Reply

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55926/1/22383_ftp.pd

Reply

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34293/1/38_ftp.pd

Semiparametric Regression for Periodic Longitudinal Hormone Data from Multiple Menstrual Cycles

We consider Semiparametric regression for periodic longitudinal data. Parametric fixed effects are used to model the covariate effects and a periodic nonparametric smooth function is used to model the time effect. The within–subject correlation is modeled using subject-specific random effects and a random stochastic process with a periodic variance function. We use maximum penalized likelihood to estimate the regression coefficients and the periodic nonparametric time function, whose estimator is shown to be a periodic cubic smoothing spline. We use restricted maximum likelihood to simultaneously estimate the smoothing parameter and the variance components. We show that all model parameters can be easily obtained by fitting a linear mixed model. A common problem in the analysis of longitudinal data is to compare the time profiles of two groups, e.g., between treatment and placebo. We develop a scaled chi-squared test for the equality of two nonparametric time functions. The proposed model and the test are illustrated by analyzing hormone data collected during two consecutive menstrual cycles and their performance is evaluated through simulations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65472/1/j.0006-341X.2000.00031.x.pd

The Risk for Infant Mortality among Adolescent Childbearing Groups

Objective: To evaluate risk disparities and risk factors for infant mortality among adolescent childbearing age groups. Methods: We combined the 1995 and 1996 comprehensive U.S. birth cohorts provided by the National Center for Heath Statistics. Our analysis included 777,762 singleton, first births to women aged 12-19 years linked to 4631 infant deaths. We used both bivariate comparisons and multivariable logistic regression for our analysis, with infant mortality as our main outcome measure. Results: Rates of infant mortality are substantially higher for ≤15-year-olds (8.1/1000 live births) compared with 16-17-year-olds (6.3/1000 live births) and 18-19-year-olds (5.4/1000 live births). Even after adjusting for risk factors associated with poor outcomes, including alcohol use, tobacco use, and prenatal care use, the risk for infant mortality was 1.6 (95% confidence interval [95% CI] 1.4, 1.7) times greater for infants of mothers ≤15 years old as compared with those mothers 18-19 years old. In the ≤15-year-old group, 62% of fathers were not reported on the child's birth certificate. Not reporting the father was associated with a 24% increased risk for infant mortality after adjusting for maternal and infant risk factors. Conclusions: Childbearing in ≤15-year-olds is associated with a substantial increased risk for infant mortality compared with childbearing in older adolescence. This study suggests that not reporting the father on a birth certificate is a potential risk marker. Risk differences among adolescent age groups may be important to consider when creating tailored intervention and prevention strategies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63403/1/154099902762203722.pd

Interpregnancy weight retention patterning in women who breastfed

This study compares weight change in lactating women with an 18-month interpregnancy interval with woman who also breastfed but did not have an immediate subsequent pregnancy. Cases were women who breastfed an index infant for 6 months and subsequently became pregnant within 18 months (cases = 25), and the controls also breastfed an index infant for 6 months but had no ensuing pregnancy (controls = 20) within 18 months. The pattern of postpartum weight retention following the initial pregnancy was not statistically different in cases compared to the controls. However, following their ensuing subsequent pregnancy, cases were 1.3 kg heavier than their average weight after their baseline pregnancy ( P = 0.02). The best predictor of this greater weight was their weight change during the interpregnancy interval ( P = 0.03). Total weight gain during the gestational period of the subsequent pregnancy was not associated with the greater weight following the subsequent pregnancy. Likewise, estimates of the amount of energy as calories or physical activity levels were not significant predictors of this greater weight following the subsequent pregnancy. These findings suggest that monitoring of postpartum weight, even in breastfeeding women, is essential. These findings indicate that breastfeeding women begin the next postpartum interval weighing more than the amount observed in the initial postpartum period. J. Matern.–Fetal Med. 7:89–94, 1998. © 1998 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35150/1/7_ftp.pd

Relating smoking, obesity, insulin resistance, and ovarian biomarker changes to the final menstrual period

To determine if smoking, obesity, and insulin resistance mediated age at final menstrual period (FMP), we examined anti-Müllerian hormone (AMH), inhibin B, and follicle-stimulating hormone (FSH) as biomarkers of changing follicle status and ovarian aging. We performed a longitudinal data analysis from a cohort of premenopausal women followed to their FMP. Our results found that smokers had an earlier age at FMP ( P < 0.003) and a more rapid decline in their AMH slope relative to age at FMP ( P < 0.002). Smokers had a lower baseline inhibin B level relative to age at the FMP than nonsmokers ( P = 0.002). Increasing insulin resistance was associated with a shorter time to FMP ( P < 0.003) and associations of obesity and time to FMP were observed ( P = 0.004, in model with FSH). Change in ovarian biomarkers did not mediate the time to FMP. We found that smoking was associated with age at FMP and modified associations of AMH and inhibin B with age at FMP. Insulin resistance was associated with shorter time to FMP independent of the biomarkers. Interventions targeting smoking and insulin resistance could curtail the undue advancement of reproductive aging.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79293/1/j.1749-6632.2010.05523.x.pd

A comparison of periodontal disease among rural Amish and non-Amish adults

Periodontal disease can be more efficiently studied within a homogeneous population where genetic influences and lifestyles are similar enough to negate their effect on the disease process. This study focuses on an Amish population in southern Michigan who isolate themselves from outside influences and their non-Amish neighbors. A total of 425 Amish and 290 non-Amish were contacted resulting in 330 Amish and 215 non-Amish who were examined in their homes giving a participation rate of 76.2%. Ages ranged from 18 to 82 years. Prevalence of periodontal disease tended to be higher among males and increased with age. There were slightly more Amish females (52%) than non-Amish (49%). Means of periodontal conditions for Amish were 1.35 mm for attachment loss, 2.59 mm for pocket depth, 0.24 for calculus, 0.77 for plaque and 0.74 for gingivitis. For non-Amish, the means were 1.03 mm for attachment loss, 2.38 mm for pocket depth, 0.40 for calculus, 0.95 for plaque and 0.87 for gingivitis. It is of interest that the Amish do not practice routine oral hygiene. Only 36.8% of Amish reported brushing at least 1 × a day compared to 84.6% of non-Amish. Similarly, only 8.2% of Amish reported flossing at least 1 × a week compared to 40.8% of non-Amish.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75729/1/j.1600-051X.1994.tb00734.x.pd

Thyroid stimulating hormone (TSH) concentrations and menopausal status in women at the mid-life: SWAN

objective We evaluated menopausal symptoms, menstrual cycle bleeding characteristics and reproductive hormones for their associations with thyroid stimulating hormone (TSH) concentrations in women at the mid-life from five ethnic groups. methods This report is from the baseline evaluation of the Study of Women's Health Across the Nation (SWAN), a community-based multiethnic study of the natural history of the menopausal transition. Enrollees were 42–52 years old (pre- and early perimenopausal) African American, Caucasian, Chinese, Hispanic and Japanese women ( n  = 3242). Enrollees were interviewed about self-reported diagnosed hypo- and hyperthyroidism or thyroid treatment, menopausal symptoms and menstrual cycle bleeding characteristics. Serum was assayed for TSH, oestradiol, testosterone, FSH and SHBG. results There were 6·2% of women with TSH > 5·0 mIU/ml and 3·2% with TSH  5·0 mIU/ml ( P  < 0·008) or < 0·5 mIU/ml ( P  < 0·02). Women with TSH values outside the range of 0·5–5·0 mIU/ml were more likely to report shorter or longer menstrual periods ( P  = 0·004 for both) than women within that range. FSH, SHBG, dehydroepiandrosterone sulphate (DHEA-S), testosterone, and oestradiol concentrations were not associated with TSH concentrations. conclusion In mid-aged women, there was a 9·6% prevalence of TSH values outside the euthyroid range of 0·5–5·0 mIU/ml. Although TSH was associated with bleeding length and self-reported fearfulness, it was not associated with indicators of the menopausal transition, including menopausal stage defined by bleeding regularity, menopausal symptoms or reproductive hormone concentrations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73917/1/j.1365-2265.2003.01718.x.pd

Associations of testosterone and sex hormone binding globulin with adipose tissue hormones in midlife women

Objective: Regulators of adipose tissue hormones remain incompletely understood, but may include sex hormones. As adipose tissue hormones have been shown to contribute to numerous metabolic and cardiovascular disorders, understanding their regulation in midlife women is of clinical importance. Therefore, we assessed the associations between testosterone (T) and sex hormone binding globulin (SHBG) with leptin, high molecular weight (HMW) adiponectin, and the soluble form of the leptin receptor (sOB‐R) in healthy midlife women. Design and Methods: Cross‐sectional analyses were performed using data from 1,881 midlife women (average age 52.6 (±2.7) years) attending the sixth Annual follow‐up visit of the multiethnic Study of Women's Health Across the Nation. Results: T was weakly negatively associated with both HMW adiponectin and sOB‐R ( r = −0.12 and r = −0.10, respectively; P < 0.001 for both), and positively associated with leptin ( r = 0.17; P < 0.001). SHBG was more strongly and positively associated with both HMW adiponectin and sOB‐R ( r = 0.29 and r = 0.24, respectively; P < 0.001 for both), and more strongly and negatively associated with leptin ( r = −0.27; P < 0.001). Adjustment for fat mass, insulin resistance, or waist circumference only partially diminished associations with HMW adiponectin and sOB‐R, but attenuated associations with leptin. In conclusion, in these midlife women, lower SHBG values, and to a lesser extent, higher T levels, were associated with lower, or less favorable, levels of adiponectin and sOB‐R, independent of fat mass. Conclusions: These data suggest that variation in these adipose hormones resulting from lower SHBG levels, and possibly, though less likely, greater androgenicity, may contribute to susceptibility for metabolic and cardiovascular outcomes during midlife in women.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97532/1/20256_ftp.pd

Estradiol and its metabolites and their association with knee osteoarthritis

Objective To determine if levels of endogenous estrogen or estrogen metabolites are associated with an increased risk of developing knee osteoarthritis (OA) in women. Methods Serum estradiol (E 2 ) and 2 urinary estrogen metabolites (2-hydroxyestrone and 16Α-hydroxyestrone) with radiographically defined prevalent and incident knee OA in 842 white and African American women from the Southeast Michigan Arthritis Cohort. Results The mean age and body mass index (BMI) of women in the cohort were 42.3 years and 28.5 kg/m 2 , respectively. Women who developed radiographically defined knee OA had significantly greater odds of having baseline endogenous early follicular phase estradiol concentrations in the lowest tertile (0.86; OR 1.86, 95% CI 1.01–3.44 compared with women with ratios in the 0.54–0.86 range), after adjustment for other covariates. Conclusion There were significant associations of lower baseline serum estradiol and urinary 2-hydroxyestrone with developing knee OA in middle-aged women.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55806/1/22005_ftp.pd