Childhood adversities and adult-onset asthma: a cohort study

Objectives: Childhood adversities may be important determinants of later illnesses and poor health behaviour. However, large-scale prospective studies on the associations between childhood adversities and the onset of asthma in adulthood are lacking. Design: Prospective cohort study with 7-year follow-up. Setting: Nationally representative study. Data were collected from the Health and Social Support (HeSSup) survey and national registers. Participants: The participants represent the Finnish population from the following age groups: 20-24, 30-34, 40-44, and 50-54 years at baseline in 1998 (24 057 survey participants formed the final cohort of this study). The occurrence of childhood adversities was assessed at baseline with a six-item survey scale. The analyses were adjusted for sociodemographic characteristics, behavioural health risks and common mental disorders. Primary and secondary outcomes: The survey data were linked to data from national health registers on incident asthma during a 7-year follow-up to define new-onset asthma cases with verified diagnoses. Results: A total of 12 126 (59%) participants reported that they encountered a childhood adversity. Of them 3677 (18% of all) endured three to six adversities. During a follow-up of 7 years, 593 (2.9%) participants were diagnosed with incident asthma. Those who reported three or more childhood adversities had a 1.6-fold (95% CI 1.31 to 2.01) greater risk of asthma compared to those without childhood adversities. This hazard attenuated but remained statistically significant after adjustment for conventional risk factors (HR 1.33; 95% CI 1.06 to 1.67). Conclusions: Adults who report having encountered adversities in childhood may have an increased risk of developing asthma.