Quitting smoking may restore hematological characteristics within five years.
Van Tiel E, Peeters PH, Smit HA, Nagelkerke NJ, Van Loon AJ, Grobbee DE, and Bueno-de-Mesquita HB
Annals of Epidemiology. Aug 2002
(DOI : 10.1016/s1047-2797(01)00282-4)