Impact of immigration on burden of tuberculosis in Umbria: a low-incidence Italian region with high immigrants rates

Background In Italy, Tubercolosis (TB) has increasingly become a disease for specific population subgroups such as immigrants. In 2008 TB incidence among Italians was 3.8/100.000, TB incidence among foreign born persons was 52,1/ 100.000. Methods To describe the trend in TB incidence from 1999 to 2008 in Umbria: a low-incidence Italian region with high immigrants rates (9.7%), we utilized data 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 lowincidence countries and it is characterized by particular clinical features and risk factors.