Table 5.

Incidence rate ratios (95% confidence intervals) using Poisson regression for bivariate associations between incidence of acute lower respiratory infections and risk factors for children under two years of age in the Mirpur birth cohort, January 2008 – March 2011

	Age groups (in months)
	0 – 23	0 – 11	12 – 23
Child risk factors
Weighed <2500 grams within 72 hrs of birth	1.38 (1.12 – 1.69)*	1.39 (1.06 – 1.79)*	1.40 (1.01 – 1.93)*
Wasted at beginning of age interval†	1.28 (1.03 –1.59)*	1.30 (0.99 – 1.71)	1.23 (0.89 – 1.71)
Male	1.23 (1.00 – 1.51)*	1.22 (0.94 – 1.59)	1.24 (0.90 – 1.72)
Exclusively breast fed for 5 – 6.3 months	0.80 (0.60 – 1.07)	0.96 (0.89 – 1.03)	-
Household risk factors
Per each additional person per square meter of living space	0.99 (0.89 – 1.11)	1.00 (0.87 – 1.16)	0.97 (0.81 – 1.16)
Mother has more than elementary education	0.98 (0.78 – 1.22)	0.83 (0.61 – 1.12)	1.23 (0.88 – 1.72)
Own cell phone and television	0.92 (0.75 – 1.12)	0.92 (0.71– 1.20)	0.92 (0.67 – 1.27)
Member of household smokes cigarettes indoors	1.21 (0.98 – 1.50)	1.28 (0.97 0 1.67)	1.12 (0.80 – 1.58)
Ever use biomass for cooking	1.10 (0.74 – 1.62)	1.18 (0.72 – 1.93)	0.98 (0.52 – 1.87)
Per each hour PM2.5 concentrations exceeded 100 µg/m3	1.04 (0.99 – 1.08)	1.07 (1.01 – 1.13)*	0.98 (0.92 – 1.07)

^*p-value ≤0.05

^†At 3 months for the 0 – 23 months and 0 – 11 months age groups, and at 12 months for the 12 – 23 months age group.