Tuberculosis among nurses in Aichi Prefecture, Japan

To elucidate TB transmission among nurses. The subjects of this retrospective study were 1,283 TB women aged 20-59 years registered in Aichi Prefecture between 1989 and 2003. All registration files were reviewed to identify their occupation and working places. A total of 80 nurses were found among TB registers. Their age distribution was 45 (56.2%) in 20-29 years, 15 (18.8%) in 30-39 years, 14 (17.5%) in 40-49 years, and 6 (7.5%) in 50-59 years. The proportion of nurses aged 20-29 years decreased from 74.2% in 1989-93 to 24.0 % (p < 0.001) in 1999-2003, while those aged 40-49 years increased from 2.9% to 32.0% (p < 0.01). Regarding working places, 19 (23.8%) were in 4 TB hospitals, 54 (67.4%) in other 35 hospitals, 6 (7.5%) in 6 clinics, and one (1.3%) was in a home. The proportion of nurses in TB hospitals decreased from 31.4% in 1989-1993 to 4.0% (p < 0.05) in 1999-2003. Out of 73 nurses working in hospitals, 58 (79.5%) were working in hospitals with more than 250 beds with an emergency department. TB incidence were 49.1 per 100,000 population among 73 nurses working in hospital, and 14.3 among 6 nurses working in clinic, 39.5 among total 80 nurses, and 13.2 among 1203 women other than nurses. The relative risk was 3.7 for hospital nurses, 1.1 for clinic nurses, and 3.0 for whole 80 nurses. These findings suggest that TB incidence for nurses is 3-fold higher than age-matched women other than nurses, and that hospital nurses are infected with TB more frequently than clinic nurses.