Fewer colds, less asthma? A hypothesis to explain the fall in childhood asthma in the UK

Abstract

UK asthma prevalence fell significantly between 1993 and 2000. In children aged <5 years hospital admissions for asthma fell by 52% and primary care presentations in children under 14 years by over 40%. From 1994 to 2000, primary care consultations for acute respiratory infections in all age groups fell by 36%, and for the common cold by 46%. Isolates for respiratory syncytial virus notified to the Health Protection Agency voluntary reporting scheme fell by 56% between 1993 and 2003. Falls in UK birth rate and improvements in living conditions were reported by the Office of National Statistics over this time. The authors hypothesise that the fall in asthma reflects a fall in respiratory infections, the most important proximal trigger for asthma exacerbations, and that this in turn may be related to a fall in household members to a number too low for effective virus transmission. Future research into the prevalence of asthma must consider the effect of changing respiratory virus burden on populations.

Early origins of health disparities: Burden of infection, health, and socioeconomic status in U.S. children

“…Our finding that an increased burden of infection is associated with a higher likelihood of reporting asthma or chronic respiratory problems is consistent with recent evidence from the U.K. that a decline in cold viruses was associated with declining rates of asthma between 1993 and 2003, thought to be due to the role these viruses played in exacerbating respiratory problems (Urquhart, Anderson, & McKenzie, 2008). While our infection burden measure did not include any cold or respiratory viruses, to the extent that they share common exposure, transmission, or susceptibility pathways with our measured pathogens, they might have been picked up in our latent infection burden index.…”

Changing prevalence of wheeze, rhinitis and allergic sensitisation in late childhood: findings from 2 Isle of Wight birth cohorts 12 years apart

“…Allergic conditions are complex diseases where multiple environmental exposures, hereditary factors and gene-environment interactions play important roles [13]. One of the criticisms for this paper would be not looking at all the plausible factors such as decreasing birth rate, changes in family sizes, changes in living conditions and respiratory viral infections [12,31]. Parental history is a known risk factor for developing allergic airway diseases [32,33], and prenatal smoke exposure is associated with the development of asthma [33].…”