Association of Urinary Phthalate Metabolites With Erectile Dysfunction in Racial and Ethnic Groups in the National Health and Nutrition Examination Survey 2001-2004

Abstract

Phthalates are endocrine-disrupting compounds detectable in more than 75% of the U.S. population with differential distributions across racial and ethnic groups, and they have been linked with reduced levels of serum testosterone. This study aims to investigate the associations of phthalate metabolites with erectile dysfunction (ED) and to determine whether these associations vary by race/ethnicity among men in the United States. Analyzed data for 12 phthalate metabolites from 3,746 men (≥20 years old), who participated in the National Health and Nutrition Examination Survey 2001-2004 cross-sectional study, were included. Metabolites included MBP, MCHP, MEP, MEHP, MiNP, MBzP, MMP, MCPP, MEHHP, MEOHP, MiBP, and MECPP. Racial/ethnic groups included non-Hispanic Blacks ( n = 770), non-Hispanic Whites ( n = 2,147), and Mexican Americans ( n = 829). ED was assessed by a single question during a self-paced, computer-assisted self-interview. In racial/ethnic stratified analyses, there were higher MBP and MBzP concentrations that had a strong-dose response association with lower prevalence odds of ED among Mexican Americans, p_trend < .01, and p_trend = .03, respectively. Similarly, a significant inverse association between MEHHP and likelihood of ED among non-Hispanic Black men ( p_trend < .04) was observed. Furthermore, significant inverse associations between higher concentrations of phthalates and ED were identified only in minority populations. Further investigations, particularly prospective studies, are warranted to determine the role of phthalates on the biological mechanism(s) associated with ED. A focus may be placed on testosterone levels which are suggested to be affected by phthalates, and also low levels of testosterone are suggested to increase the risk of ED.

Keywords: NHANES; erectile dysfunction; phthalates; race and ethnicity.

Figure 1.

Association of mono-n-butyl phthalate (MBP) with erectile dysfunction (ED) in total population and stratified by race and ethnicity. Note. MBP was analyzed in continuous (C) and in quartiles (Q1-Q4) format. Adjusted for age, race/ethnicity (only in total population), physical activity (vigorous and moderate), smoking status, education, obesity, diabetes, and urinary creatinine. Diamonds and errors bars indicate point estimates and 95% confidence intervals, respectively. Only among Mexican American men, there was a significant inverse association between MBP and ED (p_trend < .01).

Figure 2.

Association of mono-benzyl phthalate (MBzP) with erectile dysfunction (ED) in total population and stratified by race and ethnicity. Note. MBP was analyzed in continuous (C) and in quartiles (Q1-Q4) format. Adjusted for age, race/ethnicity (only in total population), physical activity (vigorous and moderate), smoking status, education, obesity, diabetes, and urinary creatinine. Diamonds and errors bars indicate point estimates and 95% confidence intervals, respectively. Only among Mexican American men, there was a significant inverse association between MBzP and ED (p_trend = .03).

Figure 3.

Association of Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) with erectile dysfunction (ED) in total population and stratified by race and ethnicity. Note. MEHHP was analyzed in continuous (C) and in quartiles (Q1-Q4) format. Adjusted for age, race/ethnicity (only in total population), physical activity (vigorous and moderate), smoking status, education, obesity, diabetes, and urinary creatinine. y-Axis indicates odds ratio. Diamonds and errors bars indicate point estimates and 95% confidence intervals, respectively. Only among non-Hispanic Black men, there was a significant inverse association between MEHHP and ED (p_trend = .04).