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Press releases Saturday 21 May 2005

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(1) New study questions benefits of aspirin for the over 70s

(2) Eight aspects of early life put UK children at risk of obesity

(3) Premature use of stem cell therapy could put patients at risk

Online First
(1) New study questions benefits of aspirin for the over 70s

(Epidemiological modelling of routine use of low dose aspirin for the primary prevention of coronary heart disease and stroke in those aged 70)
http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38456.676806.8F

The benefits of giving low dose aspirin to healthy people from the age of 70 to prevent heart disease are offset by increased cases of serious bleeding, argue researchers in a study published online by the BMJ this week.

Using a model, the team simulated the broad implications of routine use of aspirin in a population of 20,000 men and women aged 70-74 with no cardiovascular disease.

The model suggests that any benefits gained from the use of low dose aspirin (prevention of heart attacks) may be offset by increased cases of serious bleeding.

The figures also indicate that the overall balance of harm and benefit could tip either way. Therefore, the temptation to blindly implement low dose aspirin for prevention of heart disease in elderly people must be resisted, say the authors.

These findings reinforce the need for a clinical trial to establish the true benefit or harm of aspirin in elderly people, and underscore the importance of targeting preventive treatment to those who are likely to benefit most, they conclude.

Contact:
Mark Nelson, Chair, Discipline of General Practice, School of Medicine, University of Tasmania, Hobart, Australia Email: mark.nelson@utas.edu.au

Online First
(2) Eight aspects of early life put UK children at risk of obesity

(Early life risk factors for obesity in childhood: cohort study)
http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38470.670903.E0

Three year old children who spend more than eight hours watching television per week are at an increased risk of obesity, finds a study published online by the BMJ this week.

This is just one of eight aspects of early life found to be linked to obesity in UK children, and these results support the theory that the early life environment can determine later risk of obesity.

The study involved 8,234 children aged 7 years and a further sample of 909 children who were taking part in a large UK study of parents and children. Height and weight were measured and body mass index (BMI) was calculated.

In the entire group, four factors were independently associated with a risk of obesity at age 7:
• Increasing birth weight
• Parental obesity (one or both parents)
• More than eight hours spent watching television per week at age 3 years
• Short sleep duration (less than 10.5 hours per night at age 3 years

A further four factors were significant for the children in the additional sample:
• Size in early life
• Rapid weight gain in the first year
• Rapid catch-up growth between birth and two years
• Early development of body fatness in the pre-school years, before the age at which body fat should be increasing (at age 5/6 years)

The precise mechanisms by which these variables might increase the risk of obesity are complex, say the authors. For instance, parental obesity may increase the risk of obesity through genetics, or by shared family characteristics in the environment such as food preferences.

Duration of night time sleep may affect growth hormone secretion or reduce the child±s exposure to food intake in the evening. Alternatively, children who are more physically active may sleep longer at night. Finally, television viewing may confer risk through a reduction in energy expenditure or an increase in dietary intake.

±Our study provides evidence of the role of the early life environment in the later risk of obesity,± say the authors.

±Most interventions to prevent obesity have tried to change lifestyles of children and adolescents and have been unsuccessful. Future interventions might focus on environmental changes targeted at relatively short periods in early life, attempting to modify factors during pregnancy, in infancy, or in early childhood, which are independently related to later risk of obesity.±

Contact:
John Reilly, Reader in Paediatric Energy Metabolism, University of Glasgow Division of Developmental Medicine, Yorkhill Hospitals, Glasgow, Scotland Email: jjr2y@clinmed.gla.ac.uk

(3) Premature use of stem cell therapy could put patients at risk

(Stem cell therapy: hope or hype)
http://bmj.com/cgi/content/full/330/7501/1159

The premature use of stem cell therapy could put many patients at risk of viral or prion diseases unless appropriate safety systems are in place, warn experts in this week±s BMJ.

The use of human embryonic stem cells has been hailed as the next major step in the battle against serious degenerative disorders, such as diabetes and Parkinson±s disease. But is this just hype, and how much hope should patients invest in this technology? These are some of the issues that will be discussed at a public debate in London next week.

The lessons of premature application of gene therapy, the devastation caused by HIV transmission to people with haemophilia, and the crisis caused by bovine spongiform encephalopathy (BSE) should all be learning opportunities, say the authors.

Expansion of stem cell cultures could allow a single stem cell line to be used for many hundreds, if not thousands of patients, exponentially amplifying the potential risk of disease transmission from a single infected donor.

Change is on the way, however. By April 2006, all laboratories for in vitro fertilisation and laboratories for producing cell lines with therapeutic intent will have to comply with the EU Directive on tissues and cells. This will cover selection of donors, testing, and procurement of the starting material for cell lines, tracking cells from donor to recipient, and reporting of adverse events.

The authors suggest a novel alternative approach whereby the expanded stem cell lines themselves could be tested for a variety of pathogens before they are released. This would provide an additional safety step and provide an alternative in the armamentarium for testing these important donations for transplantation.

The drive to be the first to produce cell lines for therapy without appropriate controls could compromise safety for recipients and could lead this technology into the realms of quackery, say the authors. Such fears are already being realised in India and Russia, where action may be needed to limit or prevent the escalating numbers of clinics offering stem cell cures for all sorts of ills.

Stem cell therapy needs to be nurtured safely and methodically to provide real benefit to patients in the future, they conclude.

Contact:
Public Relations Office, King±s College London, UK

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