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Background: Early puberty is a common worldwide problem. Different parameters as genetics, metabolic diseases, obesity, as well as environmental factors may affect the age of puberty. This systematic review aims to survey the related literature on the effects of environmental pollutants and especially organohalogens and phthalates on early puberty. Materials and Methods: A systematic review of papers published in the English language was completed in January 2014. Studies on the associations of organohalogens and phthalates with the puberty time were included. A literature search was conducted in EMBASE, PubMed, Scopus, ISI Web of Science, and Cochrane Library from 1995 to January 2014; moreover manual search through references of relevant manuscripts was considered. The literature search identified 212 papers, of which 13 papers fulfilled the inclusion criteria of the current study. Two reviewers independently identified relevant papers for potential inclusion and assessed the methodological quality. Results: This review included 6572 participants in nine countries from three continents (Europe, North America, and Asia). Different studies determined the effects of pollutants on maturation signs and pubertal stages and confirmed the association of organohalogens and phthalates with early puberty. Conclusion: Based on the studied literature, environmental pollutants surround and accumulate in human societies and their adverse health effects are well documented. It can be concluded that organohalogens and phthalates are disturbing the normal process of puberty timing; especially their influence on early maturation in girls should be underscored. [ABSTRACT FROM AUTHOR]

Background: This study aims to assess the relationship of serum Mg and vitamin D levels in a nationally-representative sample of Iranian adolescents. Methods: The study participants consisted of 330 students, aged range from 10 to 18 years, consisting of an equal number of individuals with and without hypovitaminosis D. The correlation between serum 25 hydroxy vitamin D (25(OH) D) and magnesium (Mg) concentrations was determined. Results: The mean age of participants was 14.74 ± 2.587 years, without significant difference between those with hypovitaminosis D and those without it. The mean 25(OH) D level was 6.34 ± 1.47 ng/ml in the group with hypovitaminosis D and 39.27 ± 6.42 ng/ml in the group without it. The mean Mg level was 0.80 ± 0.23 mg/dl with lower level in the group with hypovitaminosis D than in others (0.73 ± 0.22 mg/dl vs. 0.87 ± 0.22 mg/dl, respectively) and according to t-test analysis, significant lower levels in the deficient group was observed (P = 0.0001). The linear regression analysis showed the meaningful relationship between Mg and 25(OH) D serum levels (P = 0.0001). Conclusions: Our study revealed significant associations between serum Mg and 25(OH) D levels. This finding may be of use for further studies on the prevention and management of hypovitaminosis D in children and adolescents. Further longitudinal studies shall evaluate the underlying mechanisms and the clinical significance of the current findings. [ABSTRACT FROM AUTHOR]