Chapter 25 - Bone Acquisition in Adolescence

Abstract

This chapter summarizes some of the knowledge that has accrued recently on the characteristics of normal bone mass development during pre-, peri-, and post-pubertal period. Many factors, more or less independently, are supposed to influence bone mass accumulation during growth. The list of these determinants classically includes heredity, sex, dietary components (calcium, proteins), endocrine factors (sex steroids, calcitriol, IGF-I), mechanical forces (physical activity, body weight), and exposure to other risk factors. Quantitatively, the most prominent determinant appears to be genetically related. Puberty is considered to be a period with major behavioral changes and alterations in lifestyle. It is also assumed that important modifications in food habits occur during pubertal maturation, particularly in affluent societies. However, there is still a lack of quantitative and qualitative information regarding the evolution of both micro- and macro-nutrient intakes in relation to pubertal maturation. Among nutrients other than calcium, various experimental and clinical observations point to the existence of a relationship between the level of protein intake and either calcium–phosphate metabolism or bone mass, or even osteoporotic fracture risk. Nevertheless, any long-term influence of dietary protein on bone mineral metabolism and skeletal mass so far has been difficult to identify. Apparently contradictory information suggests that either a deficient or an excessive protein supply could negatively affect the balance of calcium and the amount of bony tissue contained in the skeleton.