The Journal of clinical endocrinology and metabolism
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J. Clin. Endocrinol. Metab. · Nov 2014
ReviewEndocrine disorders in adolescent and young female athletes: impact on growth, menstrual cycles, and bone mass acquisition.
Puberty is a crucial period of dramatic hormonal changes, accelerated growth, attainment of reproductive capacity, and acquisition of peak bone mass. Participation in recreational physical activity is widely acknowledged to provide significant health benefits in this period. Conversely, intense training imposes several constraints, such as training stress and maintenance of very low body fat to maximize performance. Adolescent female athletes are therefore at risk of overtraining and/or poor dietary intake, which may have several consequences for endocrine function. The "adaptive" changes in the hypothalamic-pituitary-gonadal, -adrenal, and somatotropic axes and the secretory role of the adipose tissue are reviewed, as are their effects on growth, menstrual cycles, and bone mass acquisition. ⋯ Young female athletes present a high prevalence of menstrual disorders, including delayed menarche, oligomenorrhea, and amenorrhea, characterized by a high degree of variability according to the type of sport. Exercise-related reproductive dysfunction may have consequences for growth velocity and peak bone mass acquisition. Recent findings highlight the endocrine role of adipose tissue and energy balance in the regulation of homeostasis and reproductive function. A better understanding of the mechanisms whereby intense training affects the endocrine system may orient research to develop innovative strategies (ie, based on nutritional or pharmacological approaches and individualized modalities of training and competition) to improve the medical care of these adolescents and protect their reproductive function.
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J. Clin. Endocrinol. Metab. · Nov 2014
Differences in overlapping meta-analyses of vitamin D supplements and falls.
Overlapping meta-analyses on the same topic are common and often report discordant results. An Endocrine Society (ES) meta-analysis reported that vitamin D with calcium reduced the risk of falls, whereas vitamin D monotherapy had no effect. Despite meta-analyzing an overlapping set of trials, we concluded that vitamin D with or without calcium had no effect on falls. ⋯ Methodological differences in utilizing data from the same trials directly led to substantially different conclusions between meta-analyses about the efficacy of vitamin D supplements on falls. More detailed reporting of meta-analyses is necessary to allow readers to understand the discordant results from overlapping meta-analyses.
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J. Clin. Endocrinol. Metab. · Nov 2014
Impact of duration of critical illness on the adrenal glands of human intensive care patients.
Adrenal insufficiency is considered to be prevalent during critical illness, although the pathophysiology, diagnostic criteria, and optimal therapeutic strategy remain controversial. During critical illness, reduced cortisol breakdown contributes substantially to elevated plasma cortisol and low plasma ACTH concentrations. ⋯ Lipid depletion and reduced ACTH-regulated gene expression in prolonged critical illness suggest that sustained lack of ACTH may contribute to the risk of adrenal insufficiency in long-stay ICU patients.