July 9, 2011

Smoking Could Reduce Risk Of Joint Replacement Surgery

"¨Men who smoke have less of a risk of needing joint replacement surgery than those who have never lit up a cigarette, according to a new study published online in the journal Arthritis & Rheumatism.

"¨The study, which was led by George Mnatzaganian, a Ph. D. student at the University of Adelaide in Australia, analyzed study data of more than 11,000 subjects and discovered that those who had smoked for 48 years or more had a 42% to 51% lower risk of needing a total knee or hip replacement than those who had never done so.

"¨"Researchers analyzed clinical data from baseline through March 2007, identifying 857 men who had joint replacement surgery following the screening," Arthritis & Rheumatism publishers Wiley-Blackwell said in a July 8 press release. "Of those having surgery, 59% had total knee replacement and 41% had total hip replacement. Subjects were categorized into three age groups: 65-69 years, 70-74 years, and 75 or more years of age.

"¨"Analysis showed that being overweight independently increased total joint replacement risk, while smoking lowered the risk, which was most evident after 23 years of smoking exposure," they added, noting that "vigorous exercise increased risk of joint replacement in men in the 70-74 year age group."

"¨"Our study is the first to demonstrate a strong inverse correlation between smoking duration and risk of total joint replacement," Mnatzaganian said in a statement. "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 cohort of men."

"¨Further investigation is required on the subject, he added.

"¨According to MedPage Today Senior Staff Writer Todd Neale, body weight was also determined to be a predictor of total joint replacement, with the risk of surgery increasing along with body weight in each of the three age groups subjects were divided into.

"¨Neale notes that those who weighed at least 193 pounds were four times as likely to require total joint replacement as those weighing at least 43 pounds less.

"¨"Mnatzaganian and his colleagues acknowledged some limitations of the study, including the lack of direct evaluations of osteoarthritis status among the participants; possible misclassification of socioeconomic status; the use of self-reported physical activity levels; and the collection of patient characteristics at baseline only," the MedPage Today reporter added.

"¨In addition to Mnatzaganian, Philip Ryan, Paul E. Norman, David C. Davidson, and Janet E. Hiller are credited as authors of the study, which is entitled "Smoking, Body Weight, Physical Exercise and Risk of Lower Limb Total Joint Replacement in a Population-Based Cohort of Men."

"¨Arthritis & Rheumatism is an official monthly journal of the American College of Rheumatology (ACR) and the Association of Rheumatology Health Professionals (ARHP).


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