Determinants of bone strength and fracture incidence in adult Finns: Cardiovascular Risk in Young Finns Study (the GENDI pQCT study)

Peripheral bone strength and fracture risk were studied in young adult Finns. Peripheral bone measures were associated with risk factors of osteoporosis in young adults and discriminated between those with and without low-energy fractures. In men, trabecular bone loss at peripheral bone sites starts before the age of 40 years. Purpose: This is a cross-sectional study of the determinants of bone strength and fracture risk in young Finns using peripheral quantitative computed tomography (pQCT) and quantitative ultrasound (QUS). Methods: pQCT scans were performed in 1,884 subjects at distal and shaft sites of non-dominant radius and left tibia, and QUS measures (n = 1,415) at the left calcaneus. Lifestyle factors and medical conditions affecting bone health were assessed with questionnaires. Results: In men, the youngest age cohort had the lowest trabecular volumetric bone mineral density (vBMD) at radius and tibia (difference between the youngest and the oldest, 4.4% and 5.6%, respectively, P < 0.001) and lowest speed of ultrasound at the calcaneus (difference 0.5%, P = 0.016). In women, bone traits did not differ by age groups. When sexes were pooled, underweight (relative risk (RR) = 2.95, P < 0.001), excess alcohol intake (1.52, P = 0.036), smoking (1.29, P = 0.025), Crohn's disease or inflammatory bowel syndrome (2.43, P = 0.016), epilepsy (2.54, P = 0.011), use of corticosteroids (2.01, P < 0.001) and inactivity (1.34, P = 0.045) increased the risk of low trabecular vBMD. RRs for low-energy fractures were excess alcohol intake (2.58, P = <0.001), anorexia (3.74, P = 0.041) and hypogonadism (2.08, P = 0.015). Same risk factors predicted BMD and fractures in both sexes. Trabecular bone mineral content, vBMD and bone strength index showed greatest differences (4-9%; P < 0.05) between those with and without low-energy fractures. Conclusions: Peripheral QCT traits are associated with common risk factors of osteoporosis in young Finns and discriminate between those with and without low-energy fractures. In men, trabecular bone loss at peripheral bone sites starts before the age of 40 years. © 2010 International Osteoporosis Foundation and National Osteoporosis Foundation and National Osteoporosis Foundation.