Research Notebook

Moderate Physical Activity May Reduce Chronic Disease in Older Women

Regular, moderate-intensity exercise may be critically important for postmenopausal women who want to reduce their risk of cancer, heart disease and other diseases, a new study indicates.

Exercise effectively reduces intra-abdominal fat, a hidden risk factor for many chronic illnesses, according to researchers at the Fred Hutchinson Cancer Research Center in Seattle.

"Even if a woman who exercises regularly doesn't see the benefits of dramatic weight loss on her scale, our results indicate that she can feel confident that she is improving her health ... ," says Anne McTiernan, M.D., Ph.D., director of Fred Hutchinson's Prevention Center, and lead author of the study.

Intra-abdominal, or visceral, fat increases the risk for diabetes and cardiovascular disease. The fat also can raise insulin levels, which promotes the growth of cancer cells.

People with high levels of intra-abdominal fat may not even know it, McTiernan says, because it is hidden, deposited around organs within the abdomen. "Most women don't know about intra-abdominal fat, but they should, since it is the most clinically significant type of fat and it's where women tend to store fat after menopause."

The only accurate way to determine the presence of intra-abdominal fat is with imaging procedures such as CT or MRI scans. Little data exists on intra-abdominal obesity because the procedures are so costly, McTiernan says.

The yearlong study involved more than 170 previously sedentary, overweight, postmenopausal Seattle area women. None took hormones to treat menopausal symptoms. Half were randomly assigned to a moderate-intensity aerobic exercise group, and half attended a weekly hourlong stretching class.

At the end of the study, the exercisers had lost between 3.4 percent and 6.9 percent of their intra-abdominal fat. Women who worked out most frequently experienced the largest decreases in weight and intra-abdominal fat. Women in the stretching group, in contrast, experienced a slight gain in intra-abdominal fat.

"This study gives us direct evidence that exercise can affect biology related to cancer and other chronic diseases in older women," McTiernan says.

The study, funded by the National Cancer Institute, is the largest randomized clinical trial to assess the effect of exercise on overall and intra-abdominal obesity in postmenopausal women. The results are published in the Jan. 15, 2003, issue of the Journal of the American Medical Association.

CDC: Annual Flu Deaths Higher Than Previously Estimated

The number of people who die each year in the United States from influenza is significantly higher than previously thought, according to the Centers for Disease Control and Prevention (CDC).

Using new and improved statistical models, CDC scientists estimate that an average of 36,000 people (up from 20,000 in previous estimates) die from influenza-related complications annually.

In addition, about 11,000 people die each year from respiratory syncytial virus (RSV), a virus that causes upper and lower respiratory tract infections primarily in young children and older adults. The CDC study, published in the Jan. 8, 2003, issue of the Journal of the American Medical Association, found that most deaths caused by RSV occur in Americans ages 65 and older.

"We've known for some time that influenza and RSV have a profound impact on public health," says CDC Director Julie Gerberding, M.D., M.P.H. "However, these data indicate that the magnitude of the problem is larger than we once thought."

CDC researchers believe that the increase can be explained in part by the aging of the U.S. population. Over the past several decades, the number of people ages 85 and older has doubled. Also, the most virulent of influenza viruses in recent years, influenza A (H3N2), has been the most common strain circulating during the last decade.

Vaccinating those at greatest risk of serious complications from influenza will continue to be the primary strategy for preventing influenza-associated deaths. A new policy allows nursing homes, hospitals, and home health-care providers serving Medicare and Medicaid beneficiaries to remind patients about the benefits of annual vaccinations.

"More high-risk people than ever before are getting their flu shots and that is certainly good news," Gerberding says. "However, it is crucial that we continue to get the message out regarding the importance of high-risk people getting their flu shots each and every year."

The study also points out the need for research into better influenza vaccines that are more protective in those over 65 and into RSV vaccines that are effective in both young children and older people, the CDC says.

Study: No Link Between Folic Acid and Twins

Results from a study involving almost a quarter of a million women in China show that taking folic acid to reduce the risk of neural tube birth defects does not increase a woman's chances of giving birth to twins. The study, which appears in the Feb. 1, 2003, issue of the British journal The Lancet, was conducted by the Centers for Disease Control and Prevention (CDC) and the Peking University Health Sciences Center in China.

Studies conducted during the past several decades have shown the consumption of folic acid before conception and during pregnancy can reduce the incidence of spina bifida and other neural tube defects. However, the results of some earlier, smaller studies raised the question of whether an increase in multiple births can be associated with the consumption during pregnancy of vitamin supplements containing folic acid.

This is the first scientific study of its kind done on a large population of young women with accurate records of their folic acid use before conception and during the early months of pregnancy. Twin pregnancies often result in premature birth, leading to complications and long-term health problems for the children.

"This is good news for women in the United States, in China, and around the world," says José Cordero, M.D., director of the CDC's National Center on Birth Defects and Developmental Disabilities. "Taking folic acid before and during early pregnancy to prevent some serious birth defects in their babies should not increase a woman's chances of having a twin pregnancy."

Among the more than 240,000 women in the study, there was no difference in the rates of twin births for women who took a folic acid pill daily and those who did not take any.

Since the Public Health Service's 1992 recommendation urging women to increase their levels of folic acid prior to becoming pregnant, the incidence of spina bifida has been reduced by 32 percent in the United States.