Low metacarpal index predicts hip fracture: a prospective population study of 3,561 subjects with 15 years of follow-up.
BACKGROUND
Metacarpal index (MCI), measured from hand radiographs as the ratio between combined cortical thickness and bone diameter, has been suggested for assessment of bone mass and risk of osteoporotic fracture. We studied MCI for its ability to predict hip fractures.


METHODS
Hand radiographs were taken and MCI determined in 3,561 subjects from a representative population sample of 8,000 Finns who were 30 years of age or over in 1978-80. Record linkage to the National Hospital Discharge Register identified 117 subjects who had been hospitalized for primary treatment of hip fracture by the end of 1994.


RESULTS
High age, low body mass index, tall stature and smoking at baseline showed, independently of each other, significant associations with low MCI. Low MCI was a strong predictor of hip fracture. When adjusted for all potential confounding factors, the relative risk of hip fracture per decrement of MCI by one standard deviation (0.1) was 1.5 (95% CI 1.2-1.8).


CONCLUSIONS
Low MCI is associated with known risk factors of osteoporosis and predicts hip fracture. Since hand radiographs are easily available at low cost, measurements of MCI can be used as an alternative approach to find osteoporotic individuals with a high risk of hip fracture.
Haara
Mikko
M
Bone and Cartilage Research Unit (BCRU), University of Kuopio, Finland. mhaara@hytti.uku.fi
Heliövaara
Markku
M
Impivaara
Olli
O
Arokoski
Jari P A
JP
Manninen
Pirjo
P
Knekt
Paul
P
Kärkkäinen
Alpo
A
Reunanen
Antti
A
Aromaa
Arpo
A
Kröger
Heikki
H
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D015519:Bone Density; D005260:Female; D005500:Follow-Up Studies; D006225:Hand / Q000000981:diagnostic imaging*; D006620:Hip Fractures / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D006801:Humans; D008297:Male; D050279:Metacarpal Bones / Q000000981:diagnostic imaging*; D008663:Metacarpus / Q000033:anatomy & histology*; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015663:Osteoporosis, Postmenopausal / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires