Fear of lung cancer, heart disease, high blood pressure and other diseases may not be enough to encourage smokers to quit smoking, but premature aging might. Smokers look older than non smokers and a study published in The Lancet (March 24, 2001;357:935-936) explains how. Smoke from tobacco increases levels of matrix metalloproteinase 1 (MMP-1), which causes collagen to break down. The damage causes skin to lose its elasticity. The skin loses tone, and wrinkles more easily.  The damage is similar to scar formation and is irreversible.