Table 3. Association between selected characteristics and sero-response proportion (≥4-fold rise).

			Crude analysis			Multivariate model*
Category	N	n (%)	OR	(95%CI)	P value	OR	(95% CI)		P value
Sex
Male	36	28 (78)	1.00			1.00
Female	12	10 (83)	1.43	(0.26–7.89)	0.683	9.28	(0.22–390)		0.243
Age
<57	15	12 (80)	1.00			1.00
57–64	14	12 (86)	0.50	(0.21–10.6)	0.685	0.28	(0.01–6.12)		0.417
65+	19	14 (74)	0.70	(0.14–3.56)	0.667	0.63	(0.04–9.79)		0.738
			(Trend P = 0.622)			(Trend P =0.666)
Type
Type 1	7	5 (71)	1.00			1.00
Type 2	41	33 (80)	1.65	(0.27–10.1)	0.588	2.59	(0.05–149)		0.645
Duration of disease (years)
<10	24	19 (79)	1.00			1.00
10+	24	19 (79)	1.00	(0.25–4.03)	1.000	0.48	(0.04–5.92)		0.567
HbA1c (%)
<6.5	10	8 (80)	1.00			1.00
6.5–7.5	20	17 (85)	1.42	(0.20–10.2)	0.730	0.97	(0.06–15.3)		0.985
7.6+	18	13 (72)	0.65	(0.10–4.18)	0.650	0.13	(0.005–3.51)		0.223
			(Trend P = 0.527)			(Trend P = 0.243)
Body mass index (kg/m2)
<22.1	13	8 (62)	1.00			1.00
22.1–23.8	16	11 (69)	1.38	(0.30–6.40)	0.685	4.30	80.35–52.6)		0.254
23.9+	19	19 (100)	N.A.			N.A.
			(Trend P =0.012)			(Trend P =0.008)
Treatment of DM
Insulin-	21	15 (71)	1.00			1.00
Insulin+	27	23 (85)	1.52	(0.57–4.06)	0.409	4.22		(0.26–70.3)		0.316
Prevaccination titer
<1:10	37	30 (81)	1.00			1.00
1: 10–1:20	11	8 (73)	0.62	(0.13–2.96)	0.551	0.26		(0.01–6.02)		0.403

Logistic regression model. *Model included all variables in the table.