Table 1.
Multiethnic Cohort Participant Characteristics.
| Characteristic | Overall N=7,059 | Outcome | ||
|---|---|---|---|---|
| SPLC N=163 | Deceased N=5,646 | Censored N=1,250 | ||
| Age at IPLC diagnosis (years), mean (SD) | 74.3 (8.3) | 72.2 (8.1) | 74.0 (8.2) | 76.2 (8.7) |
| BMI (kg/m2)a, mean (SD) | 25.9 (4.7) | 26.1 (4.6) | 25.9 (4.7) | 26.2 (4.8) |
| Sex, N (%) | ||||
| Male | 3,949 (55.9) | 84 (51.5) | 3,297 (58.4) | 568 (45.4) |
| Female | 3,110 (44.1) | 79 (48.5) | 2,349 (41.6) | 682 (54.6) |
| Race/ethnicity, N (%) | ||||
| African American | 1,798 (25.5) | 37 (22.7) | 1,477 (26.2) | 284 (22.7) |
| Japanese American | 1,603 (22.7) | 37 (22.7) | 1,289 (22.8) | 277 (22.2) |
| Latino | 998 (14.1) | 20 (12.3) | 723 (12.8) | 255 (20.4) |
| Native Hawaiian | 573 (8.1) | 14 (8.6) | 481 (8.5) | 78 (6.2) |
| White | 1,714 (24.3) | 47 (28.8) | 1,382 (24.5) | 285 (22.8) |
| Other | 373 (5.3) | 8 (4.9) | 294 (5.2) | 71 (5.7) |
| Education, N (%) | ||||
| High school or less | 3,592 (50.9) | 71 (43.6) | 2,974 (52.7) | 547 (43.8) |
| Some college or graduate | 2,811 (39.8) | 77 (47.2) | 2,170 (38.4) | 564 (45.1) |
| Postgraduate | 626 (8.9) | 15 (9.2) | 481 (8.5) | 130 (10.4) |
| Unknown | 30 (0.4) | 0 (0.0) | 21 (0.4) | 9 (0.7) |
| Personal history of cancer, N (%) | ||||
| Yes | 1,824 (25.8) | 52 (31.9) | 1,429 (25.3) | 343 (27.4) |
| No | 5,235 (74.2) | 111 (68.1) | 4,217 (74.7) | 907 (72.6) |
| Family history of lung cancer, N (%) | ||||
| Yes | 622 (8.8) | 14 (8.6) | 483 (8.6) | 125 (10.0) |
| No | 6,437 (91.2) | 149 (91.4) | 5,163 (91.4) | 1,125 (90.0) |
| Smoking status, N (%) | ||||
| Never | 863 (12.2) | 19 (11.7) | 607 (10.8) | 237 (19.0) |
| Former | 3,243 (45.9) | 72 (44.2) | 2,603 (46.1) | 568 (45.4) |
| Current | 2,953 (41.8) | 72 (44.2) | 2,436 (43.1) | 445 (35.6) |
| Smoking pack-yearsb, mean (SD) | 27.0 (20.0) | 31.2 (21.3) | 28.0 (20.0) | 22.1 (19.5) |
| Cigarettes per dayb, mean (SD) | 15.5 (10.0) | 17.6 (10.8) | 16.0 (9.9) | 13.3 (10.2) |
| Smoking quit yearsb,c, median (IQR) | 0.5 (0–13) | 0.3 (0–11) | 0.5 (0–13) | 4.0 (0–18) |
| IPLC stage, N (%) | ||||
| Local | 1,223 (17.3) | 93 (57.1) | 702 (12.4) | 428 (34.2) |
| Regional | 1,583 (22.4) | 51 (31.3) | 1,185 (21.0) | 347 (27.8) |
| Distant | 3,811 (54.0) | 17 (10.4) | 3,378 (59.8) | 416 (33.3) |
| Unknown | 442 (6.3) | 2 (1.2) | 381 (6.7) | 59 (4.7) |
| IPLC histology, N (%) | ||||
| Adenocarcinoma | 2,832 (40.1) | 95 (58.3) | 2,070 (36.7) | 667 (53.4) |
| Squamous cell carcinoma | 1,401 (19.8) | 36 (22.1) | 1,120 (19.8) | 245 (19.6) |
| Large cell carcinoma | 225 (3.2) | 9 (5.5) | 189 (3.3) | 27 (2.2) |
| Small cell lung carcinoma | 731 (10.4) | 3 (1.8) | 651 (11.5) | 77 (6.2) |
| Otherd | 1,870 (26.5) | 20 (12.3) | 1,616 (28.6) | 234 (18.7) |
| IPLC surgery, N (%) | ||||
| Yes | 1,512 (21.4) | 120 (73.6) | 830 (14.7) | 562 (45.0) |
| No | 4,942 (70.0) | 34 (20.9) | 4,264 (75.5) | 644 (51.5) |
| Unknown | 605 (8.6) | 9 (5.5) | 552 (9.8) | 44 (3.5) |
| IPLC radiotherapy, N (%) | ||||
| Yes | 2,375 (33.6) | 26 (16.0) | 2,050 (36.3) | 299 (23.9) |
| No | 4,496 (63.7) | 137 (84.0) | 3,443 (61.0) | 916 (73.3) |
| Unknown | 188 (2.7) | 0 (0.0) | 153 (2.7) | 35 (2.8) |
| IPLC chemotherapy, N (%) | ||||
| Yes | 2,299 (32.6) | 23 (14.1) | 1,906 (33.8) | 370 (29.6) |
| No | 4,426 (62.7) | 139 (85.3) | 3,454 (61.2) | 833 (66.6) |
| Unknown | 334 (4.7) | 1 (0.6) | 286 (5.1) | 47 (3.8) |
| Met the USPSTF criteria, N (%) | ||||
| Yes | 2,058 (29.2) | 68 (41.7) | 1,755 (31.1) | 235 (18.8) |
| No | 5,001 (70.8) | 95 (58.3) | 3,891 (68.9) | 1,015 (81.2) |
| Follow-up (months), median (IQR) | 10.0 (3–33) | 46.0 (15–78) | 7.0 (2–17) | 59.0 (35–111) |
Demographic variables were collected from the baseline Multiethnic Cohort questionnaire except smoking-related variables (see below). Age at IPLC diagnosis, IPLC stage, IPLC histology, and IPLC therapies were obtained through linkage to SEER registries. The 2013 USPSTF lung cancer screening eligibility was calculated using age at IPLC diagnosis and smoking-related variables from the MEC questionnaires. Percentages may not sum to 100% due to rounding. Abbreviations: N sample size, SPLC second primary lung cancer, IPLC initial primary lung cancer, SD standard deviation, BMI body mass index, kg kilogram, m meter, IQR interquartile range, USPSTF United States Preventive Services Task Force.
BMI was unknown in 80 (1.1%) participants: 0 (0.0%) SPLC, 72 (1.3%) deceased, and 8 (0.6%) censored.
Smoking-related variables are from the questionnaire closest in time and prior to the date of IPLC: at baseline or at 10-year follow-up, if available (N=1,872).
Smoking quit years were assessed only among ever smokers (N=6,196).
Other histologies are listed in the Supplementary Methods and include histologies such as adenosquamous, lung neuroendocrine tumors, carcinoma not otherwise specified, and others.