Background: Atherosclerosis is an important medical problem of modern society. High environmental tobacco smoke in casino is associated with an accelerated atherogenic process. We have previously shown vitamin B12 and C supplementation improves vascular reactivity and may be beneficial in vascular protection.
Objective: To evaluate the impact of vitamin supplementation on atherosclerosis (brachial artery reactivity FMD and carotid intima-media thickness IMT) in subjects exposed to high environmental tobacco smoke.
Design: Double-blind 2x2 factorial design fashion.
Setting: Computer randomization in 4 treatment groups: placebo (n=24), vitamin B12 (n=21), vitamin C (n=23) and vitamin B12+C (n=23) groups.
Participants: 91 passive-smoking casino employees (19.2% male, mean age 45.0±8.2 years).
Intervention: Subjects were randomized to receive vitamin B12 (500µg daily), vitamin C (200mg daily), vitamin B12+C or image-matched placebo capsules for 1 year.
Measurement: Brachial FMD and carotid IMT (surrogate atherosclerotic markers) were measured by ultrasound at baseline and on completion at 12 months.
Methods: 91 passive smoking casino employees (19.2% male, mean age 45.0±8.2 years) were randomized to receive vitamin B12 (500µg daily), vitamin C (200mg daily), vitamin B12+C or image-matched placebo capsules in double-blind 2 x 2 factorial design fashion for 1 year. Brachial FMD and carotid IMT (surrogate atherosclerotic markers) were measured by ultrasound at baseline and 12 months.
Results: Of the 78 (85.7%) passive-smoking employees completed the study, 11.5% had hypertension, 5.1% diabetes mellitus and 15.4% hypercholesterolemia. There were no significant changes in their blood pressures, lipid profiles, glucose and body mass index after supplementation for 1 year, but mild decrease in DBP (p<0.001) and blood creatinine (p<0.01) after combined vitamin B12 and C, and significant increase in blood B12 after vitamin B12 (p<0.01) and vitamin B12+C supplementations (p<0.001). Brachial FMD and cartotid IMT improved after the 3 vitamin supplementations (p<0.001), but not after placebo, being more significant after combined vitamin supplementations (p<0.0001). No adverse effects were reported.
Conclusion: Vitamin B12 or C supplementation in passive smokers improved vascular reactivity and structures at 1 year, with implication in long term atherosclerosis prevention.
Keywords: Passive smokers; atherosclerotic surrogates; brachial arterial reactivity; carotid intima-media thickness; vitamin B/C supplementation.