Inactivity in Men Is Linked to Broken Bones

Inactive men may have a substantially increased risk for broken bones of all
kinds, and especially for hip fractures, a study has found.
Even after controlling for health and behavioral variables, researchers
reported, sedentary men were more than one and a half times as likely as
active ones to suffer a broken bone, and more than two and a half times as
likely to break a hip.
Although they are unsure of the mechanism, the authors theorize that
exercise may work by increasing skeletal strength and muscle mass, and
improving balance. The active men in the study did three or more hours a
week of intense physical activity.
The researchers studied health records of 2,205 men beginning at age 49 to
51, and then followed them for up to 35 years, during which 482 men had at
least one fracture. The men were interviewed and examined again at ages 60,
70, 77 and 82. At the end of the follow-up period, 896 of the men were still
living.
At each of the five interviews, the scientists posed the same questions
about watching television and movies, engaging in other sedentary
activities, walking or cycling for pleasure, and engaging in sports. They
also administered exercise tests and performed muscle biopsies to measure
physical fitness, confirming that the men who reported higher levels of
exercise were in fact more fit. By linking records with job titles, they
were also able to include information on physical activity at work.
The researchers found that the men who maintained the highest levels of
activity had the fewest fractures, and that those with the lowest levels had
the most. The association held true for all fractures, but was especially
strong for broken hips. Moreover, men who increased their exercise saw a
corresponding decrease in the number of fractures.
"It's never too late to start exercising," said Dr. Karl Michaelsson, the
lead author and a professor of surgery and epidemiology at Uppsala
University in Uppsala, Sweden. But he was reluctant to offer specific
exercise advice.
"You can't say to an 85-year-old that he should start vigorous exercise
three hours a week," Dr. Michaelsson said. "Also, we only asked if the men
were engaged in physical activity regularly. What kind of physical activity
has the greatest effect, we don't really know."
The scientists controlled for a large range of variables that might
influence physical activity and fracture risk: smoking; marital status;
education; alcohol use; body mass index; self-reported chest, joint, or back
pain; plus a large number of illnesses including cardiovascular,
gastrointestinal, neurological, inflammatory and others.
Dr. Elizabeth Shane, a professor of medicine and osteoporosis specialist who
was not involved in the study, said she was impressed with the methodology.
"The stress testing and muscle biopsies increase the biological plausibility
of the results," Dr. Shane said. "We always recommend physical activity to
our patients, and it's helpful to know that it does seem to be associated
with a decreased risk of fracture."
The study has other significant strengths, even though it was not a
randomized trial. The researchers began monitoring the men before the age
when most fractures occur, and the data, gathered from registers using the
individual personal registration number given to all Swedish citizens, is
highly reliable. Finally, the long follow-up allowed researchers to take
health and lifestyle changes over time into account. [RT]