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Table 2 Characteristics of infants and their biological mothers (N = 374)

From: β2-Adrenergic receptor promoter haplotype influences the severity of acute viral respiratory tract infection during infancy: a prospective cohort study

 

Caucasian (N = 261)

African American (N = 113)

P value

Infant characteristics

Birth weight (grams) (N = 372), median (IQR*)

3345 (3090, 3657)

3147 (2892, 3430)

<0.001

Gestational age (weeks) (N = 371), median (IQR)

39 (38,40)

39 (38,40)

0.498

Male gender, n (%)

140 (54)

67 (59)

0.313

Age at enrollment (weeks), median (IQR)

10 (6, 21)

18 (7, 35)

<0.001

Breastfeeding, n (%)

152 (58)

46 (41)

0.002

Daycare attendance, n (%)

68 (26)

39 (35)

0.096

Secondhand smoke exposure (N = 371), n (%)

158 (61)

64 (57)

0.486

Having siblings, n (%)

198 (76)

85 (75)

0.894

Insurance type, n (%)

 Private

111 (43)

9 (8)

<0.001

 Medicare

135 (52)

101 (89)

 

 None

15 (6)

3 (3)

 

Season of enrollment, n (%)

 2004 – 2005

42 (16)

21 (19)

0.590

 2005 – 2006

76 (29)

38 (34)

 

 2006 – 2007

75 (29)

31 (27)

 

 2007 – 2008

68 (26)

23 (20)

 

RSV positive

180 (69)

59 (52)

0.002

Lower respiratory tract infection vs. upper respiratory infection, n (%)

213 (82)

72 (64)

<0.001

Bronchiolitis severity score (n = 373), median (IQR)

6.5 (3, 9)

4 (1, 7)

<0.001

Maternal characteristics

Maternal age at enrollment (years)

27 (22, 31)

24 (21, 27)

<0.001

Maternal education, years (n = 313), n (%)

 <12

42 (19)

16 (17)

0.004

 12

56 (25)

41 (44)

 

 >12

122 (55)

36 (39)

 

Maternal asthma, n (%)

50 (19)

27 (24)

0.298

  1. Abbreviations: IQR interquartile range