Friday, March 7, 2014

Inadequate sleep predicts risk of heart disease, diabetes in obese adolescents


Obese adolescents not getting enough sleep? A study in today's The Journal of Pediatrics, shows they could be increasing their risk for developing diabetes, heart disease and stroke.

Lack of sleep and obesity have been associated with an increased risk of cardiovascular and metabolic diseases in adults and young children.

However, the association is not as clear in adolescents, an age group known for lack of adequate sleep, and with an obesity and overweight prevalence of 30 percent in the United States.

Researchers at the University of Michigan Health System and Baylor University studied 37 obese adolescents, ages 11-17. Their risk factors for type 2 diabetes and cardiovascular disease, such as fasting cholesterol and blood sugar, waist circumference, body mass index, and blood pressure, were measured to create a continuous cardiometabolic risk score.

The adolescents were fitted with a physical activity monitor, worn 24 hours a day for seven days to measure typical patterns of physical activity and sleep.

One-third of the participants met the minimum recommendation of being physically active at least 60 minutes a day. Most participants slept approximately seven hours each night, usually waking up at least once. Only five of the participants met the minimal recommended eight and a half hours of sleep per night.

Even after controlling for factors that may impact cardiometabolic risk, like BMI and physical activity, low levels of sleep remained a significant predictor of cardiometabolic risk in obese teens.

This shows that even among those already considered at risk for cardiometabolic disease, in this case obese teens' decreased sleep duration was predictive of increased cardiometabolic risk. The study cannot determine whether lack of sleep causes cardiometabolic disease or if obesity, or other factors cause sleep disturbances.

"However, the strong association between sleep duration and cardiometabolic risk score independent of the effects of body composition and physical activity suggest a potential influence of sleep duration on cardiometabolic health in obese adolescents," says lead author Heidi IglayReger, Ph.D., supervisor of the Physical Activity Laboratory at the Michigan Metabolomics and Obesity Center.

These data provide evidence that objective sleep assessment may be a useful screening tool to identify at-risk adolescents.

Future studies are needed to determine if improving sleep duration would decrease the risk of developing cardiometabolic diseases.


E-cigarettes: Gateway to nicotine addiction for US teens


First national analysis strongly associates e-cigarettes with smoking for many adolescents


E-cigarettes, promoted as a way to quit regular cigarettes, may actually be a new route to conventional smoking and nicotine addiction for teenagers, according to a new UC San Francisco study.

In the first analysis of the relationship between e-cigarette use and smoking among adolescents in the United States, UCSF researchers found that adolescents who used the devices were more likely to smoke cigarettes and less likely to quit smoking. The study of nearly 40,000 youth around the country also found that e-cigarette use among middle and high school students doubled between 2011 and 2012, from 3.1 percent to 6.5 percent.

"Despite claims that e-cigarettes are helping people quit smoking, we found that e-cigarettes were associated with more, not less, cigarette smoking among adolescents," said lead author Lauren Dutra, a postdoctoral fellow at the UCSF Center for Tobacco Control Research and Education.

"E-cigarettes are likely to be gateway devices for nicotine addiction among youth, opening up a whole new market for tobacco," she said.

The study will be published online on March 6 in JAMA Pediatrics.

E-cigarettes are battery-powered devices that look like cigarettes and deliver an aerosol of nicotine and other chemicals. Promoted as safer alternatives to cigarettes and smoking cessation aids, the devices are rapidly gaining popularity among adults and youth in the U.S. and around the world. Unregulated by the U.S. Food and Drug Administration, e-cigarettes have been widely promoted by their manufacturers as a way for people to quit smoking conventional cigarettes. They are sold in flavors such as chocolate and strawberry that are banned in conventional cigarettes because of their appeal to youth.

In the new UCSF study, the researchers examined survey data from middle and high school students who completed the National Youth Tobacco Survey in 2011 and 2012.

The authors found that the devices were associated with higher odds of progression from experimenting with cigarettes to becoming established cigarette smokers. Additionally, adolescents who smoked both conventional cigarettes and e-cigarettes smoked more cigarettes per day than non-e-cigarette users.

Contrary to advertiser claims that e-cigarettes can help consumers stop smoking conventional cigarettes, teenagers who used e-cigarettes and conventional cigarettes were much less likely to have abstained from cigarettes in the past 30 days, 6 months, or year. At the same time, they were more likely to be planning to quit smoking in the next year than smokers who did not use e-cigarettes.

The study's cross-sectional nature didn't allow the researchers to identify whether most youths initiated with conventional cigarettes or e-cigarettes. But the authors noted that about 20 percent of middle school students and about 7 percent of high school students who had ever used e-cigarettes had never smoked regular cigarettes – meaning that some kids are introduced to the addictive drug nicotine through e-cigarettes, the authors said.

"It looks to me like the wild west marketing of e-cigarettes is not only encouraging youth to smoke them, but also it is promoting regular cigarette smoking among youth," said senior author Stanton A. Glantz, PhD, UCSF professor of medicine and director of the Center for Tobacco Control Research and Education.

The new results are consistent with a similar study of 75,000 Korean adolescents published last year by UCSF researchers, which also found that adolescents who used e-cigarettes were less likely to have stopped smoking conventional cigarettes (visit bit.ly/1fFNWbc to learn more).

In combination, the two studies suggest that "e-cigarettes may contribute to nicotine addiction and are unlikely to discourage conventional cigarette smoking among youths," said the scientists.

The federal Centers for Disease Control and Prevention reported last year that the majority of adolescents who have ever smoked e-cigarettes also have smoked regular cigarettes. An estimated 1.78 million U.S. students have used the devices as of 2012, the CDC reported.


Energy drinks linked to teen health risks


The uplifting effects of energy drinks are well advertised, but a new report finds consumption among teenagers may be linked with poor mental health and substance use.

Researchers are calling for limits on teen’s access to the drinks and reduction in the amount of the caffeine in each can.

The paper by researchers at the University of Waterloo and Dalhousie University, published in Preventive Medicine, found that high school students prone to depression as well as those who are smoke marijuana or drink alcohol are more likely to consume energy drinks than their peers.

 “While it remains unclear why these associations exist, the trend is a concern because of the high rate of consumption among teenagers,” said Sunday Azagba, a researcher at the Propel Centre for Population Health Impact at the University of Waterloo and lead author on the paper.  “These drinks appeal to young people because of their temporary benefits like increased alertness, improved mood and enhanced mental and physical energy.”

Among the 8210 high school students surveyed, nearly two thirds reported using energy drinks at least once in the past year, with more than 20 percent consuming them once or more per month. Younger high school students were more likely to consume energy drinks than older ones.

“Marketing campaigns appear designed to entice youth and young adults,” said Azagba. “It’s a dangerous combination, especially for those at an increased risk for substance abuse.”

Energy drinks have been associated with a number of negative health effects, including cardiovascular symptoms, sleep impairment and nervousness and nausea. The side effects are caused by the beverages’ high concentration of caffeine.

“Given the negative effects of excessive caffeine consumption as well as the coincident occurrence of the use of energy drinks and other negative behaviors in teens, the trends we are seeing are more than cause for concern,” said Azagba.

In recent years energy drink sales have skyrocketed, with sales forecasted to reach $20 billion in 2013 in the United States alone.

“In our opinion, at the very least steps should be taken to limit teens’ access to energy drinks, to increase public awareness and education about the potential harms of these drinks and to minimize the amount of caffeine available in each unit,” said Azagba. “This won’t eliminate the problem entirely, but steps like these can help mitigate harm to our youth that appears to be associated with consumption of these drinks. This is something we need to take seriously. Change won’t happen without a concerted effort.”

The study was based on data from the 2012 Student Drug Use Survey, consisting of a representative sample of junior and senior high school students from three provinces in Atlantic Canada.