Introduction: Norway has one of the highest reported incidences of osteoporotic fracture. Since, bone mineral density (BMD) is a strong predictor of future fracture risk, high peak bone mass achievement is essential. This study is the first to examine BMD in a population-based study including Norwegian adolescents. Here we compare the measured BMD with international reference ranges and explore predictors of BMD in this population.
Methods: In 20102011 all first year comprehensive school students (1100 participants, aged 1617 years) in the Tromsø region were invited to participate in the Fit Futures study, an expansion of the Tromsø study. Altogether 508 girls and 530 boys attended the survey providing an attendance rate >90%. BMD at the total hip and femoral neck was measured as g/cm2 by DEXA (GE Lunar prodigy, Lunar Corporation, Madison, WI, USA). Lifestyle variables were collected by self-administered questionnaires and interviews.
Results: The mean BMD was 1.060 (S.D. 0.124) g/cm2 at the total hip and 1.066 (S.D. 0.123) g/cm2 at the femoral neck in girls; in boys 1.116 (S.D. 0.147) and 1.103 (S.D. 0.150) g/cm2 at the total hip and femoral neck, respectively, with values falling within published Lunar reference data for this age range. Weight, self-reported physical activity level and early sexual maturation were positively associated with BMD at both femoral sites in girls. In boys, weight and self-reported physical activity level was associated with BMD at total hip, at the femoral neck also completed sexual maturation. Other lifestyle factors, medication use or chronic diseases had no influence on BMD.
Conclusion: Despite the heavy fracture burden among Norwegian adults, bone mineral accrual appears similar in Norwegian adolescents compared to other age matched European adolescents. Physical activity has a positive impact on BMD levels in these age groups. This finding deserves further exploration.
18 - 21 May 2013
European Calcified Tissue Society