Table 5.

Association of serum IgM levels with isolated ileal disease.

Serum IgM	Crude	Model 1a	Model 2b
Quartile 1 of serum IgM	2.97 (1.845–4.78)	2.5 (1.525–4.1)	1.82 (1.07–3.1)
Quartile 2 of serum IgM	2.47 (1.535–3.97)	2.145 (1.32–3.49)	1.92 (1.14–3.24)
Quartile 3 of serum IgM	1.52 (0.94–2.46)	1.4 (0.85–2.28)	1.17 (0.69–1.98)
Quartile 4 of serum IgM	Reference	Reference	Reference
P for trend	<0.001	<0.001	0.008
Per-SD increase	0.62 (0.51–0.75)	0.67 (0.55–0.815)	0.74 (0.6–0.91)

Data are odds ratio (95% confidence interval).

^aAdjusted for gender, age at diagnosis.

^bAdjusted for gender, age at diagnosis, history of appendectomy and intestinal surgery, serum IgA and IgG, perianal disease, complicated disease, and disease activity.