Women’s exposure to phthalates in relation to use of personal care products

Abstract

Background

Several phthalates, particularly diethyl phthalate (DEP) and di-n-butyl phthalate (DnBP), can be used in personal care products (PCPs) to fix fragrance and hold color. We investigated associations between women’s reported use of personal care products within the 24 hours prior to urine collection and concentrations of several urinary phthalate metabolites.

Methods

Between 2002–2005, 337 women provided spot urine samples and answered questions regarding their use of thirteen PCPs at a follow-up visit 3–36 months after pregnancy. We examined associations between urinary concentrations of several phthalate metabolites and use of PCPs using linear regression.

Results

Use of individual PCPs ranged from 7% (nail polish) to 91% (deodorant). After adjusting for age, education, and urinary creatinine, women reporting use of perfume had 2.92 times higher (95% CI: 2.20–3.89) concentration of monoethyl phthalate (MEP, the primary metabolite of diethyl phthalate) than other women. Other PCPs that were significantly associated with MEP included: hair spray, nail polish, and deodorant. MEP concentrations increased with the number of PCPs used.

Conclusion

PCP use was widespread in this group of recently pregnant women. Women’s use of PCPs, particularly of perfumes and fragranced products, was positively associated with urinary concentration of multiple phthalate metabolites.

Introduction

Phthalates, diesters of phthalic acid, are used in numerous products, including pharmaceuticals, personal care products, adhesives, paints, toys, medical devices, and building supplies (Schettler, 2006). Because phthalates are not chemically bound additives in these products, phthalates may leach, migrate, and evaporate from these products, resulting in human exposure via multiple routes from direct or indirect contact. Due to their widespread use in common, everyday products, exposure to phthalates is nearly ubiquitous in westernized societies.

Phthalates can enter the body through many routes, including: ingestion of phthalate-containing foods, dermal application of products containing phthalates, and inhalation of air containing phthalate particulates (Wormuth et al., 2006), with route of exposure differing by phthalate compound. For example, diethyl phthalate (DEP), used in multiple personal care products, is more likely to enter the body through dermal or inhalational exposure whereas di(2-ethylhexyl) phthalate (DEHP), a commonly used plasticizer, enters the body through dietary ingestion more often than other routes of exposure.

Researchers have been increasingly concerned about the health effects from exposure to phthalates, especially during critical times of gestational and infant development. For instance, animal and human models have demonstrated that increasing exposure to phthalates, particularly metabolites of di-n-butyl phthalate (DnBP) and DEHP, can disrupt the development of male reproductive organs (Moore et al., 2001; Nassar et al., 2010; Ormond et al., 2009; Parks et al., 2000; Swan, 2006; Thomas et al., 1982). Postnatal exposure to phthalates has also been associated with health effects. Phthalate metabolites in breast milk have been associated with neonatal hormone levels (Main et al., 2006). Additionally, adult exposures have been associated with adverse impacts on male reproductive health (Duty et al., 2003; Hauser et al., 2006; Hauser et al., 2007; Meeker et al., 2009).

Some phthalates are included in personal care products (PCPs) because of their ability to hold color, denature alcohol, and fix fragrance. In tests of personal care products, DEP and, to a lesser extent, DnBP have been detected more often and at higher concentrations than other phthalates, particularly in perfumes and other heavily fragranced products (Houlihan et al., 2002; Hubinger and Havery, 2006; Koniecki et al., 2011; Sarantis et al., 2010; Shen et al., 2007). However, phthalates are seldom listed on product labels because current United States regulations do not require listing individual fragrance components (Gervin, 2008). Additionally, no premarket approval is required before selling personal care products, though there is some industry self-regulation through the Cosmetics Ingredient Review (CIR) panel (Termini and Tressler, 2008). Previous studies have reported that use of certain personal care products were positively associated with urinary concentrations of the metabolites of DEP and other phthalates (e.g., DnBP, di-isobutyl phthalate (DiBP), dimethyl phthalate (DMP)) (Api, 2001; Berman et al., 2009; Duty et al., 2005; Houlihan et al., 2002; Hubinger and Havery, 2006; Sathyanarayana et al., 2008; Schettler, 2006).

The goal of this study was to examine the associations between concentrations of urinary phthalate metabolites, particularly metabolites of DEP, DnBP, DiBP and DMP, and reported use of personal care products within the 24 hours prior to urine collection in a cohort of women who brought their children to a postnatal visit (within three years of birth).

Methods

Study Group

The women of this study were originally recruited into the Study for Future Families (SFF), which was originally designed to assess the geographic variability of semen quality of their partners. SFF is a multi-center, pregnancy cohort study that recruited at prenatal clinics in Los Angeles, California (Harbor-UCLA and Cedars-Sinai), Minneapolis, Minnesota (University of Minnesota Health Center), Iowa City, Iowa (University of Iowa) and Columbia, Missouri (University Physicians), from September 1999 through January 2005. Methods are described at length elsewhere (Swan et al., 2005).

Eighty-five percent of the participants in SFF agreed to be recontacted and eligible women were invited back for a second phase (SFFII) where the child of the pregnancy would undergo a physical examination. Eligibility criteria for the second phase of the study were: the pregnancy ended in a live birth, the infant was less than 28 months old (later expanded to 36 months old), the mother lived within 50 miles of a clinic, and the mother agreed to at least one study visit. Those visits occurred between April 2002 and December 2005. The analyses for this paper include women who completed a questionnaire and provided a spot urine sample at that study visit (n=337). There were no significant differences in demographics between eligible women who participated versus eligible women who did not participate. Human subject protection committees approved of and the participants signed informed consents for both phases of this study. The involvement of the Centers for Disease Control and Prevention (CDC) laboratory was determined not to constitute engagement in human subject research.

Demographic and Exposure Data

Information on the demographic variables used as covariates in this analysis were obtained from a questionnaire administered to the women during the first phase of the study (SFF). The women’s use of personal care products in the 24 hours preceding the collection of their urine sample was obtained in a postnatal self-administered questionnaire completed during the second phase of the study (SFFII). Women indicated “yes”, “no”, or “not sure” about use of any of the following: hair spray or hair gel, crème rinse/conditioner, shampoo, other hair care products, makeup (powder or liquid foundation), lipstick (not clear), rouge and blusher, eye makeup (mascara, liner, shadow), nail polish or nail polish remover, perfume/cologne, bar soap, liquid soap/body wash, lotion/mist (hand, body, or sun screen), and deodorant. No woman indicated using hair dye, hair bleach, hair permanent, or hair straightener/relaxer within the preceding 24 hour time period, so those products were not included in the analysis.

Phthalate Metabolites Measurements

Women provided a spot urine sample on the same day that they completed the questionnaire that asked about personal care products use. After collection, the urine was transferred to cryovials, and stored at −20°C until it was shipped to the Division of Laboratory Sciences, National Center for Environmental Health, CDC for analysis. Briefly, the analytical method started with an enzymatic deconjugation and solid-phase extraction. Phthalate metabolites were separated using high-performance liquid chromatography and quantitatively detected using isotope-dilution tandem mass spectrometry, as described elsewhere in greater detail (Kato et al., 2005; Silva et al., 2004). The CDC laboratory received no additional participant information. In addition to the study samples, quality control materials and blanks were analyzed to monitor method performance. The limits of detection (LOD) varied slightly by metabolite, but all were in the low nanogram per milliliter range. The nine phthalate metabolites presented in this paper are: monoethyl phthalate (MEP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), monobenzyl phthalate (MzBP), mono(3-carboxypropyl) phthalate (MCPP), monomethyl phthalate (MMP), mono-isobutyl phthalate (MiBP), and mono-n-butyl phthalate (MnBP). Urinary creatinine was also measured using enzymatic reactions for each sample to assess urinary dilution.

Statistical Analysis

Phthalate metabolites concentrations below the LOD were given a value of the LOD divided by the square root of two(Hornung and Reed, 1990).. All phthalate metabolites concentrations were log₁₀-transformed for analysis to normalize the right-skewed distributions.

For univariate and bivariate analyses, phthalate metabolites concentrations were divided by creatinine before log₁₀-transformation. For multivariable analyses modeling log₁₀-transformed phthalate metabolites concentrations, the square root of creatinine was included only as an independent covariate because this transformation provided the best linearity with the dependent variables.

In addition to the nine phthalate metabolites concentrations, one additional measure was examined: molar sum of four metabolites of DEHP. The summary measure for DEHP combines the 3 DEHP primary and secondary metabolites measured (MEHP, MEHHP, MEOHP).

We analyzed several variables for possible confounding including: age at sample collection, employment, race, smoking, ethnicity, and education. Age was modeled as a continuous variable. Race, employment, smoking, ethnicity, and education were made dichotomous variables. These covariates were chosen a priori based on previous studies linking those variables with phthalate exposure and/or use of personal care products (Duty et al., 2005; Maxwell, 2000; Wu et al., 2010). After analyzing bivariate correlations and distributions, only age and education remained as possible confounders and were included in all multivariable models.

Factor analysis was performed on the use of personal care products to understand patterns of reported use. Using the Kaiser criterion of retaining factors with eigenvalues greater than one (Kaiser, 1960), two factors were obtained from the analysis. Makeup foundation, lipstick, and eye makeup defined Factor 1; shampoo and conditioner defined Factor 2. This analysis prompted the creation of two additional summary variables by combining the basic makeup and the basic hair care variables as proxies for these two factors.

Point-biserial correlations were used to assess associations between the continuous and dichotomous variables (Tate, 1954). Multivariable linear regression adjusted the associations for age, education, and square root of creatinine. Results of the multivariable regression are presented as the phthalate metabolite concentration ratio and confidence limits for women who used the product compared to those who did not use it. The ratio was calculated by taking antilog of the multiple linear regression beta coefficients. Statistical significance was set at p< 0.05. All analyses were performed in SAS 9.2 (SAS Institute Inc., Cary, NC).

Results

Demographics

The characteristics of our sample of 337 women are shown in Table 1. Our sample is predominantly white, educated women in their mid-20’s to mid-30’s. Most women reported having private insurance (77%) and having attended at least some college (91%). They were 30.1± 5.1 years old and the median time since giving birth was 15 months (range: 1 to 37 months). More women came from Minnesota (37%) than any of the other participating study centers. 8% of the women reported being pregnant at their post-natal visit.

Table 1.

Characteristics of Study Population (N=337)

Characteristic	N (%)
Age
25 and under	50 (15)
26 to 30	95 (28)
31 to 35	114 (34)
Over 35	69 (20)
Missing	9 (3)
Race
White	308 (91)
Black	10 (3)
Other	19 (6)
Ethnicity
Hispanic	41 (12)
Not Hispanic	296 (88)
Education
High School or less	29 (9)
Some College or College Graduate	204 (61)
Any Graduate School	103 (30)
Health Insurance1
None	30 (9)
Private	261 (77)
Government	48 (14)
Employed
Yes	216 (64)
No	121 (36)
State
California	69 (21)
Minnesota	126 (37)
Missouri	90 (27)
Iowa	52 (15)
Currently Pregnant
Yes	28 (8)
No	291 (86)
Don’t Know	15 (5)
Missing	3 (1)
Currently Breastfeeding
Yes	118 (35)
No	219 (65)

¹Questionnaire allowed selection of one or more health insurance options, sum does not equal 337

Urinary Phthalate Metabolites

Spot urine samples from 337 women were analyzed for nine phthalate metabolites (98 women did not have MMP concentration quantified) (Table 2). For most of the phthalates, metabolite concentrations were detectable for most women. The most commonly detected metabolites were MEP (99.4%) and MEOHP (99.1%) and the least frequently detected metabolites were MMP (75.7%) and MCPP (78.6%). All urine samples contained at least two metabolites above the limit of detection and eight or nine metabolites in more than 87% of the women (Figure 1).

Table 2.

Summary Statistics of Urinary Phthalate Metabolites Concentrations (μg/g creatinine) (n=337)

Parent	Metabolite	Log10-transformed		Untransformed			%>LOD
		Mean	SD	Percentiles
				25th	50th	75th
DnBP	MnBP	3.30	0.35	13.03	18.93	30.30	97.9
DiBP	MiBP	2.64	0.39	2.47	4.33	7.28	88.4
DEHP	MEHHP	3.36	0.43	12.16	20.80	38.10	98.5
	MEHP	2.81	0.45	3.34	6.02	11.28	88.1
	MEOHP	3.23	0.40	9.47	14.96	27.64	99.1
DEP	MEP	4.15	0.56	58.91	125.16	292.11	99.4
DMP1	MMP	2.35	0.38	1.27	2.09	4.00	75.7
BzBP	MBzP	3.17	0.40	9.12	14.62	25.78	98.2
DnOP Other high molecular weight phthalates	MCPP	2.37	0.33	1.42	2.25	3.46	78.6
Σ DEHP2		1.22	0.40	0.08	0.11	0.17

¹Not all urine samples were analyzed for MMP, so for MMP N=239

²DEHP in nmol/L

FIGURE 1.

Number of Phthalate Metabolites above LOD in Urine Samples (N=377)

Personal Care Product Use

The reported use of PCPs varied widely by product type. As shown in Table 3, the most commonly used PCP was deodorant with 91% of women reporting use within the past 24 hours. Shampoo and lotion were the next most frequently reported products used by 80% and 70% of the women, respectively. Nail polish or nail polish remover had the fewest women reporting use at 7%, followed by other unspecified hair care products at 9%. As shown in Figure 2, all women reported using at least one PCP within the past 24 hours and 25% of the women reported using nine or more PCPs. The median number of reported products used was 7 (data not shown). Some PCPs were often reported together (correlation > 0.3; p<0.05) such as: makeup, eye makeup, and lipstick; shampoo and conditioner; and eye makeup and hairspray (data not shown).

Table 3.

Correlations between Personal Care Products and Urinary Phthalate Metabolite Concentrations (N=337)

Product	Used in past 24h (%)	DnBP	DiBP	DEHP			DEP	DMP	BBzP	DnOP + others	Summary Measure
		MnBP	MiBP	MEHHP	MEHP	MEOHP	MEP	MMP	MBzP	MCPP	ΣDEHP
Hair spray or hair gel	47	−0.07	−0.05	−0.03	−0.01	−0.02	0.16*	−0.10	−0.06	0.00	−0.03
Crème rinse/Conditioner	65	−0.04	−0.08	0.06	0.06	0.05	0.12*	−0.03	−0.01	0.01	0.07
Shampoo	80	−0.03	−0.04	−0.02	−0.04	−0.02	0.10	−0.04	0.01	−0.03	−0.03
Other hair care products	9	0.04	0.00	−0.06	−0.06	−0.06	0.12*	−0.12	0.08	−0.07	−0.06
Makeup (powder or liquid foundation)	50	−0.10	−0.15*	−0.02	0.04	−0.01	0.03	0.07	−0.04	0.00	−0.02
Lipstick (not clear), rouge and blusher	46	−0.05	−0.01	−0.05	0.05	−0.03	0.09	0.12	0.00	−0.04	−0.04
Eye makeup (mascara, liner, shadow)	54	−0.01	−0.10	0.00	0.02	0.01	0.09	0.04	0.03	0.00	−0.01
Nail polish or Nail polish remover	7	0.08	−0.04	−0.04	−0.05	−0.04	0.10	0.05	0.00	0.03	−0.05
Bar soap	65	0.04	0.02	−0.01	−0.02	−0.02	0.11*	0.03	0.07	−0.11*	−0.02
Liquid soap/Body wash	68	−0.01	0.01	−0.04	0.03	−0.01	−0.03**	0.03	0.01	0.13	−0.02
Lotion/Mist (hand, body, or sun screen)	70	−0.02	−0.02	−0.04	0.02	−0.04	0.19	0.20*	0.06	0.03	−0.02
Deodorant	91	−0.03	−0.03	0.08	0.03	0.08	0.17*	0.01	0.07	−0.03	0.08
Perfume/Cologne	32	0.19**	0.12*	−0.06	−0.09	−0.08	0.39**	−0.05	0.08	−0.03	−0.08

^*p<0.05;

^**p<0.001

All metabolites are creatinine-adjusted and log₁₀-transformed

FIGURE 2.

Number of Products Reported to be Used within Past 24 Hours

Bivariate Analysis

Bivariate analysis of personal care product use and phthalate metabolites concentrations is presented in Table 3. The strongest and most significant correlations were seen between PCPs and urinary MEP and, to a lesser extent, MnBP and MiBP, the metabolites of DnBP and DiBP, respectively. Perfume (r=0.39), lotion (r=0.20), deodorant (r=0.17), hair spray (r=0.16), crème rinse (r=0.12), other hair products (r=0.12), and bar soap (r=0.11) were all positively and significantly associated with MEP urinary concentrations. Urinary concentrations of MnBP and MiBP were associated with foundation makeup (MiBP: r=−0.15) and perfume (MnBP: r=0.19; MiBP: r=0.12).

No strong or significant correlations were found between any of the PCPs and the urinary concentrations of MEHHP, MEHP, MEOHP, MBzP, or ΣDEHP; therefore, the remainder of the analyses only includes MEP, MnBP, MiBP, and MMP, the main metabolite of DMP.

As the total number of PCPs reportedly used in the past 24 hours increased, so did the median creatinine-adjusted, log₁₀-transformed MEP concentrations (Figure 3). Adjusted median MiBP, MnBP, and MMP urinary concentrations did not increase with increasing number of products used.

FIGURE 3.

The change in select phthalate metabolite median concentrations in relation to the total number of personal care products used in the past 24 hours

Multivariable Analysis

Table 4 shows the results of multivariable linear regression analyses of phthalate metabolites concentration as a function of personal care product use after adjusting for education, creatinine, and age.

Table 4.

Ratio of Phthalate Metabolite Concentration in Women Reporting PCP Use Compared to Women Reporting No Use in the Past 24 Hours (N=328)¹,²

Product	Phthalate Metabolite
	MnBP		MiBP		MEP		MMP
	Ratio (95% CI)	Adj. R2	Ratio (95% CI)	Adj. R2	Ratio (95% CI)	Adj. R2	Ratio (95% CI)	Adj. R2
Hair
Hair spray or hair gel	1.07 (0.79–1.12)	0.48	0.85 (0.70–1.03)	0.38	1.75 (1.33–2.30)**	0.34	0.83 (0.68–1.01)	0.19
Crème rinse/Conditioner	0.87 (0.73–1.06)	0.48	0.82 (0.66–1.00)	0.38	1.34 (0.99–1.81)	0.31	0.99 (0.80–1.22)	0.17
Shampoo	0.93 (0.75–1.16)	0.48	0.86 (0.67–1.09)	0.38	1.43 (1.01–2.02)*	0.31	0.91 (0.72–1.17)	0.18
Other hair care products	1.11 (0.82–1.50)	0.48	1.00 (0.72–1.40)	0.37	1.69 (1.04–2.74)*	0.31	0.81 (0.57–1.16)	0.18
Makeup
Makeup (powder or liquid foundation)	0.84 (0.71–1.00)	0.48	0.79 (0.66–0.96)*	0.39	1.12 (0.85–1.48)	0.31	1.16 (0.96–1.41)	0.18
Lipstick (not clear), rouge and blusher	0.94 (0.79–1.13)	0.48	1.02 (0.84–1.23)	0.37	1.42 (1.08–1.88)*	0.32	1.23 (1.01–1.49)*	0.19
Eye makeup (mascara, liner, shadow)	1.02 (0.85–1.21)	0.48	0.92 (0.76–1.12)	0.38	1.36 (1.03–1.79)*	0.31	1.22 (1.00–1.48)*	0.19
Nail polish or Nail polish remover	1.31 (0.91–1.89)	0.48	0.84 (0.56–1.25)	0.38	2.08 (1.17–3.70)*	0.32	1.25 (0.85–1.85)	0.18
Bath
Bar soap	1.09 (0.90–1.30)	0.48	0.99 (0.81–1.21)	0.37	1.37 (1.02–1.83)*	0.31	1.09 (0.89–1.33)	0.17
Liquid soap/Body wash	0.92 (0.77–1.12)	0.48	0.98 (0.80–1.21)	0.37	0.98 (0.73–1.32)	0.30	0.97 (0.78–1.20)	0.17
Lotion/Mist (hand, body, or sun screen)	0.96 (0.79–1.16)	0.48	0.84 (0.68–1.03)	0.38	1.72 (1.27–2.31)**	0.33	1.22 (0.99–1.50)	0.18
Other
Deodorant	1.08 (0.79–1.48)	0.48	1.03 (0.73–1.45)	0.37	2.83 (1.73–4.61)**	0.34	1.43 (0.99–2.05)	0.19
Perfume/Cologne	1.38 (1.14–1.66)*	0.50	1.30 (1.05–1.61)*	0.39	2.92 (2.20–3.89)**	0.41	1.04 (0.83–1.29)	0.17

^*p<0.05;

^**p<0.001

¹Values adjusted for age, square root creatinine, and any graduate school education vs. less

²Age was missing for 9 women who were not included in this analysis

MEP urinary concentration was significantly associated with use of many products, from bar soap (ratio: 1.37; 95% CI: 1.02–1.83) to perfume/cologne (ratio: 2.92; 95% CI: 2.20–3.89). Foundation makeup had an inverse relationship with MiBP concentrations (ratio: 0.79; 95% CI: 0.66–0.96). MMP concentration was marginally associated with both lipstick and eye makeup (ratios of 1.23 and 1.22, respectively). MnBP concentration was significantly associated only with perfume or cologne use (ratio: 1.38; 95% CI: 1.14–1.66), adjusted R-squared =0.50.

Multivariable regression of total number of PCPs used on log₁₀ urinary MEP concentration (adjusting for age, creatinine, and graduate school education) showed a beta coefficient of 0.08 (95% CI: 0.06 – 0.11). Other multivariable regressions of urinary phthalate metabolite concentrations were not significant (data not shown).

Basic Makeup and Basic Hair Care

To account for the correlation in product use, a factor analysis was performed, resulting in two oblique factors; only Basic Hair Care products (Factor 1, including shampoo and conditioner) and Basic Makeup (Factor 2 including eye makeup, foundation, and lipstick). The personal care products associated with the two factors were then included in regression models, together with perfume, and examined in association with the urinary concentrations of MEP, MiBP, MnBP, and MMP. The multivariable regression coefficients (adjusting for age, education, and creatinine) are presented in Table 5. Perfume use was significantly positively associated with the concentrations of all metabolites except MMP, which was associated with only Basic Hair Care products. Of note is how the crude and combined associations of Basic Hair Care and Basic Makeup with MEP concentrations are significant, but the inclusion of perfume in a multivariable model reduces those effect estimates. Using the factor scores from the factor analysis showed similar associations and confidence intervals for these regressions (data not shown).

Table 5.

Regression Coefficients and P-values of Aggregated Product Use by Factor Category and Phthalate Metabolites Concentrations¹

Phthalate Metabolite	Model	Basic Makeup		Basic Hair		Perfume
		beta	p	beta	p	beta	p
MnBP	Basic Makeup	−0.015	NS
	Basic Hair			−0.029	NS
	Perfume					0.138	0.0011
	Makeup and Hair	−0.014	NS	−0.028	NS
	Makeup, Hair, and Perfume	−0.025	NS	0.032	NS	0.155	0.0003
MEP	Basic Makeup	0.054	0.029
	Basic Hair			0.089	0.027
	Perfume					0.466	<0.0001
	Makeup and Hair	0.051	0.040	0.084	0.036
	Makeup, Hair, and Perfume	0.019	NS	0.072	0.054	0.449	<0.0001
MiBP	Basic Makeup	−0.021	NS
	Basic Hair			−0.051	0.067
	Perfume					0.115	0.014
	Makeup and Hair	−0.019	NS	−0.049	0.079
	Makeup, Hair, and Perfume	−0.028	0.099	−0.052	0.057	0.135	0.004
MMP	Basic Makeup	0.040	0.023
	Basic Hair			−0.012	NS
	Perfume					0.015	NS
	Makeup and Hair	0.040	0.022	−0.016	NS
	Makeup, Hair, and Perfume	0.041	0.023	−0.016	NS	−0.005	NS

¹after adjusting for creatinine, age, and graduate school education; NS, not significant

Discussion

Nearly all of the women in our study reported using multiple personal care products in the 24 hours prior to urine collection, with over a quarter of them using more than 9 different products. This widespread use of personal care products aligns with previous research on the usage patterns of PCPs (Hall et al., 2007; Loretz et al., 2006; Loretz et al., 2008; Loretz et al., 2005; Wu et al., 2010). In our analyses, use of these products was positively associated with the urinary concentration of the metabolites of several phthalates, particularly MEP, the primary metabolite of DEP. This finding was expected given that previous research has connected DEP to personal care products and cosmetics (Api, 2001; Berman et al., 2009; Duty et al., 2005; Houlihan et al., 2002; Hubinger and Havery, 2006; Just et al., 2010; Koniecki et al., 2011; Romero-Franco et al., 2011; Sathyanarayana et al., 2008; Schettler, 2006).

Exposure to perfume resulted in a 2.92 fold difference in MEP concentration compared to not using perfume. These are relative numbers, but to put it in more concrete terms, the regression equations predict that a 31-year old woman without a graduate school education and an average creatinine concentration would have an MEP concentration of 97.3 ng/mL if she did not use perfume and 284.0 ng/mL if she did use perfume. Similarly, our data showed increasing use of PCPs was significantly association with increased urinary MEP concentrations. So, if the same 31-year old woman used any three products, her expected urinary MEP concentration would be 66.8 ng/mL; however, if she used eight products, that expected concentration would be 170 ng/mL.

Our results are consistent with those of other studies that have examined associations between use of personal care products and urinary concentration of phthalate metabolites. Other studies have focused on men, children and pregnant women, whereas our study examined a population of recently pregnant women (in fact, the same families in whom baby product use and infant phthalate metabolite concentrations were examined by Sathyanarayana et al. 2008). Like the study of minority pregnant women in New York City, we found that perfume use was significantly related to MEP urinary concentrations (Just et al., 2010). Additionally, Duty and colleagues’ study of men and personal care products found the same association with men’s cologne (Duty et al., 2005). Estimates showed similar effect magnitudes of perfume/cologne use on MEP urinary concentrations such that after adjusting for urinary dilution and covariates, someone exposed to perfume or cologne, on average, had twice the urinary concentration of MEP compared to someone not exposed. Also like Berman et al, Duty et al and Sathyanarayana et al, we found a dose-response effect of increasing use of personal care products and urinary levels of MEP (Api, 2001; Berman et al., 2009; Duty et al., 2005; Houlihan et al., 2002; Hubinger and Havery, 2006; Sathyanarayana et al., 2008; Schettler, 2006).

Because personal care products are often not used one at a time and often products are used simultaneously or in quick succession, our analysis used factor analysis to account for correlations in product use. We found two factors or personal care use patterns among our population of women: basic hair care (shampoo and conditioner) and basic makeup (foundation, lipstick, and eye makeup). Using summary scores for these factor variables, we performed additional regressions to assess how using multiple products affected urinary phthalate metabolite concentrations. As shown in Table 6, while there were some associations between the basic hair and basic makeup groups and phthalate metabolites concentrations, the inclusion of perfume as a covariate dominated the regression models.

Table 6.

Comparison of Phthalate Metabolite Concentrations across Several Populations of Women

Country	United States						Israel	Mexico	Spain	Sweden	Germany
	Multiple States			New York	Wisconsin	North Carolina
Author	Current Study	NHANES		Just	Peck	Hines	Berman	Romero-Franco	Casas	Hogberg	Fromme
Phthalate Metabolites		1	1	2				3	2
MEP	125.2	221.5	202.8	199	62.3	73.1	140.5	83.2	324.0	39.0	NA
MnBP	18.9	22.0	21.1	36	25.4	14.0	45.9	72.4	27.5	50.0	46.8
MiBP	4.3	1.3	5.91	NA	7.9	3.8	27.7	8.36	29.9	15.0	45.2
MMP	2.1	1.4	1.21	NA	NA	<LOD	NA	NA	NA	1.9	NA
Age Mean(SD)	30.1 (5.1)	29.6 (8.5)	29.1 (8.1)	26 (5)	34.8 (8.4)	30.8 (4.7)	31.1 (4.9)	53 (NA)	30 (NA)	30 (3.5)	35.5 (13.2)
Population	Postpartum	Reproductive age, 18–45 years		Pregnant minority	Reproductive-age Hmong	Lactating	Pregnant	No Breast Cancer	Pregnant	Lactating	Healthy
Study Year (N)	1999–2002 (337)	2003–2004 (492)	2005–2006 (500)	2003–2006 (164)	1999–2005 (45)	2004–2005 (33)	2006 (19)	2007 (108)	2004–2008 (118)	2003 (38)	2005 (27)

μg/g creatinine median values unless noted

1. unpublished data analysis, no sample weighting used

2. ng/ml median values (not creatinine corrected)

3. ng/ml geometric means (not creatinine corrected)

NA, Not available

<LOD, Less than the limit of detection

Phthalate metabolite concentrations in this population were comparable to those reported in other studies with similar populations of women (see Table 6). Interestingly, there are some relatively large differences in MiBP and MnBP concentrations across studies. For example, the study of healthy Germans had a median of 45 μg/g MiBP compared to the median of 3.8 μg/g MiBP among lactating women from North Carolina.

Urinary excretion gives little indication of the initial dose of a topical application. Janjua’s experimental study of whole-body topical phthalate application recovered <6% of the initial phthalate parent compound dose after 1 day (Janjua et al., 2008). Given the small amount of recovered dose for products spread on the skin, no reliable conclusions can be drawn concerning the extent of exposure to our study population despite the finding of strong associations between topical product use and phthalate metabolite concentrations.

For DEP, dermal irritation is also of concern because of the widespread use of this phthalate in dermally applied products, but there are no reports of primary dermal irritation with undiluted DEP (Api, 2001) and there are no reports of oral or inhalation toxicity of DEP (Agency for Toxic Substances and Disease Registry (ATSDR), 1995). While there is little evidence from animal studies that DEP is reproductively toxic, several human studies have reported reproductive changes in male infants in association with concentration of MEP in prenatal urine samples (Main et al., 2006; Swan, 2008) and in adult males (Duty et al., 2003; Hauser et al., 2007; Jonsson et al., 2005). The disparity between these results in rodent and human studies has not been resolved, but may reflect the fact that reproductive toxicity testing in animals is via oral administration, rather than dermal or inhalation, the routes by which humans are primarily exposed to DEP.

Fragrance has emerged as the strongest predictor among PCPs of urinary concentrations of certain phthalate metabolites. In our initial analyses, we attempted to study the relationship between “fragrance” and urinary concentrations of phthalate metabolites. Unfortunately, self-reported data on fragranced personal care products is of questionable reliability. First, products marketed as fragrance-free may have phthalate-containing masking agents added to cover their chemical odors (de Groot and Frosch, 1997; Scheinman, 1999). Second, products marketed as “natural” may also contain phthalates, even though the consumer believes them to be chemical-free. In both cases, subjects’ responses would be misclassified, potentially biasing results.

One limitation of this study is that we performed analysis by product category because brand names were not collected in our questionnaire. Our analysis, therefore, treated all products in a category as interchangeable. The Houlihan cosmetics study reported that phthalate content of products in the same category ranged considerably from undetectable to relatively high levels (2002). However, even brand name information would not have remedied this limitation because products of the same category produced by the same company had a range of phthalate concentrations and not all brands have been tested for the phthalate content of their products, nor did we analyze any of the products used for their phthalate content. By combining products by category, we likely increased misclassification of exposure but non-differentially, so any bias in the effect estimates is likely to be toward the null.

Phthalate metabolite concentration varies within subject, even within a day (Preau et al., 2010) so that assessment of phthalate exposure based on multiple samples is less variable than that based on a single spot sample. This is of particular concern when one is attempting to assess exposure over an extended period (for example the first trimester of pregnancy), and relating this exposure to a developmental outcome. However, in this paper we are attempting to relate reported product use in a brief (24-hour) window to phthalate metabolite concentrations in urine collected at the end of that window. For these purposes, the single spot sample should provide a fairly adequate exposure measure.

Our questionnaire also did not ask about the frequency or amount of product used by the participants. The questionnaire’s recall period was relatively short—a span of 24 hours—since the half-lives of phthalate compounds are on the order of hours, not days. We expected that some of our participants used products more often, or in greater quantity, than others but no single product in any excessive quantity (Loretz et al., 2006). Frequency and amount were sources of variability that we could not explain with our models, which had adjusted R² values in the 30–50% range.

Conclusion

Women use multiple personal care products each day, which exposes them to a number of chemicals, including phthalates. Our study showed the strongest positive associations between personal care products and urinary concentrations of MEP; however, MiBP and MnBP also exhibited correlations with PCP use. After accounting for product use patterns, perfume emerged as the strongest, most significant predictor of MEP urinary phthalate metabolite concentrations.

Abbreviations

BzBP

benzylbutyl phthalate

DiBP

di-isobutyl phthalate

DnBP

di-n-butyl phthalate

DEHP

di(2-ethylhexyl) phthalate

DEP

diethyl phthalate

DMP

dimethyl phthalate

DnOP

di-n-octyl phthalate

MCPP

mono(3-carboxypropyl) phthalate

MEP

monoethyl phthalate

MiBP

mono-isobutyl phthalate

MEHHP

mono(2-ethyl-5-hydroxyhexyl) phthalate

MEHP

mono(2-ethylhexyl) phthalate

MEOHP

mono(2-ethyl-5-oxohexyl) phthalate

MnBP

mono-n-butyl phthalate

MzBP

monobenzyl phthalate

PCP

personal care product

SFF

Study for Future Families

SFFII

Study for Future Families, phase II