The surprising findings, published today in the international journal Arthritis & Rheumatism, indicate that while smoking is linked to a whole host of health problems leading to premature death, long-term smokers are less vulnerable to osteoarthritis.
Principal investigators Professor Philip Ryan and PhD student George Mnatzaganian from the University’s Discipline of Public Health studied the clinical records of 11,000 men aged between 65-83 years of age in Perth.
Men who had smoked for more than 48 years were up to 51% less likely to have undergone total joint replacements (knees and hips) than men who had never smoked.
The researchers found that men who were overweight and very active – especially those in the 70-74 age groups – were also more likely to require hip and knee replacements.
While this is not the only study to demonstrate a link between smoking and decreased risk of osteoarthritis, it is the first to report a strong, inverse relationship between the duration of smoking and risk of total joint replacement.
“We are definitely not endorsing smoking as a safe health practice as it is linked to a whole range of serious diseases, including stroke, heart disease and cancer, which cause premature death,” Professor Ryan says.
“However, this study shows that further research is needed to understand why smoking appears to offer protection against osteoarthritis. Other studies have drawn links between smoking and increases in cartilage volume, and more work needs to be done in this area.”
Total hip and knee replacements are among the most common elective surgeries performed in developed countries.
In 2010, more than 37,443 people underwent total knee replacements in Australia and more than 26,000 people had total hip replacement surgery. Demand for both procedures – particularly knee replacements – is increasing year on year.
Severe osteoarthritis is cited as the most frequent cause for undergoing these operations. It causes pain and stiffness in the joints, with studies indicating that older age, females, and obesity increase the risk of developing osteoarthritis.
“Despite these findings, the fact remains that any possible beneficial effect of smoking on osteoarthritis is far outweighed by other health risks,” Professor Ryan says.