Within-person reproducibility of urinary bisphenol A and phthalate metabolites over a 1 to 3 year period among women in the Nurses’ Health Studies: a prospective cohort study

Environmental Health

Research

Mary K Townsend¹  A Heather Eliassen²  Frank B Hu³  Xingnan Li⁴  Adrian A Franke⁴ 

[1] Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, 181 Longwood Ave, MA 02115, Boston, USA;Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, 181 Longwood Ave, MA 02115, Boston, USA;Department of Epidemiology, Harvard School of Public Health, 677 Huntington Ave, MA 02115, Boston, USA;Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, 181 Longwood Ave, MA 02115, Boston, USA;Department of Epidemiology, Harvard School of Public Health, 677 Huntington Ave, MA 02115, Boston, USA;Department of Nutrition, Harvard School of Public Health, 665 Huntington Ave, MA 02115, Boston, USA;University of Hawai’i Cancer Center, 701 Ilalo St, HI 96813, Honolulu, USA;

关键词: Adult;    Biological markers/urine;    Bisphenol a;    Phthalate metabolites;    Reproducibility;   

DOI  :  10.1186/1476-069X-12-80

 received in 2013-05-02, accepted in 2013-08-21,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundAssociations of bisphenol A and phthalates with chronic disease health outcomes are increasingly being investigated in epidemiologic studies. The majority of previous studies of within-person variability in urinary bisphenol A and phthalate metabolite concentrations have focused on reproducibility over short time periods. Long-term reproducibility data are needed to assess the potential usefulness of these biomarkers for prospective studies, particularly those examining risk of diseases with long latency periods. Low within-person reproducibility may attenuate relative risk estimates and reduce statistical power to detect associations with disease. Therefore, we assessed within-person reproducibility of bisphenol A, eight phthalate metabolites, and phthalic acid in spot urine samples over 1 to 3 years among women enrolled in two large cohort studies.MethodsWomen in the Nurses’ Health Study and Nurses’ Health Study II provided two spot urine samples, 1 to 3 years apart (n = 80 women for analyses of bisphenol A; n = 40 women for analyses of phthalate metabolites; n = 34 women for analyses of phthalic acid). To measure within-person reproducibility, we calculated Spearman rank correlation coefficients and intraclass correlation coefficients for creatinine-adjusted concentrations of bisphenol A, phthalate metabolites, and phthalic acid.ResultsOver 1 to 3 years, within-person variability of bisphenol A was high relative to total variability (intraclass correlation coefficient = 0.14) and rankings of bisphenol A levels between time-points were weakly correlated (Spearman correlation = 0.19). Seven of the eight phthalate metabolites and phthalic acid demonstrated moderate within-person stability over time (Spearman correlation or intraclass correlation coefficient = 0.39-0.55). Restricting analyses to first-morning urine samples did not alter results.ConclusionsSingle measurements of bisphenol A in spot urine samples were highly variable within women over 1 to 3 years, indicating that investigation of associations between a single urinary bisphenol A measurement and disease risk may be challenging in epidemiologic studies. The majority of urinary phthalate metabolites and phthalic acid appeared moderately reproducible within women over time, suggesting single measurements may be useful in epidemiologic studies, although observed relative risks can be substantially attenuated.

【 授权许可】

CC BY   
© Townsend et al.; licensee BioMed Central Ltd. 2013