Title: Association Between Urinary Bisphenol A Concentration and Obesity Prevalence in Children and Adolescents
1Association Between Urinary Bisphenol A
Concentration and Obesity Prevalence in Children
and Adolescents
- Leonardo Trasande, MD, MPP
- Teresa Attina, MD, PhD, MPH
- Jan Blustein, MD, PhD
2Bisphenol A (BPA)
Discovered by Aleksandr Dianin, 1891
- Used to manufacture polycarbonate resin
- Found in canned food, polycarbonate bottled
liquids and other consumer products - Breakdown product of coatings intended to prevent
metal corrosion in food and beverage containers - Recently banned from baby bottles and sippy cups
by US Food and Drug Administration - Comprehensive, cross-sectional study of dust,
indoor and outdoor air, and solid and liquid food
in preschool age children suggested that dietary
sources constitute 99 of BPA exposure
Schecter et al. Environ Sci Technol.
201044(24)9425-9430 Wilson et al. Environ Res.
Jan 2007103(1)9-20. Tavernise S. New York
Times, 17 July 2012 edition.
3BPA in humans
- Exposure is ubiquitous
- Studies suggest brief half-life (4-43 hours)
- But BPA also detected in fat
- Urinary levels of BPA do not decline rapidly with
fasting time, suggesting accumulation in body
tissues
Stahlhut et al. Environ Health Perspect.
2009117(5)784-789. Volkel et al.Chem Res
Toxicol. 200215(10)1281-1287. Fernandez et al.
Reprod Toxicol. Aug-Sep 200724(2)259-264.
4BPA and obesity
- Laboratory studies suggest that BPA disrupts
multiple metabolic mechanisms, - Occurs at exposure levels commonly seen in US
population - Urinary BPA concentration has been associated
with - Adult obesity
- Adult diabetes, cardiovascular diagnoses and
abnormalities in liver function - Increased frequency of later coronary artery
disease in later life - Differences in heart rate variability and blood
pressure in elderly
Masuno et al. J Lipid Res. 200243(5)676-684 Saku
rai K et al. Br J Pharmacol. 2004141(2)209-214 C
arwile JL, Michels KB. Environ Res.
2011111(6)825-830 Lang al. JAMA.
2008300(11)1303-1310 Melzer et al. PLoS One.
20105(1)e8673 Melzer et al. Circulation.
2012125(12)1482-1490 Bae et al. Hypertension
201260786-793
5BPA and childhood obesity?
- Children are known to be uniquely vulnerable to
environmental chemicals - Yet no studies to date connecting environmental
chemical exposures to obesity - We examined associations of urinary BPA
concentration with body mass in 6-19 year olds in
NHANES 2003-8. - NHANES is a federal survey of the nations
health, conducted nationally through mobile
testing sites. - Sample was 2838 US children, representative of
the US
6Quantifying BPA and body mass
- BPA
- Urinary concentrations from Centers for Disease
Control and Prevention (CDC)s laboratories - We transformed the concentrations in two ways
- Divided the sample into fourths based on BPA
concentration (lowest to highest) - Also looked at linear BPA concentration
(expressed as the logarithm to normalize the
distribution) - Body mass
- Height and weight measured by CDCs trained staff
- We transformed these in two ways
- Standardized BMI (weight in kilograms divided by
height in meters squared) for age and gender into
Z-scores - Classified overweight as at/above 85th percentile
for age and gender (obese at/above 95th
percentile)
7Other factors that were considered
- Simultaneously examined other factors associated
with obesity - Age group (6-11 and 12-19 years)
- Gender
- Racial/ethnic group
- Socioeconomic status
- Caregiver education
- Serum cotinine level (tobacco smoke exposure)
- Television watching
- Caloric intake
- Urinary dilution (creatinine)
8Key characteristics of the sample
34.1 overweight
17.8 obese
- Median BPA 2.8 ng/mL
- Caloric intake and television watching not
associated with BPA, but BPA was associated with
overweight and obesity
9Main (multivariable) results
Quartile (Percentile) Prevalence Odds Ratio BMI Z-score
1 (0-24) 10.3 Reference Reference
2 (25-49) 20.1 2.24 0.12
3 (50-74) 19.0 2.08 0.16
4 (75) 22.3 2.57 0.22
plt0.05 plt0.01 plt0.001
10Specificity of association
- We also examined chemically similar environmental
phenols used in sunscreens and soaps - Urinary concentrations of these similar phenols
were not associated with obesity
11Race-specific effects
- Associations of BPA concentration with obesity
(but not BMI Z-score) were isolated to whites,
and were absent in Hispanics and Blacks. - If obese whites have unique dietary behaviors
that predispose them to increases in urinary BPA,
then this could explain our results, though there
is no evidence to support this. - A difference in genetic or other predisposition
is another plausible explanation.
12Caveats
- Reverse causation is possible
- Obese children ingest more foods that contain BPA
- Urinary BPA represents more recent exposure,
rather than the chronic exposure that is more
likely to lead to obesity - BPA may disrupt metabolism earlier in life than
in the childhood and adolescent years we studied
13Nonlinear association
- Consistent with biological activity of many
hormones - Duplicated in many studies
- Dr. Linda Birnbaum (NIEHS Director) has
emphasized that regulatory policymakers should
include information about non-linear
associations, when they deliberate.
Vandenberg LN et al. Endocr Rev. Jun
201233(3)378-455. Birnbaum Environ Health
Perspect. Apr 2012120(4)A143-144.
14Summary
- First report of an association of an
environmental chemical exposure with childhood
obesity in a nationally representative sample - Association evident when exposure and outcome are
modeled in a number of different ways - Adjusted prevalence of obesity of 22.3 (among
children in the highest uBPA quartile, compared
with a 10.3 prevalence among those in the lowest
uBPA quartile.
15L Trasande and coauthors Association Between
Urinary Bisphenol A Concentration and Obesity
Prevalence in Children and Adolescents