Risk of Anaphylaxis Among New Users of GLP-1 Receptor Agonists: A Cohort Study

OBJECTIVE

To assess risk of anaphylaxis among patients with type 2 diabetes mellitus who are initiating therapy with a glucagon-like peptide 1 receptor agonist (GLP-1 RA), with a focus on those starting lixisenatide therapy.

RESEARCH DESIGN AND METHODS

A cohort study was conducted in three large, U.S. claims databases (2017-2021). Adult (aged ≥18 years) new users of a GLP-1 RA who had type 2 diabetes mellitus and ≥6 months enrollment in the database before GLP-1 RA initiation (start of follow-up) were included. GLP-1 RAs evaluated were lixisenatide, an insulin glargine/lixisenatide fixed-ratio combination (FRC), exenatide, liraglutide or insulin degludec/liraglutide FRC, dulaglutide, and semaglutide (injectable and oral). The first anaphylaxis event during follow-up was identified using a validated algorithm. Incidence rates (IRs) and 95% CIs were calculated within each medication cohort. The unadjusted IR ratio (IRR) comparing anaphylaxis rates in the lixisenatide cohort with all other GLP-1 RAs combined was analyzed post hoc.

RESULTS

There were 696,089 new users with 456,612 person-years of exposure to GLP-1 RAs. Baseline demographics, comorbidities, and use of other prescription medications in the 6 months before the index date were similar across medication cohorts. IRs (95% CIs) per 10,000 person-years were 1.0 (0.0-5.6) for lixisenatide, 6.0 (3.6-9.4) for exenatide, 5.1 (3.7-7.0) for liraglutide, 3.9 (3.1-4.8) for dulaglutide, and 3.6 (2.6-4.9) for semaglutide. The IRR (95% CI) for the anaphylaxis rate for the lixisenatide cohort compared with the pooled other GLP-1 RA cohort was 0.24 (0.01-1.35).

CONCLUSIONS

Anaphylaxis is rare with GLP-1 RAs. Lixisenatide is unlikely to confer higher risk of anaphylaxis than other GLP-1 RAs.

Pediatric Medical Subspecialist Use in Outpatient Settings

Importance

A first step toward understanding whether pediatric medical subspecialists are meeting the needs of the nation's children is describing rates of use and trends over time.

Objectives

To quantify rates of outpatient pediatric medical subspecialty use.

Design, Setting, and Participants

This repeated cross-sectional study of annual subspecialist use examined 3 complementary data sources: electronic health records from PEDSnet (8 large academic medical centers [January 1, 2010, to December 31, 2021]); administrative data from the Healthcare Integrated Research Database (HIRD) (14 commercial health plans [January 1, 2011, to December 31, 2021]); and administrative data from the Transformed Medicaid Statistical Information System (T-MSIS) (44 state Medicaid programs [January 1, 2016, to December 31, 2019]). Annual denominators included 493 628 to 858 551 patients younger than 21 years with a general pediatric visit in PEDSnet; 5 million beneficiaries younger than 21 years enrolled for at least 6 months in HIRD; and 35 million Medicaid or Children's Health Insurance Program beneficiaries younger than 19 years enrolled for any amount of time in T-MSIS.

Exposure

Calendar year and type of medical subspecialty.

Main Outcomes and Measures

Annual number of children with at least 1 completed visit to any pediatric medical subspecialist in an outpatient setting per population. Use rates excluded visits in emergency department or inpatient settings.

Results

Among the study population, the proportion of girls was 51.0% for PEDSnet, 51.1% for HIRD, and 49.3% for T-MSIS; the proportion of boys was 49.0% for PEDSnet, 48.9% for HIRD, and 50.7% for T-MSIS. The proportion of visits among children younger than 5 years was 37.4% for PEDSnet, 20.9% for HIRD, and 26.2% for T-MSIS; most patients were non-Hispanic Black (29.7% for PEDSnet and 26.1% for T-MSIS) or non-Hispanic White (44.9% for PEDSnet and 43.2% for T-MSIS). Annual rates for PEDSnet ranged from 18.0% to 21.3%, which were higher than rates for HIRD (range, 7.9%-10.4%) and T-MSIS (range, 7.6%-8.6%). Subspecialist use increased in the HIRD commercial health plans (annual relative increase of 2.4% [95% CI, 1.6%-3.1%]), but rates were essentially flat in the other data sources (PEDSnet, -0.2% [95% CI, -1.1% to 0.7%]; T-MSIS, -0.7% [95% CI, -6.5% to 5.5%]). The flat PEDSnet growth reflects a balance between annual use increases among those with commercial insurance (1.2% [95% CI, 0.3%-2.1%]) and decreases in use among those with Medicaid (-0.9% [95% CI, -1.6% to -0.2%]).

Conclusions and Relevance

The findings of this cross-sectional study suggest that among children, 8.6% of Medicaid beneficiaries, 10.4% of those with commercial insurance, and 21.3% of those whose primary care is received in academic health systems use pediatric medical subspecialty care each year. There was a small increase in rates of subspecialty use among children with commercial but not Medicaid insurance. These data may help launch innovations in the primary-specialty care interface.

Development and Validation of Claims-Based Definitions to Identify Incident and Prevalent Inflammatory Bowel Disease in Administrative Healthcare Databases

BACKGROUND

To facilitate inflammatory bowel disease (IBD) research in the United States, we developed and validated claims-based definitions to identify incident and prevalent IBD diagnoses using administrative healthcare claims data among multiple payers.

METHODS

We used data from Medicare, Medicaid, and the HealthCore Integrated Research Database (Anthem commercial and Medicare Advantage claims). The gold standard for validation was review of medical records. We evaluated 1 incidence and 4 prevalence algorithms based on a combination of International Classification of Diseases codes, National Drug Codes, and Current Procedural Terminology codes. The claims-based incident diagnosis date needed to be within ±90 days of that recorded in the medical record to be valid.

RESULTS

We reviewed 111 charts of patients with a potentially incident diagnosis. The positive predictive value (PPV) of the claims algorithm was 91% (95% confidence interval [CI], 81%-97%). We reviewed 332 charts to validate prevalent case definition algorithms. The PPV was 94% (95% CI, 86%-98%) for ≥2 IBD diagnoses and presence of prescriptions for IBD medications, 92% (95% CI, 85%-97%) for ≥2 diagnoses without any medications, 78% (95% CI, 67%-87%) for a single diagnosis and presence of an IBD medication, and 35% (95% CI, 25%-46%) for 1 physician diagnosis and no IBD medications.

CONCLUSIONS

Through a combination of diagnosis, procedural, and medication codes in insurance claims data, we were able to identify incident and prevalent IBD cases with high accuracy. These algorithms can be useful for the ascertainment of IBD cases in future studies.

Incidence, Prevalence, and Racial and Ethnic Distribution of Inflammatory Bowel Disease in the United States

BACKGROUND & AIMS

We sought to estimate the incidence, prevalence, and racial-ethnic distribution of physician-diagnosed inflammatory bowel disease (IBD) in the United States.

METHODS

The study used 4 administrative claims data sets: a 20% random sample of national fee-for-service Medicare data (2007 to 2017); Medicaid data from Florida, New York, Pennsylvania, Ohio, and California (1999 to 2012); and commercial health insurance data from Anthem beneficiaries (2006 to 2018) and Optum's deidentified Clinformatics Data Mart (2000 to 2017). We used validated combinations of medical diagnoses, diagnostic procedures, and prescription medications to identify incident and prevalent diagnoses. We computed pooled age-, sex-, and race/ethnicity-specific insurance-weighted estimates and pooled estimates standardized to 2018 United States Census estimates with 95% confidence intervals (CIs).

RESULTS

The age- and sex-standardized incidence of IBD per 100,000 person-years was 10.9 (95% CI, 10.6-11.2). The incidence of IBD peaked in the third decade of life, decreased to a relatively stable level across the fourth to eighth decades, and declined further. The age-, sex- and insurance-standardized prevalence of IBD was 721 per 100,000 population (95% CI, 717-726). Extrapolated to the 2020 United States Census, an estimated 2.39 million Americans are diagnosed with IBD. The prevalence of IBD per 100,000 population was 812 (95% CI, 802-823) in White, 504 (95% CI, 482-526) in Black, 403 (95% CI, 373-433) in Asian, and 458 (95% CI, 440-476) in Hispanic Americans.

CONCLUSIONS

IBD is diagnosed in >0.7% of Americans. The incidence peaks in early adulthood and then plateaus at a lower rate. The disease is less commonly diagnosed in Black, Asian, and Hispanic Americans.

Comparing Patient-Reported Outcomes Among Anti-TNF Experienced Patients With Ulcerative Colitis Initiating Vedolizumab Versus Tofacitinib

Background

Primary and secondary nonresponse to anti-tumor necrosis factor (TNF) therapy is common in patients with ulcerative colitis (UC), yet limited research has compared the effectiveness of subsequent biological therapy.

Objective

We sought to compare the effectiveness of vedolizumab and tofacitinib in anti-TNF experienced patients with UC, focusing on patient-prioritized patient-reported outcomes (PROs).

Methods

We conducted a prospective cohort study nested within the Crohn's & Colitis Foundation's IBD Partners and SPARC IBD initiatives. We identified anti-TNF experienced patients with UC initiating vedolizumab or tofacitinib and analyzed PROs reported approximately 6 months later (minimum 4 months, maximum 10 months). Co-primary outcomes were Patient Reported Outcome Measurement Information System (PROMIS) domains of Fatigue and Pain Interference. Secondary outcomes included PRO2, treatment persistence, and need for colectomy.

Results

We compared 72 vedolizumab initiators and 33 tofacitinib initiators. At follow-up, Pain Interference (P = .04), but not Fatigue (P = .53) was lower among tofacitinib initiators. A trend toward higher Social Role Satisfaction was not significant. The remainder of secondary outcomes (PRO2, treatment persistence, colectomy) did not differ between treatment groups.

Conclusions

Among anti-TNF experienced patients with UC, Pain Interference 4-10 months after treatment initiation was lower among tofacitinib users as compared with vedolizumab users. Many, but not all, secondary endpoints and subanalyses also favored tofacitinib. Future studies with larger sample sizes are needed to further evaluate these findings.

Comparing Patient-Reported Outcomes Among Anti-TNF-Experienced Patients with Crohn's Disease Initiating Vedolizumab Versus Ustekinumab

BACKGROUND

Primary and secondary non-response to anti-tumor necrosis factor (TNF) therapy is common in patients with Crohn's disease (CD), yet limited research has compared the effectiveness of subsequent biological therapy.

OBJECTIVE

We sought to compare the effectiveness of vedolizumab and ustekinumab in anti-TNF-experienced patients with CD, focusing on patient-prioritized patient-reported outcomes (PROs).

METHODS

We conducted a prospective, internet-based cohort study nested within IBD Partners. We identified anti-TNF-experienced patients initiating with CD vedolizumab or ustekinumab and analyzed PROs reported approximately 6 months later (minimum 4 months, maximum 10 months). Co-primary outcomes were Patient-Reported Outcome Measurement Information System (PROMIS) domains of Fatigue and Pain Interference. Secondary outcomes included patient-reported short Crohn's disease activity index (sCDAI), treatment persistence, and corticosteroid use. Inverse probability of treatment weighting (IPTW) was used to control for a number of potential confounders and incorporated into linear and logistic regression models for continuous and categorical outcomes, respectively.

RESULTS

Overall, 141 vedolizumab and 219 ustekinumab initiators were included in our analysis. After adjustment, we found no differences between treatment groups in our primary outcomes of Pain Interference or Fatigue or the secondary outcome of sCDAI. However, vedolizumab was associated with lower treatment persistence (OR 0.4, 95% CI 0.2-0.6) and higher corticosteroid use at follow-up assessment (OR 1.7, 95% CI 1.1-2.6).

DISCUSSION

Among anti-TNF experienced patients with CD, Pain Interference or Fatigue was not significantly different 4-10 months after starting ustekinumab or vedolizumab. However, reduced steroid use and increased persistence suggest superiority of ustekinumab for non-PRO outcomes.

Childhood asthma diagnoses declined during the COVID-19 pandemic in the United States

BACKGROUND

Prior studies have documented declines in pediatric asthma exacerbations and asthma-related health care utilization during the COVID-19 pandemic, but less is known about the incidence of asthma during the pandemic.

METHODS

We conducted a retrospective cohort study of children under age 18 without a prior diagnosis of asthma within a large US commercial claims database. Incident asthma was defined using a combination of diagnosis codes, location of services, and medication dispensing. Crude quarterly rates of asthma diagnosis per 1000 children were calculated, and the incidence rate ratio and 95% confidence interval were estimated for newly diagnosed asthma during versus before the pandemic using negative binomial regression, adjusted for age, sex, region, and season.

RESULTS

Compared with 3 years prior to the pandemic, crude incident diagnosis rates of asthma decreased by 52% across the first four quarters of the US pandemic. The covariate-adjusted pandemic-associated incidence rate ratio was 0.47 (95% confidence interval 0.43, 0.51).

CONCLUSIONS

New diagnoses of childhood asthma in the US declined by half during the first year of the pandemic. These findings raise important questions whether pandemic-related changes in infectious or other triggers truly altered the incidence of childhood asthma beyond the well-described disruptions in healthcare access.

Validity of ICD-10-CM diagnoses to identify hospitalizations for serious infections among patients treated with biologic therapies

PURPOSE

Identifying hospitalizations for serious infections among patients dispensed biologic therapies within healthcare databases is important for post-marketing surveillance of these drugs. We determined the positive predictive value (PPV) of an ICD-10-CM-based diagnostic coding algorithm to identify hospitalization for serious infection among patients dispensed biologic therapy within the FDA's Sentinel Distributed Database.

METHODS

We identified health plan members who met the following algorithm criteria: (1) hospital ICD-10-CM discharge diagnosis of serious infection between July 1, 2016 and August 31, 2018; (2) either outpatient/emergency department infection diagnosis or outpatient antimicrobial treatment within 7 days prior to hospitalization; (3) inflammatory bowel disease, psoriasis, or rheumatological diagnosis within 1 year prior to hospitalization, and (4) were dispensed outpatient biologic therapy within 90 days prior to admission. Medical records were reviewed by infectious disease clinicians to adjudicate hospitalizations for serious infection. The PPV (95% confidence interval [CI]) for confirmed events was determined after further weighting by the prevalence of the type of serious infection in the database.

RESULTS

Among 223 selected health plan members who met the algorithm, 209 (93.7% [95% CI, 90.1%-96.9%]) were confirmed to have a hospitalization for serious infection. After weighting by the prevalence of the type of serious infection, the PPV of the ICD-10-CM algorithm identifying a hospitalization for serious infection was 80.2% (95% CI, 75.3%-84.7%).

CONCLUSIONS

The ICD-10-CM-based algorithm for hospitalization for serious infection among patients dispensed biologic therapies within the Sentinel Distributed Database had 80% PPV for confirmed events and could be considered for use within pharmacoepidemiologic studies.

Testosterone Therapy in Relation to Prostate Cancer in a U.S. Commercial Insurance Claims Database

BACKGROUND

We conducted a study to assess whether testosterone therapy (TT) alters prostate cancer risk using a large U.S. commercial insurance research database.

METHODS

From the HealthCore Integrated Research Database (HIRD), we selected men ages 30 years or greater who were new users of TT during 2007 to 2015. We selected two comparison groups: (i) unexposed (matched 10:1) and (ii) new users of phosphodiesterase type 5 inhibitor (PDE5i). Incident prostate cancer was defined as diagnosis of prostate cancer within 4 weeks following prostate biopsy. Propensity scores and inverse probability of treatment weights were used in Poisson regression models to estimate adjusted incidence rates, incidence rate ratios (IRR), and 95% confidence intervals (CI). Subgroup analyses included stratification by prostate cancer screening, hypogonadism, and follow-up time.

RESULTS

The adjusted prostate cancer IRR was 0.77 (95% CI, 0.68-0.86) when comparing TT with the unexposed group and 0.85 (95% CI, 0.79-0.91) in comparison with the PDE5i group. Inverse associations between TT and prostate cancer were observed in a majority of subgroup analyses, although in both comparisons estimates generally attenuated with increasing time following initial exposure. Among TT users, duration of exposure was not associated with prostate cancer.

CONCLUSIONS

Men who received TT did not have a higher rate of prostate cancer compared with the unexposed or PDE5i comparison groups. The inverse association between TT and prostate cancer could be the result of residual confounding, contraindication bias, or undefined biological effect.

IMPACT

This study suggests that limited TT exposure does not increase risk of prostate cancer in the short term.

Prenatal Stress as a Modifier of Associations between Phthalate Exposure and Reproductive Development: results from a Multicentre Pregnancy Cohort Study

BACKGROUND

Prenatal phthalate exposure is associated with altered male reproductive tract development, and in particular, shorter anogenital distance (AGD). AGD, a sexually dimorphic index of prenatal androgen exposure, may also be altered by prenatal stress. How these exposures interact to impact AGD is unknown. Here, we examine the extent to which associations between prenatal phthalate exposure and infant AGD are modified by prenatal exposure to stressful life events (SLEs).

METHODS

Phthalate metabolites [including those of diethylhexyl phthalate (DEHP) and their molar sum (ΣDEHP)] were measured in first trimester urine from 738 pregnant women participating in The Infant Development and the Environment Study (TIDES). Women completed questionnaires on SLEs, and permitted infant AGD measurements at birth. Subjects were classified as 'lower' and 'higher' stress (0 first trimester SLEs vs. 1+).We estimated relationships between phthalate concentrations and AGD (by infant sex and stress group) using adjusted multiple regression interaction models.

RESULTS

In the lower stress group, first trimester ΣDEHP was inversely associated with two measures of male AGD: anoscrotal distance (AGD-AS; β = -1.78; 95% CI -2.97, -0.59) and anopenile distance (AGD-AP; β = -1.61; 95% CI -3.01, -0.22). By contrast, associations in the higher stress group were mostly positive and non-significant in male infants. No associations were observed in girls.

CONCLUSIONS

Associations between prenatal phthalate exposure and altered genital development were only apparent in sons of mothers who reported no SLEs during pregnancy. Prenatal stress and phthalates may interact to shape fetal development in ways that have not been previously explored.

Environmental exposure to di-2-ethylhexyl phthalate is associated with low interest in sexual activity in premenopausal women

Phthalates, a ubiquitous class of environmental chemicals, may interfere with typical reproductive hormone production both in utero and in adulthood. Although they are best known as anti-androgens, increasingly, evidence suggests that phthalates, particularly di-2-ethylhexyl phthalate (DEHP), may also suppress estrogen production. Given that both androgens and estrogens are essential for sexual function, particularly sexual interest, it is plausible that adult exposure to phthalates alters sexual function. To this end, we used data from 360 women participating in a pregnancy cohort study (the Study for Future Families) to examine whether urinary phthalate metabolite concentrations were associated with two dimensions of self-reported sexual dysfunction in the months prior to conception: lack of sexual interest and vaginal dryness. Women in the highest quartile of urinary concentrations of mono-2-ethyl-5-hydroxyhexyl phthalate, a DEHP metabolite, had 2.58 (95% CI 1.33, 5.00) times the adjusted odds of reporting that they almost always or often lacked interest in sexual activity, and results were similar for mono-2-ethyl-5-oxohexyl phthalate (aOR: 2.56, 95% CI 1.32, 4.95), another DEHP metabolite. Self-reported vaginal dryness was not associated with any phthalate metabolite concentration. This study is novel in its focus on sexual function in relation to environmentally relevant (rather than occupational) exposure to phthalates in adult women and these preliminary findings merit replication in a large, prospective study. Better understanding how adult exposure to phthalates may affect reproductive health, including sexual function, is of public health interest given that virtually all Westerners are exposed to phthalates.

Differences in ovarian hormones in relation to parity and time since last birth

OBJECTIVE

To examine ovarian function in relation to parity and time since last birth.

DESIGN

Cross-sectional study.

SETTING

Health-care program in California.

PATIENT(S)

346 naturally cycling women, aged 18 to 39 years.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Mean follicular urinary estradiol metabolite concentration (E1C) (cycle days -8 to -1), mean luteal progesterone metabolite concentration (PdG) (days 0 to +10), and cycle phase lengths in ovulatory cycles.

RESULT(S)

After the women had collected daily urine samples for up to eight menstrual cycles, we measured the E1C and PdG using enzyme-linked immunoassay. The cycle phase lengths were calculated from the hormone profiles and daily diaries. Women who had given birth within the previous 3 years had lower E1C than the nulliparous women and women who last given birth >3 years earlier. Among the parous women, E1C was positively associated with the time since last birth. Women who last gave birth >3 years earlier had longer follicular phases than the nulliparous women. There were no associations between parity and PdG or luteal phase length.

CONCLUSION(S)

Our cross-sectional data suggest that ovarian function differs in nulliparous and parous women and is positively associated with the time since last birth. Longitudinal research is needed to explore within-woman changes in ovarian function prepartum and postpartum.

Evidence for sexually dimorphic associations between maternal characteristics and anogenital distance, a marker of reproductive development

Data from animal models, historical cohorts, and modern epidemiologic studies have suggested that maternal characteristics can affect reproductive health of offspring; however, distinguishing between prenatal and postnatal contributions is difficult. Anogenital distance (AGD), the distance from the anus to the genitals, is believed to be a biomarker of prenatal androgen exposure in many species, and in humans it has been associated with several adult reproductive health outcomes. We used data from a pregnancy cohort study conducted in 4 US cities from 1999-2005 to examine whether AGD measurements in infants were associated with maternal self-reported age at conception, age at menarche, age at first birth, parity, and gravidity. AGD was measured in 289 infants (140 male, 149 female) born to study participants. After adjustment for relevant covariates, in linear regression models stratified by infant sex, maternal age was positively associated with AGD in male infants (AGD, anus to penis: β = 0.50, P = 0.002; AGD, anus to scrotum: β = 0.29, P = 0.02) but not female infants. Parity was inversely associated with AGD (anus to scrotum; β = -1.68, P = 0.03) in male infants. No other maternal characteristic predicted AGD in either sex. The mechanism underlying the unexpected relationship between maternal characteristics and AGD is unknown; however, we suggest several possibilities for future study.

Prenatal exposure to stressful life events is associated with masculinized anogenital distance (AGD) in female infants

In animal models, prenatal stress programs reproductive development in the resulting offspring, however little is known about effects in humans. Anogenital distance (AGD) is a commonly used, sexually dimorphic biomarker of prenatal androgen exposure in many species. In rodents, prenatally stressed males have shorter AGD than controls (suggesting lower prenatal androgen exposure), whereas prenatally stressed females have longer AGD than controls (suggesting greater prenatal androgen exposure). Our objective was to investigate the relationship between stressful life events in pregnancy and infant AGD. In a prospective cohort study, pregnant women and their partners reported exposure to stressful life events during pregnancy. Pregnancies in which the couple reported 4+ life events were considered highly stressed. After birth (average 16.5 months), trained examiners measured AGD in the infants (137 males, 136 females). After adjusting for age, body size and other covariates, females born to couples reporting high stress had significantly longer (i.e. more masculine) AGD than females born to couples reporting low stress (p=0.015). Among males, high stress was weakly, but not significantly, associated with shorter AGD. Our results suggest prenatal stress may masculinize some aspects of female reproductive development in humans. More sensitive measures of prenatal stress and additional measures of reproductive development are needed to better understand these relationships and clarify mechanisms.

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

Several phthalates, particularly diethyl phthalate (DEP) and di-n-butyl phthalate, can be used in personal care products (PCPs) to fix fragrance and hold color. We investigated associations between women's reported use of PCPs within the 24 h before urine collection and concentrations of several urinary phthalate metabolites. Between 2002 and 2005, 337 women provided spot urine samples and answered questions regarding their use of 13 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. 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 DEP) than other women. Other PCPs that were significantly associated with MEP concentrations included: hair spray, nail polish, and deodorant. MEP concentrations increased with the number of PCPs used. 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.

Socioeconomic factors and phthalate metabolite concentrations among United States women of reproductive age

INTRODUCTION

Relatively little is known about the socioeconomic correlates of phthalate metabolite urine concentrations among the general population, exposures of increasing public health concern, particularly for women of reproductive age.

METHODS

We pooled data from the 2001-2008 cycles of the National Health and Nutrition Examination Survey to examine the associations between phthalate metabolite concentrations (including the molar sum of four di-2-ethylhexyl phthalate (DEHP) metabolites, the molar sum of two dibutyl phthalate (DBP) metabolites, and metabolites of benzylbutyl phthalate (BzBP) and diethyl phthalate (DEP)) with socioeconomic indicators (including ethnicity, education, income, and food security status) among women 20 to 39 years age. We also derived a socioeconomic status summary measure using factor analysis and investigated its associations with metabolite concentrations.

RESULTS

In fully adjusted models, the lowest quartile of overall socioeconomic status was associated with 1.83 (95% CI=1.54-2.17) times the concentrations of mono-benzyl phthalate (MBzP), and 0.72 (95% CI=0.54-0.98) times the concentrations of (molar sum) DEHP metabolites compared with the highest quartile of overall socioeconomic status. This latter association was driven primarily by educational attainment. All Non-White ethnicities combined had 1.24 (95% CI=1.09-1.40) times the concentrations of (molar sum) DBP metabolites, 1.32 (95% CI=1.12-1.56) times the mono-ethyl phthalate (MEP) concentrations, and 0.82 (95% CI=0.71-0.96) the concentrations of MBzP of Non-Hispanic Whites.

CONCLUSIONS

Biomarkers of phthalate exposure vary with socioeconomic factors in women of reproductive age in the United States. Given the public health concern surrounding phthalate exposure, more research is needed to elucidate the reasons for these differences.