E-cigarettes are interrupting the progress in reducing teen use of nicotine in Southern California, a new study finds.

The findings from the University of Southern California go against the expectation of e-cigarette advocates that teens are switching from smoking to vaping, which is generally considered safer.

Instead, the study suggests that some teens are vaping who would have been nonsmokers anyway in the absence of e-cigarettes. This increase the number of teens who may be using nicotine, because most vaping liquids contain some level of nicotine.

However, a researcher who advocates vaping for smoking cessation pointed to a federally funded study indicating teen cigarette use patterns in California differ dramatically from the country as a whole. That means the results don’t apply nationwide, he said.

Using data from the USC Children’s Health Study, researchers examined the cigarette use of five groups of Southern California high school students who graduated in 1995, 1998, 2001, 2004, and 2014. It included e-cigarette use for the 2014 group; e-cigarettes became available in the U.S. in 2007.

Researchers found that 13.7 percent of 12th-graders used either cigarettes or e-cigarettes. That is substantially greater than the 9 percent rate of smoking in 2004. They concluded that the increase was due to some students taking up vaping who were not smoking.

Moreover, the rate of teen smoking in the Southern California high school students dropped only another percentage point in that decade, to just under 8 percent in 2014.

The study was published in the journal Pediatrics. It can be found at http://bit.ly/socalteenvape. The study was led by Jessica Barrington-Trimis, a postdoctoral scholar research associate in the Department of Preventive Medicine at the Keck School of Medicine of USC.

“If teenagers who vape are using e-cigarettes instead of cigarettes, we would have expected to see the decline in smoking rates continue through 2014,” Barrington-Trimis said in a study press release. “But what we’ve seen is a downward trend in cigarette use from 1995 to 2004 but no further decrease in cigarette smoking rates in 2014.”

E-cigarettes are thus interfering with efforts to reduce smoking, the study said.

The data suggest that at least some of the teens who are vaping would not have smoked cigarettes. — USC Children’s Health Study

“Smoking prevalence among Southern California adolescents has declined over 2 decades, but the high prevalence of combined e-cigarette or cigarette use in 2014, compared with historical Southern California smoking prevalence, suggests that e-cigarettes are not merely substituting for cigarettes and indicates that e-cigarette use is occurring in adolescents who would not otherwise have used tobacco products,” the study stated.

The study includes e-cigarettes among “tobacco products.” The U.S. Food and Drug Administration hasredefined how it uses the term “tobacco products” to include e-cigarettes, which are tobacco-free and may not even contain nicotine, to justify regulating them.

The FDA funded the study, along with the National Cancer Institute at the National Institutes of Health.

E-cigarettes pose dangers to teens even if they don’t smoke, the researchers wrote.

“Use of e-cigarettes, even without nicotine, may normalize tobacco product use behaviors more generally, which could then lead to increased rates of addiction via use of other nicotine-containing products, including cigarettes and other harmful combustible tobacco products. Second, in addition to lifelong problems associated with nicotine dependence, exposure to nicotine in adolescence adversely affects cognitive function and development.”

The researchers cautioned that the results may not have any larger significance.

“Although national results may not be generalizable to Southern California (and vice versa), we cannot exclude the possibility that e-cigarette use is substituting for these combustible tobacco products,” the study stated.

California contrast

Dr. Michael B. Siegel, a vaping researcher at Boston University, went a good deal further in criticizing the use of the USC study for understanding teen e-cigarette use nationally.

“In fact, comparable data from the national Monitoring the Future survey refute the findings in this paper,” said Siegel, who supports vaping for smoking cessation, by email.

“On a national level, there was a HUGE decline in current smoking among high school seniors from 2004-2014, which was accompanied by a large increase in e-cigarette use, such that the overall use of nicotine products among these youth did not change much.

“Nationally, overall nicotine use has remained about the same, but the profile of that use has changed, with a shift from combustible tobacco products (tobacco cigarettes) to electronic (non-tobacco cigarettes),” Siegel said.

In December, the Monitoring the Future study reported that teen smoking rates among grades 8, 10 and 12dropped to an historic low in 2015.

The percentage of students saying that they smoked at all in the last 30 days dropped from 8.0 percent to 7.0 percent between 2014 and 2015. The study said this drop is statistically significant.

Grade 12 showed the highest rate of smoking. In 2015, 11.4 percent reported smoking in the last 30 days. In 2014, 13.6 percent smoked. In 2004, 25 percent smoked.

Siegel said this “drastic difference” between teen smoking in California and nationwide makes it invalid to extrapolate the USC study nationally.

“Clearly, what happened in California is atypical so it is important not to draw generalized conclusions from this study for the national situation.”

In addition, the USC study failed to ask whether vaping teens were using liquids with nicotine, Siegel said.

“The Monitoring the Future study reported that about 60 percent of youth vapers use e-cigarettes without nicotine (they only contain flavorings),” he wrote. “Therefore, it is still possible that overall nicotine use among these California youth did not go up (since the majority of the youth e-cigarette users may not have been using nicotine-containing e-cigarettes).

Some of the data from the Monitoring the Future study isn’t so positive for vaping advocates. Also in December, the study reported that only 10 percent of students surveyed used e-cigarettes to quit smoking. Four times more — 40 percent — vaped out of curiosity and because the vapors taste good.

Siegel further said that the definition of using e-cigarettes in the USC study, of any use within the last 30 days, doesn’t equate with habitual use. It would also pick up experimenters who are not truly vapers.

“Finally, even if it is true that among this specific population, the overall use of nicotine has increased, that is not necessarily a bad thing for the overall public health,” Siegel wrote.

“We do not know whether e-cigarette use among youth has any significant adverse health impact, so it is possible that the benefits from the observed decline in cigarette smoking far outweigh minor risks associated with the use of non-tobacco vaping products.”

What we don’t know

That last point — about the state of knowledge of potential harm from e-cigarette use — is strongly disputed among tobacco control experts such as Siegel.

Stanton Glantz, a UC San Francisco professor and a leading opponent of tobacco and e-cigarettes, wrote Saturday on his blog that recent studies suggest that e-cigarettes may be one-third to one-half as harmful as cigarette smoking, maybe higher.

Glantz was referring to studies that found potential cardiovascular harm from vaping, as well as reduced resistance to infection, as measured in cell samples taken from nonsmokers, smokers and vapers.

UC San Diego and VA San Diego researchers have reported other potential dangers of e-cigarette use, including increasing the resistance of the “superbug” MRSA and causing DNA damage.

But the studies also found that extracts from cigarette smoke were even more toxic. Moreover, none of these studies actually prove e-cigarettes cause disease in actual vapers; they measure markers believed to correlate with disease. Those markers may be misleading.

Potential signs of harm have also been observed in coffee, but more recent research has found the worries to be overblown. Recent research has found that coffee provides significant health benefits.

But coffee has been around for hundreds of years, while e-cigarettes are a 21st-century invention. So research is still in its early stages, and people have to make do with incomplete information.

Siegal has said the best way to determine risk of e-cigarettes is by conducting a randomized controlled trial. However, even if one were started immediately, it would probably take years to get meaningful information.




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