Factors that determine bone mass and strength
Heredity is the most important factor for strong bones. Genes determine the variation in peak bone mass, the maximum bone density, for 60-80%. Nutrition and exercise also play important roles in the development of the bones while growing (children) and in the maintenance phase of the bone tissues (adults, elderly).
Bones consist of a protein matrix, which is filled with calcium phosphate and other minerals, such as sodium, magnesium, potassium and zinc. During life, bone tissue is constantly broken down (resorption) and built up again (formation) for recovery after minor ‘damage’ and for adjustment of the strength to the load exerted on a bone. From birth up to the age of about 30 years, the formation of bone exceeds the bone resorption and so the bone density increases, resulting in a peak bone mass (PBM). In the period between birth and the age of 2 years bones are growing fast. A second period of fast bone growth is seen during adolescence.1,2 The peak bone mass decreases as from the age of 50, more with women (figure 1) than with men. The higher the peak bone mass, the stronger the bones at a later age.3,4,5 It is important to pay attention to the build-up of bones already from a young age. A 10% increase of the peak bone mass of children reduces the risk of a fracture related to osteoporosis at a later age by 50%.1,2
Figure 1: Course of the bone mass during life with women
Factors determining the bone mass
Genetic factors determine the variation in peak bone mass for 60 to 80%. Besides, sufficient (weight-bearing) physical exercise and a diet with sufficient calcium, vitamin D and protein play important roles. Hormones (sex and growth hormones), ethnicity, gender, use of medicines, BMI, smoking and use of alcohol are decisive for the bone mass as well.1,5
Figure 2: Factors influencing the peak bone mass
Source: Rizzoli et al., 2012
Bone strength is influenced by changes in the structure (size and shape) and composition [cortical (compact) bone, trabecular (sponge-like) bone, amount of cartilage] of the bone.6 A high peak mass at a young age and the decrease of bone loss at a later age are two ways to reduce osteoporosis risk.7 The nutrients calcium, vitamin D, protein and phosphorus, as well as the interaction between these nutrients, play important roles in the creation of strong and healthy bones; an inadequate intake of these nutrients may lead to bone fractures.8 An inadequate intake of protein may also reduce muscle mass, which increases the risk of a fracture caused by a fall.
Figure 3: Schematic view of the effects of an inadequate intake of calcium, vitamin D, protein and phosphorus related to the risk of a hip fracture
Source: Bonjour et al., 2013
Good nutrition and a healthy lifestyle are essential for healthy, strong bones during the entire life. At an older age, strong bones and well-developed muscles are important to remain mobile and independent for a longer time.1,2
- International Osteoporosis Foundation. Invest in your bones. How diet, life style and genetics affect bone development in young people. International Osteoporosis Foundation, 2001. Zwitserland, Nyon.
- International Osteoporosis Foundation. Bone development in young people. International Osteoporosis Foundation, 2013. Verkregen via iofbonehealth.org in December 2013.
- Dawson-Hughes, B, El-Hajj Fuleihan G, Clark P el at. Bone care for the postmenopausal woman. International Osteoporosis Foundation 2013. Zwitserland, Nyon.
- Huth PJ, DiRienzo DB, Miller GD. Major scientific advances with dairy foods in nutrition and health. Journal of Dairy Science, 2006; 89(4):1207-1221.
- Rizzoli R, Luisa Bianchi M, Garabédian M, McKay HA, Moreno LA. Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly. Bone, 2010; 46:294-305.
- Weaver CM, Gordon CM, Janz KF, Heaney, RP et al. The national osteoporosis foundation’s position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations. Osteoporosis International 2016, 27(4):1281–1386.
- Weaver CM. Milk consumption and bone health. JAMA Pediatrics, 2013. Editorial.
- Bonjour,JP, Kraenzlin M, Levasseur R, Warren M, Whiting S el at. Dairy in adulthood: From foods to nutrient interactions on bone and skeletal muscle health. Journal of the American College of Nutrition, 2012; 32(4):251–263.