Both weight gain and weight loss in postmenopausal women are associated with increased incidence of fracture, but at different anatomical sites, according to a US study.
The findings, published in the British Medical Journal, also challenge the traditional view that weight gain protects against fractures.
Researchers from the University of California investigated associations between postmenopausal change in body weight and incidence of fracture.
They analysed data on over 120,000 healthy postmenopausal women aged 50-79 who were followed for an average of 11 years. Each year, participants were weighed and asked to report fractures of the upper limb, lower limb, and central body.
Change in body weight was categorised as stable (a change of less than 5% from initial weight), weight loss (a decrease of 5% or more since initial examination), and weight gain (an increase of 5% or more since initial examination).
Results at the third annual visit show that, during an average of 11 years of follow-up, compared with stable weight, weight loss was associated with a 65% increase in hip fracture, a 9% increase in upper limb fracture, and a 30% increase in central body fracture.
Also, compared with women who had stable weight, weight gain was associated with a 10% increase in upper limb fractures and an 18% increase in lower limb fractures, but no difference in central body fractures.
Compared with stable weight, unintentional weight loss was associated with an increased risk of hip and spine fractures, whereas intentional weight loss was associated with an increased risk of lower limb fractures, but a decreased risk of hip fractures.
“The findings “have clinical and research implications and challenge the traditional clinical paradigm of weight gain protecting against fractures,” said the authors.
“Clinicians should be aware that even intentional weight loss is associated with increased rates of lower limb fractures,” they added.
Read the full research in the British Medical Journal