The timing of adrenarche in Maya girls, Merida, Mexico.

BACKGROUND: Adrenarche involves maturation of the hypothalamic-pituitary-adrenal axis and increased production of dehydroepiandrosterone and its sulfate ester, dehydroepiandrosterone-sulfate (DHEA-S). It occurs at ages 6 to 8 in industrialized populations, marking the transition from childhood to juvenility and cognitive development at middle childhood. Studies in subsistence level populations indicate a later age (8-9) for adrenarche, but only two such studies currently exist for comparison. AIMS: To investigate adrenarcheal age among Maya girls and its association with body composition and dietary variables. We hypothesized adrenarche would occur earlier given the current dual burden of nutrition in Mexico. MATERIALS AND METHODS: 25 Maya girls aged 7 to 9 from Merida, Mexico using ELISAs to measure salivary DHEA-S, standard anthropometry for height, weight, and skinfolds, bioelectrical impedance for body composition variables, as well as a food frequency questionnaire for dietary information. RESULTS: Our hypothesis was rejected-adrenarche occurred close to 9 years. While no measures of body composition were significantly associated with adrenarcheal status, girls eating meat and dairy products more frequently had significantly higher DHEA-S levels. DISCUSSION: Like other populations living in ecologically challenging environments, adrenarche occurred relatively late among Maya girls. Adrenarche has been linked to measures of body composition, particularly, the adiposity or body mass index rebound, but no relevant anthropometric measures were associated, possibly because of the small sample. CONCLUSION: Further studies are required to illuminate how adrenarcheal variation relates to developmental plasticity, body composition, pubertal progression, and animal product consumption in other transitional populations.

Childhood environment influences adrenarcheal timing among first-generation Bangladeshi migrant girls to the UK.

BACKGROUND: Adrenarche is a key early life event that marks middle childhood at approximately 7 years of age. Earlier work with British-Bangladeshi migrant women suggested that environmental conditions experienced before adrenarche influence adult reproductive function. We therefore investigated whether Bangladeshi children who migrate to the United Kingdom (UK) reach adrenarche earlier than non-migrants in Bangladesh or the United Kingdom. METHODS AND FINDINGS: Healthy girls, aged 5-16 years, were recruited from schools in Sylhet, Bangladesh and London, England comprising four groups: Sylhetis (n = 165), first-generation migrants to the United Kingdom (n = 42), second-generation girls (n = 162), and British girls of European origin (n = 50). Anthropometric measurements were collected together with questionnaire data for migration and socioeconomic characteristics. Saliva samples were assayed for dehydroepiandrosterone (DHEAS) using enzyme-linked immunosorbent assays. Multiple linear regressions tested for group differences in anthropometric and socioeconomic variables and DHEAS levels. Median ages at adrenarche (DHEAS>400 pg/ml) were estimated using Weibull regression models for parametric survival analysis. Hazard ratios for reaching adrenarche earlier and 95% confidence intervals (CI), both unadjusted and adjusted for anthropometric variables, were estimated from the survival analyses. First-generation migrants had a median age at adrenarche (5.3 years) that was significantly earlier than Sylheti (7.2), second-generation (7.4), and European (7.1) girls. In univariate analyses, first-generation girls reached adrenarche significantly earlier than Sylhetis [HR (CI): 2.8 (1.4-5.5]. In multivariate models, first generation girls still reached adrenarche earlier than Sylhetis after adjusting for height [HR(CI): 1.9 (0.9-4.1)] and weight [HR(CI):1.7 (0.8-3.8)], but these results were attenuated. CONCLUSIONS: We suggest that rapid catch-up growth experienced by first generation girls during early childhood may explain their advanced adrenarche. The environmental conditions leading to an earlier adrenarche, as well as the health implications of this early transition, merit further exploration.

Prediction models for insulin resistance in girls with premature adrenarche. The premature adrenarche insulin resistance score: PAIR score.

AIM: The purpose of this study was to develop an accurate regression model to predict insulin resistance in girls with premature adrenarche. METHODS: The insulin sensitivity index was calculated from the frequently sampled intravenous glucose tolerance test with tolbutamide. Thirty-five prepubertal girls (23 Caribbean-Hispanic and 12 African-American; mean age 6.8 years) were studied. The insulin sensitivity index was compared to birth weight, body mass index (BMI), the presence of acanthosis nigricans (AN), insulin-like growth factor 1, insulin-like growth factor binding protein 1, sex hormone binding globulin, lipid profile, and adrenocorticotropic hormone stimulated androgens. RESULTS: The best prediction models included birth weight, BMI, and AN (model 1: R(2) = 0.78) and BMI, AN, and serum 17-OH pregnenolone (model 2: R(2) = 0.76). When viewed as screening tests, a cutoff value <5.5 (premature adrenarche insulin resistance score) in both equations showed a sensitivity of 100% and a specificity of 85%. CONCLUSION: Born small for gestational age, premature adrenarche, obesity, AN, and higher serum 17-OH pregnenolone levels may confer negative, but independent, health risks.