Higher Serum Insulin Concentrations Positively Influence the Bone Mineral Density in African American Adolescents

• Type of Material: Article
• Authors: Ambika P. Ashraf, University of Alabama; Jessica A. Alvarez, Emory University; Carrie Huisingh, University of Alabama; Krista Casazza, University of Alabama; Barbara Gower, University of Alabama
• Language: English
• Date: 2013-01-10
• Publisher: SCIENCEDOMAIN International
• Publication Version: Final Published Version
• Copyright Statement: © 2013 Ashraf et al
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.9734/BJMMR/2013/2720
• Title of Journal or Parent Work: British Journal of Medicine and Medical Research
• ISSN: 2231-0614
• Volume: 3
• Issue: 4
• Start Page: 1050
• End Page: 1061
• Grant/Funding Information: The NORC core lab (P30DK56336) and DRTC core lab (P60DK079626) for laboratory analyses and body composition analyses are supported by grants from the National Institutes of Health.; JAA was supported by the American Heart Association (Greater Southeast Affiliate).; This study was funded by UAB Diabetes Research Training Center (P60 DK- 079626) and by Child Health Research Center Grant K12 HD043397 (T0909180013), and was supported by the Center for Clinical and Translational Science (5UL1 RR025777).
• Keywords: ethnic differences; bone mass; insulin secretion; Bone mineral density
• Research Categories: Health Sciences, Nutrition; Health Sciences, General

Abstract

Background: Puberty is a developmental stage of increased insulin resistance that also is a critical period for bone mass accrual. Historically, African Americans (AA) have lesser risk for osteoporotic fractures compared to European Americans (EA). AA also have higher incidence of insulin resistance. The possibility that bone health and insulin secretion or concentrations are linked has not been investigated. Aims: We aimed to examine the associations of bone mineral density (BMD) and bone mineral apparent density (BMAD) with insulin sensitivity and secretion in healthy adolescent girls and healthy female adults and to evaluate ethnic differences in these associations. Study Design: Observational cohort design. Place and Duration of the Study: University of Alabama at Birmingham, between January 2010 and September 2011. Methodology: Healthy, female, non-smoking adolescents and young adults (14–55 years) were enrolled in this observational cohort study. Results: Adolescents had significantly higher fasting insulin (P=0.0002), insulin area under the curve [AUC] (P= 0.0004) and lower insulin sensitivity (P=0.0005) compared to adults. Among adolescents, AA race was significantly associated with BMD (β=0.086, P=0.01) and BMAD (β=0.0075, P=0.002); however, adjusting for insulin AUC explained this difference. Insulin AUC (β=0.0006, P=0.029) and fasting insulin (β=0.0005, P=0.01) were positively associated with BMAD only in AA adolescents. Insulin AUC and fasting insulin were not significant predictors of BMD for adults. Conclusion: The higher insulin concentration among AA adolescents is associated with increased BMD and higher BMAD.