Research has demonstrated that many individuals with Crohnâs ileitis share a genetic mutation that may play a significant role in disease development. A hypersensitive immuno-response to a pathogenic presence, such as bacteria, within the gastrointestinal tract is also suspected of contributing to the disease's onset.
Secondary osteoarthritis occurs less frequently than primary (also known as idiopathic) osteoarthritis. Primary osteoarthritis means that there is no known cause for the joint breakdown.
The definition of primary osteoarthritis is more nebulous. Although this form of osteoarthritis is related to the aging process and typically occurs in older individuals, it is, in the broadest sense of the term, an idiopathic phenomenon, occurring in previously intact joints and having no apparent initiating factor.