Table 4.
Prevalence and association of dermatomyositis with sunburn and sun exposures in the year prior to diagnosis, by self-reported sensitivity to sun*
| Mild sunburn/tanning/no reaction |
Painful or severe sunburn |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| DM | PM/IBM | DM vs. PM/IBM | DM | PM/IBM | DM vs. PM/IBM | ||||
| Effect | n (%) | n (%) | OR (95% CI) | P | n (%) | n (%) | OR (95% CI)† | P | Interaction P |
| Sunburn | |||||||||
| ≥ 2 sunburns | 75 (19) | 52 (11) | 2.05 (1.36–3.09) | 0.0006 | 58 (26) | 39(18) | 1.17 (0.69–2.00) | 0.562 | 0.219 |
| 1 sunburn | 77 (19) | 71 (15) | 1.44 (0.99–2.09) | 0.057 | 53 (23) | 36 (16) | 1.25 (0.73–2.14) | 0.414 | 0.976 |
| No Sunburn | 251 (62) | 364 (75) | 1.00 (REF) | 116 (51) | 145 (66) | 1.00 (REF) | |||
| Combined sun exposure | |||||||||
| High/Mod-High | 48 (15) | 55 (14) | 1.76 (1.06, 2.91) | 0.028 | 25 (13) | 24 (13) | 1.74 (0.78, 3.88) | 0.177 | 0.561 |
| Moderate | 198 (60) | 206 (52) | 1.60 (1.13, 2.27) | 0.008 | 94 (49) | 86 (47) | 0.99 (0.61, 1.61) | 0.962 | 0.129 |
| Low/None | 83 (25) | 134 (34) | 1.00 (REF) | 73 (38) | 72 (40) | 1.00 (REF) | |||
Abbreviations: DM=Dermatomyositis; PM=Polymyositis; IBM=Inclusion body myositis; UV=Ultraviolet radiation; REF=referent group; Mod=moderate
*
Models are limited to participants diagnosed between the ages of 18 and 65 years, and after January 1st, 1990. Total IIM includes dermatomyositis, polymyositis, and inclusion body myositis.
†
Odds ratios (OR) and 95% confidence intervals (CI) adjusted for gender, age, and skin tone.