Endocrinology Lay summaries

2014

Body fat contributes to peak bone mass in young women

Keywords: fat mass, lean body mass, peak bone mass, young adults

What is already known about this subject:

  • The amount and density of our bones (‘bone mass’) increases though childhood and adolescence and peaks during early adulthood. Bone mass then decreases as we age.
  • Achieving a maximal bone mass is the best protection against age-related bone loss and bone fractures.
  • It is known that body weight and lean body mass are important determinants of a person’s bone mass, but the role of body fat is not clear.

What this Raine study adds:

  • Body composition, bone mineral content, bone area and bone mineral density data from whole body scans in young adults participating in the Raine study revealed that the amount of body fat was strongly associated with bone mass in young women, but was not important in determining bone mass in young men. Lean body mass was an important determinant of bone mass in both young men and women.
  • The type of body fat was important; visceral fat (unhealthy fat around the internal organs) was associated with lower bone mass.
  • Body composition is an important contributor to bone health.

Zhu, K., Briffa, K., Smith, A., Mountain, J., Briggs, A M., Lye, S., … Walsh, J. P. (2014). Gender differences in the relationships between lean body mass, fat mass and peak bone mass in young adults. Osteoporosis International, 25(5), 1563-70. doi:10.1007/s00198-014-2665-x. [publink]

Bone mass in young adults is related to their mothers’ vitamin D levels during pregnancy

Keywords: Vitamin D, bone mass, pregnancy, young adults

What is already known about this subject:

  • A person’s bone mass peaks during early adulthood and then declines with age. A high peak bone mass is considered the best protection against age-related bone loss and fractures.
  • Bone mass is mostly determined by an individual’s genetics and environmental factors such as diet and physical activity; but maternal vitamin D levels during pregnancy may also be important.
  • Vitamin D deficiency is common during pregnancy in Australian women, but it is not yet clear if a mother’s vitamin D levels can influence her child’s bone development.

What this Raine study adds:

  • Measurement of vitamin D levels in blood samples collected from pregnant women participating in the Raine study and peak bone mass as measured by whole body DXA scans in their children at 20 years of age revealed that higher maternal vitamin D levels were associated with greater peak bone mass in their offspring.
  • Children of mothers with vitamin D deficiency had lower bone density, and this may translate to an increased risk of osteoporotic fractures in later life.
  • Vitamin D supplementation in pregnant women may be beneficial for bone development in their children.

Zhu, Kun, Andrew J O Whitehouse, Prue H Hart, Merci Kusel, Jenny Mountain, Stephen Lye, Craig Pennell, and John P Walsh. 2014. “Maternal Vitamin D Status during Pregnancy and Bone Mass in Offspring at 20 Years of Age: A Prospective Cohort Study.” Journal of Bone and Mineral Research : The Official Journal of the American Society for Bone and Mineral Research 29 (5) (May): 1088-95. doi:10.1002/jbmr.2138. [publink]