One of the best-understood areas of long term post reproductive health are the changes in bone that occur upon loss of the estrogenic support of skeletal metabolism.
To fully understand this area it is important to be aware of the fact that the skeleton is maintained by a constant process of remodeling with bone being laid down by osteoblasts and resorbed by osteoclasts. The balance of the rates of resorption vs. deposition is affected by many different factors, one of which is estrogen.
An important consideration is the attainment of peak bone mass. Bone density naturally increases during childhood, reaching a peak between 20 and 30 years of age. Males generally achieve a greater peak bone density in comparison to females. After peak bone mass attainment in women there is a steady decline until the menopause, then an accelerated phase of bone loss until 60yrs, followed by further steady declines until death. After the age of 60 in women the likelihood of osteoporotic fractures of the hip and spine increases.
Osteoporosis is defined as ‘a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture’. It is more frequent in women than men to an approximate ratio of 4:1. The likelihood of a person developing osteoporosis is influenced by several factors, including:
- Family history of osteoporosis or hip fracture
- Long term steroid use
- Premature ovarian insufficiency and hypogonadism
- Medical treatment of gynaecological conditions with induced menopause
- Disorders of thyroid and parathyroid metabolism
- Disorders of gut absorption, malnutrition, liver disease
The risk of development of fracture according to various risk factors can be calculated using the freely available FRAX tool.