American journal of epidemiology
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Multicenter Study
Similar relation of age and height to lung function among Whites, African Americans, and Hispanics.
Current guidelines recommend separate spirometry reference equations for whites, African Americans, and Mexican Americans, but the justification for this recommendation is controversial. The authors examined the statistical justification for race/ethnic-specific reference equations in adults in the Third National Health and Nutrition Examination Survey (1988-1994) and the Multi-Ethnic Study of Atherosclerosis Lung Study (2000-2006). Spirometry was measured following American Thoracic Society guidelines. "Statistical justification" was defined as the presence of effect modification by race/ethnicity among never-smoking participants without respiratory disease or symptoms and was tested with interaction terms for race/ethnicity (× age and height) in regression models. ⋯ Findings were similar in the Multi-Ethnic Study of Atherosclerosis Lung Study. The associations of age and height with lung function are similar across the 3 major US race/ethnic groups. Multiethnic rather than race/ethnic-specific spirometry reference equations are applicable for the US population.
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Multicenter Study
Longitudinal study of prepregnancy cardiometabolic risk factors and subsequent risk of gestational diabetes mellitus: The CARDIA study.
This study examined prepregnancy cardiometabolic risk factors and gestational diabetes mellitus (GDM) in subsequent pregnancies. The authors selected 1,164 women without diabetes before pregnancy who delivered 1,809 livebirths between 5 consecutive examinations from 1985 to 2006 in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. The authors measured prepregnancy cardiometabolic risk factors and performed multivariate repeated-measures logistic regression to compute the odds of GDM adjusted for race, age, parity, birth order, and other covariates. ⋯ Among overweight women, 26.7% with 1 or more cardiometabolic risk factors developed GDM versus 7.4% with none. Metabolic impairment exists before GDM pregnancy in nondiabetic women. Interconceptual metabolic screening could be included in routine health assessments to identify high-risk women for GDM in a subsequent pregnancy and to potentially minimize fetal exposure to metabolic abnormalities that program future disease.
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Multicenter Study
Association of environmental tobacco smoke exposure in childhood with early emphysema in adulthood among nonsmokers: the MESA-lung study.
Mechanical stress to alveolar walls may cause progressive damage after an early-life insult such as exposure to environmental tobacco smoke (ETS). This hypothesis was examined by using data from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort aged 45-84 years, free of clinical cardiovascular disease, recruited from 6 US sites in 2000-2002. The MESA-Lung Study assessed a fractal, structural measure of early emphysema ("alpha," lower values indicate more emphysema) and a standard quantitative measure ("percent emphysema") from cardiac computed tomography scans. ⋯ Analyses included 1,781 nonsmokers (<100 cigarettes, 20 cigars, or 20 pipefulls in their lifetime and urinary cotinine levels <100 ng/mL); mean age was 61 years (standard deviation, 10), and 65% were women. Childhood ETS exposure from 2 or more smokers (17%) compared with none (52%) was associated with 0.05 lower alpha and 2.8 higher percent emphysema (P for trend = 0.04 and 0.01, respectively) after adjustment for demographic, anthropometric, parental, and participant characteristics, as well as adult exposures (e.g., cumulative residential air pollution exposure, exposure to ETS as an adult). Childhood ETS exposure was associated with detectable differences on computed tomography scans of adult lungs of nonsmokers.
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Women with a previous stillbirth are known to be at increased risk of stillbirth in subsequent pregnancies. However, few studies have addressed the association between other complications of pregnancy and the future risk of stillbirth. Using linkage of national pregnancy and perinatal death registries, the authors performed a retrospective cohort study of 133,163 women having a second birth in Scotland between 1992 and 2001 whose first infant was liveborn. ⋯ There was a statistically significant positive interaction between previous delivery of a SGA infant and previous preeclampsia (p = 0.01): Women with this combination in their first pregnancy had an approximately fivefold risk of unexplained stillbirth in the second pregnancy (HR = 4.95, 95% CI: 2.63, 9.32). Associations were stronger with SGA unexplained stillbirths. The authors conclude that complicated first births of liveborn infants are associated with an increased risk of unexplained stillbirth in the next pregnancy.
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Follow-up information on subsequent pregnancies after mifepristone (RU486)-induced abortion is scarce. The authors examined whether one mifepristone-induced first-trimester abortion affects the outcome of a subsequent wanted pregnancy. In a study conducted in 1998-2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China, the authors enrolled 4,925 women with no history of induced abortion, 4,931 women with one previous mifepristone-induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth. ⋯ Although the mean birth weight of infants born to women with mifepristone abortion was 33 g (95% confidence interval: 17, 49) higher than that of infants born to women with no abortion, the frequencies of low birth weight and mean lengths of pregnancy were similar. There were no significant differences in risk of preterm delivery, frequency of low birth weight, or mean infant birth weight in the comparisons of women with previous mifepristone abortion and women with surgical abortion. This study suggests that one early abortion induced by mifepristone in nulliparous women has no adverse effects on the outcome of a subsequent pregnancy.