bone resorption disease osteoporosis A condition of reduced bone mass, with decreased cortical thickness and a decrease in the number and size of the trabeculae of cancellous bone (but normal chemical composition), resulting in increased fracture incidence. Osteoporosis is classified as primary (Type 1, postmenopausal osteoporosis; Type 2, age-associated osteoporosis; and idiopathic, which can affect juveniles, premenopausal women, and middle-aged men) and secondary osteoporosis (which results from an identifiable cause of bone mass loss). COHD:80502 DOID:11476 EFO:0003882 GARD:0011932 ICD10:M81 ICD10:M81.0 ICD9:733.0 ICD9:733.00 ICD9:733.09 MESH:D010024 MONDO:0005298 NCIT:C3298 OMIM:166710 SCTID:64859006 fracture, hip, susceptibility to osteoporosis, involutional