Incidence and Prevalence of Sarcoidosis
The frequency of sarcoidosis (the percentage of a population infected at a given time) is largely unknown because many cases are asymptomatic and are never reported. Often, sarcoidosis is discovered by a chest x-ray done for other purposes, or it is not seen until autopsy after death.
According the the NIH's National Heart, Lung, and Blood Institute, the occurrence of sarcoidosis was considered rare in the United States until fairly recently. It was detected in large numbers during a mass chest x-ray screening of U.S. military personnel in the 1940s. In 1990, Congress declared a Sarcoidosis Awareness Day to increase awareness of the disease.
Although usually considered a fairly mild condition, sarcoidosis can be very serious and life-threatening, especially in certain racial and ethnic groups. For example, in the United States, young African-American men suffer the most severe form of sarcoidosis and have the highest mortality rate.
Unlike most lung diseases, sarcoidosis actually occurs more frequently in nonsmokers than smokers. It is not clear why.
Geographical Incidence of Sarcoidosis
The frequency of sarcoidosis varies from place to place. In some areas it is high, and in others it is low. In Sweden, for example, where sarcoidosis is considered very common, more than 60 people out of every 100,000 are affected; in New York, 39 out of every 100,000 are affected, and in Spain, only 1.2 per 100,000 are infected. Sarcoidosis is rarely reported in the Middle East, China, SE Asia, or among the Inuit or Native North Americans.
Racial Variation of Sarcoidosis
Within a geographical area, the frequency and course of the disease vary considerably among racial groups. In one study of sarcoidosis in London, for example, the incidence of sarcoidosis in W. Indian and Asian immigrants is 10 times higher than in the indigenous Caucasian population. Also, in the immigrant population, there is a greater need for corticosteroid treatment and a lower chance for full recovery.
In another study, researchers found that sarcoidosis in S. Africa occurs in 23 out of every 100,000 black persons, 12 of every 100,000 mixed race persons, and 4 of every 100,000 Caucasians.
In the United States, various studies have shown that sarcoidosis occurs in 1080 of every 100,000 African Americans, compared to less than 8 of every 100,000 Caucasians.
Gender & Sarcoidosis
African American women develop sarcoidosis twice as often as African American men. Caucasian women and men are equally likely to develop it.
Age & Sarcoidosis
The highest prevalence of sarcoidosis occurs in people who are between 25 and 34 years old.