IRCT20170420033551N7 IRCT 2019-07-15 Kashan University of Medical Sciences Effect of vitamin D supplementation in cigarette smokers The effects of vitamin D supplementation on mental health parameters, oxidative stress and inflammatory biomarkers in cigarette smokers 2019-06-10 anticipated 60 Complete https://irct.ir/trial/40691 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: To decrease potential confounding effects, all participants will have stratified randomization according to BMI (<25 and ≥25 kg/m2) and age (<40 and ≥40 y). Then, participants in each block will be randomly allocated into two treatment groups to take either supplements or placebo. Randomization will be done by the use of computer software, Blinding description: Placebo has been used to achieve masking of participants and investigators. The researchers and patients will be concealed until the final analyses by a trained staff. 2 Nicotine dependence in cigarette smokers. Intervention 1: Intervention group: 50000 IU vitamin D (Zahravi, Tabriz, Iran), once every 2 weeks, for 24 weeks orally. Intervention 2: Control group: Placebo (Barij Essence, Kashan, Iran), once every 2 weeks, for 24 weeks orally. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is Undecided - It is not yet known if there will be a plan to make this available