Concern about serious harm from the use of long-acting beta-agonists in asthmatic children is not new. While systematic reviews consistently show an increase in the rate of life-threatening exacerbations of asthma in patients on long-acting beta-agonists, it is uncertain whether or not concomitant use of inhaled corticosteroids is protective. This recent meta-analysis pooled all available data for both salmeterol and formoterol, and included previously unpublished data supplied to the US Food and Drug Administration from drug manufacturers. The authors compared ‘concomitant’ (consistent) to ‘variable’ (inconsistent) use of inhaled corticosteroids. The primary outcome measure was catastrophic asthma events (i.e. asthma-related intubations or deaths). Pooled data on over 36 500 adults and children found long-acting beta-agonists, irrespective of the use of inhaled corticosteroids, were associated with a significant increase in catastrophic asthma events; Odds Ratio (OR) = 2.10 (95% confidence interval (CI) 1.37–3.22). This is the first study showing that inhaled corticosteroids offer no protection, and the results were similar for both children and adults. An unexpected finding was the higher risk in trials with controlled concomitant inhaled corticosteroid use (OR = 8.2, 95% CI 1.1–61.2) than trials with no inhaled corticosteroid use (OR = 2.2, 95% CI 1.37–3.22). Despite the rarity of the outcome (59 events in 19 000 patients on long-acting beta-agonists, and 26 events in 17 500 patients on placebo), clinicians must carefully consider the risks and benefits of prescribing long-acting beta-agonists to children, particularly given that the data on their efficacy in children is weak. Submitted by: Craig Mellis (craig.mellis@sydney.edu.au) The role of cats and dogs in allergy is controversial. The authors examined 636 children of atopic parents annually from 1 year of age and performed skin prick testing (SPT). At 4 years of age, 90 children (14%) had eczema. Dog ownership before 1 year of age reduced the risk of eczema by 60% compared with no dog (Odds Ratio (OR) = 0.4, 95% confidence interval 0.2–0.7). Children with no dog in the home before 1 year who were or became SPT-positive to dog had a 3.9-fold increased risk of eczema, but this was only 30 of the 325 children with no dog, and does not imply causation. In contrast, cat ownership before 1 year was associated with an OR of 1.0 (0.6–1.7) of developing eczema. Of the 121 children with a cat in the home at 1 year, 13 became skin test-positive and seven (57%) developed eczema, so although the OR for skin positivity with a cat in the home was 13.3, this only refers to a very small number of children. This study suggests dog ownership may protect infants against developing eczema. Cat ownership does not affect the risk of eczema, although cat sensitisation is associated with eczema in a small number of children. However, this is only one of many studies, causation is unproven and killing cats is illegal. Reviewers: David Isaacs, davidi@chw.edu.au; Nick Wood, NicholW3@chw.edu.au This retrospective study analysed the live-birth prevalence of cystic fibrosis (CF) in Victoria, Australia before and after the introduction of routine newborn screening in 1989.1 Newborn screening for CF involves measuring neonatal immunoreactive trypsinogen (IRT) blood levels, a test with a sensitivity of around 95% for CF. Before 1991 an abnormal IRT was followed by a sweat test, but since 1991 an abnormal IRT result is followed by DNA testing and a sweat test is performed if the patient is heterozygous for the ΔF508 gene mutation. Prescreening (1979–1988), the live-birth prevalence of CF was 3.96 per 10 000 live births (95% confidence interval (CI) 3.48 to 4.49) compared with 3.28 per 10 000 live births (95% CI 2.97 to 3.63) from 1989 to 2006 postscreening. This 17% reduction in prevalence is attributed to the use of prenatal genetic testing on subsequent pregnancies by parents of infants with a positive newborn screening test. In the prescreening period, 10 prenatal tests were recorded (offered when there was a previous affected child or family history of CF), compared with 304 prenatal tests in the postscreening period. Most parents with an affected fetus on prenatal testing elected to terminate the pregnancy (70 of 76 affected pregnancies). The decline in the live-birth prevalence is more modest than the authors expected. Their explanation is the lack of uptake of wider family genetic testing for gene carrier status and the fact that 95% of parents with a baby identified as having CF on screening have no family history of CF. Link: http://adc.bmj.com/content/95/7/531.full Submitted by Jenny Gardner (jmg79@hermes.cam.ac.uk) and Aleisha Nielsen (AleishaN@chw.edu.au)