Silva · Environmental health perspectives 2004 · Cross-sectional biomonitoring survey · n=2540

Urinary levels of seven phthalate metabolites in the U.S. population from the National Health and Nutrition Examination Survey (NHANES) 1999-2000.

Cited 972 times in the scientific literature.

Level 4 - case-series / case-control

Cross-sectional biomonitoring survey

PubMed 14998749 · doi:10.1289/ehp.6723 · record verified 2026-08-27

What was done

Researchers measured urinary concentrations of monoester metabolites of seven phthalates in approximately 2,540 urine samples collected from participants aged 6 years and older in the 1999–2000 U.S. National Health and Nutrition Examination Survey (NHANES).

What was found

Metabolites monoethyl phthalate (MEP), monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), and mono-(2-ethylhexyl) phthalate (MEHP) were detected in > 75% of samples. Monoisononyl phthalate, mono-cyclohexyl phthalate, and mono-n-octyl phthalate were infrequently detected (percentages not given). Non-Hispanic Black participants had significantly higher MEP concentrations than Mexican Americans and non-Hispanic white participants. Children had significantly higher levels of MBP, MBzP, and MEHP, but lower MEP levels, than adolescents and adults. Females had significantly higher concentrations of MEP, MBzP, and MBP than males, with similar MEHP levels. Exact numeric concentrations were not reported in the abstract.

Why it matters

This study provides representative baseline biomonitoring data showing widespread exposure to multiple phthalates in the general U.S. population, identifying higher exposure burdens among children and females.

Limits

The study is a cross-sectional survey using spot urine measurements without assessment of temporal variability or clinical health outcomes. Children under 6 years were excluded, and exact metabolite concentrations were omitted from the abstract.

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