Table 1.
Baseline Characteristics in the Framingham Heart Study and COPDGene Cohort Stratified by Age Group
| Age Group |
P Value* | |||
|---|---|---|---|---|
| Age < 60 yr [Number (%) or Median (IQR)] | Age ≥ 60 yr and <70 yr [Number (%) or Median (IQR)] | Age ≥ 70 yr [Number (%) or Median (IQR)] | ||
| Framingham Heart Study | 1,017 (66) | 332 (22) | 192 (12) | — |
| ILA | 44 (4) | 41 (12) | 91 (47) | <0.0001 |
| Sex, F | 473 (47) | 189 (57) | 99 (52) | 0.43 |
| BMI, kg/m2 | 28 (25–32) | 28 (25–32) | 28 (25–31) | <0.0001 |
| Pack-years smoking | 0 (0–8) | 5 (0–20) | 8 (0–24) | <0.0001 |
| Current smoking | 71 (7) | 16 (5) | 3 (2) | <0.0001 |
| CAC score† | 0 (0–19) | 48 (0–270) | 246 (40–725) | <0.0001 |
| COPDGene Study‡ | 272 (29) | 410 (44) | 246 (27) | — |
| ILA | 10 (4) | 10 (2) | 14 (6) | <0.0001 |
| Sex, F | 128 (47) | 171 (42) | 97 (39) | 0.09 |
| BMI | 27 (23–31) | 27 (23–31) | 27 (24–31) | 0.74 |
| Pack-years smoking | 41 (32–57) | 51 (40–74) | 56 (39–76) | <0.0001 |
| Current smoking | 148 (54) | 111 (27) | 26 (11) | <0.0001 |
| CAC score† | 2 (0–102) | 86 (3–291) | 193 (29–543) | <0.0001 |
| African American race | 85 (31) | 59 (14) | 19 (8) | <0.0001 |
| GOLD stage | 0.01 | |||
| 2 | 114 (38) | 131 (30) | 88 (34) | |
| 3 | 99 (33) | 138 (31) | 95 (37) | |
| 4 | 84 (28) | 172 (52) | 77 (30) | |
| Percent emphysema (<−950 HU)§ | 7 (2–23) | 16 (5–29) | 16 (7–26) | 0.004 |
Definition of abbreviations: BMI = body mass index; CAC = coronary arterial calcium; COPDGene = Genetic Epidemiology of Chronic Obstructive Pulmonary Disease; GOLD = Global Initiative for Chronic Obstructive Lung Disease; HU = Hounsfield units; ILA = interstitial lung abnormalities; IQR = interquartile range.
P values represent the between-group differences. In the Framingham Heart Study, P values are from generalized estimating equations to adjust for familial correlation. In the COPDGene Study, P values are from Fisher exact tests for categorical variables and Kruskal-Wallis tests for continuous variables.
The CAC score is calculated using the Agatston scoring method (24). There were 158 COPDGene participants missing a CAC score in this subset.
All COPDGene participants in this subset had a GOLD grade ≥ 2 for chronic obstructive pulmonary disease.
Percent emphysema is calculated as the percentage of the lung below −950 Hounsfield units. There were 37 COPDGene participants missing percent emphysema in this subset.