if you're a pensioner cannabis is good for you

CANNABIS could be used to protect older people against osteoporosis, according to researchers at a Scottish university.

Osteoporosis, caused by weakening of the bones, can lead to crippling pain, making sufferers susceptible to broken bones.

Half of all women and one in five men in the UK are likely to suffer from the condition, which leads to 200,000 fractures.Scientists investigating the effects of cannabis on bone health found its impact varies dramatically with age.

The team found that while cannabis could reduce bone strength in young people, it may protect against osteoporosis in later life.

Researchers showed a molecule found in the body which can be activated by cannabis – called the type 1 cannabinoid receptor (CB1) – is key to development of the condition.

While it was known that when CB1 comes into contact with cannabis, it has an impact on bone regeneration, it was not clear whether the drug had a positive or negative effect.

Researchers, funded by the Arthritis Research Campaign, studied mice lacking the CB1 receptor. They then used compounds, similar to those in cannabis, which activated the receptor. They found that compounds increased the rate at which bone tissue was destroyed in the young.

The study also showed that the same compounds decreased the bone loss in older mice and prevented the accumulation of fat in the bones, which is known to occur in humans with osteoporosis.

The results of the study are published in this month's Cell Metabolism.

Stuart Ralston, Arthritis Research Campaign professor of rheumatology at the University of Edinburgh, who led the research, said he was not advocating older people smoke cannabis.

"This is an exciting step forward, but we must recognise that these are early results and more tests are needed on the effects of cannabis in humans to determine how the effects differ with age in people," he said.

"I'm not saying older people should be smoking joints as these contain tobacco. We want to find a cannabis-like derivative which could target the skeleton and not affect the brain."

Debate over the health benefits of the drug has been wide-ranging.

Don Barnard, of the Legalise Cannabis Alliance, said: "People have known for hundreds if not thousands of years that cannabis can be used for medical conditions. We are very concerned that sick people are denied the use of cannabis and doctors who want to prescribe it are threatened with jail.

"Painkillers mask the pain, meaning you push more at something like gardening, then suffer for it the next day. Smoking a joint puts the pain into the background but it doesn't allow you to overstep the mark."

Dr Claire Bowring, medical policy officer at the National Osteoporosis Society, said: "This is an exciting study but we look forward to further research to see if these effects are mirrored in humans."