Table 2.
Cotinine levels by smoking behavior and genotype in current smokers*
| BRHS |
BWHHS |
EPIC Case‡ |
EPIC Control‡ |
Midspan |
Patch II |
PiP |
||||||||
| Smoking behavior or No. of risk alleles in current smokers† | Participants, No. (%) | Cotinine, median (IQR), nmol/L | Participants, No. (%) | Cotinine, median (IQR), nmol/L | Participants, No. (%) | Cotinine, median (IQR), nmol/L | Participants, No. (%) | Cotinine, median (IQR), nmol/L | Participants, No. (%) | Cotinine, median (IQR), nmol/L | Participants, No. (%) | Cotinine, median (IQR), nmol/L | Participants, No. (%) | Cotinine, median (IQR), nmol/L |
| Smoking status | ||||||||||||||
| Never Smokers | 1066 (30%) | 0.79 (0.28–2.16) | 2081 (56%) | 0.57 (0.28–1.31) | 92 (12%) | 1.58 (0.21–3.00) | 685 (44%) | 1.76 (0.60–4.07) | 847 (45%) | 2.84 (1.70–5.67) | 0 (0%) | 0 (0%) | ||
| Former Smokers | 2162 (60%) | 1.13 (0.28–4.31) | 1203 (33%) | 0.80 (0.28–2.22) | 221 (29%) | 2.25 (0.92–5.01) | 549 (35%) | 1.88 (0.82–4.49) | 526 (28%) | 3.40 (1.70–9.08) | 0 (0%) | 0 (0%) | ||
| Current Smokers | 385 (10%) | 1330.2 (791.1–1814.2) | 400 (11%) | 1219.5 (745.8–1786.4) | 445 (59%) | 1401.5 (1036.4–1767.7) | 314 (20%) | 968.5 (507.5–1386.8) | 499 (27%) | 1444.2 (800.2–1896.0) | 451 (100%) | 1535.0 (1167.6–1945.9) | 438 (100%) | 1526.2 (1102.2–2042.4) |
| Number of risk alleles | ||||||||||||||
| 0 | 175 (45%) | 1171.8 (675.3–1735.4) | 171 (43%) | 1090 (645.8–1612.6) | 151 (34%) | 1272.2 (936.2–1644.8) | 129 (41%) | 930.17 (491.3–1310) | 242 (48%) | 1383.8 (764.5–1809.3) | 190 (42%) | 1464 (1090.3–1879.1) | 191 (44%) | 1421.7 (1044.6–1944.3) |
| 1 | 171 (45%) | 1385.8 (818.3–1956.1) | 185 (46%) | 1264.7 (790.7–1902.2) | 203 (46%) | 1498.8 (1059.1–1804.1) | 145 (46%) | 991.8 (548.7–1386.8) | 201 (41%) | 1484.5 (840.4–1942.5) | 198 (44%) | 1539.9 (1207.4–1904.3) | 198 (45%) | 1559.4 (1125.8–2075.3) |
| 2 | 39 (10%) | 1681.4 (1243.9–2072.4) | 44 (11%) | 1399.6 (964.5–2027.2) | 91 (20%) | 1504.2 (1139.9–1843.1) | 40 (13%) | 1021.4 (556.6–1629.9) | 56 (11%) | 1522.6 (832.2–1971.0) | 63 (14%) | 1787.7 (1338.9–2151.2) | 49 (11%) | 1847.1 (1381.4–2264.6) |
BRHS = British Regional Heart Study; BWHHS = British Women’s Heart and Health Study; EPIC = European Prospective Investigation into Cancer and Nutrition; IQR = interquartile range between 25th and 75th percentile; PiP = Patch in Practice.
Typical cotinine values (never smokers and former smokers approximately 5 nmol/L; current smokers >85 nmol/L) (47). Number of risk alleles expressed as zero, one, or two copies of the rs1051730 T allele or rs16969968 A allele.
Cotinine levels and self-reported cigarette consumption differed in current smoker case subjects (EPIC Case) and control subjects (EPIC Control). Cotinine levels were higher in the EPIC Case subsample (mean level = 1391 nmol/L, SD = 588) than the EPIC Control subsample (mean level = 1006 nmol/L, SD = 589) even after adjustment for cigarette consumption (two-sided Kruskal–Wallis P < .001), indicating possible differences in smoking behavior (eg, depth of inhalation). This difference at baseline may have contributed to the likelihood of a subsequent lung cancer diagnosis. Therefore, the EPIC case subjects and control subjects were analyzed and presented separately in this study.