[1165.7] Daily Vitamin C in Pregnant Smoking Women Decreases Wheezing in Their Offspring through One Year of Age: Randomized Trial and Interaction with Maternal Nicotinic Receptor Polymorphisms
Cindy T. McEvoy. Pediatrics, Oregon Health & Science University, Portland, OR; Pediatrics, PeaceHealth Southwest Medical Center, Vancouver, WA; Obstetrics & Gynecology, Vancouver Clinic, Vancouver, WA; Obstetrics & Gynecology, Providence Portland Maternal Clinic, Portland, OR; Linus Pauling Institute, Oregon State University, Corvallis, OR; Pediatrics, University of Southern California, Los Angeles, CA.
BACKGROUND: We have reported significantly improved pulmonary function tests (PFTs) at birth in offspring delivered to pregnant smoking women randomized to daily vitamin C versus placebo. We now report the incidence of wheezing within the first year of life.
OBJECTIVE: We hypothesized that infants of smoking pregnant women randomized to daily vitamin C would have decreased wheezing through one year of life compared to those randomized to placebo.
DESIGN/METHODS: Pregnant women unable to quit smoking were randomized to daily vitamin C (500 mg) versus placebo. A reference group of non smoking pregnant women was also studied. Genotyping (171 mothers and 162 newborns) for rs16969968 which codes for a structural variant in α5 nAChR associated with nicotine dependence and lung disease was also done. The primary outcome was newborn PFTs and a secondary outcome was clinical respiratory symptoms through one year of age. The respiratory history was captured with a validated questionnaire.
RESULTS: 159 infants of randomized smoking women (76 to vitamin C and 83 to placebo) and 76 of non smoking women were studied at delivery. 92% of infants had follow up through one year of age. Further analysis of the effect of maternal α5 nicotinic receptor genotype, showed that infants of pregnant smokers homozygous or heterozygous for the rs16969968 risk allele and randomized to vitamin C had a significantly decreased incidence of wheezing compared to those randomized to placebo (14% vs 48%; p=0.01).
|Non smokers (n=70)||Vitamin C treated (n=70)||Placebo treated (n=77)||Unadjusted p value||Adjusted p value*||Adjusted relative risk (95% CI)|
|At least one episode of wheezing (%)||27%||15 (21%)||31 (40%)||0.02||0.019||0.53 (0.32, 0.90)|
|Medication for wheezing (%)||10%||9 (13%)||17 (22%)||0.19||0.14||0.58 (0.28, 1.20)|