In which of the following age group myelodysplastic syndromes (MDS) are most common?

Idiopathic MDS is a disease of the elderly; the mean age of onset is 68 years. There is a slight male preponderance. MDS is rare in children, but monocytc leukemia can be seen. Therapy- related MDS is not age-related and may occur in as many as 15% of patients within a decade following intensive combined modality treatment for cancer. So the single best answer of choice is '>50'. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Pages 624-25; R Alagappan Manual of Practical Medicine, 3rd Edition, Page 352-53.