Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Small studies suggest exogenous estrogen may improve vitamin D status, but the etiology is unclear because women who use hormones may make lifestyle choices that differentially affect vitamin D status.', 'Our objective was to investigate the association between use of hormonal contraception and 25-hydroxy-vitamin D (25(OH)D).', 'We used linear regression modeling of cross-sectional data to estimate percent change in season-adjusted serum 25(OH)D with estrogen use after adjustment for other factors.', 'At the enrollment clinic visit (2010-2012) into a cohort study of uterine fibroids, each subject provided a blood sample, had anthropomorphic variables and skin reflectance measured, and answered questionnaires on demographics, dietary and supplement intake, contraceptive use, reproductive and medical history, and behaviors.', 'A total of 1662 African American women, community volunteers, 23-34 years old, living in the Detroit, Michigan, area were included.', 'None.', 'Serum 25(OH)D was measured.', 'Serum 25(OH)D concentrations were low (70% <20 ng/ml). Current use of an estrogen-containing contraceptive was associated with a 20% (95% confidence interval: 14-27) increase in 25(OH)D after adjustment. There was no increase in 25(OH)D among participants who had used estrogen in the past, but were not current users, indicating that results were unlikely to be due to unmeasured confounding by factors related to contraceptive choice.
Answer: The increase in 25(OH)D with use of estrogen-containing contraceptives raise mechanistic questions regarding the biological pathways involved, and highlights the need for studies that examine possible endogenous estrogen effects on vitamin D.
Does use of Estrogen-Containing Contraception be Associated With Increased Concentrations of 25-Hydroxy Vitamin D?

Context: Increased oxidative stress and myocyte apoptosis co-exist in the remote non-infarcted myocardium (RM) following a large myocardial infarction. We proposed that these phenomena are causally related.', 'On day 3 after induction of myocardial infarction, Sprague-Dawley rats were randomized to receive probucol and pyrrolidine dithiocarbamate (MI-T), or vehicle only (MI) for 7 weeks. Control rats (C) received vehicle. At 7 weeks, lipidperoxidation within the RM was assessed by measuring thiobarbituric acid reactive substances, which were significantly increased in MI vs. C, while MI-T was not different from C. There was a significant increase in cardiac myocytes positive for in situ TdT-UTP nick-end labeling within the RM in MI vs. C, which was inhibited in MI-T. Furthermore, internucleosomal DNA fragmentation was clearly demonstrated on agarose gels from RM in the MI group, while it was much less apparent on gels from RM in the C and MI-T groups. Western blot analysis showed a significant increase in p53, Bax and caspase-3 protein expression within the RM of MI vs. C, all of which were inhibited in the MI-T group. Furthermore, there was evidence for an increase in caspase-3 activity within the RM from MI vs. C, which was normalized in the MI-T group.
Answer: Long-term treatment with the antioxidants probucol and pyrrolidine dithiocarbamate attenuates oxidative stress, myocyte apoptosis, caspase-3 like activity and the expression of p53, bax and caspase-3 within RM in rats after a large myocardial infarction.
Do antioxidants attenuate myocyte apoptosis in the remote non-infarcted myocardium following large myocardial infarction?

Context: Myocardial scarring leads to cardiac dysfunction and poor prognosis. The prevalence of and factors associated with unrecognized myocardial infarction and scar have not been previously defined using contemporary methods in a multiethnic US population.', 'To determine prevalence of and factors associated with myocardial scar in middle- and older-aged individuals in the United States.', 'The Multi-Ethnic Study of Atherosclerosis (MESA) study is a population-based cohort in the United States. Participants were aged 45 through 84 years and free of clinical cardiovascular disease (CVD) at baseline in 2000-2002. In the 10th year examination (2010-2012), 1840 participants underwent cardiac magnetic resonance (CMR) imaging with gadolinium to detect myocardial scar. Cardiovascular disease risk factors and coronary artery calcium (CAC) scores were measured at baseline and year 10. Logistic regression models were used to estimate adjusted odds ratios (ORs) for myocardial scar.', 'Cardiovascular risk factors, CAC scores, left ventricle size and function, and carotid intima-media thickness.', 'Myocardial scar detected by CMR imaging.', 'Of 1840 participants (mean [SD] age, 68 [9] years, 52% men), 146 (7.9%) had myocardial scars, of which 114 (78%) were undetected by electrocardiogram or by clinical adjudication. In adjusted models, age, male sex, body mass index, hypertension, and current smoking at baseline were associated with myocardial scar at year 10. The OR per 8.9-year increment was 1.61 (95% CI, 1.36-1.91; P <\u2009.001); for men vs women: OR, 5.76 (95% CI, 3.61-9.17; P <\u2009.001); per 4.8-SD body mass index: OR, 1.32 (95% CI, 1.09-1.61, P =\u2009.005); for hypertension: OR, 1.61 (95% CI, 1.12-2.30; P =\u2009.009); and for current vs never smokers: 2.00 (95% CI, 1.22-3.28; P =\u2009.006). Age-, sex-, and ethnicity-adjusted CAC scores at baseline were also associated with myocardial scar at year 10. Compared with a CAC score of 0, the OR for scores from 1 through 99 was 2.4 (95% CI, 1.5-3.9); from 100 through 399, 3.0 (95% CI, 1.7-5.1), and 400 or higher, 3.3 (95% CI, 1.7-6.1) (P ≤ .001). The CAC score significantly added to the association of myocardial scar with age, sex, race/ethnicity, and traditional CVD risk factors (C statistic, 0.81 with CAC vs 0.79 without CAC, P =\u2009.01).
Answer: The prevalence of myocardial scars in a US community-based multiethnic cohort was 7.9%, of which 78% were unrecognized by electrocardiography or clinical evaluation. Further studies are needed to understand the clinical consequences of these undetected scars.

Does prevalence and correlate of Myocardial Scar in a US Cohort?