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. Author manuscript; available in PMC: 2020 Apr 1.
Published in final edited form as: Clin Exp Allergy. 2019 Jan 3;49(4):419–429. doi: 10.1111/cea.13320

Table 2.

Risk of asthma or recurrent wheeze (asthma/recurrent wheeze) in the offspring’s first three years of life by parental asthma diagnosis, maternal asthma and maternal asthma control status in Vitamin D Antenatal Asthma Reduction Trial (VDAART) adjusted for potential confounders using stepwise regression models

Univariable analysis Multivariable analysis Main variable: maternal and paternal asthma diagnosis status Multivariable analysis Main variable: maternal asthma and control status
Variable HR 95% CI P-value Adjusted HR 95% CI P-value Adjusted HR 95% CI P-value
Parental asthma diagnosis
    Both non-asthmatics
    Paternal asthma but no maternal asthma
    Maternal asthma but no paternal asthma
    Both asthmatics
1(Ref)
1.03
1.84
1.95

0.67–1.59
1.36–2.49
1.20–3.16

0.90
<0.001
0.008
1(Ref)
0.90
1.70
2.30

0.51–149
1.17–2.40
1.35–3.84

0.62
0.006
0.003 		Not included ----- -----
Maternal asthma status
    Non-asthmatics
    Asthmatics with controlled asthma
    Asthmatics with uncontrolled asthma (at least one episode during pregnancy)		 1(Ref)
1.55
2.80
1.14–2.1
1.98–3.99
<0.001
<0.001		 Not included ----- ----- 1 (Ref)
1.70
2.40 		----
1.17–2.40
1.50–3.50 		------
0.005
<0.001
Maternal age 0.95 0.93–0.97 <0.001 ----- ----- ----- ------ ------ ------
Gestational age at delivery ≥37 weeks vs <37 weeks 0.41 0.29–0.59 <0.001 0.43 0.26–0.71 0.002 0.44 0.26–0.73 0.002
Trial arm Placebo vs vitamin D intervention 1.31 1.00–1.71 0.0515 ----- ----- -----
Cord blood Vitamin D (ng/mL)
    Sufficient vs. insufficient (≥30 vs <30)
0.61
0.44–0.83
0.002
0.66
0.47–0.90
0.012
0.67
0.49–0.92
0.012
Offspring Sex
    Male vs. Female
1.64
1.25–2.16
<0.001
1.72
1.24–2.40
0.009
1.76
1.27–2.45
0.001
Clinical site
    Boston
    San Diego
    St. Louis
1(Ref)
0.52
0.98

0.37–0.75
0.72–1.33

<0.001
0.91		 ------ ------ ----- ----- ----- -----
Race
    White
    African American
    Other
1(Ref)
1.59
0.82

1.19–2.13
0.53–1.29

0.002
0.39		 ------ ------ ------ ----- ----- -----
Maternal marital status
    Married vs. Unmarried or Divorced)
0.54
0.40–0.71
<0.001
0.60
0.40–0.82
0.002
0.62
0.44–0.87
0.006
Parity
    1 vs ≥ 2
1.05
0.8–1.4
0.72		 ---- ----- ----- ----- ----- -----
Maternal education
    College and above vs. less
    than College
0.64
0.47–0.86
0.004		 ----- ----- ----- ----- ----- -----
Body mass index at first appointment
    BMI≥25 vs. BMI<25 kg/m2
1.13
0.84–1.5
0.42		 ----- ----- ----- ------ ------ ------
Maternal eczema history
    Yes vs. no
1.10
0.83–1.46
0.50		 ----- ----- ----- ----- ----- -----

Abbreviation: HR, hazard ratio. Hazard ratios for the outcome were estimated using a Weibull model; HRs and CIs are 2 sided.