The hygiene environment during childhood may affect susceptibility to sarcoidosis: A case-control study of environmental risk factors.

BACKGROUND

This study investigated the association between the development of sarcoidosis and environmental factors, focusing on the childhood hygiene environment.

METHODS

This case-control study used a questionnaire administered to patients with sarcoidosis and residence-matched controls (age 18 to <90 years) in 7 prefectures between 2018 and 2020. Logistic regression analysis was performed to identify risk factors, including adulthood lifestyle history, childhood hygiene environment, and history of infections.

RESULTS

One hundred sixty-four patients with sarcoidosis and 1779 controls (641 men, 1138 women) were enrolled. Multivariate analysis showed that smoking history during adulthood was associated with developing sarcoidosis (odds ratio [OR], 2.09; 95 % confidence interval [CI], 1.16-3.75). For the childhood hygiene environment, attending nursery school (OR, 2.76; 95 % CI, 1.57-4.84) and use of well water (OR, 2.89; 95 % CI, 1.65-5.07) at age 0-2 years were associated with developing sarcoidosis. The OR of attending nursery school at age 3-6 years (OR, 1.79; 95 % CI, 0.89-3.61) was lower than that at age 0-2 years, but the OR of use of well water at age 3-6 years (OR, 2.89; 95 % CI, 1.59-5.26) was still high. By contrast, the risk of developing sarcoidosis was lower for being breastfed (OR, 0.36; 95 % CI, 0.15-0.88). Development of sarcoidosis was associated with history of tuberculosis (OR, 5.82; 95 % CI, 1.28-26.53).

CONCLUSIONS

Both adulthood lifestyle history and childhood hygiene environment were associated with sarcoidosis. Daily direct exposure to diverse microorganisms during childhood may increase the likelihood of antigens for granuloma formation entering the body and also modify susceptibility to sarcoidosis.