P2-517 Socioeconomic status (SES) related to bone properties in Canadian adolescent females?

Abstract

Osteoporosis is a bone condition characterized by low bone mass and increased susceptibility to fractures in older adults, particularly females. Peak bone mass (PBM) is accrued by age thirty in females. It is imperative adequate PBM be acquired in adolescent females to minimize future risk for osteoporosis. There is limited literature on the relationship between SES as a risk factor and bone properties in adolescent females. In a cross-sectional study of Canadian adolescent females (n = 430) from six randomly selected schools in Southern Ontario, multivariable regression analyses were used to assess the association between parental SES indices and bone speed of sound (SOS) in a multilevel model with participants nested in schools. Bone SOS was measured by transaxial quantitative ultrasound at the distal radius and mid-tibia. SES was determined by matching residential address for each participant with Statistics Canada 2006 Census data for their census area. Mean age was 15.7 +/- 1.1 years. Multilevel analysis found a significant difference in SOS among schools at both radial and tibial sites (p < .001). Multivariable regression analysis indicated significant positive relationships for both median family income (p = .003) and median household income (p = .003) with tibial SOS adjusted for grade, weight, body mass index, smoking and alcohol use. Further analysis of average family income (p = .006) and average household income (p = .003) also indicated significant positive relationships with tibial SOS. These data suggest that school and SES at the census aggregate variable level are important predictors for bone SOS in female adolescents when analyzed separately. School appears to dominate over SES census variables when analyzed together.