Blood lead levels and delayed onset of puberty in a longitudinal study of Russian boys
Department of Pediatrics; Department of Cell Biology
Medical Subject Headings
Adolescent; Body Size; Child; Cohort Studies; Food Habits; Health Surveys; Humans; Lead; Lead Poisoning; Longitudinal Studies; Male; Proportional Hazards Models; Puberty, Delayed; Russia; Sexual Maturation; Socioeconomic Factors
OBJECTIVE: We evaluated the association of blood lead levels (BLLs) with pubertal onset in a longitudinal cohort of Russian boys.
METHODS: A total of 489 Russian boys were enrolled in 2003-2005, at 8 to 9 years of age, and were monitored annually through May 2008. Cox proportional-hazards models were used to evaluate the association of BLLs at enrollment with time to pubertal onset during follow-up monitoring.
RESULTS: A total of 481 boys had BLLs, with a median of 3 microg/dL and 28% with values of > or =5 microg/dL. The proportion of pubertal boys increased with age, from 12% at age 8 to 83% at age 12 for testicular volume of >3 mL, from 22% to 90% for genitalia stage 2 or higher, and from 4% to 40% for pubic hair stage 2 or higher. After adjustment for potential confounders including BMI and height, boys with high BLLs (> or =5 microg/dL) had 24% to 31% reduced risk of pubertal onset, on the basis of testicular volume of >3 mL (hazard ratio [HR]: 0.73 [95% confidence interval [CI]: 0.55-0.97]; P = .03), genitalia staging (HR: 0.76 [95% CI: 0.59-0.98]; P = .04), and pubic hair staging (HR: 0.69 [95% CI: 0.44-1.07]; P = .10), compared with those with lower BLLs. Pubertal onset occurred 6 to 8 months later, on average, for boys with high BLLs, compared with those with BLLs of <5 microg>/dL.
CONCLUSION: Higher BLLs were associated with later pubertal onset in this prospective study of peripubertal Russian boys.
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Citation: Pediatrics. 2010 May;125(5):e1088-96. Epub 2010 Apr 5. Link to article on publisher's site