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Table 1 Summary of data sources for environmental exposures.

From: An integrated model of environmental factors in adult asthma lung function and disease severity: a cross-sectional study

Data source and exposure

Measurement/analysis

Variable format

Telephone interview

   Secondhand smoke (SHS)

Validated self-report measure (48)

Dichotomous: <1 vs. ≥1 hour/day

   Occupational exposure to vapors, gas, dusts, or fumes (VGDF)

Self-report checklist measure (47)

Categoric: compared to employed with no VGDF exposure (ref), and not employed

Home visit

   Wall dampness

Hand-held moisture meter

Continuous: percent moisture

   House plants, air filter, wood heating source, dog in home

Check-list

Dichotomous: present vs. absent

Laboratory measures, from samples collected at home visit

   Total dust

Gravimetric weight

Continuous: bedroom sample

   Can f1 antigen

ELISA

Continuous: concentration in μg/g dust (maximum of bedroom or living room sample)

   Anti-Can f1 specific IgE

Immunocap

Dichotomous: elevated (≥25 kU/l) vs. not

   Endotoxin

Limulus assay

Dichotomous: lowest quartile concentration in EU/mg dust (maximum of bedroom or living room sample) vs. all others

   Glucan

Sandwich ELISA

Dichotomous: highest quartile concentration in μg/g dust (maximum of bedroom or living room sample) vs. all others

Metal concentrations

(Cu, Fe, Mg, V, Zn)

Aqueous extracts by inductively coupled plasma-mass spectrometry

Dichotomous: highest quartile concentration in μg/g dust (bedroom sample) vs. all others

Contextual data, matched to residential addresses via geocoding

   Neighborhood socioeconomic characteristics

2000 Census, measured at the block group level

Continuous: 2 factors derived from principal components analysis of 13 SES variables

   Land use

U.S. Geological Survey National Land

Cover Dataset

Dichotomous: Urban/built environment vs. agricultural/forested

   Distance from residence to roadway

Tele Atlas/Geographic Data

Continuous: meters to nearest road

 

Technology Dynamap database

Continuous: km to nearest major road

   Air quality

Air pollution: CA Air Resources Board

Air Quality Data, Environmental

Protection Agency Air Quality Data Retrieval System

Continuous: 2 factors derived from principal components analysis of 8 variables: (ozone, PM2.5, PM10-2.5, NO2, summer and winter temperatures and wind speeds)

 

Climate: Bay Area Air Quality Management District, National Weather Service

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