Lead poisoning prevention requires knowledge of lead sources and of appropriate residential lead standards. Data are severely lacking on lead sources for Native American children, many of whom live in rural areas. Further, the relation of mining waste to blood lead concentrations (BPbs) of rural children is controversial. In collaboration with the eight tribes of northeastern Oklahoma, we assessed lead sources and their effects on BPbs for rural Native American and White children living in a former mining region. Venous blood lead, residential environmental (soil, dust, paint, water), and caregiver interview (e.g., hand-to-mouth behaviors, socioeconomic conditions) data were obtained from a representative sample of 245 children 1-6 years of age. BPbs ranged from 1 to 24 µg/dL. There were no ethnic differences in BPbs

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Purpose-Alcohol administered to laboratory animals has been shown to suppress pubertyrelated hormones and delay puberty by interfering with ovarian development and function. The effects of early substance use on human pubertal development are relatively unexplored.Methods-This cross-sectional study of 3106 females, ages 11-21, evaluates the association between prepubertal alcohol and tobacco use and onset of puberty. Ages at initial breast development, body hair growth and menarche were self-reported. Prepubertal alcohol and tobacco use were defined as age at first use preceding the age of pubertal development and accompanied by regular use. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazard models. Logistic regression was used to estimate the association between substance use and delayed puberty, defined as lack of breast development by age 13.Results-Unadjusted models indicated prepubertal tobacco use was associated with longer time to breast development (HR=0.74; 95% CI 0.65-0.85) and body hair growth (HR=0.81; 95% CI 0.71-0.93). Prepubertal alcohol use was associated with later breast development (HR=0.71; 95% CI 0.57-0.88). The direction of the observed associations remained consistent after adjusting for covariates, but the magnitude of effects were attenuated and the upper bound of the 95% CIs exceeded the null value. Girls who used alcohol before puberty had four times the odds of having delayed puberty (OR=3.99; 95% CI 1.94-8.21) compared to non-users. Conclusion-The results of this study suggest the endocrine-disrupting effects of alcohol and tobacco use may alter the timing of pubertal development. These cross-sectional findings warrant further investigation.

Children First (C1), a nurse home visitation programme for first-time mothers, was implemented statewide in Oklahoma in mid-1997. The objective of this study was to compare the risks of low (< 2500 g) and very low birthweight (< 1500 g), preterm (< 37 weeks) and very preterm (< 30 weeks) deliveries and infant mortality between mothers participating and not participating in C1. All 239,466 Oklahoma birth certificates were reviewed. The C1 and birth certificate databases were matched to identify C1 participants. Mother's age at delivery, education level, race, marital status, prior pregnancy loss or pregnancy risk factors, birthweight and gestational age at delivery were measured from the birth certificates. Death certificates were matched to the birth certificates to identify infant deaths. A Bayesian multivariable logistic regression was used to analyse the data. Among single mothers without pregnancy risk factors, the risks of all study outcomes were lower for participants in C1: adjusted odds ratio (aOR) 0.89, [95% Bayesian Credible Interval (BCI) 0.79, 1.00] for preterm delivery; aOR 0.71, [95% BCI 0.50, 0.98] for very preterm delivery; aOR 0.86, [95% BCI 0.75, 0.98] for low birthweight; aOR 0.77, [95% BCI 0.56, 1.02] for very low birthweight and aOR 0.36, [95% BCI 0.17, 0.63] for infant mortality. These risk reductions were not observed among married mothers. In both single and married mothers, the presence of pregnancy risk factors reduced the impact of C1 on lowering the risk of low birthweight and preterm deliveries. The C1 programme targets young, pregnant women of low socio-economic level. We found that among single mothers, the risks of perinatal adverse outcomes are reduced or similar to those found in non-participating mothers. A reduced effect of C1 in the presence of pregnancy risk factors may be because mothers with pregnancy risk factors who did not participate in C1 received better prenatal care, or that C1 interventions do not impact these particular factors. C1 shows promise in reducing infant mortality in single mothers. Lower incidence of preterm and very preterm deliveries is especially interesting and future analyses should focus on isolating programme components specifically associated with influencing these outcomes.