Last updated at 1:41 AM on 21st July 2010
A hormone which regulates our internal bodyclock may also help treat osteoporosis. Now a pill form of the hormone, melatonin, is being given to women over 45 as part of a clinical trial to test the benefits.
Osteoporosis is a condition affecting the bones, causing them to become weak and fragile and increasing the risk of fractures. There are around 300,000 osteoporosis-related fractures each a year as a result.
The condition affects both women and men of all ages, although it’s most commonly associated with postmenopausal women.
Fragile: A scan showing the bones of an osteoporosis patient
This is because the female hormone oestrogen plays a key part in bone health – and after the menopause, production of oestrogen falls.
This leads to changes in the bone production cycle.
In healthy young bones, there is a constant cycle of new growth and removal of old bone – known as bone turnover. As we age, more bone is removed, causing a loss of bone density and other changes, which together make the bones more fragile.
Traditional treatment includes drugs called bisphosphonates, which work by blocking the breakdown of bone; strontium ranelate, a drug which stimulates new bone growth, and vitamin D, which makes bones stronger.
HRT, which raises levels of oestrogen in the body, has been used, too, but long-term use over a number of years has been shown to increase the risk of stroke.
In the new study at the University of Pittsburgh in the U. S. , researchers are looking at melatonin as an alternative treatment.
Melatonin is a hormone which is secreted by the pineal gland in the brain. It is produced in the hours of darkness and maintains the body’s internal 24-hour body clock. It also helps control the timing and release of female reproductive hormones.
Previous studies have pointed to a connection between melatonin and osteoporosis. In one American study, women who worked nightshifts for more than 20 years were more likely to suffer wrist or hip fractures.
Night-shift workers have lower night- time melatonin levels, possibly because they’re exposed to light at night. (Bright lights in the evening or too little light during the day can disrupt the body’s normal melatonin cycle.)
Meanwhile, animal studies have shown melatonin in bone marrow. This is where stem cells – the building blocks of the body – are produced.
By increasing the amount of the hormone in animals with osteoporosis, scientists have been able to encourage bone growth.
Melatonin also has a powerful antioxidant effect, so may help to prevent the inflammation and damage that leads to bone breakdown.
In the new trial in Pittsburgh, which is due to last six months, 20 women aged 45 to 52 will take a synthetic version of the hormone in pill form before bed. They will have their bone density tested before and after the treatment.
They will also be monitored to see whether improved hormone levels have an effect on their general well-being.
‘ We expect women taking melatonin to show an improvement in overall bone health,’ say the researchers. ‘We also expect them to have better control over their menopausal symptoms, better quality of life and less sleep disturbances.’
The add: ‘This research might prove an inexpensive, efficient way to help some of the millions who have osteoporosis.’
British experts remain circumspect about the new approach.
‘We’re always glad to see new research into osteoporosis, and look forward to the results of this initial trial,’ says Rob Dawson, of the National Osteoporosis Society.
‘However, much more work is needed before any benefits of melatonin can be assessed.
‘Melatonin has cropped up in clinical research about bone health, but as yet there have been no proven connections to warrant large trials.’.