Age-related and historical changes in the clinical characteristics of sarcoidosis in Japan

National surveys conducted in Japan between 1960 and 2004 suggest a gradually increasing incidence of sarcoidosis in women >50 years old with increased involvement of the eye, skin, and heart. However, whether this involvement is due to the increased age at diagnosis is still unclear. We aimed here to identify the age-related differences in organ involvement in sarcoidosis in Japan, as well as the historical changes in clinical characteristics and the age-specific distribution of cases at diagnosis.

We reviewed 588 consecutive Japanese patients newly diagnosed with sarcoidosis between 1974 and 2012 at Jichi Medical University Hospital. We compared organ involvement between subgroups differentiated by sex and age (<45 years; n = 275; ≥45 years; n = 313) at diagnosis and identified historical changes in the age-specific distribution in 10-year intervals.

Younger patients had more common involvement of extrathoracic lymph nodes, parotid/salivary gland, and liver, while older patients had more common involvement of non-lymphatic extrathoracic organs such as the eye, heart, muscle, and kidney. The age at diagnosis has consistently increased over the past four decades. The monophasic distribution in men has tended to become biphasic, and the biphasic distribution in women monophasic. Increasing trends were apparent for hypercalcemia and involvement of the gastrointestinal tract, skin, nervous system, muscle, and kidney.

Elderly patients at diagnosis had various extrathoracic involvement including eye, skin, and cardiac lesions. Moreover, the age at diagnosis of sarcoidosis has continued to increase in both sexes, influencing the recent trends in clinical characteristics.