Objectives: Previous studies indicate that about half of boys and one fourth of girls suffer a fracture before the age of 16 years. Similarly, children of European descent are more prone to fracture. Here we aimed to investigate at the population level the influence of sex, ethnic background and bone mineral density (BMD) on the occurrence of bone fractures in children of school age.
Methods: This study (n=3,633 children with complete information) is embedded in the Generation R Study, a prospective multiethnic pregnancy/birth cohort in Rotterdam, The Netherlands. Children were classified by ethnic background using questionnaire information on parental country of birth and grouped into Europeans and Non-Europeans (Asian and African origin combined). Fractures occurring since birth were registered in questionnaires filled at 9 years of age by parents. Total body (less head) BMD (TB-BMD) and lean mass (LM) were measured using an iDXA densitometer (GE-Lunar) at a mean age of 6 and 10 years. Risk (odds) of fracture was estimated from logistic regression models adjusted for age, height, weight, lean mass fraction and standardized TB-BMD. Statistical significance was set at P<0.05.
Results: Among all participants with a mean age of 9.74 years (S.D.=0.29), 49.4% were males and 87.1% Europeans. Fracture was reported in 521 children (14.3%). As compared to girls, no significant difference in the odds of fractures was seen in boys (OR =1.04, 95%CI 0.841.28; P=0.74). Children from European ancestry had almost twice higher fracture risk than non-Europeans (OR =1.7, 95%CI 1.192.30; P=0.003). One S.D. decrease in TB-BMD was associated with 26% higher risk of fracture at a mean age of six (OR=1.26, 95%CI 1.101.44; P=0.001) and 43% higher risk at a mean age of nine (OR=1.43, 95%CI 1.241.62; P=4.26×10−7) years.
Conclusion: Total body BMD is a determinant of fracture risk in children of both sexes. Odds of fracture did not differ between boys and girls of school age, but are higher in children of European ancestry even after correction for TB-BMD and body composition. Whether this association is due to differences in physical activity between the ethnic groups remains to be determined.
Disclosure: The authors declared no competing interests.