Patients will be enrolled in the study for 3 years and will be randomly assigned to one of two groups. The first group will receive nitroglycerin ointment, while the second group will receive placebo ointment. All patients will be given a calcium supplement with vitamin D to be taken daily, and will be instructed to rub the given ointment on their skin daily. Study visits will occur at Month 2 and every six months after Month 2. Phone interviews will be conducted with patients every 2 months throughout the study.