Malaria or kalimbe: how to choose?

Table 1 Risk factors of first malaria attack in Amerindian children [2]

		Hazard Ratio	95%CI	p
Vegetation around the home: % cleared	< 50%	1
	50--75%	0.62	0.43--0.88	0.008
	> 75%	0.5	0.31--0.81	0.005
Distance from the home to the river	< 20 m	1
	20--40 m	0.56	0.37--0.85	0.006
	40--80 m	0.72	0.47--1.09	0.128
	80--120 m	0.52	0.28--0.94	0.033
	> 120 m	0.5	0.30--0.86	0.012
Home: number of occupants	≤ 6	1
	7	1.54	0.98--2.44	0.061
	8--11	1.9	1.29--2.81	0.001
	> 11	2.03	1.27--3.23	0.003
Ethnicity	Emerillon	1
	Wayampi	0.552	0.401--0.796	< 0.001
Clothing	Kalimbe	1
	Modern	0.64	0.46--0.90	0.011

Results for the multivariate Cox model, stratified for year of birth (saturated model with 23 variables which were significant at p > 0.25 in univariate analysis. The most parsimonious model was selected manually using log-likelyhood ratio test). Automated forward and backward stepwise elimination were consistent with the manual procedure above. Analysis time: 563.68 person-years. Proportional hazards assumption was checked (Schoenfeld: p = 0.862)