CaMos: unique study provides insights into osteoporosis

[Guest guest]

CaMos: unique study provides insights into osteoporosis

Rheumawire

Jul 14, 2004

Veronique Duqueroy

Montreal, QC - More than 10% of men and women 50 years of age and older

have fractures in their spine, according the Canadian Multicentre

Osteoporosis Study (CaMos) [1]. In the same age range, using the World

Health Organization definition, the prevalence of osteoporosis is 16% in

women and 7% men.

" More important is the finding that 60% of women and 50% of men 50 years

of age or older are at increased risk of bone fracture. They have twice

the risk of minimum-trauma fracture as determined by bone-density

measurement, " principal investigator Dr Alan Tenenhouse (Montreal

General Hospital, McGill University Bone Centre, Montreal, QC) tells

rheumawire.

CaMos is the first Canadian population-based longitudinal study on

bone-mineral density (BMD) and osteoporosis. Initiated in 1995, it

involves 9 423 people (6 539 women) from the age of 25 to 103 and takes

place in 9 centers across Canada. Phase 1 of the study consisted of a

5-year data collection effort including baseline/related health

questionnaire (SF-36), evaluation of BMD by DEXA (lumbar spine and hip)

and by heel ultrasound. X-rays of thoracic and lumbar spine were also

performed in men and women 50 years of age or older, and blood and urine

samples were collected from a subset of participants of all ages.

" This is a very large random population and it is extremely rare, if not

unique, in osteoporosis studies. So we are quite confident in our

results, " said Tenenhouse.

Completed at the end of 2002, phase 1 showed that 10% of men and women

(>50 years old) had spinal fractures, most of them asymptomatic. These

results were obtained from spinal x-rays. " Most of these participants

have back pain, but when you ask them if they have or had fractures, 70%

to 80% of them will say no, " said Tenenhouse. " This study shows how

frequent fractures are and how rarely they are clinically reported. And

we know that nonclinical spinal fractures are a very good marker for

future fractures. "

With a prevalence of osteoporosis of 7% in men 50 years of age and older

(16% in women), the CaMos data show that " men are at great risk of

developing osteoporosisit is not only a women's disease, " Tenenhouse

emphasized.

Other unexpected results of CaMos came out from the younger population.

First, the peak bone mass seems to occur earlier than previously thought

in both men and women. " This is the first time we that we have seen

that. We thought that 25 years old was the peak bone mass. "

Second, in women 25 to 45 years old, oral contraceptive use was

associated with lower BMD. " This result was statistically significant, "

Tenenhouse told rheumawire.

In the Calgary CaMos group (n=188), mild vitamin-D deficiency was very

common, especially in the winter. " Virtually the whole study population

(97%) was deemed to have vitamin-D insufficiency, " writes Dr

Rucker, CaMos investigator in Calgary. During the study, participants

were asked to take no more than 200 IU of vitamin D (the amount commonly

found in multivitamin preparations) and blood samples were collected

every 3 months. Lower vitamin-D levels were noticed in fall and winter

and were associated with increasing age and an increase in body mass

index. Since Calgary is one of the sunniest places in Canada, it is

likely that these results apply to all Canadians. " The Canadian

population is at increased risk for vitamin-D deficiency, " adds

Tenenhouse, " certainly due to its geographical location. "

The ongoing phase 2 of the study began in January 2002 and focuses on

the measure of bone markers, such as C-telopeptide, parathyroid hormone,

and vitamin-D metabolites. It will also examine candidate genes such as

those associated with vitamin-D metabolism, estrogen action, and

collagen metabolism. The idea is to develop methods for the early

detection of people at increased risk of developing osteoporosis or

fracture.

The investigators are also seeking younger participants, in their teens

and early twenties, to determine at what age the peak bone mass really

occurs. This could help to establish appropriate prevention programs

against osteoporosis.

Source

The Canadian Multicentre Osteoporosis Study website.

Available at: http://www.camos.org/

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org