We investigated the association between the development of sarcoidosis and personal or family medical history, with a focus on immune-mediated inflammatory diseases (IMIDs), in a Japanese population.

In this exploratory case-control study, self-administered questionnaires were completed by 164 patients with newly diagnosed sarcoidosis (64 men, 100 women) who visited public health centres in 7 prefectures between 2018 and 2020 to apply for medical expense subsidies (cases) and by 1779 community-dwelling controls (641 men, 1138 women) undergoing municipal health checkups (controls). The questionnaire collected information on personal and family medical histories, including IMIDs. Logistic regression analyses adjusted for age and sex were used to identify risk factors associated with onset of sarcoidosis.

A history of IMIDs was associated with a greater likelihood of sarcoidosis (adjusted odds ratio [aOR] 3.05, 95 % confidence interval [CI] 1.79–5.21). Increased risk was observed for rheumatoid arthritis (aOR 2.63, 95 % CI 1.06–6.53), Sjögren's syndrome (aOR 14.39, 95 % CI 4.30–48.10), and hypothyroidism (aOR 4.91, 95 % CI 2.20–10.97). Some conditions, such as asthma, lymphoma, and insulin use, showed possible associations, with wide CIs including 1.0. Additionally, a family history of sarcoidosis was strongly associated with disease occurrence (aOR 21.30, 95 % CI 3.86–117.68), supporting a potential genetic predisposition consistent with previous epidemiological findings.

This study suggests that sarcoidosis may be associated with IMIDs in the Japanese population. However, its findings should be interpreted with caution, given its exploratory design and limited statistical power.