Measuring Environmental Phenols and Cotinine in Urine of Pregnant
Minnesota Women: the Riverside Prenatal Biomonitoring Pilot Project
Jessica Nelson PhD, Adrienne Kari MPH, Carin Huset PhD, Jean Johnson PhD
Background and Purpose
Biomonitoring Results
In 2007 the Minnesota Legislature passed a law charging the
Minnesota Department of Health (MDH) to conduct four
biomonitoring pilot projects to inform the development of a
statewide biomonitoring program. One of these projects involved
characterizing the range and distribution of a to-be-determined
chemical in a group of 90 individuals from 3 defined populations.
A separate clause of the legislation directed MDH to “conduct
biomonitoring of pregnant women and minors on a voluntary
basis, when scientifically appropriate.”
Environmental phenols
Cotinine
• BPA detected in 56% of women, methyl paraben in 94%, propyl
paraben in 85%, ethyl paraben in 44%, and butyl paraben in 11%.
Due to difference in LODs, percent detections not directly
comparable to NHANES.
• Cotinine detected in 15% of women (Fig. 4); 14% classified
as active smokers.5 Women with lower household incomes
more likely to have cotinine detected.
• Geometric mean (GM) BPA concentration 2.2 g /g creatinine, methyl
paraben 73 g/g, and propyl paraben 14 g/g (Table 2, Fig. 3).
• Cotinine not detected in 85%. These women not exposed to
tobacco smoke or exposed to low levels through
secondhand smoke.
Figure 4. Participants by cotinine detection
Table 2. Environmental phenol concentrations ( g/g creatinine)
GM Median
IQR
Min
Max
With the recommendation of the Environmental Health Tracking
and Biomonitoring program’s science Advisory Panel, a suite of
environmental phenols and cotinine were chosen as the chemical
measures of interest and the target population as pregnant
women from 3 different ethnic/racial backgrounds. Environmental
phenols include bisphenol A (BPA), used in polycarbonate plastic
and the lining of food cans, and parabens, used in products such
as shampoo and lotion. Cotinine, a metabolite of nicotine, is an
indicator of exposure to tobacco. Both are measured in urine.
Bisphenol A
2.2
2.4
0.6 - 5.3
0.2
46.9
Methyl paraben 73.3
110.9
30 - 247.5
0.4
1157.9
Propyl paraben
13.8
18.1
2.9 - 60.9
0.4
363.2
Ethyl paraben
*
1.6
<LOD - 5.0
0.3
384.5
Butyl paraben
*
0.6
<LOD - 1.4
0.2
45.9
* Not calculated: proportion of results <LOD too high to provide valid result
Participant Recruitment
The project was ancillary to the Riverside Birth Study (RBS)
conducted by researchers at the University of Minnesota. The
RBS enrolled women receiving prenatal care at two Minneapolis
health clinics. Most women were in their first trimester when they
joined the study.
• BPA and parabens differed by income and race/ethnicity (Fig. 1 &
2). BPA and methyl paraben highest in lowest income group (not
significant). BPA, methyl, and propyl paraben higher in non-white
than white women; methyl paraben 3½ times higher (p=0.01).
Figure 1. BPA by income and race/ethnicity
Women who had consented to the RBS and agreed to future
contact received information about the MDH pilot project. Those
who indicated interest were given a urine collection kit.
Participants collected and froze a single urine sample, which was
delivered via courier to the MDH Public Health Laboratory.
Discussion
Of the 122 women who were contacted about the pilot project, 66
provided a urine sample. Women were from a range of income
levels, and most were white (Table 1).
Table 1. Participant characteristics (n = 66)
N
Figure 2. Parabens by income and race/ethnicity
Annual household income
< $20,000
> $20,000 - < $80,000
> $80,000
16
23
27
30%
35%
35%
White
Black/African American
Hispanic/Latino
Asian
Other
46
8
4
4
4
Conclusion
24%
35%
41%
Race/ethnicity
70%
12%
6%
6%
6%
• BPA levels similar to U.S. women in NHANES1 (Fig. 3; GM
2.2 g /g compared to 2.4). Other studies have measured BPA in
pregnant women, with GMs from 1.7 g /g in Cincinnati and the
Netherlands to 4.1 g /g in Norway.2-4
• Paraben levels lower than U.S. women (for methyl paraben, GM
73 g /g compared to 126; for propyl paraben, 14 g /g compared
to 22). Few studies have measured parabens in pregnant women.
Figure 3. Distribution of environmental phenols
MedTox Laboratory (St. Paul, MN) analyzed urine samples for
cotinine and creatinine, a measure of urinary dilution. The limit of
detection for cotinine was 20 ng/mL.
Concentration ( g/g)
Laboratory Analysis Methods
MDH’s Public Health Laboratory analyzed urine samples for
environmental phenols using online solid phase extraction
coupled to liquid chromatography with tandem mass
spectrometry (SPE LC/MS/MS). The method analyzed free and
conjugated species; results are presented for total analyte.
Analytes measured included BPA and methyl, propyl, butyl, and
ethyl paraben. The limit of detection for all analytes was 1 g/L.
Because this was a small pilot project in a convenience sample,
we cannot conclude that these exposures represent all
Minnesota women. Due to issues with recruitment, our
population did not achieve the desired racial/ethnic distribution;
our “non-white” category included women from many
backgrounds. Future studies should be larger and include more
participants from non-white racial/ethnic groups to identify
exposure disparities.
In addition, for short-lived compounds such as cotinine and
environmental phenols, there is substantial intraindividual
variation in urinary levels. The analyte LODs limited
conclusions we could draw regarding percent detections and
exposure to environmental tobacco smoke.
%
Age
mean (sd) 29.8 (5.4)
19-27
20
28-31
23
32-41
23
Results were similar to data from state and national surveys:
• In 2008 Minnesota Pregnancy Risk Assessment Monitoring
Survey (MN PRAMS) and information from birth certificates,
13.8% of pregnant women were smokers.6
• In 1999-2006 NHANES, 13% of pregnant women were
smokers.7
This project demonstrated MDH’s ability to conduct
biomonitoring in pregnant women. It showed that, in a small
group of Minnesota women, exposures to environmental
phenols and tobacco were not elevated compared to other
populations, and provided some evidence of disparities in
exposure to parabens and BPA that deserve future attention.
Finally, the project taught MDH a number of important lessons
as we plan for future biomonitoring activities in Minnesota.
References
1.
2.
3.
4.
5.
6.
7.
Centers for Disease Control and Prevention. Fourth National Report on
Human Exposure to Environmental Chemicals.
http://www.cdc.gov/exposurereport/. Dec 2009.
Braun et al. 2011. Environ Health Perspect. Jan;119(1):131-7.
Ye et al. 2008. Environ Res. Oct;108(2):260-7.
Ye et al. 2009. Int J Hyg Environ Health. Sep;212(5):481-91.
Based on MedTox Laboratory definition: cotinine + nicotine > 200 ng/mL.
Minnesota PRAMS, personal communication, April 2011.
Dietz et al. 2011. Am J Epidemiol. Feb 1;173(3):355-9.
Acknowledgements
We thank project participants and Dr. Logan Spector and Megan
Slater from the University of Minnesota. We also acknowledge the
contributions of numerous MDH staff and the EHTB Advisory
Panel. The project was funded by the Minnesota State
Legislature. For more information, contact the MDH Environmental
Public Health Tracking and Biomonitoring program:
www.health.state.mn.us/tracking
[email protected]
651-201-5900.