Urinary phthalate metabolite concentrations and diabetes among women in the National Health and Nutrition Examination Survey (NHANES) 2001-2008.
BACKGROUND
Previous studies have shown that women have higher urinary concentrations of several phthalate metabolites than do men, possibly because of a higher use of personal care products. Few studies have evaluated the association between phthalate metabolites, diabetes, and diabetes-related risk factors among women.


OBJECTIVE
We explored the association between urinary phthalate metabolite concentrations and diabetes among women who participated in a cross-sectional study.


METHODS
We used urinary concentrations of phthalate metabolites, analyzed by the Centers for Disease Control and Prevention, and self-reported diabetes of 2,350 women between 20 and 79 years of age who participated in the NHANES (2001-2008). We used multiple logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) and adjusted for urinary creatinine, sociodemographic characteristics, dietary factors, and body size. A secondary analysis was conducted for women who did not have diabetes to evaluate the association between phthalate metabolite concentrations and fasting blood glucose (FBG), homeostasis model assessment-estimated insulin resistance, and glycosylated hemoglobin A1c.


RESULTS
After adjusting for potential confounders, women with higher levels of mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), monobenzyl phthalate (MBzP), mono-(3-carboxypropyl) phthalate (MCPP), and three di-(2-ethylhexyl) phthalate metabolites (ΣDEHP) had an increased odds of diabetes compared with women with the lowest levels of these phthalates. Women in the highest quartile for MBzP and MiBP had almost twice the odds of diabetes [OR = 1.96 (95% CI: 1.11, 3.47) and OR = 1.95 (95% CI: 0.99, 3.85), respectively] compared with women in the lowest quartile. Nonmonotonic, positive associations were found for MnBP and ΣDEHP, whereas MCPP appeared to have a threshold effect. Certain phthalate metabolites were positively associated with FBG and insulin resistance.


CONCLUSIONS
Urinary levels of several phthalates were associated with prevalent diabetes. Future prospective studies are needed to further explore these associations to determine whether phthalate exposure can alter glucose metabolism and increase the risk of insulin resistance and diabetes.
Brigham and Women's Hospital and Harvard Medical School, 1620 Tremont St., Division of Women's Health, 3rd Floor, Boston, MA 02120, USA. tjames-todd@bics.bwh.harvard.edu
Tamarra
T
James-Todd
Richard
R
Stahlhut
John D
JD
Meeker
Sheena-Gail
SG
Powell
Russ
R
Hauser
Tianyi
T
Huang
Janet
J
Rich-Edwards
D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000139:chemically induced / Q000453:epidemiology*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009749:Nutrition Surveys; D010795:Phthalic Acids / Q000652:urine*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D004785:Environmental Pollutants; D010795:Phthalic Acids