Quotes of the Day

Brittle bones can be more than just a bother for anyone who is getting on in years. About 10 million Americans have osteoporosis — a gradual thinning of the bones — and 1.5 million of them will suffer a fracture this year. That's why doctors were so interested in a pair of studies published in the New England Journal of Medicine last week on the relationship between osteoporosis and a common amino acid called homocysteine. Not only do the reports suggest an easy way to determine early on who is most vulnerable to osteoporosis, but they also hint at a totally new way to treat it.

One study, led by Robert McLean at the Hebrew Rehabilitation Center for the Aged in Massachusetts, found that men with the highest homocysteine levels were four times as likely to develop hip fractures as men with the lowest levels. The second study, from researchers at Erasmus University in the Netherlands, found that men and women with the highest levels of homocysteine had twice the risk of suffering a fracture compared with those with the lowest levels.

It turns out that doctors already know quite a bit about homocysteine. Since an elevated level of it has been linked to a greater risk of heart disease, many Americans are already getting their homocysteine regularly tested. Doctors also know how to treat high homocysteine levels using supplements of folic acid and other B vitamins.

But don't start popping those vitamin pills just yet. It's still not clear whether homocysteine actually causes bone loss (although there are hints that it may prevent key building blocks of bone from bonding together). And that means that doctors don't know for sure whether lowering your homocysteine level can actually reduce your chances of getting a hip fracture. They also don't yet know how much folic acid and vitamin B are needed to protect bone.

Meanwhile, you have other options for keeping your bones strong. Exercising with weights and making sure you have enough calcium and vitamin D in your diet are good ways to start. Estrogen, which used to be prescribed to postmenopausal women in part to prevent osteoporosis, is no longer recommended because it carries too high a risk of breast cancer. And there are other drug treatments available that are safe and effective.

• Alice Park