Asthma among Sámi in Sweden: a population-based register study

A population-based study has reported a higher prevalence of self-reported asthma among the Sámi compared with the general Swedish population. However, it remains unclear whether this reflects a true difference or reporting bias. This study aimed to estimate asthma incidence among the Sámi and compare it with that of the non-Sámi population using register-based data from 1993 to 2018. We conducted a retrospective cohort study using the Sámi electoral roll and the reindeer ownership register to identify Sámi individuals. Each Sámi participant was matched with four non-Sámi controls by age, sex and municipality. Asthma cases were identified through the National Patient Register, covering inpatient and specialist outpatient care. Incidence rate ratios (IRRs) were estimated using sex-stratified Poisson regression models. The study included 13,311 Sámi individuals and 53,219 controls. Sámi men (IRR = 1.19, 95% CI = 1.00-1.41) and women (IRR = 1.23, 95% CI = 1.04-1.45) had higher rates of specialist asthma diagnoses than controls. Sámi men, but not women, also had a higher risk of asthma-related hospitalisation (IRR = 1.43, 95% CI = 1.07-1.90). These findings suggest a higher asthma burden among the Sámi. Further research is needed to clarify underlying risk factors and inform targeted public health interventions.