Table 1.
Characteristics of African American Study Participants Stratified by Cohort and Asthma Status
| Variable | SAPPHIRE Cohort |
SAGE II Cohort |
GCPD-A |
P Value for the Comparison of Cases across Cohorts* | |||
|---|---|---|---|---|---|---|---|
| Case Patients (n = 1,143) | Control Subjects (n = 797) | Case Patients (n = 393) | Control Subjects (n = 492) | Case Patients (n = 1,042) | Control Subjects (n = 1,763) | ||
| Age at enrollment, yr† | 25.57 ± 12.74 | 39.45 ± 12.59 | 13.28 ± 3.58 | 15.82 ± 3.73 | 5.29 ± 4.25 | 9.88 ± 5.48 | <0.001 |
| Sex, F | 622 (54.4) | 542 (68.0) | 180 (45.8) | 289 (57.3) | 588 (56.4) | 879 (49.4) | <0.001 |
| Proportion of African ancestry‡ | 0.80 ± 0.11 | 0.81 ± 0.10 | 0.77 ± 0.13 | 0.78 ± 0.12 | 0.70 ± 0.14 | 0.70 ± 0.15 | <0.001 |
| BMI, kg/m2† | 30.53 ± 9.45 | 31.78 ± 7.86 | 23.80 ± 6.56 | 24.81 ± 6.91 | 20.5 ± 6.18 | 20.9 ± 6.39 | <0.001 |
| BMI percentile§ | — | — | 76.28 ± 24.15 | 70.64 ± 26.98 | — | — | — |
| Percentage of predicted FEV1, %† | 87.05 ± 19.75 | 96.26 ± 15.34 | 98.86 ± 13.81 | 103.45 ± 13.16 | 89.45 ± 18.92 | 99.10 ± 8.75 | <0.001 |
| Age of asthma onset‖ | |||||||
| 0–1 yr | 740 (64.7) | — | 161 (41.0) | — | 219 (21) | — | <0.001 |
| 2–4 yr | 403 (35.3) | — | 232 (59.0) | — | 823 (79) | — | |
| Average age of asthma onset, yr | 1.45 ± 1.23 | — | 2.0 ± 1.30 | — | 2.12 ± 1.25 | — | |
| ACT score ≤ 19¶ | 574 (50.2) | — | — | — | — | — | — |
Definition of abbreviations: ACT = Asthma Control Test; BMI = body mass index; GCPD-A = Study of the Genetic Causes of Complex Pediatric Disorders–Asthma; SAGE II = Study of African Americans, Asthma, Genes and Environment; SAPPHIRE = Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race–Ethnicity.
Data are shown as mean ± SD or n (%).
Differences in patient characteristics among individuals with asthma from the three cohorts were assessed using a chi-squared test for categorical variables and ANOVA for continuous variables.
Measured at the time of study enrollment.
Proportion of African ancestry was estimated using genome-wide autosomal polymorphisms.
BMI percentile was estimated using growth charts specific for age and sex.
Available at http://www.cdc.gov/nccdphp/dnpao/growthcharts/resources/sas.htm. Age of asthma onset was based on patient or parent self-report.
A composite ACT score ≤ 19 indicates poorly controlled asthma.