31, 2002, 2649 were diagnosed as having incident invasive breast cancer and 593 were diagnosed as having in situ breast cancer. Information was collected at cohort entry on participation in strenuous and moderate recreational activities during successive periods from high school through the current age or age 54 years (if older at enrollment) and in the past 3 years. A summary measure of long-term activity up to the current age, or age 54 years if older, was constructed for each woman.

RESULTS

Invasive breast cancer risk was inversely associated with long-term strenuous activity (>5 vs </=0.5 h/wk per year: relative risk, 0.80; 95% confidence interval, 0.69-0.94; P trend = .02), as was in situ breast cancer risk (>5 vs </=0.5 h/wk per year: relative risk, 0.69; 95% confidence interval, 0.48-0.98; P trend = .04). Strenuous and moderate long-term activities were associated with reduced risk of ER-negative (strenuous: P trend = .003; moderate: P trend = .003) but not ER-positive (strenuous: P trend = .23; moderate: P trend = .53) invasive breast cancer.

CONCLUSION

These results support a protective role of strenuous long-term exercise activity against invasive and in situ breast cancer and suggest differing effects by hormone receptor status.