Epidemiology of tubercolosis in a low-incidence Italian region (1999-2008)

In Italy, Tuberculosis (TB) has increasingly become a disease for specific population subgroups such as immigrants. Although from 1974 in Italy the TB incidence for whole population is stable below 10 new cases/100.000 inhabitants, TB incidence in immigrants is considerably higher than Italians. In 2008 TB incidence among Italians was 3.8/100.000, TB incidence among foreign born persons was 52,1/100.000. Objectives To describe the trend in TB incidence from 1999 to 2008 in Umbria: a low-incidence Italian region with high immigrants rates (9.7 %), exploring main differences between foreign-born and nativeborn. Methods Data were obtained from the Regional Information System for Infectious Diseases. Personal data, citizenship, occupational status, professional position, sector of activity and site of the disease (pulmonary, extra-pulmonary and disseminated) of all notified TB cases were extracted. Using a linear regression model we estimated trends for number of cases and incidence rates; with a logistic regression model we estimated the effect of a set of covariates on the probability of being affected by TB. Result 590 TB cases were reported of whom 43 % were immigrants. The annual proportion of foreign-born cases on the total TB notifications increased from 20.3 % in 1999 to 49.2 % in 2008. In 2008 39.7 new cases per 100.000 were registered among foreign-born subjects and 33.05/100.000 adding 20 % of estimated irregular presences to the denominators. TB incidence among Italians was 3.8/ 100.000. But a linear regression analysis showed a statistically significant decreasing trend in the notification rate among foreign-born people (coef: -7.32, r2: 0.57, p\0.05). 74.2 % of reported TB cases were diagnosed with pulmonary disease, 23.1 % had a diagnosis of extrapulmonary TB and only 2.7 % with disseminated TB. The probability to be affected by extra-pulmonary is significantly larger in foreign patients (95 % CI = 0.48–1.07). Foreign unskilled workers report a higher probability to be affected by TB (95 % CI = 6.01–60.4) than Italy born ones (95 % CI = 0.75–2.45). Unemployment instead is significant only for the not-Italy born group (95 % CI = 2.78–6.13). Conclusion Increasing immigration rates may affect TB epidemiology. The analysis of incidence trends is an important tool to identify specific sub-group at risk. TB among immigrants is a public health problem in Umbria and in Italy as well as in other low-incidence countries and it is characterized by particular clinical features and risk factors.