Outlook: Obesity Epidemic

Ms. Farley is a freelance medical writer based in Wakefield, Rhode Island.

More Bad News for Overweight and Obese People

The American Cancer Society reported that last year cancer killed 7.6 million people worldwide. According to The Lancet, individuals who are overweight face an increased threat of developing cancer?in addition to the already established link to heart disease. Although the level of cancer risk may depend on gender and ethnicity, carrying too much weight has been associated with both common and rare malignant tumors. Specifically, research has produced evidence that excessive weight is linked to colon cancer and breast cancer, as well as tumors in the kidneys, esophagus, thyroid, uterus, and gallbladder. Although evidence does not support cause and effect between obesity and cancer, it does support a considerable link.

Researchers from the University of Manchester and Christie Hospital National Health Service Foundation Trust in England determined that a higher body mass index increased cancer risk in men as follows:

• Esophageal tumor?52%
• Thyroid cancer?33%
• Colon and kidney tumors?24% Obesity also was linked to rectal cancer and malignant melanoma in this patient population.

In women, the increased risk was assessed as follows:

• Endometrial tumor?59%
• Gallbladder cancer?59%
• Esophageal tumor?51%
• Kidney cancer?34%

Obesity in women also was associated with an increased risk of postmenopausal breast cancer, as well as pancreatic, thyroid, and colon cancer.

Asthma Symptoms Persistent, Continuous in Obese Patients

A study published in the January 2008 issue of Thorax suggests that obesity can make asthma symptoms worse. It has already been shown that obese people have a higher risk of developing asthma; this study demonstrates that their symptoms are more persistent and more severe, leading to more absenteeism from work. The study group included more than 3000 adults with asthma; one third of the group was obese. When compared with normal-weight adults with asthma, the obese group was 66% more likely to report continuous asthma symptoms, and 42% were more likely to have what is classified as severe persistent asthma. Although researchers were unable to prove that obesity alone makes asthma symptoms worse, their results showed enough of a correlation between obesity and asthma symptoms to recommend weight control as a "fundamental part of asthma management."

New Obesity Drug on the Horizon

A new weight loss drug developed by Merck & Co Inc, known as taranabant, has been shown to suppress food intake and increase metabolism; it is not without its drawbacks, however, as adverse effects include gastrointestinal (GI) distress and psychiatric problems. Targeting the same triggers that cause marijuana smokers to get hungry, this drug will block the same pleasure centers in the brain, known as cannabinoid receptors, but will cause people to feel less hungry. Taranabant, which is in the same class of drugs as rimonabant (Acomplia), prompted concern when some users reported suicidal ideation. A new study yielded no such suicidal thoughts among users, however. The study included 533 obese patients who took placebo or taranabant in 0.5-, 2-, 4-, or 6-mg daily doses. The placebo group lost 2.6 lb during the 12-week study period, whereas the 6-mg/day group lost 11 lb in the same period of time.

It is important to note that higher doses meant an increase in side effects (eg, more than 53% of those in the 6-mg group reported GI problems, such as diarrhea, nausea, frequent bowel movements, and vomiting). In addition, 27% of the same group reported psychiatric effects, such as anxiety, mood swings, depression, insomnia, irritability, or nervousness.

In another study of 36 overweight or obese people for 24 hours, researchers uncovered the following data on different doses of taranabant, a high dose of sibutramine (Meridia), and placebo, and how they reduced caloric intake.

Drug

Reduction of Food Intake (% of calories)

Placebo

?

4 mg taranabant

1%

12 mg taranabant

22%

30 mg sibutramine

12%

By taking the 12-mg dose of taranabant, a person's 2000-calorie/day intake could be reduced to 1600 calories/day On behalf of the Obesity Society, Steven R. Smith, MD, associate director of clinical research at Pennington Biomedical Research Center in Baton Rouge, Louisiana, noted that, if this class of obesity drug was to make it to market, it would "need to be reserved for people who have complications related to their obesity, such as type 2 diabetes, high blood pressure, or severe osteoarthritis." He added that taranabant would be best for those with a body mass index of >30.

New Treatment Approach: Pinpoint Cause of Overeating

Scientists have found the area of the brain that they believe controls the desire to overeat. At the Brookhaven National Laboratory, magnetic resonance images were reviewed to see how the brain responds when satiety messages are transmitted from the stomach at various stages of fullness. What they observed was activity in different areas of the brain in normal-weight and in overweight people. In overweight people, at the point of fullness, the left posterior amygdala had less activation. Overweight people also were not likely to report feeling full, despite having eaten a moderately sized meal. These findings offer researchers a path to follow when developing new treatment strategies. The study was published in the February 2008 issue of NeuroImage.