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Table 1 Parameter estimates with 95% confidence interval (in parentheses) for the time-to-first malaria based on different univariable and multivariable shared frailty models

From: The effect of dams and seasons on malaria incidence and anopheles abundance in Ethiopia

Covariates Univariable model Multivariable models
   HR(95% CI) Adjusted HR (95% CI)
Distance   0.989(0.894, 1.093) 0.990(0.896, 1.093) 0.995(0.900, 1.100) 0.993(0.899,1.096)
Sex Female(ref) 1.000 1.000 1.000 1.000
  Male 0.951(0.803, 1.127) 0.952(0.804, 1.127) 0.952(0.804, 1.128) 0.952(0.804, 1.127)
Age ≤ 3 years(ref) 1.000 1.000 1.000 1.000
  3 to 7 years 1.663 (1.117, 2.474) 1.804 (1.211, 2.687) 1.678 (1.126, 2.500) 1.802 (1.210, 2.685)
  ≥ 7 years 1.656 (1.098, 2.498) 1.791 (1.182, 2.713) 1.686 (1.112, 2.554) 1.790 (1.182, 2.712)
Year Year 1(ref) 1.000 1.000 1.000 1.000
  Year 2 0.991(0.837, 1.1756) 0.921(0.773, 1.097) 0.983(0.826, 1.170) 0.933(0.785, 1.110)
Mosquito density   1.006 (1.001, 1.011) 0.997(0.992, 1.003) 1.006 (1.001, 1.011)  
Season Dry season(ref) 1.000 1.000   1.000
  Long rainy season 4.415 (3.390, 5.750) 4.545 (3.478, 5.938)   4.455 (3.421, 5.802)
  Short rainy season 2.182 (1.580, 3.013) 2.178 (1.576, 3.008)   2.174 (1.574, 3.004)
  1. Significant at P < 0.05, Significant at P < 0.01.
  2. Hazard Ratio (HR): is an expression of the hazard or chance of infected with malaria in a particular category as a ratio of the hazard of the events occurring in the reference category. i.e. Estimates of hazard ratios correspond to the hazard of contracting malaria for a child divided by the hazard for a child in the reference category.