Incidence of tuberculosis in mountain areas and surrounding townships: dose-response relationship by geographic analysis.

PURPOSE: The incidence of tuberculosis (TB) in Taiwan is known to be high in aboriginal mountain areas and low in the surrounding non-mountain areas. The aim of this study was to assess whether TB incident cases in the surroundings of mountain areas decreased with distance from foci of mountain areas. METHODS: The mountain areas in Taiwan are adjacent to each other and divided into four geographic groups. Townships with high TB incidence in each group were treated as the foci of TB infection. The surrounding townships were then classified, by distance away from foci, into three levels: < 20 km, 20 to 40 km, and 40 to 60 km. Data were obtained on a total of 84,366 TB cases from 1991 to 1997 from the Taiwan Tuberculous Disease Registry Center. RESULTS: The incidence of TB in each of the four groups was significantly higher in the mountain areas compared with non-mountain areas, with relative risks ranging from 8.4 (95% confidence interval [CI], 7.8-9.1) for the southern group to 15.0 (95% CI, 13.4-16.9) for the northern group. Relative risks for surrounding townships decreased with distance in all four groups. Such a gradient relationship was statistically significant. CONCLUSIONS: A significant dose-response relationship between distance from townships with a high incidence of TB and the incidence of TB in the surrounding areas has been demonstrated.

Risk factors associated with death in a 12-month cohort analysis of tuberculosis patients: 12-month follow-up after registration.

The aim of the study was to investigate the risk of death for 12 months follow-up after registration of tuberculosis (TB), using a nationwide population-based retrospective cohort study. A total of 33851 new TB cases were enrolled from 2006 to 2008. Of these, 5584 (16.5%) patients died during the follow-up period because of TB, and 4224 (12.5%) patients died because of other causes. Multivariate survival analysis revealed that age, HIV, chronic kidney disease, stroke, cancer, and chronic liver disease and cirrhosis were significant risk factors associated with death. Patients of age 0 to 64 years with HIV, chronic kidney disease, cancer, stroke, chronic liver disease and cirrhosis, or diabetes had a higher risk of death than those without these comorbidities. The majority of the TB patients in Taiwan died because of causes other than TB, and death often occurred in the first 2 months after TB registration. Therefore, medical care and case management for those with comorbidities are advised to prevent death during TB treatment.

Screening for pulmonary tuberculosis among military conscripts in Taiwan.

BACKGROUND AND PURPOSE: Military service is obligatory for young men who are medically fit in Taiwan. Each year, all 19-year-old men are notified to undergo a required health check to determine their eligibility for military service. This study determined the prevalence of pulmonary tuberculosis (TB) among military conscripts in 1997 and 1998 and evaluated the effect of the mass radiographic screening program for military conscripts on the reported TB case rate. METHODS: During the annual health check, all 19-year-old men in Taiwan undergo miniature (70 x 70 mm) chest roentgenography (CXR). Those who have suspicious lesions on miniature films are notified to undergo follow-up CXR (14 x 14 inch) and sputum examinations. All these data for the period from 1997 to 1998 were analyzed to determine the prevalence of pulmonary TB. To evaluate the effect of the mass radiographic screening program among military conscripts on the reported TB case rates, annual data for newly diagnosed pulmonary TB in 1997 and 1998 were obtained from the National TB Register and analyzed by age and sex. RESULTS: A total of 305, 140 men eligible for military service underwent the required examination in 1997 and 1998. Pulmonary TB was diagnosed in 237 (0.08%) of these men, and 21 (6.9/100,000) had positive bacteriologic findings. In 1997 and 1998, the annual reported TB case rates for males and females were similar in both children and young adults, except for an early peak among men aged 19 years. CONCLUSION: The screening program resulted in a significant increase in the reported TB case rate among males aged 19 years. However, a low bacteriologic confirmation rate implies the possibility of over-diagnosis with CXR. Mass radiographic screening at the health check for military conscripts is inefficient in detecting bacteriologically confirmed TB, an observation with implications for screening policy development by the national TB program.

Pulmonary tuberculosis in the Taiwanese prison population.

BACKGROUND AND PURPOSE: Tuberculosis (TB) in prison is a serious public health problem that is fueled by overcrowding, poor nutrition and unsatisfactory medical services. To evaluate the magnitude of the TB epidemic in Taiwanese prisons, we analyzed the results of a screening program for TB among inmates. METHODS: A mass radiography screening was performed in 24 prisons and five jails from July 1998 through June 1999. The National TB Register was notified and treatment with a rifampin-based short-course anti-TB regimen was given for all cases identified in the screening. The outcome of treatment of TB inmates was determined from records of the National TB Register. RESULTS: A total of 51,496 inmates were screened. Pulmonary TB was diagnosed in 107 (258.7 per 100,000 population) inmates. Among them, 88 (82.2%) were newly diagnosed TB patients, 12 (11.2%) had a history of anti-TB treatment and were re-treated after screening, and seven (6.6%) had previously diagnosed TB and were receiving treatment at the time of screening. Of the 107 inmates with TB, 86 (80.4%) completed treatment, 17 (15.9%) were lost to follow-up due to release from prison, and four (3.7%) died (three of TB). During a mean of 26.2 +/- 4.4 months (range, 19.7-39.0 mo) post-registration follow-up, three patients who had completed treatment relapsed. CONCLUSIONS: The high prevalence of TB in prisons indicates that prison administrators and the national TB program in Taiwan need to strengthen their activity to control this disease. The establishment of a surveillance section of the national TB program to systematically collect data on TB in prisons may facilitate efforts to monitor and control TB both in prisons and the general population. Our findings also indicate that TB control in prisons should give top priority to improving mycobacteriology laboratory services to ensure the quality of sputum examinations.