Children and adolescent cell phone users at no greater risk of brain cancer than non-users, study suggests

ScienceDaily (July 28, 2011) — Children and adolescents who use mobile phones are not at a statistically significant increased risk of brain cancer compared to their peers who do not use mobile phones, according to a study published July 27 in the Journal of The National Cancer Institute.

Mobile phone usage has increased among children and adolescents in recent years. The increased usage has raised a concern about the possibility of the development of brain tumors in this population since children have a developing nervous system; also, because their head circumference is smaller, the radio frequency electromagnetic fields may penetrate regions that are deeper in their brains. However, no previous study has examined whether mobile phone usage among children and adolescents is associated with a difference in brain tumor risk.

To determine the relationship between mobile phone usage and brain tumor risk among children and adolescents, Martin Röösli, Ph.D, of the Swiss Tropical and Public Health Institute in Basel, Switzerland, and colleagues looked at the medical records of children aged 7-19 with brain tumors, identified through population registries. Researchers did face-to-face interviews with them regarding their mobile phone usage. They also consulted data from phone network providers.

The study, conducted between 2004 and 2008, included participants from Norway, Denmark, Sweden and Switzerland. They looked at data for 352 brain cancer patients, and 646 control subjects.

The researchers found that patients with brain tumors were not statistically significantly more likely to have been regular mobile phone users than control subjects. They found that 265 (75.3%) of case patients and 466 control subjects (72.1%) reported having spoken on a mobile phone more than 20 times before the time when the case patient was diagnosed. Furthermore, 194 case patients (55%) and 329 control subjects (51%) reported regular mobile phone usage. However, in a subset of study participants for whom operator recorded data were available, brain tumor risk was related to the time elapsed since the mobile phone subscription was started (but not to amount of use). No increased risk of brain tumors was observed for brain areas receiving the highest amount of exposure.

The researchers write, "Because we did not find a clear exposure-response relationship in most of these analyses, the available evidence does not support a causal association between the use of mobile phones and brain tumors." Nevertheless, since mobile phone usage among children and adolescents has increased over the years, they encourage a careful watch on the trend.

In an accompanying editorial, John D Boice, Jr., ScD. and Robert E. Tarone, PhD., of the International Epidemiology Institute in Rockville, Maryland and Vanderbilt University in Nashville, Tennessee write that Röösli and his colleagues "have filled an important gap in knowledge by showing no increased risk of brain tumors among children and adolescents who are regular cell phone users"

Boice and Tarone conclude that it is reassuring that the incidence rates of brain cancer in the general population, including children and teenagers, have not changed over the past 20 years in the United States and many other countries despite the steady and marked rise in the use of cell phones throughout the world since the 1980s. They recommend that investigators continue to monitor population incidence rates and that in the meantime, individuals who are concerned might consider alternatives to holding a cell phone up to their ears, such as using an ear piece or using the phone's speaker. They also point out that individuals should heed what is known about real risks by avoiding the use of cell phones while driving a car, because such distractions have been clearly documented to increase the risk of accidents and injuries.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Journal of the National Cancer Institute, via EurekAlert!, a service of AAAS.

Journal References:

John D. Boice, Jr and Robert E. Tarone. Cell Phones, Cancer, and Children. J Natl Cancer Inst, July 27, 2011 DOI: 10.1093/jnci/djr285Denis Aydin, Maria Feychting, Joachim Schüz, Tore Tynes, Tina Veje Andersen, Lisbeth Samsø Schmidt, Aslak Harbo Poulsen, Christoffer Johansen, Michaela Prochazka, Birgitta Lannering, Lars Klæboe, Tone Eggen, Daniela Jenni, Michael Grotzer, Nicolas Von der Weid, Claudia E. Kuehni, and Martin Röösli. Mobile Phone Use and Brain Tumors in Children and Adolescents: A Multicenter Case–Control Study. J Natl Cancer Inst, July 27, 2011 DOI: 10.1093/jnci/djr244

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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Increased risk of Parkinson's disease in methamphetamine users, study finds

ScienceDaily (July 26, 2011) — People who abused methamphetamine or other amphetamine-like stimulants were more likely to develop Parkinson's disease than those who did not, in a new study from the Centre for Addiction and Mental Health (CAMH).

The researchers examined almost 300,000 hospital records from California covering 16 years. Patients admitted to hospital for methamphetamine or amphetamine-use disorders had a 76 per cent higher risk of developing Parkinson's disease compared to those with no disorder.

Globally, methamphetamine and similar stimulants are the second most commonly used class of illicit drugs.

"This study provides evidence of this association for the first time, even though it has been suspected for 30 years," said lead researcher Dr. Russell Callaghan, a scientist with CAMH. Parkinson's disease is caused by a deficiency in the brain's ability to produce a chemical called dopamine. Because animal studies have shown that methamphetamine damages dopamine-producing areas in the brain, scientists have worried that the same might happen in humans.

It has been a challenge to establish this link, because Parkinson's disease develops in middle and old age, and it is necessary to track a large number of people with methamphetamine addiction over a long time span.

The CAMH team took an innovative approach by examining hospital records from California -- a state in which methamphetamine use is prevalent -- from 1990 up to 2005. In total, 40,472 people, at least 30 years of age, had been hospitalized due to a methamphetamine- or amphetamine-use disorder during this period.

These patients were compared to two groups: 207,831 people admitted for appendicitis with no diagnosis of any type of addiction, and 35,335 diagnosed with cocaine use disorders. A diagnosis of Parkinson's disease was identified from hospital records or death certificates. Only the methamphetamine group had an increased risk of developing Parkinson's disease.

While the appendicitis group served as a comparison to the general population, the cocaine group was selected for two reasons. Because cocaine is another type of stimulant that affects dopamine, this group could be used to determine whether the risk was specific to methamphetamine stimulants. Cocaine users also served as a control group to account for the health effects or lifestyle factors associated with dependence on an illicit drug.

"It is important for the public to know that our findings do not apply to patients who take amphetamines for medical purposes, such as attention deficit hyperactivity disorder (ADHD), since these patients use much lower doses of amphetamines than those taken by patients in our study," said Dr. Stephen Kish, a CAMH scientist and co-author.

To put the study findings into numbers, if 10,000 people with methamphetamine dependence were followed over 10 years, 21 would develop Parkinson's, compared with 12 people out of 10,000 from the general population. "It is also possible that our findings may underestimate the risk because in California, methamphetamine users may have had less access to health-care insurance and consequently to medical care," said Dr. Callaghan.

The current project is significant because it is one of the few studies examining the long-term association between methamphetamine use and the development of a major brain disorder. "Given that methamphetamine and other amphetamine stimulants are the second most widely used illicit drugs in the world, the current study will help us anticipate the full long-term medical consequences of such problematic drug use," said Dr. Callaghan.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Centre for Addiction and Mental Health, via EurekAlert!, a service of AAAS.

Journal Reference:

Russell C. Callaghan, James K. Cunningham, Jenna Sykes, Stephen J. Kish. Increased risk of Parkinson's disease in individuals hospitalized with conditions related to the use of methamphetamine or other amphetamine-type drugs. Drug and Alcohol Dependence, 2011; DOI: 10.1016/j.drugalcdep.2011.06.013

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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