title: Association of blood lead levels with onset of puberty in Russian boys.
abstract: BACKGROUND
  Epidemiologic studies suggest a temporal trend of earlier onset and longer duration of puberty, raising concerns regarding the potential impact of environmental factors on pubertal development. Lead exposure has been associated with delayed pubertal onset in girls; however, epidemiologic data in boys are limited.
  
  
  METHODS
  We used multivariable logistic regression models to explore the cross-sectional association of blood lead levels with growth and pubertal onset based on physician-assessed testicular volume (TV) and pubertal staging in 489 boys 8-9 years of age from Chapaevsk, Russia. We used multivariable linear regression models to assess associations of blood lead levels with somatic growth at the study entry visit.
  
  
  RESULTS
  The median (25th-75th percentile) blood lead level was 3 microg/dL (2-5 microg/dL). Height, weight, body mass index, birth weight, and gestational age were predictive of the onset of puberty as assessed either by TV (> 3 mL), genitalia stage (G2), or both. Blood lead level was inversely associated with height (p < 0.001) and weight (p = 0.06) after adjustment for birth weight, gestational age, and age at examination. In multivariable adjusted analyses, boys with blood lead levels > or = 5 microg/dL had 43% reduced odds of having entered G2 compared with those with lower levels (odds ratio = 0.57; 95% confidence interval, 0.34-0.95, p = 0.03).
  
  
  CONCLUSIONS
  Relatively low environmental blood lead levels were associated with decreased growth and differences in pubertal onset in periadolescent Russian boys. Future analyses of this prospective cohort will address pubertal onset and progression in relation to lead and other environmental chemicals.
authors.affiliation: Environmental and Occupational Medicine and Epidemiology Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA. rhauser@hohp.harvard.edu
authors.forename: Russ
authors.initials: R
authors.lastname: Hauser
authors.forename: Oleg
authors.initials: O
authors.lastname: Sergeyev
authors.forename: Susan
authors.initials: S
authors.lastname: Korrick
authors.forename: Mary M
authors.initials: MM
authors.lastname: Lee
authors.forename: Boris
authors.initials: B
authors.lastname: Revich
authors.forename: Elena
authors.initials: E
authors.lastname: Gitin
authors.forename: Jane S
authors.initials: JS
authors.lastname: Burns
authors.forename: Paige L
authors.initials: PL
authors.lastname: Williams
mesh_terms: D001837:Body Weights and Measures; D002648:Child; D003430:Cross-Sectional Studies; D006801:Humans; D007854:Lead / Q000097:blood* / Q000633:toxicity*; D016015:Logistic Models; D008297:Male; D011627:Puberty / Q000187:drug effects*; D012426:Russia / Q000453:epidemiology; D012959:Socioeconomic Factors
chemical_list: D007854:Lead