Early Onset Asthma, But Not Aeroallergen Sensitization, Is Associated With Lung Function Impairment in Young Adulthood-A Prospective Cohort Study.

BACKGROUND

Aeroallergen sensitization is a major factor in asthma, and asthma is associated with impaired lung function. The independent association between sensitization and lung function is unclear.

OBJECTIVES

To examine factors associated with lung function in adolescence, with special interests in sensitization and asthma.

METHODS

All schoolchildren in grade one and two (median age 8) in two municipalities in Northern Sweden were invited to a questionnaire survey of allergic diseases and skin prick tests to aeroallergens. This was repeated at ages 12 and, at 19 years also including spirometry and n = 1495 participated at all three occasions. Associations between risk factors and FEV, FVC and FEV/FVC were analysed by linear regression.

RESULTS

Aeroallergen sensitization was not associated with lung function, irrespective of age at onset, type or degree of sensitization. Early-onset asthma, both persistent (B -0.35, 95% CI -0.60 to -0.09) and in remission (B -0.43, 95% CI -0.74 to -0.12) was associated with lower FEV. Persistent asthma was associated with lower FEV/FVC (B -0.81, 95% CI -1.07 to -0.55), and remission with lower FVC (B -0.37, 95% CI -0.67 to -0.70). No interaction between asthma and sensitization was found. Maternal smoking in pregnancy was associated with lower FEV/FVC. Underweight at age 19 years was associated with lower FEV and FVC and overweight was associated with higher FEV and FVC, but lower FEV/FVC.

CONCLUSIONS

Aeroallergen sensitization was not independently associated with lung function. Early onset asthma was strongly associated with lung function impairments in young adulthood and in sensitized and non-sensitized individuals alike.