20 Desember, 2009

About your BMI

For years, you've used 2 numbers to manage your weight — the fluctuating one on your bathroom scale and the one on the tag of your favorite pair of jeans.

And then there's the body mass index (BMI). Although much emphasis has been put on this number, the question is: How meaningful is it, really?

The truth is, BMI — a statistical measure of the relationship between a person's weight and height — is useful when generalizing about groups of people. It has been used to classify people as underweight, normal weight, overweight and obese.

An adult with a BMI between 18.5 and 24.9 is considered within the normal range, according to the National Institutes of Health (NIH) in Bethesda, Md.

The NIH says a BMI between 25 and 29.9 is considered overweight, and a BMI of 30 and above is considered obese. (Calculate your BMI here. You'll need to know your height and weight.)

Generally speaking, groups of people with BMIs of 25 and above face a higher risk of serious health problems such as type 2 diabetes, cardiovascular disease, certain cancers and many other conditions. Risks are compounded as BMI increases.

But this number is not always accurate when applied to individuals, especially athletes, children, people who have lost muscle mass and the elderly. The biggest criticism of BMI is this: It fails to distinguish between muscle and fat. What's more, it doesn't measure body fat.

"BMI is a way of estimating your density," but it doesn't consider how your body's put together," says Stephen G. Rice, M.D., Ph.D., director of the Jersey Shore Sports Medicine Center in Neptune, N.J. "If you had huge muscles, you'd weigh more since muscles are dense," he says. Therefore, it's important to look at a person rather than just at his or her BMI number.

"Muscle is 15% heavier than fat," says Robert Girandola, Ph.D., an associate professor of kinesiology at the University of Southern California (USC) and a nutrition and obesity expert. "So if you do resistance training and are very active in sports, it's possible your BMI may be high while your body fat is low."

Therefore, based solely on his BMI, a muscular athlete like Arnold Schwarzenegger in his prime would be defined as obese.

Looking just at BMI is problematic for another group as well — postmenopausal women who lose muscle mass as they age. In those cases, a low BMI may underestimate a woman's body fat. "I have a patient whose BMI is 23" — well within the normal range, says Zhaoping Li, M.D., an associate professor of clinical medicine at the University of California, Los Angeles Center for Human Nutrition and its director for clinical research.

"But her body fat may be 39 [%]. She has no muscle." For women, the average body-fat percentage — remember, that's a different measure from BMI — is 25% to 31%. Thirty-two percent and higher is considered obese.

BMI also fails to consider where fat is deposited, which determines whether someone's body shape is identified as an apple or a pear. Generally, apples — those with excess abdominal fat — are more at risk for obesity- and heart-related health problems than those who are pear-shaped. Conversely, people who carry their fat on their thighs and buttocks have a lower incidence of health risks.

Ethnicity also must be taken into account. For instance, when compared with whites, Asians have lower BMIs but higher percentages of body fat, according to The American Journal of Clinical Nutrition. This means that Asians may be considered overweight with a BMI over 22.9

A better measure of fat

"We need some way of measuring body fat independent of BMI," Rice says. "The number alone without context is just a number." He points to more accurate tests of body composition like being weighed underwater and using calipers to measure skin fold thickness on various parts of the body.

Rather than simply estimating health risks related to body weight and shape, there is a simpler calculation that combines 2 easy-to-get numbers.

"For adults, a better tool is a combination of BMI and waist circumference," says Michael L.Goran, Ph.D., a professor of preventive medicine, physiology and biophysics at USC's Keck School of Medicine and associate director at its Institute for Health Promotion and Disease Prevention Research.

According to the Mayo Clinic's guidelines, women's waist measurements should be less than 35 inches, while men's should be less than 40 inches. If these figures are combined with BMI, together they can be a more accurate predictor of disease risk.

Taking action

To get a more accurate picture of your disease risk than BMI alone, follow these steps:

  • Measure the circumference of your waist at its widest part with your belly relaxed.
  • Use the 2 figures of BMI and waist circumference to find a more accurate estimation of your disease risk by consulting the chart created by the National Heart, Lung and Blood Institute, a part of NIH. According to the chart, a man considered "overweight" by virtue of a BMI between 25 and 29.9 and a waist size of 38 inches is at "increased" risk of disease. But if the same man's waist is 40 inches, he moves into the "high" risk group.

Reviwed by: Stacy Beller Stryer, M.D.

25 November, 2009

Breast Cancer, Metastatic or Recurrent

What are metastatic and recurrent breast cancer?

Monalisa Health-Breast cancer occurs when abnormal cells grow out of control in one or both breasts. Treatment often cures breast cancer if it is found before it has spread.

But even after treatment that seemed to work, cancer can come back (recur) or spread (metastasize) to other parts of the body. Cancer that comes back in or near the original site is called locally recurrent breast cancer. Cancer that spreads to other parts of the body is called metastatic breast cancer.

For most women who have had breast cancer, their greatest fear is that the cancer will come back or spread. Finding out this has happened can turn your world upside down. But there is hope. Treatment can often cure recurrent breast cancer. Although metastatic breast cancer usually cannot be cured, treatment can help you manage the disease and live longer. Some women live for many years, managing their cancer like a long-term health problem.

Why does breast cancer come back after treatment?

Even with the best treatment, cancer can come back. If just a small cluster of cancer cells remains in your body, those cells can spread through the blood or lymph system and grow. This may happen from a few months to many years after the first diagnosis.

If your breast cancer has come back, you may be tempted to second-guess your previous treatment choices. But the fact is, there is no guarantee with any treatment.

The treatment decisions you and your doctor made in the past were the right ones at that time. But now it is time to make new decisions and explore other treatment options.

What are the symptoms?

The symptoms depend on where the cancer is and how large it is. The most common places for breast cancer to spread are within the breast or to the nearby chest wall or to the liver, lungs, or bones. Common symptoms include a lump in your breast or on your chest wall, bone pain, or shortness of breath.

You may not have any symptoms. Sometimes recurrent or metastatic breast cancer is found with an X-ray or lab test.

How is it treated?

To plan your treatment, your doctor will consider where the cancer is and what type of treatment you had in the past. Your wishes and quality of life are also important factors. Treatment choices may include surgery, medicines like chemotherapy or hormone therapy, and radiation. Sometimes a mix of these treatments is used.

Treatments for breast cancer can cause side effects. Your doctor can tell you what problems to expect and help you find ways to manage them.

Clinical trials to test new cancer treatments are going on all the time. Ask your doctor if it would be a good idea to take part in one of these studies.

If treatments have not worked, a time may come when your goal shifts from curing the disease to staying as comfortable as you can. Palliative care can provide symptom relief and support for you and your loved ones so you can make the most of the time you have left.

How can you handle your feelings about having breast cancer again?

It is common to have a wide range of emotions. It may be hard to stay hopeful when you are fighting cancer for the second or third time. These ideas may help.

  • Get the support you need. Spend time with people who care about you, and let them help you. Talk to your hospital social worker if you need help with bills or other worries. Your local American Cancer Society may also be helpful.
  • Take good care of yourself. Get plenty of rest. Eat healthy meals. Get regular exercise. Try meditation or guided imagery to help you relax. These steps can help you feel as well and stay as healthy as you can.
  • Talk about your feelings. Find a support group. Talking with other people who have breast cancer can be a big help. Sharing your experience can help others too.
  • Do everything you can to stay positive. Set a goal each day to do something special for yourself or someone else.

If your emotions are too much to handle, be sure to tell your doctor. You may be able to get counseling or other types of help.

You may want to think about planning for the future. A living will lets doctors know what type of life-support measures you want if your health gets much worse. You can also choose a health care agent to make decisions in case you are not able to. It can be comforting to know that you will get the type of care you want.

 

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