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Table 3 Unadjusted associations between surfactant protein A (SFTPA1,SFTPA2) haplotypes and persistent cough or wheeze in the first year of life.a Unadjusted odds ratios (OR) and 95% confidence intervals (CI) are from ordered logistic regression models predicting symptom frequency. b (CT and MA, 1998 – 2000)

From: Respiratory symptoms among infants at risk for asthma: association with surfactant protein A haplotypes

Allele, haplotypec Nucleotide/amino acidd Estimated Frequency Distributione% (95% CI) Persistent Cough OR (95% CI) Wheeze OR (95% CI)
SFTPA1 aa 19 aa 50 aa 62 aa 133 aa 219    
   6A C/Ala C/Leu G G C/Arg 6.1% (4.0 – 8.3) 3.69 (1.71, 7.98) 4.72 (2.20, 10.11)
   6A 2 T/Val G/Val A A C/Arg 54.0% (49.3 – 58.7) 1.18 (0.63, 2.19) 1.13 (0.60, 2.14)
   6A 3 T/Val C/Leu A A C/Arg 25.6% (21.6 – 29.6) 0.81 (0.49, 1.36) 0.83 (0.49, 1.40)
   6A 4 T/Val C/Leu G A T/Trp 6.2% (4.1 – 8.4) 0.94 (0.44, 2.03) 0.70 (0.31, 1.60)
   all others       8%   
SFTPA2 aa 9 aa 91 aa 140 aa 223     
   1A C/Thr C/Pro C C/Gln   8.4% (6.0 – 10.8) 1.53 (0.75, 3.14) 1.30 (0.63, 2.71)
   1A 0 A/Asn G/Ala C C/Gln   54.2% (49.5 – 58.8) 1.13 (0.60, 2.13) 1.14 (0.59, 2.19)
   1A 1 C/Thr G/Ala T A/Lys   13.7% (10.7 – 16.7) 0.82 (0.45, 1.48) 0.87 (0.47, 1.58)
   1A 2 C/Thr G/Ala C C/Gln   10.2% (7.6 – 12.7) 0.95 (0.49, 1.84) 0.83 (0.42, 1.64)
   1A 3 A/Asn G/Ala T A/Lys   1.8% (0.7 – 2.9) 0.45 (0.08, 2.48) 0.55 (0.10, 3.06)
   1A 5 C/Thr C/Pro T C/Gln   4.6% (2.7 – 6.5) 0.43 (0.15, 1.23) 0.66 (0.24, 1.79)
   1A 6 C/Thr G/Ala T C/Gln   3.2% (1.7 – 4.7) 1.41 (0.49, 4.05) 1.54 (0.54, 4.39)
   all others       4%   
SFTPA Haplotype         
   6A/1A       5.4% (3.2 – 7.2) 3.20 (1.39, 7.36) 3.25 (1.43, 7.37)
   6A 2 /1A 0       49.0% (44.4 – 53.6) 1.20 (0.66, 2.19) 1.04 (0.57, 1.90)
   6A 2 /1A 2       1.8% (0.6 – 2.9) 1.43 (0.36, 5.70) 0.26 (0.03, 1.99)
   6A 2 /1A 3       1.0% (0.2 – 1.9) 0.65 (0.10, 4.39) 0.79 (0.11, 5.47)
   6A 3 /1A 0       4.7% (2.8 – 6.6) 1.16 (0.49, 2.74) 0.92 (0.37, 2.31)
   6A 3 /1A 1       11.3% (8.5 – 14.1) 1.12 (0.60, 2.08) 1.08 (0.57, 2.04)
   6A 3 /1A 2       5.6% (3.6 – 7.6) 0.93 (0.40, 2.16) 0.92 (0.39, 2.17)
   6A 3 /1A 6       1.7% (0.5 – 2.8) 0.91 (0.21, 4.07) 2.26 (0.55, 9.33)
   6A 4 /1A 5       2.9% (1.4 – 4.4) 0.28 (0.07, 1.07) 0.30 (0.08, 1.20)
   6A 4 /1A 6       1.8% (0.6 – 3.0) 1.88 (0.49, 7.16) 1.69 (0.44, 6.39)
   Others       14.9%   
  1. aAnalyses included infants with complete data for both SFTPA alleles and respiratory symptoms, i.e., for SFTPA1 and persistent cough (N = 203) or wheeze (N = 202); SFTPA2 and persistent cough (N = 205) or wheeze (N = 204); SFTPA and persistent cough (N = 201) or wheeze (N = 200). bSeparate ordered logistic regression analyses were performed for each outcome measure and each haplotype with all other haplotypes serving as the reference group in each model. All model results (ORs [95% CI]) include estimates of model variabillity due to ambiguity in allele haplotype assignment (see text). Number of days per year of symptoms were included in models as a 6-category variable, i.e., 0, 1–7, 8–14, 15–21, 22–28, > 28 days. Significant results (p < 0.05) are in bold-face type. c By convention, SFTPA1 allele haplotypes are denoted by 6An and SFTPA2 allele haplotypes by 1Am [17,21]. daa 62, aa 133 and aa 140 are silent. eEstimated frequency distribution of haplotypes (mean, 95% CI) for white infants.