Smoking is bad for your health, but also bad for your hips? A new study from down under Australia has found that men who smoke are less likely than nonsmokers to require total hip or knee replacement. Who knew. The researchers also found that being overweight or doing vigorous physical activity actually increased the likelihood of joint replacement.

George Mnatzaganian, a Ph.D. student stated:

“Our study is the first to demonstrate a strong inverse correlation between smoking duration and risk of total joint replacement. The independent inverse associations of smoking with risk of total joint replacement were evident also after adjusting for major confounders and after accounting for the competing mortality risk in this elderly [group] of men. Further investigation is needed to determine how smoking impacts the development of osteoarthritis (OA).”

Often, the cause of OA is unknown. It is mainly related to aging. The symptoms of OA usually appear in middle age. Almost everyone has some symptoms by age 70. However, these symptoms may be minor. Before age 55, OA occurs equally in men and women. After age 55, it is more common in women.

Australian researchers analyzed the medical records of 11,388 men who were followed from 1996-1999 to March 2007. During that time, 857 of the men had either total knee replacement (59%) or total hip replacement (41%).

The investigators found that being overweight independently increased the risk of total joint replacement, while smoking lowered the risk. This reduced risk was most evident after 23 years of smoking, and men who smoked 48 years or more were up to 51% less likely to undergo joint replacement than men who never smoked, the study showed.

According to the 2007 National Hospital Discharge Survey, about 230,000 Americans had hip replacements and 543,000 had knee replacements that year. Severe osteoarthritis was the most common reason for the procedures.

Total hip replacement is most commonly used to treat joint failure caused by osteoarthritis. Other indications include rheumatoid arthritis, avascular necrosis, traumatic arthritis, protrusio acetabuli, certain hip fractures, benign and malignant bone tumors, arthritis associated with Paget’s disease, ankylosing spondylitis and juvenile rheumatoid arthritis.

The aims of the procedure are pain relief and improvement in hip function. Hip replacement is usually considered only once other therapies, such as physical therapy and pain medications, have failed.

A total hip replacement (total hip arthroplasty) consists of replacing both the acetabulum and the femoral head while hemiarthroplasty generally only replaces the femoral head. Hip replacement is currently the most successful and reliable orthopaedic operation with 97% of patients reporting improved outcome.

Source: The American College of Rheumatology

Written by Sy Kraft