Association of ABO Blood Group Phenotype and Allele Frequency with Chikungunya Fever

Table 2

Univariate analysis for symptomatic manifestations.

Variables	Asymptomatic		Symptomatic
	RRR	95% CI	RRR	95% CI
Age (years)
<40	Reference		Reference
40–60	1.8	1.09, 2.97	1.34	0.84, 2.13
>60	1.79	1, 3.21	0.82	0.45, 1.49
Gender
Male	Reference		Reference
Female	0.6	0.38, 0.95	0.66	0.42, 1.05
ABO blood group
O	Reference		Reference
A	1.05	0.65, 1.8	1.07	0.63, 1.82
B	1.13	0.67, 1.92	0.91	0.53, 1.55
AB	0.56	0.24, 1.31	0.86	0.41, 1.78

RRR: relative risk ratio.