Abstract
Background: Phthalates are a family of synthetic
chemicals used in a wide spectrum of plastic products, such as
personal care products, building materials, food packages, medical
devices and pharmaceuticals. Phthalates are classified into low and
high molecular weight compounds. Previous studies indicate that
phthalates are related to allergic and inflammatory processes in
humans. Asthma is a common pulmonary disease characterized by
airway hypersensitivity. We conducted this analysis to evaluate the
relationship between urinary phthalate metabolite concentrations
and asthma-related outcomes.
Methods: Five 2-year cycles of the National Health and
Nutrition Examination Survey (NHANES 2003-2012) were merged for our
analysis dataset. A total of 7,298 adult participants with
available urinary phthalates metabolites, asthma, and covariate
data were included. After stratification and confounder adjustment,
logistic regression was performed that incorporated sample weights
to account for the complex, multistage probability sampling design
used to select participants that represent the
non-institutionalized US population.
Results: Mono-n-methyl phthalate (MNM) was positively
associated (OR: 1.25, CI: 1.04-1.50) with ever asthma among all
adults. Among adult females, MCNP, MCOP and MCPP were positively
associated with ever asthma (ORs=1.26-1.34). Among females
reporting ever asthma, MiBP was positively associated with past
asthma (OR: 1.83, CI: 1.10-3.04). Among black females, MCPP and
MEHP were associated with ever asthma (ORs: 1.44, CI: 1.02-2.05 and
OR: 1.55, CI 1.08-2.21, respectively). Among white females
reporting a history of asthma, MiBP was positively associated with
past asthma (OR: 2.29, CI: 1.11-4.71).
Conclusion: In this cross-sectional sample of US adults we
did not observe a consistent pattern of association with
asthma-related outcomes across the phthalate metabolites measured,
however, the associations we did observe were positive. Given the
cross-sectional design of the survey, we cannot infer causality and
because of the variable associations observed, the observations may
be a result of chance alone.
Table of Contents
Tables of
Contents…………………………………………………………………………………1
Background……………………………………………………………………………………..…...2
Phthalates………………………………………………………………………………......………2
Asthma……………………………………………………………………………………........……4
Hypothesis……………………………………………………………………………….....……...6
Methods…………………………………………………………………………………....………….6
Data Source and Study
Population…………………………………………...………….6
Measurement of Exposures and
Outcomes……….…………………………………..7
Covariates……………………………………….…………………………………………….......8
Statistical
Analysis……………………………………………………………………...……….8
Results………………………………………………………………………………………...……...9
Descriptive
statistics…………………………………………………………………..……….9
Logistic
regression……………………………………………………………………....……..10
Discussion…………………………………………………………………………………...……...11
References……...………………………………………………………………………..…………14
Appendix…………………………………………………………………………………….....…….19
About this Master's Thesis
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