[A study on chest radiographs in medical check-ups for over-staying foreigners]

During the past nine years from 1991 to 1999, Minatomachi Medical Center and other organizations have provided free medical check-ups for foreigners in Kanagawa, Tokyo and Chiba. Eighty-five percent of the total of the 2370 examined were over-staying foreigners who were not covered by national health insurance system. The ratio of male to female was two to one and the most of them were in the twenties and thirties. As for their ethnic origins from forty-three countries, the Filipinos were the largest numbers, followed by Koreans, Iranians, Bangladeshi, and Chinese/Taiwanese. As a result of chest radiographs, 82% were normal, 8.3% mostly normal, 9.6% tuberculosis shadow (TBS) including active, non active and previous, 0.09% suspected pneumonia, 0.05% suspected cardiac disease, and 0.05% suspected sarcoidosis. The TBS and active tuberculosis (ATB) rates of all examined were 9.6% and 0.69% respectively. There was no significant difference in each TBS and ATB rate between the two sexes. Seen from the age group, it was found that the more aged they were, the higher the TBS and the ATB rates were. The TBS and the ATB rates were 24.6% and 2.73% in the Koreans, 10.7% and 0% in the Chinese/Taiwanese, 10.2% and 0.65% in the Filipinos, 11.3% and 1.44% in the South-East Asians, 6.3% and 0.25% in the South Asians, 2.3% and 0% in the Iranians, 3.7% and 0% in the sub-Saharan Africans, 8.5% and 0.61% in the Latin Americans, and 0% and 0% in the Europeans/North Americans. Based on a presumed ATB rate of 0.75%, approximately two thousand cases with ATB could be calculated to exist among the estimated 270,000 over-staying foreigners. It is, therefore, important to give them more frequent medical check-ups for early detection of latent cases with ATB.