Parental asthma or allergy is strongly associated with an increased risk for asthma in offspring. Moreover, this risk is relatively unaffected by whether there is a maternal or paternal asthma history. These were among study findings published in Respiratory Medicine.
Investigators in Denmark sought to track the epidemiology of familial asthma. Specifically, the investigators assessed the relative effects parental asthma vs parental allergy on the odds of offspring having asthma, as well as the relative effects of maternal vs paternal asthma on asthma incidence, using data from the cross-sectional Danish GEneral SUburban population Study (GESUS), conducted from 2010 to 2013. The study included 21,362 adults from the suburbs of Copenhagen.
All participants completed a physical health examination with pulmonary function testing as well as a questionnaire. Logistic regression adjusted for age and sex was used to analyze the risk for asthma in those whose biological mothers or fathers had asthma. Of the cohort, 2071 participants (9.7%; mean [SD] age, 53  years; 60% female) had ever asthma (ie, had been diagnosed at some point with asthma), 1128 (5.3%; mean age 55  years; 59% female) had persistent asthma, 814 (3.8%; mean age 57  years; 60% female) had clinical asthma, and 18,086 (mean age, 56  years; 53% female) were without asthma.
The prevalence of ever asthma was increased among participants reporting asthma vs participants who did not report asthma in their biological mothers (20% vs 9%, respectively) or fathers (22% vs 9%, respectively). The prevalence of persistent asthma and clinical asthma was higher among individuals with mothers with asthma vs without asthma (12% vs 5% and 9% vs 3%, respectively) and among individuals with fathers with asthma vs those without (13% vs 5% and 9% vs 3%, respectively). Comparable differences in the prevalence rates for ever asthma, persistent asthma, and clinical asthma were seen when comparing study participants whose parents did and did not have allergies.
We conclude that in the GESUS study parental asthma or allergy were strongly linked to higher asthma risk in offspring, without a prominent maternal or paternal effect.
The odds ratio for ever asthma was increased in the offspring of mothers with asthma (2.46; 95% CI, 2.15-2.81) and fathers with asthma (2.97; 95% CI, 2.58-3.42) compared with the offspring of parents without asthma, after adjustment for age and sex. The adjusted odds ratios for persistent asthma and clinical asthma were higher among the individuals whose mothers had asthma (2.57; 95% CI, 2.17-3.04 and 2.81; 95% CI, 2.32-3.40, respectively) and whose fathers had asthma (3.02; 95% CI, 2.54-3.60 and 3.00; 95% CI, 2.46-3.67, respectively). Multivariable adjusted analyses revealed comparable increases in the risk for asthma among study participants with a family history of asthma and allergy.
No significant differences were observed in adjusted odds ratios for ever asthma, persistent asthma, or clinical asthma in the offspring of mothers vs fathers with asthma, (2.46 vs 2.97, P =.06; 2.57 vs 3.02, P =.19; and 2.81 vs 3.00, P =.64, respectively). A similar pattern occurred regarding the risk of asthma in the offspring of mothers vs fathers with allergies for persistent asthma (2.03 vs 2.49, P =.69) and clinical asthma (2.00 vs 2.58, P =.09), although this pattern did not recur with respect to ever asthma (1.96 vs 2.44, P =.03).
Multivariable adjusted analyses showed that paternal asthma was associated with a greater risk of ever asthma compared with maternal asthma, and paternal allergy was associated with a greater risk for ever asthma, persistent asthma, and clinical asthma vs maternal allergy.
Among several limitations, not all participants completed the survey, which may have led to an underestimation of some of the associations. Also, the cohort consisted primarily of White individuals, and so the findings cannot necessarily be generalized to other populations.
“We conclude that in the GESUS study parental asthma or allergy were strongly linked to higher asthma risk in offspring, without a prominent maternal or paternal effect,” said study authors. “The risk for all 3 ‘classifications’ of asthma was increased by either maternal or paternal asthma, as well as by maternal or paternal allergy history,” stated the investigators.