Table 1: Prevalence and cross-sectional association of ear infection and potential risk factors.

At baseline age 4 to 5 years% ( )Ear infection prevalence % ( ) Bivariate odds ratio and value

Study child—sex
 Male 50.9 (2537)8.5 (215)OR = 1.00
 Female49.1 (2446)7.3 (179)OR = 0.85; = 0.131
Study child—indigenous status
 Nonindigenous96.3 (4794) 7.7 (368)OR = 1.00
 Indigenous3.8 (187)13.9 (26)OR  =  1.94; P   =  0.002
Reported breastfed (months)
 1 month—yes80.2 (3976) 7.6 (301)OR = 1.00
 1 month—no19.8 (981) 9.2 (90)OR = 1.23; = 0.096
 3 months—yes71.0 (3518)7.4 (260)OR = 1.00
 3 months—no29.0 (1439)9.1 (131)OR  =  1.25; P   =  0.043
 6 months—yes57.2 (2833)7.3 (207)OR = 1.00
 6 months—no42.9 (2124)8.7 (184)OR = 1.20; = 0.080
Mother—smoking status
 Not smoking76.9 (3178) 7.4 (235)OR = 1.00
 Less than once/day3.6 (148)6.1 (9)OR = 0.81; = 0.550
 More than once/day19.5 (805)10.1 (81)OR  =  1.40; P   =  0.013
Father—smoking status
 Not smoking75.4 (2451)7.0 (172)OR = 1.00
 Less than once/day3.2 (104) 7.7 (8)OR = 1.10; = 0.792
 More than once/day21.4 (696)9.6 (67)OR  =  1.41; P   =  0.022
Mother—school completion
 Year 12+58.1 (2895) 7.6 (219)OR = 1.00
 Year 10-1134.9 (1739) 8.2 (143)OR = 1.10; = 0.376
 Year ≤96.9 (344)9.3 (32)OR = 1.18; = 0.399
Father—school completion
 Year 12+45.1 (2246) 6.5 (146)OR = 1.00
 Year 10-1133.8 (1682) 9.1 (153)OR  =  1.43; P   =  0.003
 Year ≤95.9 (295)9.5 (28)OR  =  1.45; P   =  0.008
SEIFA economic resources
 Equal or above median54.2 (2699)7.4 (200)OR = 1.00
 Below median45.8 (2284)8.5 (194)OR = 1.16; = 0.158