Two recent studies have been published on asthma. A study published in the New Zealand Medical Journal finds a decline in the prevalence of asthma in New Zealand, and a study published in Clinical and Experimental Allergy finds no link between early use of antibiotics and the development of asthma in young children.
Decline in the prevalence of asthma
A new study on asthma by Starship hospital respiratory paediatrician Professor Innes and colleagues and published in the New Zealand Medical Journal, has found that the prevalence of asthma symptoms in New Zealand is mainly decreasing, which is good news.
The explanation for this trend is unknown, but it is likely to be due to a combination of factors, including changes in unknown environmental causes of current asthma symptoms, or changes in asthma awareness or asthma treatment.
A trend of decreasing prevalence of asthma symptoms, if maintained, has positive implications in terms of reducing the burden of disease among asthmatics and reduced treatment costs.
New Zealand Herald (17 October 2008): Asthma symptoms decline
Innes Asher M, Stewart AW, Clayton T, et al. Has the prevalence and severity of symptoms of asthma changed among children in New Zealand? ISAAC Phase Three. New Zealand Medical Journal, 2008; 121 (1284): 52-63.
No link between early antibiotic use and asthma in young children
Another recent study by Professor Julian Crane of the University of Otago, Wellington, published in the August issue of Clinical and Experimental Allergy has found no link between early use of antibiotics and asthma in young children.
Children who are given antibiotics in the first three months of life often wheeze by 15 months of age, but this wheezing is more likely to be due to chest infections than the early use of antibiotics according to the new research.
The study followed a cohort of around 1000 children from Wellington and Christchurch from birth to four years of age. Analysis showed that by the time the children were 15 months old; nearly three quarters had been given antibiotics. In addition, 11.8% had asthma, 39.6% had eczema and 21.2% had a recurring itchy scaly rash and a key question is whether these health effects are linked to antibiotic use.
“Our results strongly suggest that the reason that some children who’ve been given antibiotics appear to develop asthma is because they had a chest infection and the symptoms of the chest infection in young children can be confused with the start of asthma. Antibiotics are then given to treat this respiratory condition, which may or may not be asthma, and are not a cause as has been previously suggested,” says Professor Crane.
“However our study still leaves open the possibility that antibiotics have something to do with the development of eczema and itchy skin by four years, and allergic hypersensitivity by 15 months.”
The study concludes that much of the effect of antibiotics on the development of asthma in infancy can be explained by chest infections which are often difficult to distinguish from asthma at an early age.
Dominion Post (20 October 2008, pB3): Study debunks asthma myth
Wickens K, Ingham T, Epton M, Pattemore P, Town I, Fishwick D, Crane J. New Zealand Asthma and Allergy Cohort Study Group. The association of early life exposure to antibiotics and the development of asthma, eczema and atopy in a birth cohort: confounding or causality? Clin Exp Allergy. 2008; 38(8): 1318-1324.
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