Table 4.
Associations of the MUC5B promoter variant with RA and RA-ILD characteristics stratified by smoking status
| Outcomes | Ever smokers (n = 493) |
Never smokers (n = 512) |
P for interaction | ||
|---|---|---|---|---|---|
| MUC5B promoter variant GT or TT genotype (n = 88) | No MUC5B promoter variant (n = 405) | MUC5B promoter variant GT or TT genotype (n = 67) | No MUC5B promoter variant (n = 445) | ||
| RA-ILD, n (%) | 14 (15.9) | 22 (5.4) | 6 (9.0) | 10 (2.2) | |
| Unadjusted ORa (95% CI) | 3.11 (1.64, 5.74) | 1.00 (ref) | 3.55 (1.43, 8.02) | 1.00 (ref) | 0.80 |
| Adjusted ORa,b (95% CI) | 3.35 (1.73, 6.40) | 1.00 (ref) | 3.51 (1.39, 8.17) | 1.00 (ref) | 0.92 |
| RA-ILD before or within 2 years of RA diagnosis, n (%) | 5 (5.7) | 5 (1.2) | 4 (6.0) | 2 (0.4) | |
| Unadjusted ORa (95% CI) | 4.29 (1.48, 11.55) | 1.00 (ref) | 5.73 (1.60, 18.54) | 1.00 (ref) | 0.71 |
| Adjusted ORa,b (95% CI) | 4.03 (1.34, 11.83) | 1.00 (ref) | 4.90 (1.31, 16.41) | 1.00 (ref) | 0.84 |
| RA diagnosis at age >55 years, n (%) | 40 (45.5) | 139 (34.3) | 21 (31.3) | 103 (23.1) | |
| Unadjusted ORa (95% CI) | 1.57 (1.02, 2.42) | 1.00 (ref) | 1.57 (0.94, 2.56) | 1.00 (ref) | 0.99 |
| Adjusted ORa,c (95% CI) | 1.54 (0.99, 2.39) | 1.00 (ref) | 1.42 (0.84, 2.36) | 1.00 (ref) | 0.82 |
a
OR per copy of rs35705950 G>T [GG genotype has zero copies (reference group), GT genotype has one copy, TT genotype has two copies).
b
Adjusted for age at RA diagnosis, sex, genetic ancestry and RA-GRS.
c
Adjusted for sex, genetic ancestry and RA-GRS. Bold results have statistically significant odds ratios that do not include 1.0.