To Your Health
News from the Nurses' Health Studies: Preventing Osteoporosis

by Paulette Avery, RN, MSN

Together, Nurses' Health Study and Nurses' Health Study II, with over 200,000 participants, constitute the largest and longest-running studies of women's health in the world. I've been a member of the Nurses' Health Study II since its beginning in 1989, and this month I'll share with you some of the information from a recent study newsletter.

The primary article in the newsletter deals with preventing osteoporosis. One of the benefits of taking hormone replacement therapy (HRT) is protection against osteoporosis. But with the increased health risks related to stroke, heart disease, and cancer now known to result from HRT use, it is vital that we know other ways to protect ourselves from the debilitating bone loss of osteoporosis. And in case any of you men are about to stop reading now, you should know that although less common in men, osteoporosis can affect you as well.

According to the article, adopting three lifestyle choices, namely physical activity, a healthy diet, and not smoking, "can offer as much protection against fractures as hormones do, with the added benefit of improving overall health." Physical activity works because it "forces the bone tissue to absorb calcium and become stronger." Additionally, the exercise benefits you by improving flexibility, muscle strength, and balance. All of that makes it less likely that you will fall and break a bone.

So what kind of exercise is best? You can do weight training or vigorous exercise, as both have been shown to be beneficial for bone strength. But results from the Nurses' Health Study (NHS) found that walking is also helpful. Women who walked four hours a week had a 40 percent lower risk of hip fractures. Walking for at least eight hours a week (or doing a similar activity for the same amount of time) gives postmenopausal women "the same level of protection against fractures as hormones did, while also lowering the risk of heart disease, diabetes, and stroke."

As for diet, the jury is still out on the effectiveness of dietary calcium intake and supplements. To date, "Most long-term studies have shown no link between [calcium-rich] foods and fracture risk." The NHS found women who drank two glasses of milk a day were just as likely to get a fracture as those who drank it only once a week. Calcium supplements appear to slightly increase bone mass, but studies have not yet looked at whether that increase is enough to prevent fractures. For now the National Academy of Sciences still recommends calcium intake either through diet or supplements in the following amounts: 1,000 milligrams a day for women aged 19-50, and 1,200 milligrams a day for women over 50.

NHS results indicate that postmenopausal women who take 500 IU daily of vitamin D have 40 percent fewer fractures. You can take a supplement, but also consider safe sun exposure as discussed in the May "To Your Health" column. One hundred micrograms (mcg) daily of vitamin K has also been found protective, producing a 30 percent reduction in the risk of hip fracture. And vitamin K is easily obtained through eating. You'll get about 70 mcg by eating a cup of lettuce and 300 mcg from a cup of broccoli.

When it comes to smoking, don't! If you do smoke, here's one more reason to quit. For women who no longer smoke, the 30 percent increased risk of fracture found in smokers drops within about ten years to that of women who have never smoked.

Besides helping you to prevent osteoporosis, getting regular exercise, eating well, and not smoking will also help protect you from many other chronic diseases.

Paulette Avery is a registered nurse and a freelance writer who specializes in health issues.