Body Weight and Body Mass Index Influence Bone Mineral Density in Late Adolescence in a Two-Year Follow-Up Study. The Tromsø Study: Fit Futures.

Ole Andreas Nilsen,Tore Christoffersen,Luai Awad Ahmed,Nina Emaus,Elaine Dennison,Guri Grimnes,Anne‐Sofie Furberg,Gyrd Thrane,Anne Winther,Elin Evensen

doi:10.1002/jbm4.10195

Abstract

ABSTRACTDeterminants of bone acquisition in late adolescence and early adulthood are not well‐described. This 2‐year follow‐up study explored the associations of body weight (BW), body mass index (BMI), and changes in weight status with adolescent bone accretion in a sample of 651 adolescents (355 girls and 296 boys) between 15 and 19 years of age from The Tromsø Study: Fit Futures. This Norwegian population‐based cohort study was conducted from 2010 to 2011 and was repeated from 2012 to 2013. We measured femoral neck, total hip, and total body bone mineral content and areal bone mineral density (aBMD) by dual‐energy X‐ray absorptiometry. We measured height, BW, calculated BMI (kg/m 2), and collected information on lifestyle at both surveys. Mean BMI (SD) at baseline was 22.17 (3.76) and 22.18 (3.93) in girls and boys, respectively. Through multiple linear regression, baseline BW and BMI were positively associated with ∆aBMD over 2 years of follow‐up at all skeletal sites in boys ( p < 0.05), but not in girls. ∆BW and ∆BMI predicted ∆aBMD and ∆BMC in both sexes, but the strength of the associations was moderate. Individuals who lost weight during follow‐up demonstrated a slowed progression of aBMD accretion compared with those gaining weight, but loss of BW or reduction of BMI during 2 years was not associated with net loss of aBMD. In conclusion, our results confirm that adequate BW for height in late adolescence is important for bone health. Associations between change in weight status and bone accretion during follow‐up were moderate and unlikely to have any clinical implication on adolescents of normal weight. Underweight individuals, particularly boys, are at risk of not reaching optimal peak bone mass and could benefit from an increase in BMI. © 2019 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Highlights

Osteoporosis is a major public health concern and a frequent cause of disability in Western societies.[1]
We hypothesized that higher baseline body weight (BW) and body mass index (BMI), as well as ΔBW and ΔBMI would be positively associated with changes in bone parameters, and that negative ΔBW and ΔBMI could be detrimental to bone accrual in adolescents entering young adulthood
The relationships between bone accretion and weight change were strongest among boys with low BMI/BW at baseline (Table 3, Fig. 5A and Fig. 5B). In this population‐based study we explored the associations between BW, BMI, ΔBW, and ΔBMI with changes in bone parameters in adolescents entering young adulthood

Summary

Introduction

Osteoporosis is a major public health concern and a frequent cause of disability in Western societies.[1]. It has long been established that there is an association between BW and bone mineral parameters in the adult population.[7] High BMI is generally considered to have an osteo‐protective effect, while rapid loss of BW is associated with bone loss.[8,9] In childhood and adolescence, the relationship between weight status and bone accretion is more controversial Both detrimental and protective effects of BW have been reported.[10,11,12,13,14,15,16,17,18] There are few studies with repeated measures exploring bone accretion and longitudinal relationships.[16] Obesity and overweight in childhood and adolescence are a growing concern worldwide with rising prevalence during the past decades.[19] In European countries, including Norway, there has been a shift in the BMI distribution, with an increase in BMI in the upper percentiles.[20] For health benefits, obese and overweight individuals are recommended to reduce their weight by approximately 10%. We hypothesized that higher baseline BW and BMI, as well as ΔBW and ΔBMI would be positively associated with changes in bone parameters, and that negative ΔBW and ΔBMI could be detrimental to bone accrual in adolescents entering young adulthood

Methods

Results

Conclusion