Characteristics of pubertal development in a multi-ethnic population of nine-year-old girls.
ABSTRACT Early age at menarche increases future disease risk. Secular decline in age at menarche has been attributed to body size characteristics, diet, and energy expenditure. Risk factors for puberty have been less frequently explored.
A cross-sectional study of 186 New York Metropolitan Area, 9-year-old girls (54 African-American, 70 Hispanic, 62 Caucasians) used interviewer-administered questionnaires to assess exposures. Height and weight were measured. Pediatricians assessed pubertal development according to Tanner stages.
African-Americans were more likely than Caucasians to have achieved puberty as determined by breast or hair development (stage 2 or higher) [age-adjusted odds ratios and 95% confidence intervals = 4.91 (2.15-11.19) and 4.25 (1.85-9.77), respectively]. Pubertal development was similar among Hispanics and Caucasians. Adiposity and height were significantly positively associated with breast or hair development. More sedentary activity hours non-significantly increased the likelihood of hair development. Lower energy, but higher polyunsaturated fat, consumption were suggestive of an association with breast development. Vitamin C and hair development were inversely related. No other nutrients or physical activity measures were related to pubertal development.
Results are consistent with height and adiposity being associated with pubertal development. Sedentary activity or diet might possibly influence maturation.
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ABSTRACT: Increased fat intake is associated with obesity and may make obese individuals uniquely susceptible to the effects of lipophilic aryl hydrocarbon receptor (AHR) ligands. We investigated the consequences of high-fat diet (HFD) and AHR ligands on body composition, mammary development, and hepatic P450 expression. Pregnant C57BL/6J (B6) and DBA/2J (D2) dams, respectively expressing high- or low-responsive AHR, were dosed at mid-gestation with TCDD. At parturition, mice were placed on an HFD or a low-fat diet (LFD). Body fat of progeny was measured before dosing with 7,12-dimethylbenz[a]anthracene (DMBA). Fasting blood glucose was measured, and liver and mammary glands were analyzed. Maternal TCDD exposure resulted in reduced litter size in D2 mice and, on HFD, reduced postpartum survival in B6 mice. In D2 mice, HFD increased body mass and fat in off-spring, induced precocious mammary gland development, and increased AHR expression compared with mice given an LFD. Maternal TCDD exposure increased hepatic Cyp1a1 and Cyp1b1 expression in offspring on both diets, but DMBA depressed Cyp1b1 expression only in mice fed an HFD. In D2 progeny, TCDD exposure decreased mammary terminal end bud size, and DMBA exposure decreased the number of terminal end buds. Only in D2 progeny fed HFD did perinatal TCDD increase blood glucose and the size of mammary fat pads, while decreasing both branch elongation and the number of terminal end buds. We conclude that despite having a low-responsive AHR, D2 progeny fed a diet similar to that consumed by most people are susceptible to TCDD and DMBA exposure effects blood glucose levels, mammary differentiation, and hepatic Cyp1 expression.Environmental Health Perspectives 09/2009; 117(9):1414-9. DOI:10.1289/ehp.0800530 · 7.03 Impact Factor
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ABSTRACT: Broadly stated, the Biobehavioral model proposes that what people think and feel affects the state of their health in two fundamental ways: by affecting their behavioral choices (e.g., consumption of alcoholic beverages) and/or by affecting biological processes (e.g., immune defenses) that may affect risk of disease and prognosis. Our Postdoctoral Training Program in Biobehavioral Breast Cancer Research was designed to provide trainees with the necessary intellectual background to do interdisciplinary research and become independent investigators in this underdeveloped area of research. This has been achieved through the implementation of a Core Curriculum, a seminar series, as well as "hands-on" research experience on existing and independent projects under the guidance of experienced mentors. At the conclusion of the program, nine researchers have completed the training.