Modifiable lifestyle factors linked to adult-onset asthma
MedWire News: A high body mass index (BMI) and smoking are associated with an increased risk for adult asthma, while a diet rich in fruit and fish may protect against development of the condition, Swedish study findings suggest.
“The causes of the worldwide increase in asthma seen during the last decades remain largely unexplained, but lifestyle and diet are suggested to play important roles,” explain Monica Uddenfeldt (Uppsala University) and team in the journal Respiratory Medicine.
To identify possible modifiable risk factors for adult-onset asthma, the researchers surveyed 12,560 randomly selected individuals from three age groups (16, 30–39, and 60–69 years) from two counties of Sweden in 1990. Of these, 8150 completed a follow-up questionnaire in 2003.
The researchers found that the prevalence of asthma increased significantly over the study period in all age groups, from 11.3% in 1990 to 25.0% in 2003. In total, 791 respondents developed adult-onset asthma over the 13-year period.
Analysis revealed that modifiable factors associated with an increased risk for adult-onset asthma included smoking (relative risk [RR]=1.37), increased BMI (RR=1.49 per interquartile range), and nocturnal gastro-esophageal reflux more than once a week (RR=2.16).
In contrast, a diet high in fruit and fish was protective against the development of adult-onset asthma, especially in the elderly, at an RR of 0.52.
The impact of risk factors differed between the age groups, with BMI having a significantly higher impact in the middle-aged and the elderly than in the younger age group. Nocturnal gastro-oesophageal reflux had a significantly higher impact in middle-aged and young adults compared with the elderly.
There was no significant difference in the impact of risk factors between men and women.
Uddenfeldt and colleagues conclude: “This study adds evidence to an independent relationship between certain lifestyle factors and the cumulative incidence of asthma in adults.”
They add: “Weight loss, reduced smoking, and a diet rich in fruit and fish may be of importance to prevent the onset of adult asthma.”
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By Mark Cowen