The effect of physical activity on asthma incidence over 10†years: population-based study.

Although there are many health benefits from being active, there was no benefit observed in this study from vigorous physical activity in reducing the risk of asthma onset in middle-aged adults https://bit.ly/3bEtHDn.

The Association of Early Life Viral Respiratory Illness and Atopy on Asthma in Children: Systematic Review and Meta-Analysis.

BACKGROUND: The interaction between early life viral respiratory illness and atopy in the genesis of asthma has been widely discussed in the literature as the "two-hit hypothesis." OBJECTIVE: To synthesize evidence regarding the association of childhood viral respiratory illness and atopy in the development of persistent wheezing and asthma. METHODS: A systematic review was performed, according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Human studies investigating early life associations between atopy and viral respiratory illness with outcomes of asthma and wheezing were included. Meta-analysis was performed to investigate the association of viral illness across atopic and nonatopic groups. Subgroup analysis was undertaken to investigate potential effect modification of age at outcome. RESULTS: Nine cohort studies were included, with data available for meta-analysis in 4 birth cohort studies. There was a stronger association of viral respiratory illness with persistent asthma/wheeze in atopic (odds ratio [OR], 4.02; 95% CI, 1.46-11.06) compared with nonatopic (OR, 2.32; 95% CI, 1.22-4.40) individuals; however, the evidence for this was limited. In 3 studies amenable to subanalysis based on outcome age, a stronger effect was observed up to 7 years for those with atopy (OR, 7.27; 95% CI 4.65-11.36) compared with those without atopy (OR, 3.19; 95% CI, 2.09-4.87). CONCLUSIONS: There was a stronger association between viral respiratory illness and asthma/wheeze outcomes in individuals with atopy as compared with those without atopy. When outcomes were considered at younger ages, a greater differential effect was observed. Within the limitations of the few available studies however, definite conclusions cannot be made. There was also insufficient evidence for differential effects of early versus late atopy. Further research, in particular regarding virus type, timing of atopy, and atopic phenotype, would contribute to untangling this complex association.

Physical activity and asthma: cause or consequence? A bidirectional longitudinal analysis.

BACKGROUND: There is increasing interest in the role physical activity (PA) can play in the development and management of asthma. Understanding whether PA can have a positive effect is hindered by the potential influence of asthma on PA and a lack of relevant longitudinal data, leading to a debate on the existence and direction of these links. The aim of this study was to explore whether having asthma results in lower PA levels, and/or whether lower PA levels lead to more asthma in children and adolescents. METHODS: In a population-based study of 4983 children, data on asthma and PA were collected via questionnaires and time use diaries biennially, between the ages of 6 and 14. Current asthma was defined as use of asthma medications or wheeze in the past year, and incident asthma was defined as doctor's diagnosis since the previous wave. PA was time spent doing moderate-to-vigorous physical activities in a day. Bidirectionality of this relationship was investigated using cross-lagged structural equational models. RESULTS: PA was not longitudinally associated with incident or current asthma. Similarly, there was no evidence that incident or current asthma predicted PA at any of the ages. CONCLUSIONS: Using a novel strategy to investigate bidirectionality between PA and asthma, our results suggest that asthma and PA participation are not longitudinally associated in either direction. Our findings suggest that PA does not play an important role in the development or persistence of asthma.