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17 result(s) for "Michels, Kara A."
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Postmenopausal Androgen Metabolism and Endometrial Cancer Risk in the Women’s Health Initiative Observational Study
After menopause, several androgens continue to be produced primarily by the adrenal glands; these can be converted into estrogens via aromatization or into androgen metabolites. It is unclear if androgens are associated with endometrial cancer risk independently of their being precursors to estrogens or if alternative metabolic pathways influence risk. We measured prediagnostic serum concentrations of 12 androgens and their metabolites using highly sensitive liquid chromatography-tandem mass spectrometry assays in a nested case-control study of postmenopausal women from the Women's Health Initiative Observational Study (313 endometrial cancer case subjects, 354 matched control subjects). Estrogens were previously assayed. We used conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for endometrial cancer with adjustment for confounders. Compared to the lowest concentrations, the highest levels of adrenal androgens were associated with increased endometrial cancer risk: dehydroepiandrosterone (5th vs 1st quintile: OR = 1.85, 95% CI = 1.06 to 3.25), androstenedione (OR = 2.36, 95% CI = 1.34 to 4.16), and testosterone (OR = 1.91, 95% CI = 1.12 to 3.24). Downstream androgen metabolites were not associated with endometrial cancer. Although increased risks for the parent androgens were still suggested after adjustment for unconjugated estradiol, the associations attenuated, and with the exception of androstenedione, were no longer statistically significant. We also evaluated ratios of estrogens relative to their androgenic precursors; both higher unconjugated estrone:androstenedione and higher unconjugated estradiol:testosterone were associated with increased endometrial cancer risk. We identified increased risks for endometrial cancer with the highest levels of adrenal androgens and high levels of estrogens relative to these androgens. As adrenal androgens can be aromatized to estrogens, this suggests androgens likely influence endometrial carcinogenesis via estrogen metabolism.
Serum antioxidant vitamin concentrations and oxidative stress markers associated with symptoms and severity of premenstrual syndrome: a prospective cohort study
Background It has been suggested that premenstrual syndrome (PMS) may derive from either elevated oxidative stress or reduced antioxidant vitamin levels in the body; however, these relationships have been minimally studied in a large cohort of healthy women. Our objective was to estimate the association between serum concentrations of antioxidant vitamins (A, C, and E) and markers of oxidative stress (F2-isoprostane) with symptoms and severity of PMS. Methods The BioCycle study was a prospective cohort study following 259 healthy premenopausal women aged 18–44 years for up to 2 menstrual cycles. Frequency/severity of 20 PMS symptoms were assessed via questionnaires 4 times/cycle, and antioxidant vitamins and oxidative stress biomarkers were measured up to 8 times/cycle to correspond with specific cycle phases. Generalized linear models were used to estimate associations between mean antioxidant concentrations and oxidative stress biomarkers with PMS symptoms and severity; linear mixed models were used to evaluate associations with symptom severity scores within groups (e.g. depression, cravings, pain). Results Higher concentrations of serum antioxidant vitamins were largely not associated with prevalence or severity of PMS symptoms. Though a few associations were observed, only associations between mean γ-tocopherol and decreased odds of swelling of the hands/feet survived adjustment for multiple comparisons (OR 0.33, 95% CI 0.16, 0.65, per ug/dL). However, F2-isoprostanes were associated with prevalence and severity of several symptoms specifically related to depression and cravings (depression score β  =  0.07, 95% CI 0.02, 0.12, per 10 ug/dL; cravings score β = 0.16, 95% CI 0.10, 0.22, per 10 ug/dL), as well as with classification of PMS severity (OR 1.07, 95% CI 1.01, 1.14, per 10 pg/dL), with these associations surviving adjustment for false discovery rate. Conclusions F2-isoprostanes, but not antioxidant vitamins, were associated with select PMS symptoms, as well as symptom and severity categories. Specific symptom relationships merit further research.
Trends in oral contraceptive and intrauterine device use among reproductive-aged women in the US from 1999 to 2017
Purpose Since the 1960s, increasing oral contraceptive (OC) use has mirrored decreasing ovarian cancer incidence. The impact of intrauterine devices (IUDs) on cancer risk is less well established. With improved access and increased options, we must consider how changing usage can affect cancer risks. Methods Nationally representative data from the National Health and Nutrition Examination Survey (NHANES, 1999–2016) and the National Survey for Family Growth (NSFG, 2006–2017) were used to evaluate contraceptive use over time in premenopausal women (NHANES n  = 13,179; NSFG n  = 26,262). Trends were assessed overall and by race, age, pregnancy history, education, and body mass index. Results The average annual absolute increase in self-reported IUD use was 0.81% (NSFG), while OC use decreased 0.49% in NSFG and 0.47% in NHANES. This represents a significant decrease in OC use in NSFG [annual percent change (APC) − 2.2% (95% CI − 3.4, − 1.0%), p  < 0.01]. Trends in OC use varied somewhat by pregnancy history in NHANES ( p- interaction = 0.054). In contrast, IUD use increased 6.2% annually [(1.4, 11.2%), p  = 0.03] and varied significantly by pregnancy history ( p- interaction < 0.01). Nulligravid women increased IUD use 11.0% annually [(2.6, 20.1%), p  = 0.02] compared to women with prior pregnancy at 5.2% [(0.4, 10.2%), p  = 0.04]. In 2015–2017, IUD use was 76.5% hormonal (71.1, 81.8%) and 22.9% copper (17.4, 28.3%) with greater hormonal IUD use in obese women [89.4%, (82.9, 95.9%)]. Conclusion Increasing IUD use outpaced declining OC use in premenopausal US women. There may be a resulting decreased gynecologic cancer risk as more women gain access to potentially risk-reducing contraceptives.
Associations between daily aspirin use and cancer risk across strata of major cancer risk factors in two large U.S. cohorts
Purpose Daily aspirin use has been shown to reduce risk of colorectal, and possibly other, cancers, but it is unknown if these benefits are consistent across subgroups of people with differing cancer risk factors. We investigated whether age, body mass index (BMI), smoking status, physical inactivity, and family history of cancer modify the effect of daily aspirin use on colorectal, ovarian, breast, endometrial and aggressive prostate cancer risk. Methods We pooled 423,495 individuals from two prospective, U.S.-based studies: the NIH-AARP Diet and Health Study (1995–2011) and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (1993–2009). Using Cox proportional hazards regression, we examined associations between daily aspirin use (≥ 5 days/week) and risk of colorectal, ovarian, breast, endometrial, and aggressive prostate cancer, overall and across strata of risk factors. Results Daily aspirin use was associated with a 15% reduction in colorectal cancer risk (hazard ratio [HR]: 0.85, 95% confidence interval [CI] 0.80–0.89). Risk reductions were generally consistent across strata of risk factors but attenuated with increasing BMI ( p -interaction = 0.16). For ovarian cancer, there was no significant association overall (HR: 0.93, 95% CI 0.80–1.08) but reduced risk among obese women (HR: 0.73, 95% CI 0.52–0.98, p -interaction = 0.12). Weak or null associations were observed for breast, endometrial, and aggressive prostate cancer, with no strong effect modification observed. Conclusions Daily aspirin use appears to reduce colorectal cancer risk regardless of other risk factors, though the potential modifying effect of BMI warrants further investigation and may need to be considered in risk–benefit calculations for aspirin use.
Risk factors for endometrial cancer in Black women
PurposeThe incidence of endometrial cancer (EC) has been increasing faster among Black women than among other racial/ethnic groups in the United States. Although the mortality rate is nearly twice as high among Black than White women, there is a paucity of literature on risk factors for EC among Black women, particularly regarding menopausal hormone use and severe obesity.MethodsWe pooled questionnaire data on 811 EC cases and 3,124 controls from eight studies with data on self-identified Black women (4 case–control and 4 cohort studies). We analyzed cohort studies as nested case–control studies with up to 4 controls selected per case. We used logistic regression to estimate multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs).ResultsWe observed a positive association between BMI and EC incidence (Ptrend < 0.0001) The OR comparing BMI ≥ 40 vs. < 25 kg/m2 was 3.92 (95% CI 2.91, 5.27). Abdominal obesity among those with BMI < 30 kg/m2 was not appreciably associated with EC risk (OR 1.21, 95% CI 0.74, 1.99). Associations of reproductive history with EC were similar to those observed in studies of White women. Long-term use of estrogen-only menopausal hormones was associated with an increased risk of EC (≥ 5 years vs. never use: OR 2.08, 95% CI: 1.06, 4.06).ConclusionsOur results suggest that the associations of established risk factors with EC are similar between Black and White women. Other explanations, such as differences in the prevalence of known risk factors or previously unidentified risk factors likely underlie the recent increases in EC incidence among Black women.
Associations of tubal ligation and hysterectomy with serum androgen and estrogen metabolites among postmenopausal women in the Women’s Health Initiative Observational Study
PurposeHysterectomy is associated with subsequent changes in circulating hormone levels, but the evidence of an association for tubal ligation is unclear. We evaluated whether circulating concentrations of androgens and estrogens differ by tubal ligation or hysterectomy status in postmenopausal women from the Women’s Health Initiative (WHI)-Observational Study (OS).MethodsSerum androgens and estrogens were measured in 920 postmenopausal women who did not use menopausal hormone therapy at the time of blood draw, of whom 139 self-reported a history of tubal ligation and 102 reported hysterectomy (with intact ovaries). Geometric mean hormone concentrations (GMs) and 95% confidence intervals (CIs) associated with a history of tubal ligation or hysterectomy (ever/never), as well as time since procedures, were estimated using adjusted linear regression with inverse probability of sampling weights to account for selection.ResultsCirculating levels of 12 androgen/androgen metabolites and 20 estrogen/estrogen metabolites did not differ by tubal ligation status. Among women reporting prior hysterectomy compared to women without hysterectomy, we observed lower levels of several androgens (e.g., testosterone (nmol/L): GMyes 0.46 [95% CI:0.37–0.57] vs. GMno 0.62 [95% CI:0.53–0.72]) and higher levels of estrogen metabolites, for example, 2-hydroxyestrone-3-methyl ether (GMyes 11.1 [95% CI:8.95–13.9] pmol/L vs. GMno 8.70 [95% CI:7.38–10.3]) and 4-methoxyestrone (GMyes 6.50 [95% CI:5.05–8.37] vs. GMno 4.92 [95% CI:4.00–6.05]).ConclusionWhile we did not observe associations between prior tubal ligation and postmenopausal circulating hormone levels, our findings support that prior hysterectomy was associated with lower circulating testosterone levels and higher levels of some estrogen metabolites, which may have implications for future hormone-related disease risks.
Maternal Smoking and Newborn Cytokine and Immunoglobulin Levels
Prenatal smoking exposure may lead to permanent changes in neonatal inflammation and immune response that have lifelong implications, including increased risks for atopy and respiratory disorders. The effect of maternal smoking on neonatal biomarkers of inflammation and immune response was assessed among 3459 singletons and twins in the Upstate KIDS Study. The following inflammatory biomarkers were measured using newborn dried blood spots (DBSs): interleukin (IL)-1α, IL-1 receptor antagonist, IL-6, IL-8, C-reactive protein, and tumor necrosis factor alpha. Immunoglobulins (IgE, IgA, IgM, and IgG subclasses) were also assessed. We used generalized estimating equations to calculate mean differences (β) in biomarker levels by timing of pregnancy smoking, cigarette load, and secondhand smoke exposure after adjusting for sociodemographic and lifestyle factors including maternal body mass index. Of the 344 (12%) women reporting smoking during pregnancy, about 40% continued throughout pregnancy and 13% reported smoking more than 1 pack per day. After covariate adjustment and Bonferroni correction for multiple comparisons, maternal smoking throughout pregnancy remained significantly associated with increased levels of IL-8 (β = 0.20, 95% confidence interval: 0.07, 0.32; p < .003). No significant associations were found with cigarette load or secondhand smoke exposure. Higher IgG3 levels were also associated with maternal smoking throughout pregnancy, although the association became nominally significant after adjustment for covariates (β = 0.09; 95% confidence interval: 0.0007, 0.17; p < .05). Maternal smoking throughout pregnancy was independently associated with increased IL-8 levels in newborns. Importantly, neonates of women who stopped smoking anytime in pregnancy did not have increased IL-8 levels. This study evaluated a range of inflammatory biomarkers and immunoglobulins in association with maternal smoking and timing/duration of smoking along with secondhand smoke exposure. By using DBSs, we present data from a large cohort of children born in Upstate New York. Our findings suggest that early differences in immunoregulation of neonates exposed to maternal smoking for full duration in utero may already be detected at birth.
Dietary minerals, reproductive hormone levels and sporadic anovulation: associations in healthy women with regular menstrual cycles
Although minerals are linked to several reproductive outcomes, it is unknown whether dietary minerals are associated with ovulatory function. We hypothesised that low intakes of minerals would be associated with an increased risk of anovulation. We investigated associations between dietary mineral intake and both reproductive hormones and anovulation in healthy women in the BioCycle Study, which prospectively followed up 259 regularly menstruating women aged 18–44 years who were not taking mineral supplements for two menstrual cycles. Intakes of ten selected minerals were assessed through 24-h dietary recalls at up to four times per cycle in each participant. Oestradiol, progesterone, luteinising hormone (LH), follicle-stimulating hormone (FSH), sex-hormone-binding globulin and testosterone were measured in serum up to eight times per cycle. We used weighted linear mixed models to evaluate associations between minerals and hormones and generalised linear models for risk of anovulation. Compared with Na intake ≥1500 mg, Na intake <1500 mg was associated with higher levels of FSH (21·3 %; 95 % CI 7·5, 36·9) and LH (36·8 %; 95 % CI 16·5, 60·5) and lower levels of progesterone (−36·9 %; 95 % CI −56·5, −8·5). Na intake <1500 mg (risk ratio (RR) 2·70; 95 % CI 1·00, 7·31) and Mn intake <1·8 mg (RR 2·00; 95 % CI 1·02, 3·94) were associated with an increased risk of anovulation, compared with higher intakes, respectively. Other measured dietary minerals were not associated with ovulatory function. As essential minerals are mostly obtained via diet, our results comparing insufficient levels with sufficient levels highlight the need for future research on dietary nutrients and their associations with ovulatory cycles.
BET1L and TNRC6B associate with uterine fibroid risk among European Americans
Uterine fibroid (UFs) affect 77 % of women by menopause and account for $9.4 billion in healthcare costs each year. Although UFs are heritable, genetic risk is poorly understood. The first genome-wide association study (GWAS) of UFs was recently performed in a Japanese population, with reported genome-wide significance for single nucleotide polymorphisms (SNPs) across three chromosomal regions. We tested these SNPs for association with UFs in US cohorts. Women were enrolled in the Right from the Start (RFTS) cohort and the BioVU DNA repository. UF status in both cohorts was determined by pelvic imaging. We tested 65 candidate and haplotype-tagging SNPs for association with UFs presence using logistic regression in RFTS and the top three GWAS-associated SNPs in BioVU. We also combined association results from both cohorts using meta-analysis. 1,086 European American (EA) cases and 1,549 controls were examined. Two SNP associations replicated [blocked early in transport 1 homolog ( BET1L ) rs2280543, RFTS–BioVU meta-odds ratio (OR) = 0.67 95 % confidence interval (CI) 0.38–0.96, Q  = 0.70, I  = 0, p  = 6.9 × 10 −3 ; trinucleotide repeat containing 6B ( TNRC6B ) rs12484776, RFTS–BioVU meta-OR = 1.21, 95 % CI 1.07–1.35, Q  = 0.24, I  = 28.37, p  = 8.7 × 10 −3 ). Meta-analyses combining evidence from RFTS, BioVU, and prior GWAS showed little heterogeneity in effect sizes across studies, with meta- p values between 7.45 × 10 −8 and 3.89 × 10 −9 , which were stronger than prior GWAS and supported associations observed for all previously identified loci. These data suggest common variants increase risk for UF in both EA and Japanese populations. However, further research is needed to assess the role of these genes across other racial groups.
Physical Activity From Adolescence Through Midlife and Associations With Body Mass Index and Endometrial Cancer Risk
Background Physical activity is associated with lower risk for endometrial cancer, but the extent to which the association is mediated by body mass index (BMI) in midlife is unclear. This study describes the physical activity–endometrial cancer association and whether BMI mediates this relationship. Methods Participants were 67 705 women in the National Institutes of Health-AARP Diet and Health Study (50-71 years) who recalled their physical activity patterns starting at age 15-18 years. We identified 5 long-term physical activity patterns between adolescence and cohort entry (ie, inactive, maintained low, maintained high, increasers, decreasers). We used Cox regression to assess the relationship between these patterns and midlife BMI and endometrial cancer, adjusting for covariates. Mediation analysis was used to estimate the proportion of the physical activity–endometrial cancer association that was mediated by midlife BMI. Results During an average 12.4 years of follow-up 1468 endometrial cancers occurred. Compared with long-term inactive women, women who maintained high or increased activity levels had a 19% to 26% lower risk for endometrial cancer (maintained high activity: hazard ratio = 0.81, 95% confidence interval [CI] = 0.67 to 0.98; increasers: hazard ratio = 0.74, 95% CI = 0.61 to 0.91). They also had a 50% to 77% lower risk for obesity in midlife (eg, maintained high activity: odds ratio for a BMI of 30-39.9 kg/m2 = 0.50, 95% CI = 0.46 to 0.55; and maintained high activity, odds ratio for a BMI of ≥40 kg/m2 = 0.32, 95% CI = 0.26 to 0.39). BMI was a statistically significant mediator accounting for 55.5% to 62.7% of the physical activity–endometrial cancer associations observed. Conclusions Both maintaining physical activity throughout adulthood and adopting activity later in adulthood can play a role in preventing obesity and lowering the risk for endometrial cancer.