How the Frequency and Phenotype of Sarcoidosis is Driven by Environmental Determinants.

BACKGROUND: Sarcoidosis is a systemic disease in which the personal environment seems to drive a differentiated disease frequency and clinical expression. The main epidemiological studies suggest a key influence of potential environmentally linked exposures related to the type of occupation, the household, life style, socioeconomic status, and region of residence.

OBJECTIVE: To provide an update on how sarcoidosis may be modulated by environmental factors.

DATA SOURCES: We searched PubMed for epidemiological studies.

SYNTHESIS: The risk of sarcoidosis is enhanced in people working in jobs related to agriculture, water, construction, metal machining, education, and health, and reduced in those working in jobs mainly centered on personal care. Studies have confirmed seasonal-related peaks of sarcoidosis incidence that follow geographical North-South and West-East gradients. Other personal factors include smoking, personal household exposures, and leisure activities. The evidence pointing to the crucial role of the environment in the etiopathogenesis of sarcoidosis is mounting rapidly. Few diseases so strongly combine geography, environment, gender, and ethnicity as key etiopathogenic factors, with susceptibility to any putative agent being modulated by the individual exposome and genome.

CONCLUSION: Geoepidemiological research should focus on evaluating the combined effects of environmental and genetic factors, the identification of clusters of geographically driven exposures, and more precise measurement of all personal exposures (degree of combination, length, and level of exposure).