Lipid Adjustment for Chemical Exposures

Li, Daniel; Longnecker, Matthew P.; Dunson, David B.

doi:10.1097/ede.0b013e3182a671e4

Cited by 17 publications

(10 citation statements)

References 21 publications

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“…As OCPs are lipophilic and the optimal approach to account for lipids in analyses of these measures is uncertain (Li et al, 2013; Schisterman et al, 2005), we conducted alternative analyses comparing lipid-normalized measures with wet-weight measures adjusted for total serum lipids. Though lipid-normalized measures led to stronger dose-response associations compared to wet-weight measures adjusted for serum lipids, our interpretations of the main findings were unchanged.…”

Section: Discussionmentioning

confidence: 99%

Prepubertal organochlorine pesticide concentrations and age of pubertal onset among Russian boys

Lam

Williams

Lee

et al. 2014

Environment International

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Background In animal studies, organochlorine pesticide (OCP) exposure alters pubertal development, however, epidemiological data are limited and inconsistent. Objective To evaluate the associations of serum OCP concentrations [hexachlorobenzene (HCB), β-hexachlorocylohexane (β-HCH), and p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE)] with male pubertal onset. Methods In Chapaevsk, Russia, a town environmentally contaminated with OCPs, 350 8–9 year old boys with measured OCPs were enrolled during 2003–2005 and were followed annually for eight years. We evaluated three measures of pubertal onset: testicular volume (TV) > 3 mL in either testis, or stage 2 or greater for genitalia (G2+), or pubic hair (P2+). We used multivariable interval-censored models to evaluate associations of OCPs (quartiles) with physician-assessed pubertal onset. Results In adjusted models, boys with higher HCB concentrations had later mean ages of TV > 3 mL and P2+ (but not G2+). Mean age at attaining TV > 3 mL was delayed 3.6 (95% CI: −2.6, 9.7), 7.9 (95% CI: 1.7, 14.0), and 4.7 months (95% CI: −1.4, 10.9) for HCB Q2, Q3, and Q4, respectively, compared to Q1 (trend p: 0.06). Boys with higher HCB concentrations reached P2+ 0.1 months earlier (95% CI: −5.8, 5.6) for Q2, 4.7 months later (95% CI: −1.0, 10.3) for Q3 and 4.6 months later (95% CI: −1.1, 10.3) for Q4 compared to Q1 (trend p: 0.04). There were no associations of serum β-HCH and p,p′-DDE concentrations with age of pubertal onset. Conclusion Higher prepubertal serum HCB concentrations were associated with later age of gonadarche and pubarche.

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Section: Discussionmentioning

confidence: 99%

Prepubertal organochlorine pesticide concentrations and age of pubertal onset among Russian boys

Lam

Williams

Lee

et al. 2014

Environment International

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“…Separate core models were developed for each maturity measure. Because OCPs are lipophilic and because of the potential for bias, rather than modeling lipid-normalized OCPs, we instead chose to use the wet weights for OCPs and adjust for concurrently measured serum total lipids by including this as a covariate in the model ( Li et al 2013 ; Schisterman et al 2005 ). However, we also performed an alternative analysis using quartiles of lipid-normalized serum OCP concentrations rather than wet-weight serum OCPs.…”

Section: Methodsmentioning

confidence: 99%

Prepubertal Serum Concentrations of Organochlorine Pesticides and Age at Sexual Maturity in Russian Boys

Lam

Williams

Lee

et al. 2015

Environ Health Perspect

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BackgroundFew human studies have evaluated the impact of childhood exposure to organochlorine pesticides (OCP) on pubertal development.ObjectiveWe evaluated associations of serum OCP concentrations [hexachlorobenzene (HCB), β-hexachlorocyclohexane (βHCH), and p,p-dichlorodiphenyldichloroethylene (p,p´-DDE)] with age at attainment of sexual maturity among boys.MethodsFrom 2003 through 2005, 350 8- to 9-year-old boys from Chapaevsk, Russia, with measured OCPs were enrolled and followed annually for 8 years. We used multivariable interval-censored models to evaluate associations of OCPs (quartiles) with three physician-assessed measures of sexual maturity: Tanner stage 5 for genitalia growth, Tanner stage 5 for pubic hair growth, or testicular volume (TV) ≥ 20 mL in either testis.ResultsIn adjusted models, boys with higher HCB concentrations achieved sexual maturity reflected by TV ≥ 20 mL a mean of 3.1 months (95% CI: –1.7, 7.8), 5.3 months (95% CI: 0.6, 10.1), and 5.0 months (95% CI: 0.2, 9.8) later for quartiles Q2, Q3, and Q4, respectively, compared with Q1 (p trend = 0.04). Tanner stage 5 for genitalia growth was attained a mean of 2.2 months (95% CI: –3.1, 7.5), 5.7 months (95% CI: 0.4, 11.0), and 3.7 months (95% CI: –1.7, 9.1) later for quartiles Q2, Q3, and Q4, respectively, of βHCH compared with Q1 (p trend = 0.09). Tanner stage 5 for pubic hair growth occurred 6–9 months later on average for boys in the highest versus lowest quartile for HCB (p trend < 0.001), βHCH (trend p = 0.01), and p,p´-DDE (p trend = 0.04). No associations were observed between p,p´-DDE and Tanner stage 5 for genitalia growth or TV ≥ 20 mL.Conclusions and relevanceHigher prepubertal serum HCB and βHCH concentrations were associated with a later age at attainment of sexual maturity. Only the highest quartile of serum p,p´-DDE was associated with later pubic hair maturation.CitationLam T, Williams PL, Lee MM, Korrick SA, Birnbaum LS, Burns JS, Sergeyev O, Revich B, Altshul LM, Patterson DG Jr, Hauser R. 2015. Prepubertal serum concentrations of organochlorine pesticides and age at sexual maturity in Russian boys. Environ Health Perspect 123:1216–1221; http://dx.doi.org/10.1289/ehp.1409022

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“…Li et al took a different approach to the problem, considering lipids as a concomitant variable that is not a confounder but can nevertheless improve the precision of the estimate if included in the data analysis (20). In their simulation study, they assume that the standardization approach is generally correct, but that (1/serum lipid levels) may not be the most appropriate correction factor.…”

Section: Serum Lipid Adjustmentmentioning

confidence: 99%

Lipid and Creatinine Adjustment to Evaluate Health Effects of Environmental Exposures

O’Brien

Upson

Buckley

2017

Curr Envir Health Rpt

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Purpose of review Urine- and serum-based biomarkers are useful for assessing individuals’ exposure to environmental factors. However, variations in urinary creatinine (a measure of dilution) or serum lipid levels, if not adequately corrected for, can directly impact biomarker concentrations and bias exposure-disease association measures. Recent findings Recent methodological literature has considered the complex relationships between creatinine or serum lipid levels, exposure biomarkers, outcomes, and other potentially relevant factors using directed acyclic graphs and simulation studies. The optimal measures of urinary dilution and serum lipids have also been investigated. Summary Existing evidence supports the use of covariate-adjusted standardization plus creatinine adjustment for urinary biomarkers and standardization plus serum lipid adjustment for lipophilic, serum-based biomarkers. It is unclear which urinary dilution measure is best, but all serum lipid measures performed similarly. Future research should assess methods for pooled biomarkers and for studying diseases and exposures that affect creatinine or serum lipids directly.

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Lipid Adjustment for Chemical Exposures

Cited by 17 publications

References 21 publications

Prepubertal organochlorine pesticide concentrations and age of pubertal onset among Russian boys

Prepubertal organochlorine pesticide concentrations and age of pubertal onset among Russian boys

Prepubertal Serum Concentrations of Organochlorine Pesticides and Age at Sexual Maturity in Russian Boys

Lipid and Creatinine Adjustment to Evaluate Health Effects of Environmental Exposures

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