Acrolein is an air toxic with high potency as a respiratory irritant. There is strikingly little epidemiology available for acrolein although US EPA estimates that acrolein is responsible for about 75 percent of non-cancer respiratory health effects attributable to air toxics in the United States, based on the Agency's 2005 National-Scale Air Toxics Assessment (NATA). We addressed this data gap by geographically linking 2005 NATA acrolein exposure estimates at the census tract with residences of participants in the National Health Interview Survey (NHIS) for 2000-2009 (n = 216,371). The NHIS monitors the health of the civilian, non-institutionalized population of the United States through a comprehensive interview of a nationally representative sample of households. The health outcome was self-reported asthma attack in the previous 12 months among adults 18 years and older. In the highest quintile of acrolein exposure (>0.055 ug/m3), there was a borderline statistically significant increase in asthma attack prevalence (pOR [95% CI]= 1.11 [1.00:1.23]), controlling for smoking, sex, age, education, race, poverty, insurance, access to care, urban/rural residence, and survey year. Stratifying the analysis by urban and rural residence, exposure to the highest quintile of acrolein concentration in urban areas was borderline statistically significant (1.13 [1.00:1.29]), while in rural areas it was not (1.08 [0.80:1.44]).
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Acrolein and Adult Asthma in a Nationally Representative Sample of the United States
1. Acrolein and Adult Asthma in a Nationally
Representative Sample of the United States
B. Rey de Castro, Sc.D.
Statistician
before the
International Society of Exposure Science
Baltimore, MD
October 24, 2011
National Center for Health Statistics
Office of Analysis & Epidemiology, Special Projects Branch
2. Acrolein
Aldehyde
Hazardous Air Pollutant subject to Clean Air Act
3. Ubiquitous
Combustion
Tobacco
Mobile sources, especially diesel
Airports
Wood heating & forest fires
Industrial boilers
Indoor air pollutant
Cooking
Smoking
4. Ubiquitous
Largest industrial uses
Synthesis of acrylic acid
Biocide
Two biggest emitting facilities in Alvin and Diboll, TX
Next 8 biggest: IL, VA, NE, IA, WI, KS
Top 10 responsible for 90 percent of TRI emissions.
9. Ambient Measurement Very Difficult
Highly reactive
Ambient formation
Even within samplers
Sensitive to
Sampler preparation
Sampler type
Time elapsed from preparation to analysis
Inter-laboratory variability in analysis
10. Current Ambient Methods
US EPA
TO-11a: canister sampler
TO-15: cartridge sampler
TO-15 superseding TO-11a
Resolution: hours — days
TO-15a still problematic
Subject of ongoing improvement research
Near real-time monitor
Recently developed
Quantum cascade laser IR absorption
12. Alternative 1: Exposure Biomarkers
Urine
Mercapturic acid metabolites
Analytical methods recently developed at CDC
Poster here at ISES 2011: Abstract 1120986
By Udeni Alwis, Sc.D. uAlwis@cdc.gov
Not the subject of this talk
13. Alternative 2: Modeled Exposure
US EPA National-Scale Air Toxics Assessment 2005
Nationwide estimate of chronic inhalation exposure
Census tract resolution
Hazardous air pollutants & diesel particulate matter
Diesel particulate matter
Cancer and non-cancer health effects
14.
15.
16. NATA 2005
EPA says:
Acrolein responsible for ―about 75 percent of the nationwide
average non-cancer hazard‖
Remarkable for air toxic with no epidemiology
17. Now that we have
exposure estimates,
what if we could get
health effects data?
18. Nationwide Health Effects
National Health Interview Survey 2000 — 2009
Content
Health conditions and behaviors
Access to health services
Representative sample of
United States , nationwide
Non-institutionalized
Civilian
Cross-sectional prevalence
19. National Health Interview Survey
Interview
Face to face
Computer-aided
Data
N ~ 40,000 households (~87,000 individuals) annually
Initiated in 1957
21. Complex Survey Design
Cross-sectional
Use of weighting, clustering, and stratification
Oversampling
Variance estimation complicated
Special software: SUDAAN™
Taylor series linearization method (GEE)
22. NHIS 2000 — 2009
10 years NHIS data
Adults 18 years-old and over
Self-reported asthma attack in previous 12 months
Has a doctor ever told you that you have asthma?
AND
Have you had an asthma attack in the last 12 months?
Standard CDC definition for evaluating national
asthma trends
23. NHIS Confidential Data
Aim: geographic merge with NATA 2005
Data not for public use
Geocoded NHIS subject residence
Urban/rural residence
NCHS Research Data Centers (RDCs)
Access non-public use data
Confidential data merges
Locations nationwide
24. NATA-NHIS Data Merge
NATA: NHIS:
Acrolein Adult
Exposure Asthma
Merge by
Census
Tract
Merged
NATA-
NHIS Data
25. NATA 2005 & NHIS 2000-2009
Sample size: 209, 365 subjects
72.8 percent of 287,530 subjects
Census tracts: 14,936
22.6 percent of 66,029 tracts
Asthma attacks in last 12 months: 3.98 percent subjects
29. Logistic Regression Model
Binary outcome: asthma attack last 12 months
NHIS 2000 — 2009
Self-report
Predictor of interest: acrolein quintile
NATA 2005
Inhalation exposure concentration at census tract
30. Potential Asthma Confounders
Race, sex, age, smoking, education, insurance
coverage, access to healthcare, urban/rural
residence, survey year, survey quarter
Based on prior NHIS research on asthma trends
31. Complex Survey Variance Estimation
Taylor series linearization (GEE)
Survey sample weights 2000 — 2009
Indicators for survey stratum and PSU
32. pOR by Acrolein Quintile
1.30
1.20
1.10
pOR
1.00
0.90
0.80
1 2 3 4 5
Exposure Quintile
33. Primary Result
At highest quintile of acrolein exposure
0.0551 – 0.457 µg/m3
pOR 1.11 [1.00:1.23] adult asthma
11 percent increase in adult asthma prevalence
Controlling for
race, sex, age, smoking, education, insurance
coverage, access to healthcare, urban/rural
residence, survey year, survey quarter
Reference concentration (RfC) = 0.02 µg/m3
34. Stratified Analysis by Residence
Urban at highest quintile of acrolein exposure
pOR 1.13 [1.00:1.29] adult asthma
Rural at highest quintile of acrolein exposure
pOR 1.08 [0.80:1.44] adult asthma
Controlling for
race, sex, age, smoking, education, insurance
coverage, access to healthcare, survey year, survey
quarter
35. Confounders
Statistically significant
Race, sex, age, smoking, education, access to
healthcare, urban/rural residence, survey year
Not statistically significant
Insurance coverage, survey quarter
36. Strengths
Inexpensive data collection and design
Large sample
National geographic coverage
Census tract resolution
Generalizable to US population
38
37. Limitations
Uncertainty of NATA exposure estimates
Merge bias
Cross-sectional
Acrolein from indoor air, food
Effect estimation in smaller areas severely limited
39
38. Feasible to conduct
national epidemiologic
analysis with modeled
chronic exposure estimates
for air toxics
41. Acknowledgements
Jenifer Parker, Ph.D.
Chief, NCHS OAE Special Projects Branch
Merged EPA air quality data with
• NHIS 1986 — 2005
• NHANES 1986 — 1994
• National Hospital Discharge Survey 1999 — 2005
CDC Guest Researcher Program
Research conducted in my spare time
46. Future
Tremendous potential to explore hypotheses and
prioritize risk
NATA 2005
177 air toxics and diesel particulate matter
NHIS 2000 — 2009
Great variety of health outcomes
Merges with other data
Medicare enrollment and claims
National Death Index
Social Security benefits
47. B. Rey de Castro, Sc.D.
Centers for Disease Control
National Center for Environmental Health
Atlanta, Georgia
rdecastro@cdc.gov
+1 770 488 0162
www.slideshare.net
National Center for Health Statistics
Office of Analysis & Epidemiology, Special Projects Branch
Notas do Editor
Acrolein is used as a precursor in chemical manufacture.Product of combustion, including tobacco and petroleum.Used also as a biocide.Indoor air pollutant attributable to off-gassing from building materials.
Acrolein is used as a precursor in chemical manufacture.Product of combustion, including tobacco and petroleum.Used also as a biocide.Indoor air pollutant attributable to off-gassing from building materials.
Polyamines are aliphatic cations present in all cells. In normal cells, polyamine levels are intricately controlled by biosynthetic and catabolic enzymes. The biosynthetic enzymes are ornithine decarboxylase, S-adenosylmethionine decarboxylase, spermidine synthase, and spermine synthase. The catabolic enzymes include spermidine/spermineacetyltransferase, flavin containing polyamine oxidase, copper containing diamine oxidase, and possibly other amine oxidases. Multiple abnormalities in the control of polyamine metabolism and uptake might be responsible for increased levels of polyamines in cancer cells as compared to that of normal cells.
Acrolein was even weaponized for battlefield use in World War I.
LC50: lethal concentration 50 percent, acte toxicityLOAEL: lowest observed adverse effect levelRfC: reference concentration (inhalation, lifetime, calculated from LOAEL)IDLH: immediately dangerous to life and healthSTEL: short-term exposure limitPEL: permissable exposure limit (8h TWA, enforceable)REL: recommended exposure limit (nonenforceable recommendations)AEGL1,2: acute exposure guidelines (notable effects in general and susceptible populations)
Acrolein was even weaponized for battlefield use in World War I.
Acrolein was even weaponized for battlefield use in World War I.
NATA provides national estimates of ambient concentration and exposure for nearly 200 air toxics from a comprehensive list of diverse sources.HEM3 (AERMOD): point, onroad mobile, off-road mobile sourcesASPEN: Non-point sourcesCMAQ: secondary formation and decay
HEM3 (AERMOD): point, onroad mobile, off-road mobile sourcesASPEN: Non-point sourcesCMAQ: secondary formation and decaySources of data are the NEI and monitoring data, which is run through atmospheric dispersion models to estimate ambient concentrations at the census tract level.Ambient concentration estimates are then run through an inhalation exposure model to estimate exposure concentrations at the census tract level.NATA serves as a risk screening tool with high spatial resolution.About 66,000 census tracts.
NATA provides national estimates of ambient concentration and exposure for nearly 200 air toxics from a comprehensive list of diverse sources.HEM3 (AERMOD): point, onroad mobile, off-road mobile sourcesASPEN: Non-point sourcesCMAQ: secondary formation and decay
NATA provides national estimates of ambient concentration and exposure for nearly 200 air toxics from a comprehensive list of diverse sources.HEM3 (AERMOD): point, onroad mobile, off-road mobile sourcesASPEN: Non-point sourcesCMAQ: secondary formation and decay
Here is a map of the NATA 2005 respiratory hazard index estimates for all air toxics across census tracts. This is not specific to acrolein.Where the hazard index is greater than one, the census tract’s exposure exceeds the toxicologicnoncancer reference concentration RfC.Both urban and rural census tracts appear to be at risk.
Based on NATA exposure and toxicologic reference concentrations (RfC), EPA found that acrolein is responsible for 75 percent of respiratory noncancer health effects nationwide.This is remarkable for an air toxic with strikingly little human health effects research.
10 years of data comprising 287,530 surveyed subjects representing a population of 1.6 billion people.
WeightingThe statistical weight of a sampled person is the number of people in the population that the person represents. Weights derived fromSelection probabilitiesResponse ratesPost-stratification adjustment e.g., gender, education, income, regionStratificationPopulation divided before sampling into disjoint, exhaustive groups (strata)Members termed primary sampling units (PSUs) Independent samples are taken in each strataStrata formed by similar geographic areas e.g., NHANES: partition US counties into 49 strata based on region and economic/racial characteristicsSample 2 counties (PSUs) from each strataClusteringPersons residing in a small area may have similar characteristicsThus, responses of subjects in small area are potentially correlated Correlation must be accounted for in the analysis Survey analysis programs do this through strata/PSU informationVariance EstimationLinearization: Uses a Taylor series expansion to estimate variance of non-linear estimators Default method for most programsRequires stratification and PSU information
Answers “Yes” to:Have a doctor ever told you that you have asthma?Have you had an asthma attack in the last 12 months?