Is self-reported history of eczema and hay fever a valid measure of atopy in those who report current asthma?

Age at asthma diagnosis and onset of symptoms among adults with allergic and non-allergic asthma

Background

Childhood-onset allergic asthma is the best-known phenotype of asthma. Adult-onset asthma, also an important entity, is instead often shown to be more non-allergic. There is still a lack of studies concerning the association of allergies and age at asthma onset from childhood to late adulthood. The aim of the study was to assess the age at onset of asthma symptoms and age at asthma diagnosis among adults with allergic and non-allergic asthma.

Methods

Questionnaires were sent to 2000 randomly selected Finnish adults aged 18-80 years who were dispensed medication for obstructive airway diseases during the previous year. The corrected sample size was 1978 subjects after exclusion of non-analysable data. The response rate was 40.6%. Self-reported doctor-diagnosed asthma was considered allergic if a concomitant self-reported doctor-diagnosed pollen and/or animal allergy was reported with asthma symptoms upon allergen exposure.

Results

Of the 496 participants with asthma, 42.7% were considered to have allergic asthma. The median ages at asthma diagnosis and onset of asthma symptoms were 31 (IQR 17-46) and 20 (9.25-40) years in participants with allergic asthma and 49 (37.75-58) and 40.5 (30-50) years in participants with non-allergic asthma (p < 0.001), respectively. Of the participants with asthma diagnosed at ≥30 years of age, 18% of allergic and 7% of non-allergic participants reported having had asthma symptoms under 20 years of age.

Conclusions

Both the onset of symptoms and diagnosis occurred at a younger age among adults with allergic asthma than among those with non-allergic asthma. Only a minority of adults with non-allergic asthma had already had symptoms in younghood.

Parental preconception BMI trajectories from childhood to adolescence and asthma in the future offspring

BACKGROUND

Recent evidence suggests that parental exposures before conception can increase the risk of asthma in offspring.

OBJECTIVE

We investigated the association between parental preconception Body Mass Index (BMI) trajectories from childhood to adolescence and subsequent risk of asthma in their offspring.

METHODS

Using group-based trajectory modeling from the Tasmanian Longitudinal Health Study (TAHS), we identified BMI trajectories for index participants (parents) when aged 4 to 15 years. Multinomial regression models adjusted for potential confounders were utilized to estimate the association between these early-life parental BMI trajectories and asthma phenotypes in their subsequent offspring.

RESULTS

The main analysis included 1822 parents and 4208 offspring. Four BMI trajectories from age 4 to 15 years were identified as the best fitting model: "low" (8.8%); "normal" (44.1%); "above normal" (40.2%); and "high" (7.0%). Associations were observed between father's "high" BMI trajectory and risk of asthma in offspring before the age of 10 years (RRR=1.70, 95%CI 0.98, 2.93) and also asthma ever (RRR=1.72, 95%CI 1.00, 2.97), especially allergic asthma ever (RRR=2.05, 95%CI 1.12, 3.72). These associations were not mediated by offspring birth weight. No associations were observed for maternal BMI trajectories and offspring asthma phenotypes.

CONCLUSION

This cohort study over six decades of life and across two generations suggests that the "high BMI" trajectory in fathers, well before conception, increased the risk of asthma in their offspring.