Table 4.
Associations between Lung Function and Covariates of Ancestry-Based Models among Participants in the CHS and HABC Studies.*
| Covariate | CHS (N = 579) | HABC (N = 813) | ||||
|---|---|---|---|---|---|---|
| FEV1 | FVC | FEV1:FVC | FEV1 | FVC | FEV1:FVC | |
| milliliters | milliliters | |||||
| Intercept† | 2050.7 | 2902.2 | 70.3 | 2165.8 | 2755.3 | 77.8 |
| Age (per yr)‡ | −19.78 | −22.71 | −0.09 | −17.27 | −19.86 | −0.13 |
| Sex§ | −398.04 | −640.25 | 3.24 | −348.66 | −442.68 | −0.29 |
| African ancestry (per percentage point)¶ | −2.39 | −3.46 | 0.02 | −3.99 | −5.50 | 0.01 |
| Lifetime smoking (per pack-yr)|| | −3.66 | −1.75 | −0.09 | −4.80 | −3.45 | −0.06 |
| BMI (per unit)** | −1.46 | −4.56 | 0.06 | −1.36 | −10.25 | 0.21 |
| Height (per cm)†† | 19.73 | 28.94 | −0.01 | 21.12 | 33.96 | −0.07 |
| Square of height (per cm2) | 0.07 | 0.02 | 0.01 | −0.15 | 0.09 | −0.004 |
| Study site | ||||||
| Site 1‡‡ | 26.74 | 54.55 | −0.12 | 65.86 | 121.31 | −0.28 |
| Site 2 | 54.33 | 50.67 | 1.13 | |||
| Site 3 | 59.88 | 71.89 | 0.53 | |||
The data are the milliliters (for forced expiratory volume in 1 second [FEV1] and forced vital capacity [FVC]) or ratios (for FEV1:FVC) associated with each listed covariate, after adjustment for all other covariates listed. The intercept value is added to the covariate value (after appropriate weighting) to obtain the lung-function estimate. Bold type indicates a significant association (P<0.05). CHS denotes the Cardiovascular Heart Study, and HABC the Health, Aging, and Body Composition study.
P<0.001 for all coefficients for intercept.
For coefficients for age, P<0.001 for FEV1 and FVC in the CHS and HABC cohorts.
For coefficients for sex, P<0.001 for FEV1 and FVC in the CHS and HABC cohorts, and P = 0.01 for FEV1:FVC in the CHS cohort.
For coefficients for African ancestry, P = 0.009 and P = 0.004 for FEV1 and FVC in the CHS cohort, respectively, and P<0.001 for FEV1 and FVC in the HABC cohort.
P<0.001 for coefficients for pack-years of smoking for FEV1 and FEV1:FVC in the CHS cohort and for FEV1, FVC, and FEV1:FVC in the HABC cohort.
The body-mass index (BMI) is the weight in kilograms divided by the square of the height in meters. For coefficients for BMI, P = 0.002 and P<0.001 for FVC and FEV1:FVC in the HABC cohort, respectively.
For coefficients for height, P<0.001 for FEV1 and FVC in the CHS cohort and the HABC cohort, and P = 0.045 for FEV1:FVC in the HABC cohort.
For coefficients for site 1, P = 0.03 for FEV1 and P<0.001 for FVC in the HABC cohort.