Table 2. Factors associated with Plasmodium vivax infection and clinical vivax malaria, as revealed by multiple logistic regression analysis, in Remansinho, Brazil (2010–13).

	Plasmodium vivax infection		Clinical vivax malaria
	ORa (95% CIb)	P value	ORa (95% CIb)	P value
Duffy blood group phenotype
Positive	1 (reference)		1 (reference)
Negative	0.08 (0.01–0.60)	0.0142	0.16 (0.02–1.29)	0.0849
Missing information	0.80 (0.32–2.00)	0.6362	0.41 (0.05–3.32)	0.4015
Length of residence in Amazonia (years)	0.98 (0.97–1.00)	0.0238	0.97 (0.94–0.99)	0.0082
Time since beginning of study (months)	0.93 (0.90–0.96)	<0.0001	0.92 (0.87–0.98)	0.0062
Main Occupation
Housekeeping	1 (reference)		1 (reference)
Agriculture and forestry	0.83 (0.52–1.32)	0.4325	0.97 (0.48–2.00)	0.9473
Students and minors	0.39 (0.20–0.76)	0.0058	0.26 (0.09–0.74)	0.0125

^aOR = adjusted odds ratio.

^bCI = confidence interval.