[TUBERCULOSIS SCREENING BY CHEST RADIOGRAPHY AMONG INTERNATIONAL STUDENTS AT JAPANESE LANGUAGE SCHOOLS IN OSAKA CITY].

Purpose: With a broader aim of controlling pulmonary tuberculosis (TB) among foreigners, here, we have reported the findings of chest radiography screening for TB among international students at Japanese language schools in Osaka city.

Methods: Between April 2011 and December 2013, 4,529 international students from 19 Japanese language schools in Osaka city underwent chest radiography for TB screening. The chest radiographs were studied in reference to the student's sex, age, nationality, and date of entry to Japan as well as any health conditions present at the time of screening. We further analyzed the bacterial information and pulmonary TB classification based on chest radiography findings of students who were identified to be positive for TB. Information on the implementation of health education was also gathered.

Results: The results revealed that 52.5% of the students who underwent chest radiography came from China, 20.3 % from South Korea, and 16.3% from Vietnam. Of the students, 52.9% were male and 47.1% were female. The median age of students was 23 years (range: 14-70 years). The median number of days from the first date of entry to Japan up until the radiography screening was 63 days. Based on the chest radiography findings, 71 students (1.6%) were suspected to have TB; however, further detailed examination confirmed that 19 students (0.4%) had active TB. This percentage is significantly higher than the 0.1% TB identification rate among residents in Osaka city of the same time period (P<0.001), which was also determined by chest radiography. The median age of the 19 TB positive patients was 23 years. Among them, 14 (73.7%) were male. The median time from the date of entry to Japan to the date of the chest radiography screening was 137 days. For 16 of those students, the entry to Japan was within 1 year of the radiography. Of the 19 TB positive patients, 16 (84.2%) did not have respiratory symptoms, 15 (79.0%) had sputum smear negative results, and 17 (89.5%) had no cavity. Health education was conducted in 11 schools (for a total of 12 times) in the 3-year period. A total of 257 language school staff and students attended the health education seminars.

Discussion: The identification rate of TB positive students in Japanese language schools was higher than that of the general residents in Osaka city. In addition, most of these students came to Japan within 1 year. It is also important to note that the majority of TB positive students had sputum smear negative results. This study proves that medical examination after entry to Japan would be useful for early detection of TB positive patients. Furthermore, it would be beneficial to conduct chest radiography screenings among students at language schools on a continuous basis. It is also necessary to provide health education to the staff and students in Japanese language schools. Effective methods of disseminating health education, especially on the topic of TB, should be considered.