FRIDAY, July 8 (HealthDay News) -- It is well-known that smoking
is unhealthy, yet men who smoke are less likely than nonsmokers to
require total hip or knee replacement, according to a new
The researchers also found that being overweight or doing
vigorous physical activity increased the likelihood of joint
In the study, 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 percent) or total hip replacement (41 percent).
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
percent less likely to undergo joint replacement than men who never
smoked, the study showed.
The University of Adelaide researchers also found that vigorous
exercise increased the risk of joint replacement in men aged 70 to
74, according to the study published in the July 8 online edition
of the journal
Arthritis & Rheumatism.
"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," study author George
Mnatzaganian, a Ph.D. student, said in a journal news release.
"Further investigation is needed to determine how smoking impacts
the development of osteoarthritis."
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.
The U.S. National Institute of Arthritis and Musculoskeletal and
Skin Diseases has more about