Effect of Monthly, High-Dose, Long-Term Vitamin D on Lung Function: A Randomized Controlled Trial
  Download the PDF from Vitamin D Life
Smoking reduces vitamin D - many studies contains the following
Two pathways are often proposed for how smoking decreases vitamin D:
    1) Smoking decreases Calcium. and Vitamin D is used up in replacing the Calcium
    2) Smoking injures the body, and vitamin D is used up in repairing the body
It appears that taking Vitamin D while smoking will:
    1) Decrease the incidence of the many health problems associated with smoking - even lung cancer
    2) Decrease the desire to smoke (perhaps take fewer smoking breaks?)
    3) Increase breathing capacity
Opinion: If unable to stop smoking, 
  or are a previous smoker, 
     or are getting 2nd hand smoke,
          increase Vitamin D and perhaps Omega-3 (which decreases depression, inflammation)
Vitamin D should also help people quit smoking    See bottom of page Smoking reduces vitamin D
    1) Reduces weight gain associated with quitting smoking
    2) Reduces depression associated with quitting smoking
