Influence of Childhood Exposure to a Farming Environment on Age at Asthma Diagnosis in a Population-Based Study

Abstract

Purpose: Asthma is a heterogeneous disease, and factors associated with different asthma phenotypes are poorly understood. Given the higher prevalence of farming exposure and late diagnosis of asthma in more rural Western Finland as compared with the capital of Helsinki, we investigated the relationship between childhood farming environment and age at asthma diagnosis. Methods: A cross-sectional population-based study was carried out with subjects aged 20-69 years in Western Finland. The response rate was 52.5%. We included 3864 participants, 416 of whom had physician-diagnosed asthma at a known age and with data on the childhood environment. The main finding was confirmed in a similar sample from Helsinki. Participants were classified as follows with respect to asthma diagnosis: early diagnosis (0-11 years), intermediate diagnosis (12-39 years), and late diagnosis (40-69 years). Results: The prevalence of asthma was similar both without and with childhood exposure to a farming environment (11.7% vs 11.3%). Allergic rhinitis, family history of asthma, exsmoker, occupational exposure, and BMI ≥ 30 kg/m 2 were associated with a higher likelihood of asthma. Childhood exposure to a farming environment did not increase the odds of having asthma (aOR, 1.10; 95% CI, 0.87-1.40). It did increase the odds of late diagnosis (aOR, 2.30; 95% CI, 1.12-4.69), but the odds were lower for early (aOR, 0.49; 95% CI, 0.30-0.80) and intermediate diagnosis of asthma (aOR, 0.75; 95% CI, 0.47-1.18). Conclusion:Odds were lower for early diagnosis of asthma and higher for late diagnosis of asthma in a childhood farming environment. This suggests a new hypothesis concerning the etiology of asthma when it is diagnosed late.

NSAID-exacerbated respiratory disease: a population study

“…Childhood exposure to farming environment was significantly more common in N-ERD than asthma without N-ERD, whereas a nonsignificant trend was seen compared to healthy controls. In our recent study, childhood exposure to farming environment had lower odds of early-diagnosed asthma and higher odds of late-diagnosed asthma [ 23 ].…”

Age at asthma diagnosis is related to prevalence and characteristics of asthma symptoms

“…However, it did increase the odds for having asthma diagnosed at late age (defined as age >40). 32 It has been speculated if adult-onset asthma would be a relapse rather than initiation of the disease and whether asthma symptoms beginning in adulthood would have originated in childhood. 33,34 However, subjects with adult-onset versus child-onset asthma seem to have different basic characteristics, such as gender and BMI, 2,14 which challenges this assumption.…”

The Role of Early Life Microbiota Composition in the Development of Allergic Diseases

“…Such studies have proved that there is a codependent relationship between gut microbiota and immune system development [66][67][68][69][70][71][72][73][74][75][76]. [77], preterm birth [78], formula feeding [79], and cesarean section delivery [80] increase the development of asthma in infants, while living in a big family [81] and farming environment [82] decrease asthma incidents. Increased birth weight [83] and combined feeding of breast milk and formula [84] increase food allergy development in childhood.…”

“…Exposing children to a diverse microbial environment is important for establishing a healthy immune response. Studies have shown that children who grow up in farms [82,103,116], where they have much more contact with microorganisms compared to urban environments, have a lower rate of developing allergic diseases. Studies have also indicated that early life respiratory tract colonization with certain bacteria, such as Streptococcus, Moraxella, or Haemophilus, increase the severity of lower respiratory viral infection in the first year of life, and the risk of developing asthma symptoms later in life [117].…”

“…Influencing factors in the development of allergic diseases in infancy. Factors such as antibiotic exposure[77], preterm birth[78], formula feeding[79], and cesarean section delivery[80] increase the development of asthma in infants, while living in a big family[81] and farming environment[82] decrease asthma incidents. Increased birth weight[83] and combined feeding of breast milk and formula[84] increase food allergy development in childhood.…”