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Daily vitamin C during smokers’ pregnancies significantly improved the lung function of their infants at birth and reduced the incidence of wheezing during the first year of life, compared with infants of smokers who weren’t exposed to the vitamin.
Those infants had significantly poorer respiratory outcomes, both at birth and 1 year, according to Dr. Cindy McEvoy and colleagues. The study was presented at an international conference of the American Thoracic Society and simultaneously published in the May 18 issue ofthe Journal of the American Medical Association.
While it’s not entirely clear how vitamin C influences prenatal lung development, there are tantalizing hints, wrote Dr. McEvoy of the Oregon Health and Science University, Portland, and her coinvestigators. "Supplemental vitamin C may act by blocking formation of reactive oxygen species, which stimulate abnormal patterns of airway cell proliferation, resulting in narrowed airways and abnormal airway geometry," they said.
Dr. McEvoy and her team randomized 179 pregnant smokers to either placebo or 500 mg vitamin C daily from week 16 of pregnancy. At birth, they examined two respiratory function measures: the ratio of time to peak expiratory flow/expiratory time (TPTEF:TE) and passive respiratory compliance per kg (Crs/kg). They also compared the incidences of wheezing during the first year. A control group of 76 infants from nonsmokers provided a comparator (JAMA 2014 May 18 [doi:10.1001/jama.2014.5217]).
The women were a mean age of 26 years at baseline. Most were white (about 85%), and 20% had at least some college education. In the placebo group, 36% smoked at least 10 cigarettes a day; in the active group, 41% smoked that many. All smoking mothers were offered the chance to participate in a smoking cessation program; 10% were able to stop.
At birth, infants exposed to vitamin C had significantly better lung function than nonexposed infants on both measures. The TPTEF:TE was 10% better in the exposed group (0.383 vs. 0.345) – similar to the ratio in the comparator group of infants from nonsmoking mothers. The Crs/kg was also significantly better (11%) in the vitamin C group (1.32 vs. 1.20 mL/cmH20/kg).
Almost all of the babies had 1-year follow-up (92%). At that time, the incidence of wheezing during the first year was 21% in the treated group and 40% in the placebo group (adjusted relative risk, 0.56). However, the authors noted, there was no between-group difference in the other lung function measures at 1 year.
A subgroup of 173 mothers was genotyped for two polymorphisms that are strongly associated with a lifelong risk of nicotine addiction, lung cancer, and chronic obstructive pulmonary disease.
The infants of mothers who were heterozygous for one of those (rs16969968), experienced the largest benefit from vitamin C exposure. The incidence of wheezing through 1 year in these infants was 14%, compared with 48% among those randomized to placebo.
The National Heart, Lung, and Blood Institute sponsored the study. Neither Dr. McEvoy nor any of her coauthors had any financial disclosures.
Quitting is the best way for smokers to protect their unborn babies against the harms of tobacco.
But unfortunately, quitting doesn’t always happen. Thus, the finding that vitamin C may offer babies some protection against the harms of tobacco is heartening news. Although the improvement over placebo was rather small (10%), it could have a profound effect.
"Small population-level changes in lung function may lead to significant public health benefits, and the improvements in lung function reported here could be associated with future benefit."
The study was well designed and well executed, and the 1-year endpoints intriguing. However, there is no evidence that vitamin C fully prevents or reverses the effects of maternal smoking during gestation. Thus, prenatal treatment should never be seen as a panacea.
"Achieving smoking cessation should be the primary goal for women who smoke and who intend to become pregnant. By preventing her developing fetus and newborn infant from becoming exposed to tobacco smoke, a pregnant woman can do more for the respiratory health and overall health of her child than any amount of vitamin C may be able to accomplish."
Graham L. Hall, Ph.D., is head of pediatric respiratory physiology and research at the Telethon Kids Institute, University of Western Australia, West Perth. These remarks were taken from his accompanying editorial (JAMA 2014 May 18 [doi:10.1001/jama.2014.5218]).
Quitting is the best way for smokers to protect their unborn babies against the harms of tobacco.
But unfortunately, quitting doesn’t always happen. Thus, the finding that vitamin C may offer babies some protection against the harms of tobacco is heartening news. Although the improvement over placebo was rather small (10%), it could have a profound effect.
"Small population-level changes in lung function may lead to significant public health benefits, and the improvements in lung function reported here could be associated with future benefit."
The study was well designed and well executed, and the 1-year endpoints intriguing. However, there is no evidence that vitamin C fully prevents or reverses the effects of maternal smoking during gestation. Thus, prenatal treatment should never be seen as a panacea.
"Achieving smoking cessation should be the primary goal for women who smoke and who intend to become pregnant. By preventing her developing fetus and newborn infant from becoming exposed to tobacco smoke, a pregnant woman can do more for the respiratory health and overall health of her child than any amount of vitamin C may be able to accomplish."
Graham L. Hall, Ph.D., is head of pediatric respiratory physiology and research at the Telethon Kids Institute, University of Western Australia, West Perth. These remarks were taken from his accompanying editorial (JAMA 2014 May 18 [doi:10.1001/jama.2014.5218]).
Quitting is the best way for smokers to protect their unborn babies against the harms of tobacco.
But unfortunately, quitting doesn’t always happen. Thus, the finding that vitamin C may offer babies some protection against the harms of tobacco is heartening news. Although the improvement over placebo was rather small (10%), it could have a profound effect.
"Small population-level changes in lung function may lead to significant public health benefits, and the improvements in lung function reported here could be associated with future benefit."
The study was well designed and well executed, and the 1-year endpoints intriguing. However, there is no evidence that vitamin C fully prevents or reverses the effects of maternal smoking during gestation. Thus, prenatal treatment should never be seen as a panacea.
"Achieving smoking cessation should be the primary goal for women who smoke and who intend to become pregnant. By preventing her developing fetus and newborn infant from becoming exposed to tobacco smoke, a pregnant woman can do more for the respiratory health and overall health of her child than any amount of vitamin C may be able to accomplish."
Graham L. Hall, Ph.D., is head of pediatric respiratory physiology and research at the Telethon Kids Institute, University of Western Australia, West Perth. These remarks were taken from his accompanying editorial (JAMA 2014 May 18 [doi:10.1001/jama.2014.5218]).
Daily vitamin C during smokers’ pregnancies significantly improved the lung function of their infants at birth and reduced the incidence of wheezing during the first year of life, compared with infants of smokers who weren’t exposed to the vitamin.
Those infants had significantly poorer respiratory outcomes, both at birth and 1 year, according to Dr. Cindy McEvoy and colleagues. The study was presented at an international conference of the American Thoracic Society and simultaneously published in the May 18 issue ofthe Journal of the American Medical Association.
While it’s not entirely clear how vitamin C influences prenatal lung development, there are tantalizing hints, wrote Dr. McEvoy of the Oregon Health and Science University, Portland, and her coinvestigators. "Supplemental vitamin C may act by blocking formation of reactive oxygen species, which stimulate abnormal patterns of airway cell proliferation, resulting in narrowed airways and abnormal airway geometry," they said.
Dr. McEvoy and her team randomized 179 pregnant smokers to either placebo or 500 mg vitamin C daily from week 16 of pregnancy. At birth, they examined two respiratory function measures: the ratio of time to peak expiratory flow/expiratory time (TPTEF:TE) and passive respiratory compliance per kg (Crs/kg). They also compared the incidences of wheezing during the first year. A control group of 76 infants from nonsmokers provided a comparator (JAMA 2014 May 18 [doi:10.1001/jama.2014.5217]).
The women were a mean age of 26 years at baseline. Most were white (about 85%), and 20% had at least some college education. In the placebo group, 36% smoked at least 10 cigarettes a day; in the active group, 41% smoked that many. All smoking mothers were offered the chance to participate in a smoking cessation program; 10% were able to stop.
At birth, infants exposed to vitamin C had significantly better lung function than nonexposed infants on both measures. The TPTEF:TE was 10% better in the exposed group (0.383 vs. 0.345) – similar to the ratio in the comparator group of infants from nonsmoking mothers. The Crs/kg was also significantly better (11%) in the vitamin C group (1.32 vs. 1.20 mL/cmH20/kg).
Almost all of the babies had 1-year follow-up (92%). At that time, the incidence of wheezing during the first year was 21% in the treated group and 40% in the placebo group (adjusted relative risk, 0.56). However, the authors noted, there was no between-group difference in the other lung function measures at 1 year.
A subgroup of 173 mothers was genotyped for two polymorphisms that are strongly associated with a lifelong risk of nicotine addiction, lung cancer, and chronic obstructive pulmonary disease.
The infants of mothers who were heterozygous for one of those (rs16969968), experienced the largest benefit from vitamin C exposure. The incidence of wheezing through 1 year in these infants was 14%, compared with 48% among those randomized to placebo.
The National Heart, Lung, and Blood Institute sponsored the study. Neither Dr. McEvoy nor any of her coauthors had any financial disclosures.
Daily vitamin C during smokers’ pregnancies significantly improved the lung function of their infants at birth and reduced the incidence of wheezing during the first year of life, compared with infants of smokers who weren’t exposed to the vitamin.
Those infants had significantly poorer respiratory outcomes, both at birth and 1 year, according to Dr. Cindy McEvoy and colleagues. The study was presented at an international conference of the American Thoracic Society and simultaneously published in the May 18 issue ofthe Journal of the American Medical Association.
While it’s not entirely clear how vitamin C influences prenatal lung development, there are tantalizing hints, wrote Dr. McEvoy of the Oregon Health and Science University, Portland, and her coinvestigators. "Supplemental vitamin C may act by blocking formation of reactive oxygen species, which stimulate abnormal patterns of airway cell proliferation, resulting in narrowed airways and abnormal airway geometry," they said.
Dr. McEvoy and her team randomized 179 pregnant smokers to either placebo or 500 mg vitamin C daily from week 16 of pregnancy. At birth, they examined two respiratory function measures: the ratio of time to peak expiratory flow/expiratory time (TPTEF:TE) and passive respiratory compliance per kg (Crs/kg). They also compared the incidences of wheezing during the first year. A control group of 76 infants from nonsmokers provided a comparator (JAMA 2014 May 18 [doi:10.1001/jama.2014.5217]).
The women were a mean age of 26 years at baseline. Most were white (about 85%), and 20% had at least some college education. In the placebo group, 36% smoked at least 10 cigarettes a day; in the active group, 41% smoked that many. All smoking mothers were offered the chance to participate in a smoking cessation program; 10% were able to stop.
At birth, infants exposed to vitamin C had significantly better lung function than nonexposed infants on both measures. The TPTEF:TE was 10% better in the exposed group (0.383 vs. 0.345) – similar to the ratio in the comparator group of infants from nonsmoking mothers. The Crs/kg was also significantly better (11%) in the vitamin C group (1.32 vs. 1.20 mL/cmH20/kg).
Almost all of the babies had 1-year follow-up (92%). At that time, the incidence of wheezing during the first year was 21% in the treated group and 40% in the placebo group (adjusted relative risk, 0.56). However, the authors noted, there was no between-group difference in the other lung function measures at 1 year.
A subgroup of 173 mothers was genotyped for two polymorphisms that are strongly associated with a lifelong risk of nicotine addiction, lung cancer, and chronic obstructive pulmonary disease.
The infants of mothers who were heterozygous for one of those (rs16969968), experienced the largest benefit from vitamin C exposure. The incidence of wheezing through 1 year in these infants was 14%, compared with 48% among those randomized to placebo.
The National Heart, Lung, and Blood Institute sponsored the study. Neither Dr. McEvoy nor any of her coauthors had any financial disclosures.
FROM ATS 2014
Key clinical point: Giving Vitamin C to pregnant smokers may improve newborns’ lung health.
Major finding: Lung function at birth was about 10% better in infants’ of smokers 500 mg vitamin C daily during pregnancy, compared to those who did not. The incidence of wheezing during the first year was 21% in the treated group vs. 40% in the placebo group.
Data source: A randomized, placebo-controlled study of 179 pregnant smokers.
Disclosures: The National Heart, Lung, and Blood Institute funded the study. None of the authors had financial disclosures.
