Table 5.

Association between baseline serum tryptophan level and subsequent relapse risk (targeted tryptophan analysis)

	TRP1 (Discovery)			TRP2 (Replication)
	IRR	95% CI	P‐value	IRR	95% CI	P‐value
Serum Trp (per 1 mcg/mL) (univariable)	0.99	0.91–1.08	0.908	1.00	0.92–1.09	0.965
Serum Trp (per 1 mcg/mL) (multivariable)	1.01	0.93–1.09	0.860	1.02	0.94–1.12	0.588
Age at disease onset (1‐year increment)	1.03	0.97–1.10	0.308	1.02	0.98–1.07	0.328
Sex (female)	1.35	0.86–2.11	0.187	1.07	0.68–1.68	0.785
Race/ethnicity (vs. White non‐Hispanic)			0.381			0.959
White Hispanic	1.56	0.90–2.70		0.92	0.56–1.53
Black	1.06	0.46–2.47		0.85	0.36–2.00
Other	1.22	0.66–2.26		1.03	0.56–1.90
Serum 25(OH) vitamin D (per 1 ng/mL)	1.00	0.98–1.02	0.941	0.98	0.97–1.00	0.103
DMT exposed [no = reference value]	0.84	0.47–1.49	0.543	1.50	0.81–2.78	0.191

Trp, tryptophan; DMT, disease‐modifying therapy; IRR, incidence rate ratio.