The effects of phthalate and nonylphenol exposure on body size and secondary sexual characteristics during puberty

• A dose–response relationship was observed between the concentrations of phthalic acid esters (PAE) metabolites and anthropometric indices (APs).
• Skinfold thickness, waist circumference, waist-to-height ratio and waist-to-hip ratio are indices that are more sensitive than hip circumference and body mass index (BMI) for measuring the effect of PAE exposure on obesity.
• Mono-methyl phthalate (MMP) exposure was associated with pubic hair in boys.
• No interactions were found with regard to co-exposure to PAEs and nonylphenol (NP) and either APs or pubertal maturity.

BackgroundSome phthalic acid esters (PAEs) and nonylphenol (NP) are endocrine-disrupting chemicals (EDCs) that are widely used in consumer products. Consequently, the general population is exposed simultaneously to both groups of chemicals.ObjectiveTo investigate the single- and co-exposure effects of PAEs (DMP, DEP, DnBP, DiBP, BBzP, and DEHP) and NP on obesity and pubertal maturity to compare the body sizes of general adolescents with the complainants of the phthalate-tainted foods scandal that occurred in Taiwan.MethodsThis study included 270 general adolescents aged 6.5–15.0 years and 38 complainants aged 6.5–8.5 years. Nine metabolites of the five PAEs and of NP were measured in urine. We used a questionnaire to evaluate pubertal maturity, measured anthropometric indices (APs) to assess body size, and collected urine samples to measure the two groups of chemicals.ResultsWe found that urinary PAE metabolite concentrations (specifically, metabolites of DEP, DnBP, DiBP, and DEHP) were positively associated with the APs for abdominal obesity (including skinfold thickness, waist circumference, waist-to-height ratio, and waist-to-hip) and indicated a dose–response relationship. Mono-methyl phthalate (MMP) exposure was inversely associated with pubarche among boys. The daily intake of DEHP in general adolescents exceeded the reference doses (RfD-20 μg/kg bw/day) and tolerable daily intake (TDI-50 μg/kg bw/day) by 3.4% and 0.4%, respectively. No associations were observed between NP exposure or co-exposure and the APs or pubertal maturity. No significant differences were observed between general adolescents and the complainants with regard to weight, height, or BMI.ConclusionsThe study suggests that PAE (specifically, DEP, DnBP, DiBP, and DEHP) exposure is associated with abdominal obesity in adolescents and that the APs for abdominal obesity are more sensitive than BMI for measuring obesity among adolescents. We suggest that the RfD and TDI for PAEs should be revised to provide sufficient protection.