Prenatal Exposure to Glyphosate and Its Environmental Degradate, Aminomethylphosphonic Acid (AMPA), and Preterm Birth: A Nested Case–Control Study in the PROTECT Cohort (Puerto Rico)
2021; National Institute of Environmental Health Sciences; Volume: 129; Issue: 5 Linguagem: Inglês
10.1289/ehp7295
ISSN1552-9924
AutoresMonica K. Silver, Jennifer Fernandez, Jason E. Tang, Anna McDade, Jason Sabino, Zaira Rosario, Carmen Vélez Vega, Akram N. Alshawabkeh, José F. Cordero, John D. Meeker,
Tópico(s)Pesticide Exposure and Toxicity
ResumoVol. 129, No. 5 ResearchOpen AccessPrenatal Exposure to Glyphosate and Its Environmental Degradate, Aminomethylphosphonic Acid (AMPA), and Preterm Birth: A Nested Case–Control Study in the PROTECT Cohort (Puerto Rico)is accompanied byGlyphosate Exposure during Pregnancy and Preterm Birth (More Research Is Needed) Monica K. Silver, Jennifer Fernandez, Jason Tang, Anna McDade, Jason Sabino, Zaira Rosario, Carmen Vélez Vega, Akram Alshawabkeh, José F. Cordero, and John D. Meeker Monica K. Silver Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA , Jennifer Fernandez Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA , Jason Tang NSF International, Ann Arbor, Michigan, USA , Anna McDade NSF International, Ann Arbor, Michigan, USA , Jason Sabino NSF International, Ann Arbor, Michigan, USA , Zaira Rosario University of Puerto Rico Graduate School of Public Health, University of Puerto Rico, San Juan, Puerto Rico, USA , Carmen Vélez Vega University of Puerto Rico Graduate School of Public Health, University of Puerto Rico, San Juan, Puerto Rico, USA , Akram Alshawabkeh College of Engineering, Northeastern University, Boston, Massachusetts, USA , José F. Cordero Department of Epidemiology and Biostatistics, University of Georgia, Athens, Georgia, USA , and John D. Meeker Address correspondence to John D. Meeker, Department of Environmental Health Sciences, University of Michigan School of Public Health, 1835 SPH I, 1415 Washington Heights, Ann Arbor, MI 48109-2029 USA. Email: E-mail Address: [email protected] Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA Published:19 May 2021CID: 057011https://doi.org/10.1289/EHP7295Cited by:1AboutSectionsPDF Supplemental Materials ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail AbstractBackground:Glyphosate (GLY) is the most heavily used herbicide in the world. Despite nearly ubiquitous exposure, few studies have examined prenatal GLY exposure and potentially adverse pregnancy outcomes. Preterm birth (PTB) is a risk factor for neonatal mortality and adverse health effects in childhood.Objectives:We examined prenatal exposure to GLY and a highly persistent environmental degradate of GLY, aminomethylphosphonic acid (AMPA), and odds of PTB in a nested case–control study within the ongoing Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) pregnancy cohort in northern Puerto Rico.Methods:GLY and AMPA in urine samples collected at 18±2 (Visit 1) and 26±2 (Visit 3) wk gestation (53 cases/194 randomly selected controls) were measured using gas chromatography tandem mass spectrometry. Multivariable logistic regression was used to estimate associations with PTB (delivery 2 QC samples were analyzed per concentration, 50% of the QC samples at each concentration must have met the acceptance criteria.Quantitation was performed by an Agilent 7000C GC-MS/MS operated in multiple reaction monitoring (MRM) mode by negative chemical ionization using methane as the ionization gas. The temperatures of the ion source were 150°C, the transfer line was 260°C, and the quadrupoles were 150°C. The collision gas was nitrogen gas (N2) at 1.5mL/min, and the quench gas was He at 2.25mL/min. The MRM transitions used are listed in Table S1. The first transitions were used for quantitation, and the second and third transitions were used for qualifiers.We measured specific gravity to account for urine dilution. Specific gravity was quantified at the time of urine sample aliquoting using a digital handheld refractometer (ATAGO Co., Ltd.).Determination of PTBGestational age was estimated using the American College of Obstetricians and Gynecologists (ACOG) guidelines, which are recommended as the best obstetrical estimate of gestational age. This method uses the LMP date as reported by the mother with verification by ultrasound prior to 20 wk gestation, when available. The selection of the best estimate (LMP or ultrasound) depends on both the timing of the ultrasound and the size of the difference in the estimated date of delivery that is calculated from both estimates (ACOG 2017). These methods have been well characterized and are described in detail for this cohort elsewhere (Aker et al. 2019; Ashrap et al. 2020; Ferguson et al. 2019a, 2019b). Briefly, early pregnancy ultrasounds were collected at a median of 8.4 wk gestation; ultrasound estimates were available for ∼75% of study participants. Per ACOG guidelines, LMP estimates were replaced with ultrasound estimates if the difference between the two was >5d (for ultrasound measurements taken at <9wk gestation) or 7 d (for ultrasound measurements taken at <14wk gestation) (ACOG 2017). Gestational age estimates by LMP vs. ultrasound were highly correlated in the overall sample (ρ=0.92, p<0.001), and in the subset (17%), where estimates were changed from LMP dating to ultrasound (ρ=0.63, p<0.001). PTB was defined as delivery before 37 completed wk of gestation. Spontaneous PTB was defined as PTB with premature rupture of the membranes, spontaneous preterm labor, or both (Ferguson et al. 2014). PTB with preeclampsia or with artificial membrane rupture and induced labor were classified as nonspontaneous PTB (Ferguson et al. 2014).Statistical AnalysisStatistical analyses were conducted using SAS (version 9.4; SAS Institute, Inc.). Descriptive statistics and frequencies were examined for all variables of interest. To account for urine dilution, we corrected for specific gravity using the following formula: GASG=GA[(1.019–1)/(SG−1)], where GASG is the specific gravity–corrected GLY or AMPA concentration (in micrograms per liter); GA is the observed GLY or AMPA concentration; 1.019 is the population median specific gravity; and SG is the specific gravity of the urine sample. Percentile tables were created to determine the exposure profiles for GLYSG and AMPASG in our sample; arithmetic and geometric means (GMs) were also calculated. Spearman correlation coefficients were calculated to examine relationships between GLYSG and AMPASG at both visits. To assess the ratio of within- to between-individual variability in GLYSG and AMPASG over pregnancy, we calculated intraclass correlation coefficients (ICCs) for individuals with measurements at both time points (Rosner 2000). To create a more stable estimate of individual exposure during pregnancy, we created subject-specific pregnancy averages for GLYSG and AMPASG by averaging the specific gravity–adjusted values at Visits 1 and 3.GLY and AMPA values below the limit of detection ( 33% of AMPA values being <LOD, AMPA was categorized into <LOD divided by the medium/high (median split among the detects) based on the distribution in the controls. AMPA was coded into equally sized tertiles (low/medium/high) for the visit average. pTrend-Values were derived by modeling integer-scored tertiles of GLY and AMPA as ordinal variables.Confounders considered for inclusion in our adjusted models were maternal age, level of maternal education (high school or less/some college or technical school/college degree or higher), household income ( 10%. This procedure yielded only education and prepregnancy BMI as covariates. Based on our directed acyclic graph (Figure S1), maternal age and smoking were considered potentially important confounders and were thus included in the model. Household income and prior PTB had a relatively high percentage of missing values and were excluded from our main models but included as a sensitivity analysis. Thus, our primary models were adjusted for maternal age, education, prepregnancy BMI, and maternal smoking. All adjusted models were complete case analyses.We completed several additional analyses to test the robustness of our results and explore additional variables of interest. As mentioned previously, we carried out sensitivity analyses to assess potential confounding by the variables that were not included in our final models by adjusting for household income and prior PTB. We additionally assessed for potential confounding by di-n-butyl phthalate and di-isobutyl phthalate by adding their urinary metabolites, mono-n-butyl phthalate (MBP) and mono-isobutyl phthalate (MiBP), to our models. MBP and MiBP have been previously found to be associated with increased odds of PTB in PROTECT (Ferguson et al. 2019b). MBP and MiBP were specific gravity corrected and natural log-transformed prior to inclusion in the models.We also ran our logistic regression models stratified by infant sex to test for possible sex-specific effects because rodent models have revealed the potential for endocrine disruption following GLY exposure (Manservisi et al. 2019). Unstratified logistic regression models were then used to test for statistical significance of potential sex-specific effects, by adding sex and sex–GLY or sex–AMPA interaction terms to the models and examining the statistical significance of the interaction terms.Finally, we examined two alternative outcomes of interest: spontaneous PTB and length of gestation. Spontaneous PTB was defined as premature rupture of the membranes, spontaneous preterm labor, or both, and may represent a more etiologically homogeneous subset of preterm births appropriate to explore in relation to environmental exposures (Ferguson et al. 2014). Multivariable generalized linear models were used to estimate associations between GLY and AMPA and length of gestation in weeks.Results247 women total had urinary GLY and AMPA measurements (53 cases, 194 controls), 177 at Visit 1 (35 cases, 142 controls), 208 at Visit 3 (53 cases, 208 controls), and 138 (35 cases, 103 controls) at both time points. By chance, all PTB cases had Visit 3 urine samples, with a subset of those also having a sample for Visit 1; there were no cases that had only a Visit 1 sample. The LOD was 0.20μg/L for both GLY and AMPA. GLY was detected in 79.1% and 79.3% of samples, whereas AMPA was detected in 54.2% and 51.4% of samples, for Visits 1 and 3, respectively. Quality control analysis yielded coefficients of variation ranging from 7.0% to 14.4%. GMs [geometric standard deviations (GSDs)] for GLY, at Visits 1 and 3, respectively, were 0.45 (2.17) and 0.56 (2.58) μg/L for cases and 0.44 (2.50) and 0.41 (2.56) μg/L for controls (Table 1). GMs (GSDs) for AMPA, at Visits 1 and 3, respectively, were 0.24 (2.76) and 0.33 (3.40) μg/L for cases and 0.25 (3.06) and 0.20 (2.87) μg/L for controls (Table 1). 138 (35 PTB cases and 103 term controls) participants had urine samples that were measured for GLY and AMPA at both Visits 1 and 3. ICCs were 0.24 (95% CI: 0.10, 0.46) and 0.63 (95% CI: 0.48, 0.75) for specific gravity–corrected GLY and AMPA, respectively. Specific gravity–corrected GLY and AMPA were correlated at Visit 1 (Spearman ρ=0.43, p<0.0001) and Visit 3 (Spearman ρ=0.51, p<0.0001). GLY at Visits 1 and 3 was also correlated (Spearman ρ=0.36, p<0.0001), as was AMPA (Spearman ρ=0.19, p=0.03).Table 1 Distribution of specific gravity–corrected GLY and AMPA in the urine (μg/L) at Visit 1 (18±2 wk gestation), Visit 3 (26±2 wk gestation), and the average of Visits 1 and 3 in the PROTECT cohort.Table 1 has nine main columns, namely, Analyte, Visit, Lowercase italic n, Percentage less than limit of detection which equals 0.20 microgram per liter, Arithmetic mean, standard deviation, Geometric mean, Geometric standard deviation, and Percentile. Percentile column is subdivided into seven columns, namely, tenth, twenty-fifth, Median, seventy-fifth, ninetieth, ninety-fifth, and Maximum.AnalyteVisitnPercentage <LODaAMSDGMGSDPercentile10th25thMedian75th90th95thMax.Overall sample GLY117720.90.600.440.442.430.14 (<LOD)0.280.500.791.151.552.80320820.70.650.660.442.590.14 (<LOD)0.270.470.821.341.715.36Avg.1388.60.610.410.491.980.220.310.500.821.071.482.73 AMPA117745.80.440.840.252.990.07 (<LOD)0.14 (<LOD)0.260.530.831.2210.08320847.60.380.410.233.050.06 (<LOD)0.13 (<LOD)0.230.530.851.063.08Avg.13829.00.370.290.282.150.09 (<LOD)0.17 (<LOD)0.300.470.710.861.85Preterm cases GLY13514.30.600.520.452.170.11 (<LOD)0.310.460.791.091.782.8035315.10.861.020.562.580.18 (<LOD)0.360.551.001.284.025.36Avg.355.70.670.520.541.960.290.340.510.820.971.982.73 AMPA13540.00.350.300.242.760.08 (<LOD)0.16 (<LOD)0.270.480.791.021.2535334.00.580.630.333.400.10 (<LOD)0.19 (<LOD)0.380.731.321.973.38Avg.3525.70.450.370.342.200.11 (<LOD)0.200.360.590.881.311.80Full-term controls GLY114222.50.600.430.442.500.14 (<LOD)0.280.520.791.151.531.95315522.60.580.470.412.560.13 (<LOD)0.250.450.761.341.712.52Avg.1039.70.590.370.481.990.200.280.500.841.071.341.65 AMPA114247.20.460.930.253.060.07 (<LOD)0.13 (<LOD)0.260.530.831.2210.08315552.30.310.280.202.870.06 (<LOD)0.12 (<LOD)0.210.420.670.891.52Avg.10330.10.340.260.262.130.08 (<LOD)0.16 (<LOD)0.290.420.660.771.85Note: AM, arithmetic mean; AMPA, aminomethylphosphonic acid; ASD, arithmetic standard deviation; avg., average; GLY, glyphosate; GM, geometric mean; GSD, geometric standard deviation; LOD, limit of detection; max., maximum; PROTECT, Puerto Rico Testsite for Exploring Contamination Threats.aLOD=0.20μg/L.Compared with controls, cases were more likely to be younger (50.9% of cases were <25 years of age, compared with 38.7% of controls), less educated (32.7% of cases had a high school education or less, compared with 19.4% of controls),
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