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"E-cigarettes are encouraging a new generation to become hooked on nicotine," reports the Mail Online.

E-cigarettes are devices that deliver a heated aerosol ("vapour") of nicotine in a way that mimics conventional cigarettes. But they have lower levels of toxins such as tar than a conventional tobacco cigarette. They are marketed as a safer alternative to regular smoking, or as a way to quit.

Today's headlines followed a survey of thousands of US teenagers (who were under 15 on average, meaning that those who smoked cigarettes were underage).

It found that those who had tried e-cigarettes were more likely to have smoked conventional cigarettes and less likely to be abstaining from conventional smoking than those who hadn't tried e-cigarettes.

However, it also found those who tried e-cigarettes were more likely to want to quit conventional smoking.

On average tobacco smokers die significantly younger and spend more of their shorter lives ill. Because e-cigarettes can be marketed to young people, there is a worry that if they did lead to more conventional smoking, they could have a potentially disastrous impact on public health.

This current study does suggest that e-cigarettes may not be the harmless alternative some believe, and may be acting as a "gateway drug" to conventional smoking.

However, it does not prove that is the case. It is quite plausible that existing teenage smokers are also trying e-cigarettes for a variety of reasons.

The debate about the safety and regulation of e-cigarettes is likely to continue until more robust long-term evidence emerges.

 

Where did the story come from?

The study was carried out by researchers from the Center for Tobacco Research and Education at the University of California, San Francisco, and was funded by the US National Cancer Institute.

It was published in the peer-reviewed medical journal, JAMA Pediatrics.

The Mail Online coverage was balanced and discussed the pros and cons of e-cigarettes. It also usefully brought in some wider research from 75,000 Korean adolescents "which also found that adolescents who used e-cigarettes were less likely to have stopped smoking conventional cigarettes".

 

What kind of research was this?

This was a cross-sectional study looking at whether e-cigarette use was linked to conventional cigarette smoking behaviour among US adolescents.

E-cigarettes are devices that deliver a heated aerosol of nicotine in a way that mimics conventional cigarettes while delivering lower levels of toxins, such as tar, than a conventional combusted cigarette. They are often marketed as a safer alternative to regular smoking, or as a way of helping people quit traditional smoking.

The devices are not currently regulated in the US or the UK, meaning there are limited or vague rules concerning appropriate advertising. The researchers say e-cigarettes are being aggressively marketed using the same messages and media channels that cigarette companies used to market conventional cigarettes in the 1950s and 1960s. These include targeting young people to get a new generation of smokers hooked on nicotine for life.

The researchers outline how studies have demonstrated that youth exposure to cigarette advertising causes youth smoking. Meanwhile, electronic cigarettes can be sold in flavours such as strawberry, liquorice or chocolate, which are banned in cigarettes in the US because they appeal to youths.

Given the potential for a new generation to be hooked on nicotine and then tobacco smoking in this unregulated environment, the researchers wanted to investigate whether e-cigarettes were associated with regular smoking behaviour in adolescents.

 

What did the research involve?

The researchers used existing smoking data collected from US middle and high school students in 2011 (17,353 students) and 2012 (22,529) during the large US National Youth Tobacco Survey. They analysed whether use of e-cigarettes was linked with conventional tobacco smoking and smoking abstinence behaviour.

The National Youth Tobacco Survey was described as an anonymous, self-administered, 81-item, pencil-and-paper questionnaire that included:

• indicators of tobacco use (cigarettes, cigars, smokeless tobacco, kreteks [southeast Asian clove cigarettes], pipes, and "emerging" tobacco products)
• tobacco-related beliefs
• attitudes about tobacco products
• smoking cessation
• exposure to secondhand smoke
• ability to purchase tobacco products
• exposure to pro-tobacco and anti-tobacco influences

Smoking behaviour was categorised as:

• conventional cigarette experimenters – adolescents who responded "yes" to the question "Have you ever tried cigarette smoking, even one or two puffs?"
• ever-smokers of conventional cigarettes – those who replied "100 or more cigarettes (five or more packs)" to the question "About how many cigarettes have you smoked in your entire life?"
• current smokers of conventional cigarettes – those who had smoked at least 100 cigarettes and smoked in the past 30 days
• ever e-cigarette users – adolescents who responded "electronic cigarettes or e-cigarettes, such as Ruyan or NJOY" to the question "Which of the following tobacco products have you ever tried, even just one time?"
• current e-cigarette users – those who responded "e-cigarettes" to the question "During the past 30 days, which of the following tobacco products did you use on at least one day?"

Data on intention to quit smoking in the next year, previous quit attempts and abstinence from conventional cigarettes was also collected. The analysis was adjusted for potential confounding factors such as race, gender and age.

 

What were the basic results?

The main analysis included 92.0% of respondents (17,353 of 18,866) in 2011 and 91.4% of respondents (22,529 of 24,658) in 2012 who had complete data on conventional cigarette use, e-cigarette use, race, gender and age. The mean age was 14.7, and 5.6% of respondents reported ever or current conventional cigarette smoking (of these, 5% currently smoked).

In 2011, 3.1% of the study sample had tried e-cigarettes (1.7% dual ever use, 1.5% only e-cigarettes) and 1.1% were current e-cigarette users (0.5% dual use, 0.6% only e-cigarettes).

In 2012, the 6.5% of the sample had tried e-cigarettes (2.6% dual use, 4.1% only e-cigarettes) and 2.0% were current e-cigarette users (1.0% dual use, 1.1% only e-cigarettes).

Ever e-cigarette users were significantly more likely to be male, white and older. The rates of ever-tried e-cigarettes and current e-cigarette smoking approximately doubled between 2011 and 2012.

The main analysis found use of e-cigarettes was significantly associated with:

• higher odds of ever or current cigarette smoking
• higher odds of established smoking
• higher odds of planning to quit smoking among current smokers
• among e-cigarette experimenters, lower odds of abstinence from conventional cigarettes

 

How did the researchers interpret the results?

The researchers' interpretation was clear: "Use of e-cigarettes does not discourage, and may encourage, conventional cigarette use among US adolescents."

They added that, "In combination with the observations that e-cigarette users are heavier smokers and less likely to have stopped smoking cigarettes, these results suggest that e-cigarette use is aggravating rather than ameliorating the tobacco epidemic among youths. These results call into question claims that e-cigarettes are effective as smoking cessation aids."

 

Conclusion

This study found US adolescents who use e-cigarettes are more likely to smoke conventional cigarettes. They also have lower odds of abstaining from conventional cigarettes than those who don't try e-cigarettes. On the flip side, e-cigarette users were more likely to report planning to quit conventional smoking.

The research sample was large, so is likely to provide a relatively accurate picture of the smoking behaviour of US adolescents.

These results suggest that e-cigarettes may not discourage conventional cigarette smoking in US adolescents, and may encourage it. However, because of the cross-sectional nature of the information, it cannot prove that trying e-cigarettes causes adolescents to take up conventional smoking. There may be other factors at play.

And indeed, smoking tobacco cigarettes may cause teenagers to take up e-cigarettes. For example, the type of person who may want to try smoking in the past could only try conventional smoking. Nowadays, they have e-cigarettes as an option too.

Retrospectively trying to work out if they would have taken up conventional smoking had they not tried e-cigarettes first is not possible. This question would require a cohort study that tracks behaviour over time. You would then be able to see which smoking method they took up first and if one led to the other. This was not possible using the data the researchers had to hand in the current study.

Conventional smoking has been a public health priority for many decades because, on average, smokers die significantly younger (more than a decade in some groups) and they spend more of their shorter lives ill. Consequently, any product that may increase the rates of conventional smoking among the young – such as e-cigarettes – has serious and widespread health consequences.

Currently, regulation around e-cigarettes is minimal, but there are plans to introduce stricter rules in the UK. In the meantime, this study provides some evidence that e-cigarettes may not be the harmless, safe alternative some believe, and may be acting as a gateway drug to conventional smoking.

The research stops short of proving this, so the debate on whether e-cigarettes should be treated similarly to conventional cigarettes, through advertising and sales restrictions, is likely to continue.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

E-cigarettes are 'encouraging a new generation to become hooked on nicotine'. Daily Mail, March 7 2014

Links To Science

Dutra LM and Glantz SA. Electronic Cigarettes and Conventional Cigarette Use Among US Adolescents. JAMA Pediatrics. Published March 6 2014

“Blood test that can predict Alzheimer's,” was the headline used by BBC News, the Daily Mail and The Guardian today. Similar coverage was seen across many of the front pages of other newspapers.

These headlines reflected new research showing how a simple blood test may be able to detect early signs of cognitive decline and mild Alzheimer’s disease.

US researchers discovered a panel of 10 biomarkers that, with 90% accuracy, could distinguish people who would progress to have either mild cognitive impairment or mild Alzheimer’s disease within two to three years, from those who wouldn’t.

While promising, the results were only based on a small group of adults over 70 years old who were studied over five years. Of those who developed mild cognitive impairment or mild Alzheimer’s disease, only 28 people had the test. Consequently, it is not clear if the test has any predictive power in the wider population, is applicable to younger adults, or can predict the disease more than two to three years in advance.

The Daily Mail outlined how, while the research was a breakthrough, experts had warned it would bring “ethical concerns”. This is an important point, because there is currently no cure for Alzheimer’s disease, so some people may prefer not to know they might get it. The current unrefined test means at least one in 10 would be wrongly told they will go on to develop the condition, given the severity of the disease, this may cause significant needless worry.

 

Where did the story come from?

The study was carried out by researchers from a range of US Universities and Medical institutions and was funded by the US National Institutes of Health.

The study was published in the peer-reviewed medical journal, Nature Medicine.

The media reporting was generally balanced, with many highlighting the clear ethical question of whether there is any benefit in telling people they are likely to develop a serious condition that currently has no cure. Most media sources correctly acknowledged the need for more research to confirm the usefulness of the test, and that a useable test may be many years away.

However, while this research is exciting, it is still in an early stage and so front page coverage in four national newspapers is perhaps a little over-the-top.

 

What kind of research was this?

This was a cohort study looking to see if a blood test could detect Alzheimer’s disease before symptoms developed.

Alzheimer’s disease causes a progressive dementia. It affects more than 35 million individuals worldwide and is expected to affect 115 million by 2050.

There are currently no cures for the disease and no treatments to improve symptoms to any significant degree. This is because, at the moment, it is only possible to diagnose Alzheimer’s when symptoms such as memory loss show up. Unfortunately, this is usually long after the brain has deteriorated at a cellular level, meaning the disease is well underway by the time it is diagnosed.

Current tests for detecting early disease involve invasive medical treatments, which are also time consuming and often expensive. Discovering new tests and treatments targeting early stages of Alzheimer’s, before any outwardly obvious symptoms occur (known as pre-clinical disease), is a hot topic for research. Theoretically, detecting the disease early on will enable more options to be used to stop or slow down the progress of the disease.

 

What did the research involve?

The researchers recruited a group of people aged 70 or over and analysed their blood and recorded their cognitive abilities over the next five years for signs of decline. The researchers’ examined participants’ blood samples to see if anything in the blood could be used to predict who among the cognitively normal group would develop mental impairment problems and who would not.

The researchers enrolled 525 people over the five years and subjected them to a number of questionnaires to assess their mental health, including memory, verbal reasoning, attention, functional capacities. Based on this they were divided into two groups:

• a healthy control group showing “normal” cognitive abilities
• a group with memory problems at the start of the study, defined as amnestic mild cognitive impairment (aMCI) or mild Alzheimer’s disease (AD)

The control group was selected to match the memory-impaired group on the basis of age, sex and education.

The analysis investigated how people’s mental health scores changed after each year during a five year follow up period. Specifically, they wanted to know how many healthy controls went on to develop aMCI or mild Alzheimer’s disease. The main analysis looked for differences in the blood samples of people who went on to develop aMCI or AD and those that did not.

 

What were the basic results?

The researchers analysed 126 blood samples, including from 18 people who had developed aMCI or mild Alzheimer’s disease during the study period. The blood tests pointed towards a way of distinguishing between those that would develop cognitive impairment and those that would not.

After further investigation, the researchers found a set of 10 lipids (fats) in the blood could predict the conversion of people with normal cognitive abilities to either amnestic mild cognitive impairment or Alzheimer’s disease within a two to three year timeframe with more than 90% accuracy.

Once they had the panel of 10 fats that predicted disease development, they tested it on a further group of 41 participants to validate their results. This included 10 people who developed aMCI or mild Alzheimer’s disease during the study period. Similar results were found, confirming the initial findings.

The sensitivity and specificity of the test in the validation experiments was 90%.

 

How did the researchers interpret the results?

Based on the biochemical tests, the researchers believed the panel of 10 blood fats detected may reflect a worsening of cell membrane integrity contributing to the disease. They concluded the panel of 10 lipids could act as a test that may provide an indication of early deterioration of brain function in the pre-clinical stage of Alzheimer’s disease (when the person does not yet have symptoms).

The researchers said they had found and validated a way of assessing blood samples that distinguish cognitively normal participants who will progress to have either aMCI or AD within two to three years from those who won’t. They said that their defined panel of markers featured biochemicals that have essential structural and functional roles in the integrity and functionality of cell membranes.

 

Conclusion

This small cohort study has presented a collection of 10 biomarkers that predicted with 90% accuracy 28 cognitively normal participants who progressed to have either aMCI or mild Alzheimer’s disease within two to three years compared to those who did not.

This represents a proof-of-concept that an easily administered blood test may provide a way of detecting Alzheimer’s disease at a pre-clinical stage.

The main limitation to bear in mind when interpreting this study is the relatively older group (over 70) and short predictive range investigated. This means the test was only able to detect who would develop cognitive decline in the next two to three years. For that reason, the study does not provide any information on whether the test can predict the disease any earlier, for example by testing the blood of people in their 50s. This will inevitably be the subject of further study.

The Daily Mail outlines how “experts called the breakthrough a real step forward, but warn it will bring with it ethical concerns”. This is an important point to consider because there is currently no cure for Alzheimer’s disease.

As The Independent put it, “Would anyone welcome being told that they are going to develop – and very likely die from – an incurable disorder that will eventually rob them of their memories, emotions and personality over a period of many years?”

The reaction to the news will certainly be different for different individuals, but could be emotionally and psychologically damaging for some.

Along a similar line, the current test was 90% accurate. This means at least one in 10 will be wrongly told they will go on to develop the condition, causing needless worry.

The researchers cannily point out that the test “requires external validation using similar rigorous clinical classification before further development for clinical use. Such additional validation should be considered in a more diverse demographic group than our initial cohort”.

Ultimately, this research provides proof-of-concept that a blood test may predict early stage Alzheimer’s disease, but it’s too early to say whether this test in particular is definitely effective, or could soon be used in mainstream clinical practice. Time, and more research, will tell. 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

New blood test to detect who is on the brink of dementia. The Times, March 10 2014

Blood test that predicts Alzheimer's. The Independent, March 10 2014

Breakthrough blood test that can predict the onset of Alzheimer's. Daily Express, March 10 2014

Blood test that can predict Alzheimer's: Elderly could be given early warning. Daily Mail, March 10 2014

Blood test can predict Alzheimer's, say researchers. BBC News, March 10 2014

Blood test to spot Alzheimer's Disease developed - and researchers say it's at least 90% accurate. Daily Mirror, March 10 2014

Links To Science

Mapstone M, et al. Plasma phospholipids identify antecedent memory impairment in older adults. Nature Medicine. Published online March 9 2014