Could a drug commonly used to ease chest pain in millions of people with angina help prevent bone loss in those with osteoporosis?

The results of new research that CTV News first described last December suggests there is reason for hope.

According to a just-released study in JAMA, the Journal of the American Medical Association, postmenopausal women who applied nitroglycerin ointment at bedtime for two years had modestly increased bone mineral density as well as less bone loss.

The two-year study involved 243 women with an average age of about 64 who didn't have osteoporosis. The volunteers were randomized to either apply 15 milligrams of nitroglycerin ointment to their upper arm at bedtime or a placebo cream.

The study found that compared to the women who were taking placebo. the women who took the nitroglycerin ointment had:

• a 6.7 per cent increase in bone density in the spine
• a 6.2 per cent increase in the hip
• a 7 per cent increase at the top of the thigh bone

The women also had an improvement in bone geometry and bone structure, as well as an increase in the bone formation, and a decrease in the bone breakdown.

"Together, these findings suggest that nitroglycerin may significantly decrease the risk of fractures, including fractures in long bones, such as the hip, legs, and upper arm," write the authors, who were led by Dr. Sophie Jamal, of the Women's College Research Institute and University of Toronto.

Participant Edith George said another reason to be buoyed by the study's finding is the cost: treatment with nitroglycerin is inexpensive, costing only about 5 cents per day.

"As I was told (that) I realized this is something that can be used for people with this horrific disease in third world countries," George told CTV News late last year.

It's not clear why nitroglycerin might be effective at preventing bone loss but it could relate to its effect on nitric oxide. Bone cells make nitric oxide but after women go through menopause, they have less estrogen and make less nitric oxide. The nitroglycerin cream may help to replace the chemical.

The authors note that the treatment had one clear side effect: headaches. Many of the volunteers complained of headache which caused some to drop out of the study. (Nitroglycerin can also cause headaches in patients taking it in pill form for angina.)

A full 35 per cent of participants complained of headaches in the first month of treatment compared to 5.4 per cent in the placebo group. Over time, the headaches in the treated women lessened.

As many as two million Canadians have osteoporosis, including about one in four women over the age of 50 and one in eight men. Common treatments can lead to a variety of unpleasant side-effects. For instance, bisphosphonates can lead to nausea and stomach discomfort and have been linked to a rare form of thigh bone fracture.

The Canadian research team say they are working on larger studies on the treatment, collaborating with researchers in the United Kingdom and the United States.