title: Previous physical activity relates to bone mineral measures in young women.
abstract: Exercise may increase accretion of bone, potentially reducing the risk of osteoporosis. Previous physical activity was assessed in 204 minimally active young women (18-31 yr). Bone mineral content (BMC) and bone mineral density (BMD) for the total body, femoral neck, and spine were assessed by a dual x-ray absorptiometer, and the radius by a single photon absorptiometer. Self-reported occupation and leisure activity for the 5 yr before enrollment in the study, as well as high school and college sports participation, were assigned energy expenditure (EE) values. From this information, EE variables were created as follows: 1) occupation EE + leisure EE + high school sport and/or college sport EE if within prior 5 yr (5-yr EE); 2) occupation EE + leisure EE (occupation + leisure EE); and 3) high school sport EE (high school EE). These variables were correlated with bone mineral measures and significant results follow (P < 0.05). Five-year EE and occupation + leisure EE correlated with all measures of bone health (r from 0.13 to 0.39). High school EE correlated with total body BMD (r = 0.25) and BMC (r = 0.28), femoral neck BMD (r = 0.28), radius BMC (r = 0.20), as well as spine BMD (r = 0.20) and BMC (r = 0.27). When weight was controlled, 5-yr EE and occupation + leisure EE remained correlated with all BMC measures (r from 0.14 to 0.22). When controlled for weight, high school EE remained associated with femoral neck BMD (r = 0.24), total body BMD (r = 0.20) and BMC (r = 0.26), and spine BMC (r = 0.17). To partially control for selection bias, data were also controlled for total body BMD. Five-year EE and occupation + leisure EE remained positively correlated with all measures of BMC. High school EE remained correlated both with femoral neck BMD and total body BMC. In multiple regression analyses, 5-yr EE or occupation + leisure EE were significant predictors of all measures of bone health, except femoral neck BMD. High school EE was a significant predictor for total body BMD and BMC, femoral neck BMD, and spine BMC.
authors.affiliation: Department of Foods and Nutrition, Purdue University, Indiana University Medical Center, Indianapolis, USA.
authors.forename: D
authors.initials: D
authors.lastname: Teegarden
authors.forename: W R
authors.initials: WR
authors.lastname: Proulx
authors.forename: M
authors.initials: M
authors.lastname: Kern
authors.forename: D
authors.initials: D
authors.lastname: Sedlock
authors.forename: C M
authors.initials: CM
authors.lastname: Weaver
authors.forename: C C
authors.initials: CC
authors.lastname: Johnston
authors.forename: R M
authors.initials: RM
authors.lastname: Lyle
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D005269:Femur / Q000502:physiology; D006801:Humans; D013177:Sports / Q000502:physiology