The National Institutes of Health already recommends regular physical activity for preventing diseases such as heart disease, type 2 diabetes and high blood pressure, as well as for losing or controlling weight. Now, a study supported by NIH’s National Heart, Lung, and Blood Institute (NHLBI) and the National Cancer Institute (NCI) adds a new benefit to the list. Moderate physical exercise such as brisk walking can substantially reduce the risk of stroke in women. The more women exercise, the lower their chances of having a stroke.

To arrive at their conclusion, scientists from the Harvard School of Public Health studied the medical records and physical activity questionnaires of 72,488 women between the ages of 40 and 65 who were participating in the long-term Nurses’ Health Study. The scientists found that the women who were more physically active tended to be leaner and were less likely to smoke. However, after adjusting for body weight, smoking habits, and fruit and vegetable intake, the researchers found that more physical activity was associated with less stroke.

Walking, already the most popular form of physical activity among middle-aged and older women, was extremely effective in cutting the risk of stroke. A three and a half hour per week increase in moderate physical activity like brisk walking led to a 19% reduction in total stroke and a 29% decrease in ischemic stroke, which results when the blood supply to part of the brain is suddenly interrupted.

An important finding of the study is that sedentary women who became active later in life were able to reduce their risk of stroke as well. The conclusion: it’s never too late to benefit from exercise. — by Harrison Wein, Ph.D.
JAMA 283,22:2961-2967

For more information about stroke, visit the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Information Page at <http://www.ninds.nih.gov/health_and_medical/disorders/stroke.htm> and Brain Attack: Risk Factors for a Stroke at <http://www.ninds.nih.gov/health_and_medical/pubs/stroke_bookmark.htm>.
— a report from The NIH Word on Health, October 2000.

 
Cruciferous Veggies and Lung Cancer

Years ago, scientists observed that eating vegetables, particularly the cruciferous ones that include broccoli, cabbage and bok choy, reduces the risk of lung cancer, the most common cause of cancer deaths in the U.S. among both men and women. Now, a study supported by NIH’s National Institute of Environmental Health Sciences (NIEHS) and NCI gives a clearer, if somewhat complicated, picture of how these vegetables work their magic. Key to the findings is a group of molecules in the vegetables called isothiocyanates, along with two human genes called GSTM1 and GSTT1.

Isothiocyanates inhibit lung cancer in laboratory animals, but the connection had not yet been made in people. An NIEHS researcher collaborated with scientists at the American Health Foundation, the University of Southern California and the Shanghai Cancer Institute to look at 18,244 men in Shanghai, China, where isothiocyanate-rich vegetables are a major part of the diet. They looked at the eating and smoking habits of the men, who were between the ages of 45 and 64, between 1986 and 1989 and found 159 cases of lung cancer in follow-ups stretching to 1997. The scientists found that the men with detectable levels of isothiocyanates in their urine had a 36% lower risk of developing lung cancer.

The GSTM1 and GSTT1 genes code for enzymes that help eliminate cancer-causing compounds in cigarette smoke from the body. Men who were missing both of these genes and had no isothiocyanates in their urine had a higher risk of lung cancer. But these enzymes also help remove isothiocyanates from the body. The reduction in lung cancer risk associated with isothiocyanates in the urine turned out to be greatest in the men who were missing the GSTM1 and GSTT1 genes, presumably because the isothiocyanates were able to stay in the body longer.

Doubtless, there is a complex interplay between these genes and the isothiocyanates — and probably other, as yet unidentified, factors as well. However, this research provides the first direct evidence that isothiocyanates may help reduce the risk of lung cancer. Other research has found that eating broccoli, which is rich in isothiocyanates, can protect against colon polyps in people missing GSTM1, so this effect likely applies to more than just lung cancer. The benefits of eating vegetables may vary somewhat according to your genes, but one thing is certain: it can’t hurt to eat your vegetables, and it could do a lot of good. — by Harrison Wein, Ph.D.
The Lancet 356, 724-729

For more information about lung cancer, visit <http://cancernet.nci.nih.gov/wyntk_pubs/lung.htm> or call the Cancer Information Service (CIS) at 1–800–4–CANCER (1–800–422–6237) to speak with a Cancer Information Specialist.
— a report from The NIH Word on Health, October 2000.

 
Treating Post-Stroke Depression Can Help Memory and Attention Problems

People who suffer from depression after a stroke often also suffer from problems in cognitive abilities such as memory and attention. In the past, studies of anti-depressant medicines have failed to show any cognitive improvement in people after they had a stroke. But new research supported by the NIH’s National Institute of Mental Health (NIMH) has now clearly shown that people who recover from post-stroke depression also show improvements in cognition.

Researchers at the University of Iowa studied patients who experienced depression following a stroke. Half the patients were given an anti-depressant medicine, while the other half were given an inactive placebo; neither the patients nor their doctors knew which pill they received. About three-fourths of the patients given the medicine showed recovery from their depression, compared to about one-third of those who got the placebo. Those who recovered from depression — whether they received medicine or placebo — showed much larger improvements in memory and attention than patients whose depression did not lessen.

These results suggest that the cognitive impairments associated with a stroke can be improved by any treatment that helps lessen depression. Given the high success rates of current treatments for depression — 80 percent of people with depression can be effectively treated — this study shows that the identification and treatment of depression in those who have had a stroke may be an important way to improve their cognitive functioning. — this capsule was written by Bruce N. Cuthbert, Ph. D.
Stroke, 31:1482-1486

NIMH can be reached at <http://www.nimh.nih.gov>. Further information regarding depression may be found at <http://www.nimh.nih.gov/publicat/depressionmenu.cfm>.
— a report from The NIH Word on Health, October 2000.