July 10, 2018

Story and photo by Nadir Balba

The Paper of the Month for June 2018 is "Cost effectiveness of vitamin c supplementation for pregnant smokers to improve offspring lung function at birth and reduce childhood wheeze/asthma" published in the Journal of Perinatology. This project was led by Leah Yieh, M.D., M.P.H, a recently graduated neonatal-perinatal fellow at OHSU. Its authors in descending order are Dr. Yieh, Cindy McEvoy, M.D., M.C.R., Scott Hoffmann, Aaron Caughey, M.D., Ph.D., Kelvin MacDonald, M.D., and Dmitry Dukhovny, M.D., M.P.H. 

A recurrent problem

Pregnancy can be a stressful time for expecting mothers as they are often bombarded with reams of advice on how to have a healthy child. But one recommendation is agreed on by all health care professionals: Pregnant women should always refrain from smoking. Smoking during pregnancy, among other problems, affects lung development and has been linked to a number of health ailments later in childhood, including respiratory problems, asthma and wheezing.

Despite vigorous anti-smoking campaigns, at least 10 percent of U.S. women still admit to smoking while pregnant. With the knowledge that increased public education does not decrease this surprisingly high number, researchers looked at different types of treatments and interventions that could mitigate some of the childhood health risks associated with pregnant smokers.

A promising start

Previous research in non-human primates had suggested that vitamin C could alleviate some of these health effects associated with in-utero nicotine exposure, but it had not been translated to a human population. So, beginning in 2007, Dr. McEvoy and her research team decided to test the effects of vitamin C, by performing a five-year randomized clinical trial. 

They were able to demonstrate that pregnant smokers taking 500mg/day of supplemental vitamin C, compared to those taking a placebo, had newborn infants with significantly improved pulmonary function and a decrease in wheezing through their first year of life. These were promising results, but the team wanted to prove that this treatment could work on a large population while being economically viable.

Scaling up

Dr. Yieh and her research team decided to take an analytic approach and developed an economic model that could provide a public health perspective on the utility of prescribing supplemental vitamin C at 500 mg/day for all pregnant smokers in the U.S. and analyzed its effects on the prevalence, mortality and costs associated with pediatric asthma. Asthma is one of the costliest pediatric illnesses, so understanding the potential financial impact of a nationwide intervention was a critical aim of this study.

Mary Heinricher, Ph.D., associate dean for basic research, OHSU School of Medicine, was especially impressed at the research team's ability to evaluate this type of therapy on a larger scale. "I was intrigued by this paper because this group has done a lot of interesting work at the level of individual patients to show that supplementation with Vitamin C could reduce the burden of asthma on children of women who smoked during pregnancy. This paper goes beyond that interesting body of work to model the societal and economic impacts on public health."

Cheap and effective

The current study was able to demonstrate that the economic impact of prescribing a $20 vitamin C supplementation to pregnant smokers was huge. The model predicted almost $6 million in savings from direct health care costs associated with pregnant smoking (e.g. medical care), and more than $31 million saved in other societal costs (e.g. missed school days, parental wage loss from missed work). Additionally, there are many other outcomes that were too difficult to quantify that would also be improved, such as participation in school, childhood activities, sports and self-esteem.

They also found that these results extended to a number of different clinical scenarios, including rising costs of prescribing additional vitamin C supplementation and changes in the national prevalence of smoking. In the majority of the scenarios, even with a smoking prevalence of as low as one percent of pregnant women, supplemental vitamin C was found to be a cheap and extremely effective strategy from a public health perspective.

Dr. Yieh was excited by these promising results as they proved that effects of this type of treatment could generalize well in a larger, societal model. "The clinical trials have already demonstrated that vitamin C supplementation in pregnant smokers is a safe intervention. Our study demonstrated that it is also an inexpensive therapy that may reduce the economic burden of pediatric asthma during the first 18 years of life."

The team now hopes this treatment will be adopted by and frequently used by health care providers in the near future and are planning a public health campaign to encourage obstetrical providers to prescribe additional vitamin C to pregnant smokers. 

Pictured, left to right: Dmitry Dukhovny, Scott Hoffman, Leah Yieh, Cindy McEvoy, Aaron Caughey, Kelvin MacDonald.

Resources

• Read the paper

Citation

Yieh L, McEvoy CM, Hoffman SW, Caughey AB, MacDonald KD, Dukhovny D. Cost-effectiveness of vitamin C supplementation for pregnant smokers to improve offspring lung function at birth and reduce childhood wheeze/asthma. Journal of Perinatology. 2018 May 22. doi: 10.1038/s41372-018-0135-6.

More Published Papers

• Previous School of Medicine Papers of the Month
• Recent OHSU published papers