Supplementing vitamin C to pregnant women appears to minimize the effects of smoking on respiratory health in children, and a recent study found that smoking was associated with a It has been shown to be associated with increased airway function and decreased occurrence of wheezing.
Researchers followed 251 participants in Vitamin C, a double-blind, randomized clinical trial of vitamin C (500 mg/day; n=125) administered to pregnant smokers. Placebo (n=126) treatment. Participating children completed forced expiratory flow (FEF) measurements by spirometry at age 5 years.
The primary endpoint was a prespecified FEF measure (FEF25-75) between 25% and 75% of expiratory volume at age 5 years. Secondary endpoints were his FEF measurements at 50% and 75% of expiration (FEF50 and FEF75), forced expiratory volume in 1 second (FEV1), and wheezing.
Of the 213 children from the VCSIP trial included in this follow-up study, 192 (90.1%) had successful FEF measurements at age 5 years and 212 (99.5%) were included in the wheezing analysis.
Mean FEF25-75 at age 5 years was 17.2% higher between children born to pregnant smokers who received vitamin C and children who received placebo (1.45 vs 1.24 L/s; adjusted mean difference , 0.21, 95% confidence interval) [CI]0.13–0.30; p<0.001).
Additionally, the mean FEF50 was 14.1% higher (1.59 vs. 1.39 L/s; adjusted mean difference, 0.20, 95% CI, 0.11–0.30; p<0.001) and the mean FEF75 was 25.9% higher (0.79 vs. 0.63 L/s). . /s; adjusted mean difference, 0.16, 95% CI, 0.11–0.22; p<0.001), FEV1 was 4.4% higher (1.13 vs 1.09 L; adjusted mean difference, 0.05, 95% CI, 0.01–0.09; p = 0.02).
Finally, significantly fewer children from pregnant smokers randomized to vitamin C developed wheezing (28.3% vs 47.2%; odds ratio, 0.41, 95% CI, 0.23–0.74; p= 0.003).