CHICAGO—Exercising longer or with greater intensity will not significantly increase the amount of weight lost for women who are dieting and exercising, according to an article in the September 10 issue of The Journal of the American Medical Association (JAMA), a theme issue on medical education.

According to background information in the article, an estimated 60 to 65 percent of adults in the United States are overweight. Exercise is an important component of interventions targeting overweight and obese adults, and is important for improving short-term weight loss when combined with changes in dietary intake; and is one of the best predictors of long-term weight loss. However, the optimal amount of exercise necessary to enhance long-term weight loss has not been established. But it has been believed that a higher dose and intensity of exercise may improve long-term weight loss.

John M. Jakicic, Ph.D., of the University of Pittsburgh, Physical Activity and Weight Management Research Center, Pittsburgh, and colleagues examined the effect of exercise of varying duration (moderate vs. high, about 150 min/week to 200 min/week) and intensity (moderate vs. vigorous) on weight loss and cardiorespiratory fitness following 12 months of treatment in overweight adult women.

The study was a randomized trial conducted from January 2000 through December 2001 involving 201 sedentary women (average age, 37 years); average body mass index (BMI) 32.7 (a 5'4" woman with a BMI of 33 would weigh 192 lbs.), in a university-based weight control program. Participants were randomly assigned to 1 of 4 exercise groups based on the estimated energy expenditure (1000 kcal/wk vs. 2000 kcal/wk) and exercise intensity (moderate vs. vigorous). All women were instructed to reduce intake of energy to between 1200 and 1500 kcal/d and dietary fat to between 20 percent and 30 percent of total energy intake.

Of the randomized participants, 184 completed 12 months of treatment. "Average weight loss following 12 months of treatment was statistically significant in all exercise groups (vigorous intensity/high duration = 8.9 kg [19.6 lbs.]; moderate intensity/high duration = 8.2 kg [18.1 lbs.]; moderate intensity/moderate duration = 6.3 kg [13.9 lbs.]; vigorous intensity/moderate duration = 7.0 kg [15.4 lbs.]), with no significant difference between groups. [Average] cardiorespiratory fitness levels also increased significantly in all groups (vigorous intensity/high duration = 22.0 percent; moderate intensity/high duration = 14.9 percent; moderate intensity/moderate duration = 13.5 percent; vigorous intensity/moderate duration = 18.9 percent), with no difference between groups."

"Weight loss was significant within all groups, but there was no significant effect of either exercise duration or exercise intensity on changes in body weight between groups," the authors write.

CHICAGO—Obesity is a major risk factor for the development of type 2 diabetes mellitus in children in Taiwan, according to a study in the September 10 issue of The Journal of the American Medical Association (JAMA), a theme issue on medical education.

According to background information provided by the authors, "diabetes mellitus (DM) in children and adolescents has long been considered to be primarily type 1 (i.e., insulin-dependent) DM. Type 2 (i.e., non-insulin-dependent) DM is generally considered to be a disease of adults. However, a disturbing trend of increasing prevalence of type 2 DM in children has been noted worldwide in recent years."

Jung-Nan Wei, Ph.D., from National Taiwan University, Taipei, Taiwan, and colleagues analyzed data from a national screening program of Taiwanese school children to study the rate and risk factors for childhood type 2 DM. In 1999, 2,862,083 Taiwanese children aged 6 to 18 years completed the screening which included urine testing for diabetes. A second urine screening of the15,271 students who tested positive was performed and a total of 1,809 students tested positive on both tests. Those students then had an examination by a physician that included measuring body weight, height and blood pressure, and a blood sample. Follow-up telephone interviews were conducted in 2002 with parents of those students newly identified as having diabetes from the 1999 survey to distinguish type 2 from type 1 DM.

To determine risk factors for diabetes, the researchers conducted a nested case-control study in 2002 comparing 137 children with type 2 DM with 1,000 randomly selected children without diabetes to reflect the whole student population.

"In the present study, the rate of newly identified diabetes was estimated to be 12.0 per 100, 000," the researchers report. "Of these cases, 9.5 percent had type 1 DM, 54.2 percent had type 2 DM, and 8.7 percent had drug-induced diabetes. The estimated rate of type 2 diabetes was 6.5 per 100,000." The researchers found that girls had a higher risk of type 2 diabetes compared with boys, which is an observation that has been made with other Asian populations, according to the authors. The researchers also found that a total of 54 percent of boys and 44.4 percent of girls with type 2 diabetes were obese.

"To our knowledge, the high rate of type 2 DM in this young population has never been noted before in Taiwan. Therefore, the results of this study will have significant public health ramifications," the authors comment.

CHICAGO—Minors appear to have easy access to cigarettes via the Internet because many Internet vendors either don't check ages or don't have an age verification process, according to a report in the September 10 issue of The Journal of the American Medical Association (JAMA), a theme issue on medical education.

"There is growing concern that the Internet might become a source of tobacco products for minors," the authors provide as background information in the article. "Recent studies suggest that 2 percent to 3 percent of adolescent smokers report purchasing cigarettes through the Internet." The authors report that the most common age verification method on the Internet is self-report, where the buyer clicks on a box stating that they are of legal age to buy tobacco products or they have to type in a birth date.

Kurt M. Ribisl, Ph.D., and colleagues from the University of North Carolina at Chapel Hill, conducted a study between April and July 2001 in which four adolescents, aged 11 to 15 years, attempted to purchase cigarettes via 55 Internet cigarette vendors in 12 states. The non-smoking adolescents were supervised by adults, and the researchers had approval from local law enforcement officials for this study. The minors made a total of 83 purchase attempts, 36 using money orders and 47 using credit cards.

"Internet cigarette vendors sold to minors in 76 (91.6 percent) of the 83 purchase attempts," the authors found. "Fifty of the 55 Internet vendors sold cigarettes to minors. Successful purchases occurred in 32 (88.9 percent) of 36 money order purchase attempts and 44 (93.6 percent) of 47 credit card purchase attempts. Altogether, the Internet vendors sold a total of 1,650 packs of cigarettes to the four minors." The authors add that age was never verified for any of these deliveries.

MODERATE EXERCISE JUST AS EFFECTIVE AS INTENSE WORKOUTS FOR WEIGHT LOSS