Effect of Vitamin C Supplementation for Pregnant Smokers on Offspring Airway Function and Wheeze at Age 5 Years: Follow-up of a Randomized Clinical Trial.

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 (FEF50 and 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 FEF25-75 at 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.

Vitamin C to Pregnant Smokers Persistently Improves Infant Airway Function to 12†Months of Age: A Randomised Trial.

BACKGROUND: Vitamin C (500 mg·day-1) supplementation for pregnant smokers has been reported to increase newborn pulmonary function and infant forced expiratory flows (FEFs) at 3 months of age. Its effect on airway function through 12 months of age has not been reported. OBJECTIVE: To assess whether vitamin C supplementation to pregnant smokers is associated with a sustained increased airway function in their infants through 12 months of age. METHODS: This is a prespecified secondary outcome of a randomised, double-blind, placebo-controlled trial that randomised 251 pregnant smokers between 13 and 23 weeks of gestation: 125 to 500 mg·day-1 vitamin C and 126 to placebo. Smoking cessation counselling was provided. FEFs performed at 3 and 12 months of age were analysed by repeated measures analysis of covariance. RESULTS: FEFs were performed in 222 infants at 3 months and 202 infants at 12 months of age. The infants allocated to vitamin C had significantly increased FEFs over the first year of life compared to those allocated to placebo. The overall increased flows were: 40.2 mL·sec-1 for FEF75 (adjusted 95% CI for difference 6.6 to 73.8; p=0.025); 58.3 mL·sec-1 for FEF50 (95% CI 10.9 to 105.8; p=0.0081); and 55.1 mL·sec-1 for FEF25-75 (95% CI, 9.7 to 100.5; p=0.013). CONCLUSIONS: In offspring of pregnant smokers randomised to vitamin C versus placebo, vitamin C during pregnancy was associated with a small but significantly increased airway function at 3 and 12 months of age, suggesting a potential shift to a higher airway function trajectory curve. Continued follow-up is underway.

Oral Vitamin C (500 mg/d) to Pregnant Smokers Improves Infant Airway Function at 3 Months (VCSIP). A Randomized Trial.

Rationale: We reported a randomized trial demonstrating daily supplemental vitamin C to pregnant smokers significantly improved newborn pulmonary function tests. The current study tests these results in a new cohort using infant pulmonary function tests. Objectives: To determine if infants of pregnant smokers randomized to daily supplemental vitamin C would have improved forced expiratory flows (FEFs) at 3 months of age compared with those randomized to placebo, and to investigate the association of the α5 nicotinic acetylcholine receptor. Methods: A randomized, double-blind, placebo-controlled trial was conducted at three centers. Two hundred fifty-one pregnant smokers were randomized at 13-23 weeks of gestation: 125 randomized to vitamin C (500 mg/d) and 126 to placebo. Measurements and Main Results: The primary outcome was FEF75 at 3 months of age performed with the raised volume rapid thoracic compression technique (Jaeger/Viasys). FEF50 and FEF25-75 obtained from the same expiratory curves were prespecified secondary outcomes. The infants of pregnant smokers randomized to vitamin C (n = 113) had the following FEFs at 3 months of age compared with those randomized to placebo (n = 109) as measured by FEF75 (200.7 vs. 188.7 ml/s; adjusted 95% confidence interval [CI] for difference, -3.33 to 35.64; P = 0.10), FEF50 (436.7 vs. 408.5 ml/s; adjusted 95% CI for difference, 6.10-61.30; P = 0.02), and FEF25-75 (387.4 vs. 365.8 ml/s; adjusted 95% CI for difference, 0.92-55.34; P = 0.04). Infant FEFs seemed to be negatively associated with the maternal risk alleles for the α5 nicotinic acetylcholine receptor (rs16969968). Conclusions: Although the primary outcome of FEF75 was not improved after vitamin C supplementation to pregnant smokers, the predetermined secondary outcomes FEF50 and FEF25-75 were significantly improved. These results extend our previous findings and demonstrate improved airway function (FEF50 and FEF25-75) at 3 months of age in infants after vitamin C supplementation to pregnant smokers. Clinical trial registered with www.clinicaltrials.gov (NCT01723696).

Vitamin C supplementation for pregnant smoking women and pulmonary function in their newborn infants: a randomized clinical trial.

IMPORTANCE: Maternal smoking during pregnancy adversely affects offspring lung development, with lifelong decreases in pulmonary function and increased asthma risk. In a primate model, vitamin C blocked some of the in-utero effects of nicotine on lung development and offspring pulmonary function. OBJECTIVE: To determine if newborns of pregnant smokers randomized to receive daily vitamin C would have improved results of pulmonary function tests (PFTs) and decreased wheezing compared with those randomized to placebo. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind trial conducted in 3 sites in the Pacific Northwest between March 2007 and January 2011. One hundred fifty-nine newborns of randomized pregnant smokers (76 vitamin C treated and 83 placebo treated) and 76 newborns of pregnant nonsmokers were studied with newborn PFTs. Follow-up assessment including wheezing was assessed through age 1 year, and PFTs were performed at age 1 year. INTERVENTIONS: Pregnant women were randomized to receive vitamin C (500 mg/d) (n = 89) or placebo (n = 90). MAIN OUTCOMES AND MEASURES: The primary outcome was measurement of newborn pulmonary function (ratio of the time to peak tidal expiratory flow to expiratory time [TPTEF:TE] and passive respiratory compliance per kilogram [Crs/kg]) within 72 hours of age. Secondary outcomes included incidence of wheezing through age 1 year and PFT results at age 1 year. A subgroup of pregnant smokers and nonsmokers had genotyping performed. RESULTS: Newborns of women randomized to vitamin C (n = 76), compared with those randomized to placebo (n = 83), had improved pulmonary function as measured by TPTEF:TE (0.383 vs 0.345 [adjusted 95% CI for difference, 0.011-0.062]; P = .006) and Crs/kg (1.32 vs 1.20 mL/cm H2O/kg [95% CI, 0.02-0.20]; P = .01). Offspring of women randomized to vitamin C had significantly decreased wheezing through age 1 year (15/70 [21%] vs 31/77 [40%]; relative risk, 0.56 [95% CI, 0.33-0.95]; P = .03). There were no significant differences in the 1-year PFT results between the vitamin C and placebo groups. The effect of maternal smoking on newborn lung function was associated with maternal genotype for the α5 nicotinic receptor (rs16969968) (P < .001 for interaction). CONCLUSIONS AND RELEVANCE: Supplemental vitamin C taken by pregnant smokers improved newborn PFT results and decreased wheezing through 1 year in the offspring. Vitamin C in pregnant smokers may be an inexpensive and simple approach to decrease the effects of smoking in pregnancy on newborn pulmonary function and respiratory morbidities. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00632476.

Support for spirituality in smoking cessation: results of pilot survey.

Patient spiritual resources are increasingly included in the treatment of medical conditions such as cancers and alcohol and drug dependence, but use of spiritual resources is usually excluded from tobacco dependence treatment. We hypothesized that this omission may be linked to perceived resistance from smokers. To examine this hypothesis, we conducted a pilot survey to assess whether current smokers would consider spiritual, including religious, resources helpful if they were planning to quit. Smokers at least 18 years of age at Oregon Health & Science University in Portland, Oregon, (N=104) completed a brief survey of smoking behaviors and spiritual beliefs. None were attempting to quit. Of these individuals, 92 (88%) reported some history of spiritual resources (spiritual practice or belief in a Higher Power), and of those respondents, 78% reported that using spiritual resources to quit could be helpful, and 77% reported being open to having their providers encourage use of spiritual resources when quitting. Results of logistic regression analysis indicated that those aged 31-50 years (OR=3.3), those over age 50 years (OR=5.4), and women (OR=3.4) were significantly more likely to have used spiritual resources in the past. Of the 92 smokers with any history of spiritual resources, those smoking more than 15 cigarettes/day were significantly more receptive to provider encouragement of spiritual resources in a quit attempt (OR=5.4). Our data are consistent with overall beliefs in the United States about spirituality and recent trends to include spirituality in health care. We conclude that smokers, especially heavier smokers, may be receptive to using spiritual resources in a quit attempt and that spirituality in tobacco dependence treatment warrants additional investigation and program development.