Do you know what threatens your life the most?

Below are the top causes of death for women in the United States, starting with the most common. Take this opportunity to learn about each health concern and how you can reduce your risks. What you learn may surprise you.

Surprised? Many women are. It's common to think breast cancer is the No. 1 threat to women's health when, in fact, heart disease is responsible for more deaths in women than all forms of cancer combined. Heart disease is the most significant health concern for women in the United States today, responsible for almost 366,000 deaths each year.

The common belief that heart disease affects mostly men is a dangerous myth. In reality, more women than men die of heart disease in the United States each year. But according to the American Heart Association, only 8 percent of women know that heart disease is a major threat to their health.

The good news is that heart disease is one of the most preventable health conditions. You have the power to reduce some of your risks:

• Avoid smoking and limit alcohol.
• Eat a diet rich in fruits, vegetables and grain products.
• Exercise regularly.
• Control other health conditions that may put a strain on your heart, such as high blood pressure, diabetes and high cholesterol.

If you're at special risk of heart disease, your doctor also may suggest a daily low dose of aspirin.

It's easy to believe cancer is a major threat to women's health, but the kinds of cancer women are dying of might surprise you. According to the American Cancer Society (ACS), the most common cause of cancer death in U.S. women is lung cancer. It's estimated that nearly 66,000 women in the United States died of lung cancer in 2002, with 90 percent of these deaths linked to cigarette smoking.

Breast cancer is the second-leading cause of cancer death in U.S. women, and it's estimated that more than 203,000 women were diagnosed with breast cancer in 2002. The ACS estimates that about 40,000 women die each year of breast cancer.

The third-leading cause of cancer death for women in the United States is colorectal cancer. Like heart disease, colorectal cancer is often mistakenly thought of as a man's disease, but more women than men die of colorectal cancer each year. Estimates suggest that it claims the lives of approximately 28,000 women in the United States annually.

At least one-third of all cancer deaths are related to nutrition and other controllable lifestyle factors. Do all you can to reduce your risks:

• Don't smoke or chew tobacco.
• Exercise regularly.
• Eat a healthy diet.
• Avoid excessive sun exposure.
• Limit alcohol.
• Have regular preventive health screenings.

• Know your family medical history and review it with your doctor.

About 167,000 people in the United States die of stroke each year, and almost two-thirds of them are women. Stroke not only is women's No. 3 killer but also is one of the leading causes of disability in America.

Smoking and uncontrolled high blood pressure are important risk factors for stroke. Although stroke is highly preventable, certain risk factors such as family history, age, sex and race cannot be controlled. Even if you're at increased risk of stroke, you can still take steps to prevent it:

• Don't smoke.
• Control your blood pressure.
• Lower your cholesterol.
• Limit saturated fats.
• Exercise regularly.

COPD is an overall term for a group of chronic lung conditions, including bronchitis and emphysema. The main cause of COPD is smoking, and it's strongly associated with lung cancer, the No. 1 cause of cancer death in women.

About 62,000 women in the United States die of COPD each year. The quality of life for a person with COPD diminishes as the disease progresses. Shortness of breath and activity limitations develop, and you may eventually require an oxygen tank or even mechanical respiratory assistance to breathe.

How do you reduce your risks of dying of COPD? This one's easy: Don't smoke, and avoid secondhand smoke.

Diabetes, a group of diseases that affect the way your body uses blood sugar (glucose), is a serious health condition that affects more than 17 million Americans. In 2000 it claimed the lives of almost 69,000 people in the United States, and more than half of them were women.

It's estimated that 5 million Americans don't know they have diabetes. Many people become aware of it only when they develop one of its life-threatening complications. Advanced diabetes can cause blindness, kidney disease and severe nerve damage. People with diabetes are also two to four times more likely to have heart disease and suffer from stroke.

The most common type of diabetes is type 2 diabetes (formerly called adult-onset or noninsulin-dependent diabetes). This type of diabetes, generally developing after age 40, can be prevented. Follow these steps to reduce your risk:

• Maintain a healthy weight.
• Eat a healthy diet.
• Exercise regularly.
• Get your fasting blood sugar level checked periodically.

Pneumonia and influenza combined are the sixth-leading cause of death for women in the United States today. Together they took the lives of more than 36,000 women in 2000.

When associated with other chronic health conditions, pneumonia and influenza can be life-threatening. People with COPD, asthma, heart disease, diabetes and conditions that suppress the immune system are at high risk. Because both pneumonia and influenza affect the lungs, smoking increases the danger of these two diseases.

The risk of both pneumonia and influenza can be reduced by immunizations. A yearly flu shot can be up to 90-percent effective in preventing influenza in healthy adults. The pneumococcal vaccine can reduce the risk of getting pneumonia by 60 percent to 70 percent. Stay healthy — get those shots.

Alzheimer's disease — which affects almost 4 million Americans — is a progressive, degenerative brain disease that goes beyond simple forgetfulness. What may start as slight memory loss and confusion may eventually lead to irreversible mental impairment.

More women than men have Alzheimer's. In fact, about 35,000 women die of Alzheimer's disease each year — more than twice the number of men. One reason women may be more affected is that women generally live longer, and the risk of Alzheimer's increases with age.

Current treatments focus on stabilizing the symptoms, improving well-being and easing caregiver burden.

Each year, about 34,000 women die from accidents (unintentional injuries). Although the statistics on accidental death are unclear, these top health threats for women may surprise you:

• Motor vehicle accidents. Traffic-related accidents were responsible for 40 percent of all accidental deaths for women in 2000. You can reduce your chances of a fatal crash by routinely using your seat belt, keeping your speed down and not driving while sleepy or under the influence of drugs or alcohol.

• Falls. One out of every three people over age 75 falls each year, and about 6,200 women in the United States die from such falls. Most falls — 75 percent — occur in the home, so making some common-sense changes can help prevent falls and their potentially debilitating consequences. Getting regular eye exams, exercising regularly and improving your balance also can help reduce your risk.

Leading a healthy lifestyle, getting regular checkups and paying attention to your environment can help you reduce your risk factors for many of these conditions.