TRIP

Long- and Short-term Effects of Tobacco Smoking on Circulating Concentrations of B Vitamins.

Clinical Chemistry, 2010

We sought to determine the relation between circulating concentrations of selected B vitamins and smoking status, with particular attention to longitudinal associations.
METHODS: We used baseline data from 2 B-vitamin intervention trials that included 6837 patients with ischemic heart disease.
Vitamins and metabolites, including the nicotine metabolite cotinine, were measured in plasma and serum by microbiological assays or gas/liquid chromatography-tandem mass spectrometry.
RESULTS: The highest circulating concentrations of folate and pyridoxal 5'phosphate (PLP) and lowest concentrations of total plasma homocysteine, a functional marker of folate status, were observed for self-reported never smokers, ex-smokers, and current smokers (Ptrend < 0.001).
Based on their low cotinine concentrations, we were able to identify a group of smokers that had abstained from smoking for 3 days or more.
Compared with smokers with high plasma cotinine, smokers with low cotinine had significantly higher circulating concentrations of folate, PLP, and riboflavin (all P < 0.005), and this trend continued for ex-smokers, with increasing time since smoking cessation.
CONCLUSIONS: Smoking lowered circulating concentrations of folate, PLP, and riboflavin, but concentrations increased significantly after a few days of smoking cessation.
We propose that short-term effects may be related to acute smoking-induced oxidative stress, whereas the longer-lasting effects among ex-smokers may reflect changes in diet and/or restoration of vitamin concentrations in tissue during the first few months to years after smoking cessation.