[Background and objective] The incidence and annual risk of infection of tuberculosis (TB) have decreased rapidly in Japan because of the development of anti-TB medicines and nutritional and hygienic improvements after World War II. The incidence of tuberculosis is currently high among elderly people, reflecting the fact that the prevalence rate of TB infection had been extremely high during their youth. This would suggest that most current cases of TB in the elderly are reactivation of infections acquired in their youth. TB reactivation in various organs have both common and unique aspects. We evaluated the frequency of endogenous reactivation of TB in various organs by examining the TB incidence rate over a 30-year period (1975-2005) in Japan. [Methods] The incidence rate of TB in each organ was obtained for each 10-year birth cohort, using reports of newly registered TB patients in Japan in 1975, 1985, 1995, and 2005. Specifically, the incidence rates of pulmonary TB, lymph node TB, bone-joint TB, kidney TB, and meninges TB were analyzed. [Results] Chronological changes in TB incidence rates in each organ were characterized by a rapidly declining phase followed by a stationary phase in every organ TB except pulmonary TB. Incidence rates among the already infected population in the stationary phase were 3.0 (lymph node TB), 1.2 (bone-joint TB), 0.5 (kidney TB), and 0.3 (meninges TB) per 100,000 cases, respectively. [Conclusions] Once infected with TB, the incidence rate of TB in these organs does not decrease below the above-mentioned values.

[Objective] The aim of this study was to investigate the current status of doctor's delay in diagnosing endobronchial tuberculosis (EBTB) and to elucidate the risk factors contributing to the delay. [Methods] Retrospective clinicopathological analysis. [Patients] Sixty-two patients with EBTB were admitted at our hospital between 1999 and 2010. Their backgrounds, symptoms, diagnoses at initial consultation, delay in diagnosis, and clinical examination results were analyzed. [Results] Of the 62 patients, 59 had acid-fast, bacilli-positive sputum smear test results at admission. Among the 40 patients with total diagnostic delay of more than 2 months, only 11 experienced long patients delay exceeding 2 months. However, 22 patients experienced long doctors delay of more than 2 months (28％ vs. 55％, respectively, p＜0.05), suggesting that doctors delay contributes more to total delay than patients delay. Fever was less frequent in patients with long doctors delays than in those without (0％ vs. 18％, respectively), at the initial consultation. In addition, radiographs showed that patients with long doctors delays more frequently presented with shadows in the lower lung field (50％ vs. 23％, p＜0.05), and most of these patients had noncavitary shadows on admission. All 7 patients diagnosed with bronchial asthma at the initial consultation had long doctors delays. [Conclusion] These findings demonstrate that long doctors delays in diagnosing EBTB remain an issue. The clinical features of EBTB with long doctors delays were confirmed to be quite different from those of pulmonary tuberculosis.