Press releases Monday 28 February to Friday 4 March 2011

Please remember to credit the BMJ as source when publicising an article and to tell your readers that they can read its full text on the journal's website (http://www.bmj.com).

• (1) Smoking increases risk of breast cancer in postmenopausal women
• (2) Cannabis use precedes the onset of psychotic symptoms in young people
• (3) Has suspending targets changed waiting times?

(1) Smoking increases risk of breast cancer in postmenopausal women

(Research: Association of active and passive smoking with risk of breast cancer among postmenopausal women: a prospective cohort study)
http://www.bmj.com/cgi/doi/10.1136/bmj.d1016
(Editorial: Is breast cancer associated with tobacco smoking?)
http://www.bmj.com/cgi/doi/10.1136/bmj.d1093

Postmenopausal women who smoke or used to smoke have up to a 16% higher risk of developing breast cancer compared to women who have never smoked, finds research published on bmj.com today.

The study also says that women who have had extensive exposure to passive smoking, either as children or in adulthood, may also have an excess risk of developing breast cancer.

While some previous studies have indicated that smoking increases the risk of breast cancer, the theory that passive smoking is also a risk factor, remains controversial.

The researchers, led by Dr Juhua Luo from West Virginia University and Dr Karen Margolis from the HealthPartners Research Foundation in Minneapolis, decided to carry out a large scale study following participants over a long period of time to investigate the issue further.

The research team used data from the 1993-98 Women's Health Initiative Observational study to determine links between smoking, passive smoking and breast cancer.

They analysed data for almost 80,000 women, aged between 50 and 79 years, across 40 clinical centres in the United States. In total, 3,250 cases of invasive breast cancer were identified by the researchers during ten years of follow-up.

The participants were asked a range of questions about their smoking status, for example whether they had ever smoked or were former or current smokers. Current or former smokers were asked the age at which they started smoking and the number of cigarettes smoked a day. Former smokers were asked the age at which they quit.

Questions on passive smoking related to whether the participants lived in smoking households as children and/or as adults, and whether they had worked in smoking environments.

The results show that smokers have a 16% increased risk of developing breast cancer after the menopause. The increased risk for former smokers is 9%. The highest breast cancer risk was found among women who had smoked for over 50 years or more compared with lifetime non-smokers. Women who started smoking as teenagers were also at particularly high risk. An increased risk of breast cancer continued for up to 20 years after an individual stopped smoking.

The findings also reveal that among non-smoking women, those who had been exposed to extensive passive smoking, for example over 10 years' exposure in childhood; over 20 years' exposure as an adult at home and over 10 years' exposure as an adult at work; had a 32% excess risk of breast cancer.

The authors stress, however, that their analysis of the link between breast cancer and secondhand smoke was restricted to the most extensive passive smoking category and therefore more research is needed to confirm these findings.

"Our findings highlight the need for interventions to prevent initiation of smoking, especially at an early age, and to encourage smoking cessation at all ages", Dr Margolis concludes.

In an accompanying editorial, Professor Paolo Boffetta from the Mount Sinai School of Medicine in New York, says Margolis' study "supports the hypothesis that smoking increases the risk of breast cancer, in particular when the habit starts early in life".

However, Boffetta adds that the data needs to placed in the context of the overall evidence, some of which found no increase in risk. He also agrees that the evidence on secondhand smoke is not conclusive and further studies are required

Contacts:
Research: Karen Margolis, Senior Clinical Investigator, HealthPartners Research Foundation, Minneapolis, USA
Email: Annelise.m.searle@HealthPartners.com
Editorial: Paolo Boffetta, Professor, Tisch Cancer Institute and Institute for Transitional Epidemiology, Mount Sinai School of Medicine, New York, USA
Email: paolo.boffetta@mssm.edu

(2) Cannabis use precedes the onset of psychotic symptoms in young people

(Research: Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study)
http://www.bmj.com/cgi/doi/10.1136/bmj.d738
(Editorial: Cannabis and the increased incidence and persistence of psychosis)
http://www.bmj.com/cgi/doi/10.1136/bmj.d719

Cannabis use during adolescence and young adulthood increases the risk of psychotic symptoms, while continued cannabis use may increase the risk for psychotic disorder in later life, concludes a new study published on bmj.com today.

Cannabis is the most commonly used illicit drug in the world, particularly among adolescents, and is consistently linked with an increased risk for mental illness. However, it is not clear whether the link between cannabis and psychosis is causal, or whether it is because people with psychosis use cannabis to self medicate their symptoms.

So a team of researchers, led by Professor Jim van Os from Maastricht University in the Netherlands, set out to investigate the association between cannabis use and the incidence and persistence of psychotic symptoms over 10 years.

The study took place in Germany and involved a random sample of 1,923 adolescents and young adults aged 14 to 24 years.

The researchers excluded anyone who reported cannabis use or pre-existing psychotic symptoms at the start of the study so that they could examine the relation between new (incident) cannabis use and psychotic symptoms.

The remaining participants were then assessed for cannabis use and psychotic symptoms at three time points over the study period (on average four years apart).

Incident cannabis use almost doubled the risk of later incident psychotic symptoms, even after accounting for factors such as age, sex, socioeconomic status, use of other drugs, and other psychiatric diagnoses. Furthermore, continued use of cannabis over the study period increased the risk of persistent psychotic symptoms.

There was no evidence for self medication effects as psychotic symptoms did not predict later cannabis use.

These results "help to clarify the temporal association between cannabis use and psychotic experiences," say the authors. "In addition, cannabis use was confirmed as an environmental risk factor impacting on the risk of persistence of psychotic experiences."

The major challenge is to deter enough young people from using cannabis so that the prevalence of psychosis is reduced, say experts from Australia in an accompanying editorial.

Professor Wayne Hall from the University of Queensland and Professor Louisa Degenhardt from the Burnet Institute in Melbourne, question the UK's decision to retain criminal penalties for cannabis use, despite evidence that removing such penalties has little or no detectable effect on rates of use. They believe that an informed cannabis policy "should be based not only on the harms caused by cannabis use, but also on the harms caused by social policies that attempt to discourage its use, such as criminal penalties for possession and use."

Contacts:
Research: Professor Jim van Os, Department of Psychiatry and Neuropsychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Center, Maastricht, Netherlands
Email: j.vanos@sp.unimaas.nl
Editorial: Wayne Hall, NHMRC Australia fellow and professor, UQ Centre for Clinical Research, University of Queensland, Australia
Email: w.hall@uq.edu.au

(3) Has suspending targets changed waiting times?

(Data briefing: What's happening to waiting times?)
http://www.bmj.com/cgi/doi/10.1136/bmj.d1235

Have the suspension of central performance management of the 18 week referral to treatment target, and a relaxation of the four hour Accident and Emergency target, changed waiting times asks John Appleby, Chief Economist at the King's Fund in this week's BMJ?

The English National Health Service was once notorious for its excessive waiting times. In December 1999, nearly 160,000 patients were still waiting over six months for their first outpatient appointment and over 50,000 were still waiting over a year for a bed in hospital.

But since 2000, tough targets imposed by the then Labour government have seen long waits virtually eliminated. The median waiting time - the time spent waiting by half of those on waiting lists - has also fallen, from around 18 weeks in 2007 to just one month now for inpatients admitted to hospital.

The outcome is perhaps one of the most significant achievements for the NHS in recent years, writes Appleby. But is it now winning the "war on waiting"?

Tracking waiting times since June last year gives a mixed picture, somewhat muddied by seasonal effects in changes in waiting times, he says. Although figures for December 2010 show that waits were down on the previous month, the proportion of patients still waiting over 18 weeks for hospital treatment increased by more than the seasonal effect would predict.

Meanwhile, median waits for diagnostic services are now back to the level seen in December 2007, although this largely reflects a seasonal trend.

Regardless of the effect reductions in waiting times have had on patients' health, Appleby points out that reductions in waiting are valued and are likely to have contributed to rising satisfaction with the NHS over the past decade.

All this makes the suspension of Labour's targets "an interesting experiment in the power of alternative policy levers to bear down on waiting times: notably, patient choice and the degree to which GP commissioning will reflect patients' values and their rights under the NHS Constitution," he writes.

"The coming months - and particularly the new financial year, when budgets get squeezed - will start to reveal some more consistent trends," he concludes.

Contact:
Press Office, King's Fund, London, UK
Email: mediaoffice@kingsfund.org.uk

Emma Dickinson
Tel: +44 (0)20 7383 6529
Email: edickinson@bma.org.uk

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