Table 2. RR of developing multiple myeloma by lag between sampling and diagnosis.

	MM on follow-up	Healthy on follow-up	RR	95% CI
Cases with lag >24 months:
IFA lytic
No	267	1288	1
Yes	37	221	0.8	(0.5–1.2)
IFA latent
No	302	1498	1
Yes	2	11	0.9	(0.1–4.2)
Cases with <median lag (121 months)
IFA lytic
No	144	668	1
Yes	20	143	0.6	(0.4–1.1)
IFA latent
No	163	798	1
Yes	1	13	0.4	(0.0–2.6)
Cases with at least median lag (121 months)
IFA lytic
No	146	725	1
Yes	19	95	1.0	(0.5–1.7)
IFA latent
No	164	817	1
Yes	1	3	1.7	(0.0–2.1)

RR=relative risk; MM=multiple myeloma; CI=confidence interval; IFA=immunofluorescence assay.

Method: exact conditional logistic regression, adjustment for freeze–thawing.