Health

People who quit smoking are at high risk of developing type 2 diabetes after they kick the habit, most likely due to post-quitting weight gain, a new study has found.

Experts caution, however, that the benefits of quitting smoking—including a lower risk of heart attack and lung cancer—far outweigh the risk of developing diabetes, which can be treated with diet, exercise, and medication.

The study, which was published today in the Annals of Internal Medicine, followed nearly 11,000 middle-aged people without diabetes—45% of whom were smokers—over a nine-year period. Compared to those who had never smoked, the people who quit smoking during the study had a 73% increased risk of developing type 2 diabetes three years after quitting.

The spike in diabetes risk that the researchers observed is most likely due to the extra pounds that many ex-smokers pack on after giving up cigarettes, Yeh and her colleagues note. Weight gain is a major risk factor for type 2 diabetes, and it's also one of the most common side effects of smoking cessation.

The people in the study who quit smoking gained an average of 8.4 pounds, which is in the normal range (most ex-smokers gain about 4 to 10 pounds), and those who gained the most weight showed the greatest risk for developing diabetes. The waistlines of the ex-smokers in the study also grew by an average of 1.25 inches; abdominal fat is another risk factor for diabetes.

“Quitting smoking is good," says Yeh. "[But] after quitting you should pay additional attention to weight control.”

Next Page: How to fight weight gain after quitting [ pagebreak ]
To counteract the increased risk of diabetes, people who quit smoking should implement a series of lifestyle changes in consultation with their physicians, Yeh says.

Richard D. Hurt, MD, director of the Nicotine Dependence Center at the Mayo Clinic in Rochester, Minn., recommends that people who quit smoking stick to small portions of low-fat, low-calorie foods. They should also get moving, he adds.

“Even just moderate exercise—like 30 minutes of brisk walking—reduces the urges to smoke and reduces withdrawal symptoms," he says. "People are able to distract themselves, it makes them feel better, and it uses up some of the calories."

Nicotine-replacement products may also be helpful, says Dr. Hurt, since nicotine is largely responsible for the appetite-suppressing effect of cigarettes. Nicotine patches or gum deliver nicotine much more slowly than a cigarette, however, so to suppress appetite and prevent weight gain they may need to be administered in above-average doses, says Dr. Hurt, who was not involved in the new study.

If they are taken for at least three to six months, smoking cessation drugs such as bupropion, an atypical antidepressant sold as Zyban or Wellbutrin, may also limit weight gain, Dr. Hurt says.

In addition to recommending lifestyle changes, Yeh and her colleagues also suggest that physicians keep an eye on the blood glucose levels of patients who quit smoking, as elevated glucose levels can be a warning sign for type 2 diabetes. “You should probably do more frequent glucose testing after quitting for early detection,” she says.

Despite her study's findings, Yeh is quick to emphasize that quitting smoking—or better yet, never starting in the first place—is far healthier than continuing to smoke, which can cause a host of deadly health problems ranging from heart disease to lung cancer.

Dr. Hurt agrees. “Type 2 diabetes is associated with smoking to begin with; this study found theres a 30% increased risk if youre a smoker compared to nonsmokers,” he points out. “Stopping smoking increases that risk, but its way offset by the other health gains.”

For people with milder cases of depression, fake pills may be just as effective as antidepressant drugs, a new study suggests.

The study confirmed that antidepressants are substantially better than fake pills, or placebo, in people with severe depression, but the researchers found "little evidence" that the drugs are more effective than placebo in people with milder depressive symptoms.

The findings don't mean that antidepressants dont work—only that most of the drugs' effectiveness in people with milder depression can be attributed to the placebo effect.

The implications of the study for the everyday treatment of depression may be limited, however, because the researchers looked at just two antidepressants, paroxetine (Paxil) and imipramine (Tofranil), an older antidepressant known as a tricyclic. Newer and more potent antidepressants might have produced a different result, says David Hellerstein, MD, a research psychiatrist at the New York State Psychiatric Institute in New York City who specializes in treating chronic, low-grade depression.

People on antidepressants should not stop taking them based on these new findings, Dr. Hellerstein adds. "Dont do anything rash, and talk to your doctor if you think this is relevant to you,” he says.

The study, a new analysis of data from previously conducted clinical trials, was led by Jay Fournier at the University of Pennsylvania and was published in the Jan. 6 issue of the Journal of the American Medical Association.

Fournier and his colleagues looked at 2,164 clinical trials of antidepressants in all, but they ultimately excluded all but six from their analysis for a variety of reasons—because they weren't placebo-controlled or were shorter than six weeks long, for instance.

The researchers found that, on average, the benefits of antidepressants over placebo were “minimal or nonexistent" in people whose depression was less than "very severe" according to American Psychiatric Association guidelines. Even people with "severe" depression—which is one step below “very severe”—did not experience a significant effect from antidepressants compared to placebo, the study reports.

“Its a very well done paper in a top journal, and theyre raising a serious question,” says Dr. Hellerstein. But, he says, the findings aren't comprehensive enough to indicate whether doctors should continue to prescribe antidepressants to people with mild or moderate depressive symptoms.

Next Page: Not the final word on treatment [ pagebreak ]
The drugs included in the study are rarely used as first-line treatments today, Dr. Hellerstein says, and two of the imipramine studies included in the analysis used a low dose. In addition, he says, the longest study Fournier and his team included lasted 11 weeks; some drugs take longer than that to produce their full effect, whereas the placebo effect is strongest in the first few weeks of treatment.

Both Dr. Hellerstein and Fournier also point out that the patients in the placebo arm of the studies received attention and care in addition to a fake pill. They were assessed regularly, talked about their symptoms with a professional, and received physical and psychiatric exams—all of which could have been therapeutic for people who may have been isolated, suffering in silence, or dragging themselves to work every day.

“It seems like that, in and of itself, provided some benefit for people,” Fournier says.

Fournier agrees with Dr. Hellerstein that the findings are not conclusive regarding the treatment for mild to moderate depression. “In terms of moving forward, its hard to say what the treatment should be," he says.

For his part, Dr. Hellerstein says that, although it's too early to conclude that antidepressants wont help a person whose symptoms fall below a certain threshold of severity, the new findings do suggest that psychotherapy may be more appropriate than antidepressants for people with mild depression that hasnt lasted a long time. “Its a valid question that a patient should bring to their doctors office,” he says.

In 2005, the most recent year for which statistics are available, 170 million prescriptions for antidepressants were filled in the United States, according to the U.S. Department of Health & Human Services.

Previous studies have reported that antidepressants are more likely to outperform placebo in patients who are more depressed when they begin treatment. But as Fournier and his colleagues note, these analyses examined only patients with "severe" depression or worse.

The published data on the efficacy of antidepressants in people with mild to moderate depression is limited—partly by design, according to the study.

Because people with mild to moderate depression tend to respond more readily to placebo, many antidepressant trials exclude these patients in order to minimize the placebo response rate, the study says.

Moreover, Fournier and his colleagues write, in some antidepressant trials prospective participants are given a placebo for several days or more before the trial officially begins. If they improve substantially on the placebo during this "washout period," they are excluded from the trial. Excluding people who have shown that they respond to placebo, the authors explain, may disguise the true extent of the placebo effect in the published study.