Use of paracetamol in the first year of life, or later in early childhood, is associated with increased risk of asthma, rhinoconjunctivitis (RC)*, and eczema at age 6-7 years. This is the conclusion of an Article in this week's Asthma Special Issue of The Lancet, written by Professor Richard Beasley, Medical Research Institute of New Zealand, and colleagues.
As part of phase three of the International Study of Asthma and Allergies in Childhood (ISAAC) programme, the parents or guardians of children aged 6-7 years completed written questionnaires about symptoms of asthma, conjunctivitis, and eczema, and several possible risk factors — including use of paracetamol for fever in the first year of the child's life, and frequency of paracetamol use in the previous 12 months. More than 200,000 children from 73 centres in 31 countries were analysed.
The researchers found that use of paracetamol for fever in first year of life was associated with an increased risk of asthma symptoms in children aged 6-7 years of 46%. Current use (ie, use within previous 12 months) of paracetamol was associated with a dose-dependent risk of asthma symptoms — with medium use increasing risk by 61% and high-dose increasing risk by over three times. Paracetamol use was also associated with increased risk of severe asthma symptoms, of between 22-38%. And paracetamol use in the first year of life increased risk of RC by 48% and eczema by 35%. As with asthma, use of paracetamol in the previous 12 months was associated with dose-dependent increased risks in both RC and eczema — for medium use of paracetamol, the increased risk was 18% for eczema and 32% for RC; while for high-use, risk of eczema nearly doubled while that for RC nearly trebled.
The authors conclude: "Use of paracetamol in the first year of life, and in later childhood, is associated with risk of asthma, rhinoconjunctivitis, and eczema at age 6 to 7 years. We suggest that exposure to paracetamol might be a risk-factor for the development of asthma in childhood."
They add**: "We stress the findings do not constitute a reason to stop using paracetamol in childhood. Paracetamol remains the preferred drug to relieve pain and fever in children. However the findings do lend support to the current guidelines of the World Health Organisation, which recommend that paracetamol should not be used routinely, but should be reserved for children with a high fever (38.5° C or above). The reason paracetamol became the preferred drug for treatment of fever in children was the risk of Reye's syndrome, a rare but serious complication of aspirin therapy in children. International asthma guidelines recommend that for both children and adults with asthma, paracetamol is the preferred drug to relieve pain or fever. Paracetamol is the preferred drug for asthmatics due to the risk that aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen and ibuprofen may provoke attacks of asthma."
In an accompanying Comment, Professor R Graham Barr, Columbia University, New York, USA, says: "The report from ISAAC Phase Three is the largest and most important contribution to date on the growing literature, summarised well by Beasley and colleagues, on paracetamol use and childhood asthma. It ends, appropriately, with a question rather than a conclusion and that question is about causality."
The Article and Comment authors agree that further research is urgently required including randomised controlled trials into the long-term effects of frequent use of paracetamol.
Notes to editors:
*rhinoconjunctivitis is a condition causing nasal itching, sneezing and blocking of the nose, and irritation of the eyes, in response to an allergic reaction
**quote direct from authors and not found in text of Article
Professor Richard Beasley, Medical Research Institute of New Zealand T) +64-21-40-30-60 E) Richard.beasley@mrinz.ac.nz
Professor R Graham Barr, Columbia University, New York, USA T) +1-212-305-4895 E) rgb9@columbia.edu
Full Article and Comment: http://press.thelancet.com/asthmaparacetamol.pdf
Journal
The Lancet