TY - JOUR
T1 - Effect of Vitamin C Supplementation for Pregnant Smokers on Offspring Airway Function and Wheeze at Age 5 Years
T2 - Follow-up of a Randomized Clinical Trial
AU - McEvoy, Cindy T.
AU - Shorey-Kendrick, Lyndsey E.
AU - Milner, Kristin
AU - Harris, Julia
AU - Vuylsteke, Brittany
AU - Cunningham, Michelle
AU - Tiller, Christina
AU - Stewart, Jaclene
AU - Schilling, Diane
AU - Brownsberger, Julie
AU - Titus, Hope
AU - Macdonald, Kelvin D.
AU - Gonzales, David
AU - Vu, Annette
AU - Park, Byung S.
AU - Spindel, Eliot R.
AU - Morris, Cynthia D.
AU - Tepper, Robert S.
N1 - Publisher Copyright:
© 2022 Authors. All rights reserved.
PY - 2023/1/3
Y1 - 2023/1/3
N2 - Importance: Vitamin C supplementation (500 mg/d) for pregnant smokers has been reported to increase offspring airway function as measured by forced expiratory flow (FEF) through age 12 months; however, its effects on airway function at age 5 years remain to be assessed. Objective: To assess whether vitamin C supplementation in pregnant smokers is associated with increased and/or improved airway function in their offspring at age 5 years and whether vitamin C decreases the occurrence of wheeze. Design, Setting, and Participants: This study followed up the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function (VCSIP) double-blind, placebo-controlled randomized clinical trial conducted at 3 centers in the US (in Oregon, Washington, and Indiana) between 2012 and 2016. Investigators and participants remain unaware of the treatment assignments. Forced expiratory flow measurements at age 5 years were completed from 2018 to 2021. Interventions: Pregnant smokers were randomized to vitamin C (500 mg/d) or placebo treatment. Main Outcomes and Measures: The primary outcome was the prespecified measurement of FEF between 25% and 75% expired volume (FEF25-75) by spirometry at age 5 years. Secondary outcomes included FEF measurements at 50% and 75% of expiration (FEF50and FEF75), forced expiratory volume in 1 second (FEV1), and occurrence of wheeze. Results: Of the 251 pregnant smokers included in this study, 125 (49.8%) were randomized to vitamin C and 126 (50.2%) were randomized to placebo. Of 213 children from the VCSIP trial who were reconsented into this follow-up study, 192 (90.1%) had successful FEF measurements at age 5 years; 212 (99.5%) were included in the analysis of wheeze. Analysis of covariance demonstrated that offspring of pregnant smokers allocated to vitamin C compared with placebo had 17.2% significantly higher mean (SE) measurements of FEF25-75at age 5 years (1.45 [0.04] vs 1.24 [0.04] L/s; adjusted mean difference, 0.21 [95% CI, 0.13-0.30]; P <.001). Mean (SE) measurements were also significantly increased by 14.1% for FEF50(1.59 [0.04] vs 1.39 [0.04] L/s; adjusted mean difference, 0.20 [95% CI, 0.11-0.30]; P <.001), 25.9% for FEF75(0.79 [0.02] vs 0.63 [0.02] L/s; 0.16 [95% CI, 0.11-0.22]; P <.001), and 4.4% for FEV1(1.13 [0.02] vs 1.09 [0.02] L; 0.05 [95% CI, 0.01-0.09]; P =.02). In addition, offspring of pregnant smokers randomized to vitamin C had significantly decreased wheeze (28.3% vs 47.2%; estimated odds ratio, 0.41 [95% CI, 0.23-0.74]; P =.003). Conclusions and Relevance: In this follow-up study of offspring of pregnant smokers randomized to vitamin C vs placebo, vitamin C supplementation during pregnancy resulted in significantly increased airway function of offspring at age 5 years and significantly decreased the occurrence of wheeze. These findings suggest that vitamin C supplementation for pregnant smokers may decrease the effects of smoking in pregnancy on childhood airway function and respiratory health. Trial Registration: ClinicalTrials.gov Identifier: NCT03203603.
AB - Importance: Vitamin C supplementation (500 mg/d) for pregnant smokers has been reported to increase offspring airway function as measured by forced expiratory flow (FEF) through age 12 months; however, its effects on airway function at age 5 years remain to be assessed. Objective: To assess whether vitamin C supplementation in pregnant smokers is associated with increased and/or improved airway function in their offspring at age 5 years and whether vitamin C decreases the occurrence of wheeze. Design, Setting, and Participants: This study followed up the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function (VCSIP) double-blind, placebo-controlled randomized clinical trial conducted at 3 centers in the US (in Oregon, Washington, and Indiana) between 2012 and 2016. Investigators and participants remain unaware of the treatment assignments. Forced expiratory flow measurements at age 5 years were completed from 2018 to 2021. Interventions: Pregnant smokers were randomized to vitamin C (500 mg/d) or placebo treatment. Main Outcomes and Measures: The primary outcome was the prespecified measurement of FEF between 25% and 75% expired volume (FEF25-75) by spirometry at age 5 years. Secondary outcomes included FEF measurements at 50% and 75% of expiration (FEF50and FEF75), forced expiratory volume in 1 second (FEV1), and occurrence of wheeze. Results: Of the 251 pregnant smokers included in this study, 125 (49.8%) were randomized to vitamin C and 126 (50.2%) were randomized to placebo. Of 213 children from the VCSIP trial who were reconsented into this follow-up study, 192 (90.1%) had successful FEF measurements at age 5 years; 212 (99.5%) were included in the analysis of wheeze. Analysis of covariance demonstrated that offspring of pregnant smokers allocated to vitamin C compared with placebo had 17.2% significantly higher mean (SE) measurements of FEF25-75at age 5 years (1.45 [0.04] vs 1.24 [0.04] L/s; adjusted mean difference, 0.21 [95% CI, 0.13-0.30]; P <.001). Mean (SE) measurements were also significantly increased by 14.1% for FEF50(1.59 [0.04] vs 1.39 [0.04] L/s; adjusted mean difference, 0.20 [95% CI, 0.11-0.30]; P <.001), 25.9% for FEF75(0.79 [0.02] vs 0.63 [0.02] L/s; 0.16 [95% CI, 0.11-0.22]; P <.001), and 4.4% for FEV1(1.13 [0.02] vs 1.09 [0.02] L; 0.05 [95% CI, 0.01-0.09]; P =.02). In addition, offspring of pregnant smokers randomized to vitamin C had significantly decreased wheeze (28.3% vs 47.2%; estimated odds ratio, 0.41 [95% CI, 0.23-0.74]; P =.003). Conclusions and Relevance: In this follow-up study of offspring of pregnant smokers randomized to vitamin C vs placebo, vitamin C supplementation during pregnancy resulted in significantly increased airway function of offspring at age 5 years and significantly decreased the occurrence of wheeze. These findings suggest that vitamin C supplementation for pregnant smokers may decrease the effects of smoking in pregnancy on childhood airway function and respiratory health. Trial Registration: ClinicalTrials.gov Identifier: NCT03203603.
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U2 - 10.1001/jamapediatrics.2022.4401
DO - 10.1001/jamapediatrics.2022.4401
M3 - Article
C2 - 36409489
AN - SCOPUS:85145491997
SN - 2168-6203
VL - 177
SP - 16
EP - 24
JO - JAMA Pediatrics
JF - JAMA Pediatrics
IS - 1
ER -