Utilizing Ethnicity as a Predictor of Lung Function as Indicated by MMEF in the California Children's Health Study

1. able 2. MMEF model: Reference variable is Alpine
Figure 1. Map of FEV/FVC in the 12 towns studied. Ratio is an indicator of lung function,
by most literature citing 80% as a good functionality in children.
Utilizing Ethnicity as a Predictor of Lung Function as Indicated by MMEF In The
California Children’s Health Study
Nicholas Ortega, Aaron Hodges, Ricardo Poynton
Keck School of Medicine of USC, University of Southern California, Los Angeles, CA
Table 1. Averages and SE of variables in CHS data Table 2. MMEF model: Reference variable for
race is Asian. (NaN refers to p-value < 0.01)
Background:
According to the EPA, being exposed to air pollutants at sufficient
concentrations has been found to have serious health consequences in the
respiratory system, developmental growth, and other health problems (2017).
Additionally, the EPA also noted that the mixed composition of the pollutants
we breathe depend on the area of a country, proximity to the sources of
pollutants, such as traffic and industry, and the time of year (2016). The
Children Health Study (CHS) conducted at USC investigated the effects of
environmental risk factors on children. Twelve communities in California that
varied in demographics, exposure, vegetation, temperature, and proximity to
vehicle congestion were selected. A few of the measures selected to ascertain
variation and associations were Maximal (mid) expiratory flow (MMEF),
Forced expiratory volume (FEV), and Forced vital capacity (FVC). Our aim
was to try to obtain associations between ethnicity and MMEF, FEV, and FVC
in the selected communities.
Methods:
● We used a subset of data from the CHS (cohort D) where 1200 children
with an average age of 9.9 underwent respiratory diagnostic.
● The main outcomes investigated were FEV, MMEF, and FVC. The primary
focus was showing MMEF as valid indicator of lung function through our
model.
● The MMEF model included predictors with p-value less than 0.15 and
excluded variables with collinearity.
● The model was stratified for Hispanics and Non-Hispanics
● We also investigated FEV/FVC for lung function and created a map based
on the ratio in different communities.
Results:
● For the full model, we had an adjusted R-squared value of .1227
○ The model stratified model for Non-Hispanics had an adjusted R-squared
of .129
○ The model stratified model for Hispanics had an adjusted R-squared of
.1007
Conclusions:
● Lake Gregory consistently had positive estimates when changing the
reference group in the MMEF model in comparison to all the other
communities, probably due to larger outdoor spaces at the location
● FEV/FVC ratio was practically the same in all 12 communities as shown
through figure 1, concurring with current literature.
● An investigation should be conducted stratifying African-Americans with a
larger sample size with the model. This is to explore the true implications of
the p-value’s significance within the MMEF model
● For the original model, the estimates for town names were primarily
negative. When stratifying for the Hispanic group, we found that many
towns positive estimates. There is a clear interaction between Hispanic and
community of interest.
Acknowledgements: This project was funded under the Summer Institutes in Biostatistics (SIBS) program of the National Heart, Lung, and Blood Institute grant # R25HL147236, with additional support from the Keck School of Medicine of USC, USC Norris
Comprehensive Cancer Center grant # P30CA014089 and National Institute of Environmental Health Sciences Center, grant # 5P30ES07048. Thanks to the LA’s best Program and their support throughout our project.
Citations:
Islam, T., Gauderman, W. J., Berhane, K., McConnell, R., Avol, E., Peters, J. M., & Gilliland, F. D. (2007). Relationship between air pollution, lung function and asthma in adolescents. Thorax, 62(11), 957–963. https://doi.org/10.1136/thx.2007.078964
Kit, B. K., Simon, A. E., Tilert, T., Okelo, S., & Akinbami, L. J. (2016). Differences in spirometry values between U.S. children 6-11 years and adolescents 12-19 years with current asthma, 2007-2010. Pediatric Pulmonology, 51(3), 272–279. https://doi.org/10.1002/ppul.23238
Stanojevic, S., Wade, A., Stocks, J., Hankinson, J., Coates, A. L., Pan, H., … Cole, T. J. (2008). Reference Ranges for Spirometry Across All Ages. American Journal of Respiratory and Critical Care Medicine, 177(3), 253–260. https://doi.org/10.1164/rccm.200708-1248OC
US EPA, OAR. (2015, December 3). Health and Environmental Effects of Hazardous Air Pollutants [Reports and Assessments]. Retrieved July 17, 2019, from US EPA website: https://www.epa.gov/haps/health-and-environmental-effects-hazardous-air-pollutants
US EPA, ORD. (2014, June 11). Exposure and Health Effects of Mixtures of Air Pollutants [Overviews and Factsheets]. Retrieved July 17, 2019, from US EPA website: https://www.epa.gov/air-research/exposure-and-health-effects-mixtures-air-pollutants
n = 1200 %
Sex
Male 593 0.49
Female 607 0.51
Race (%)
Asian 51 4.2
African American 57 4.8
Mixed 135 11.2
Other 283 23.6
White 659 54.9
Did not respond 15 1.2
Hispanic/Non Hispanic
Hispanic 516 0.43
Non Hispanic 684 0.57
Asthma History 171 0.15
Active Asthma 228 0.19
Father Asthma 91 0.08
Mother Asthma 117 0.1
Wheeze 374 0.33
Hayfever 189 0.17
Allergy 333 0.29
Secondhand smoke 190 0.16
Gas stove 912 0.78
Mean SD
Age 9.9 0.47
Height 139 cm 6.7
Weight 79.3 lbs 20.7
BMI 18.5 3.8
FEV 2031.2 330.7
FVC 2323.9 397.4
MMEF 2398.8 588.48
Table 3. Community selection. Relative pollutant values from CHS
study based on town location
Towns: Alpine(AL), Atascadero(AT), Lake Elsinore(LA), Lake Gregory(LG),
Lancaster(LA),Lompoc(LM), Long Beach(LB), Mira Loma(ML),
Riverside(RV), San Dimas(SD), Santa Maria(SM), Upland(UP)
Original Model Model 1 (Hispanic) Model 2 (Non-Hispanic)
Predictor Estimate P-value Estimate P-value Estimate P-value
Town Name -- 0.14 -- 0.14 -- 0.13
Hispanic 75.38 0.13 -- -- -- --
African
American -299.6 0.01 -- -- -216.61 0.13
Did Not
Respond -194.83 0.34 -- -- -- --
Mixed -27.32 0.8 -- -- 17.23 0.91
Other 18.52 0.86 -- -- 245.03 0.21
White -81.34 0.38 -- -- -2.9 0.98
Age 16.84 0.7 21.99 0.73 32.41 0.62
Height 24.82 NaN 27.09 NaN 25 NaN
BMI 1.11 0.82 -- -- 3.69 0.67
Asthma History -161.19 NaN -209.47 0.11 -160.45 0.24
Wheeze History -139.23 NaN -89.43 0.2 -156.26 0.01
Gas Stove
Present -55.1 0.22 -- -- -32 0.6
Weight -- -- -0.57 0.71 -- --
Active Asthma -- -- 55.35 0.63 -4.47 0.97
Father Has
Asthma -- -- -- -- -129.16 0.15
Secondhand
Smoke -- -- -- -- -126.81 0.07
*Due to missing values, values in table may not add up to 1200.