Tuberculosis in Turkey: high altitude and other socio-economic risk factors

In Turkey, there are insufficient data regarding the relation between altitude and the incidence of tuberculosis (TB).

This study aimed to investigate the effect of high altitude and socio-economic conditions on the incidence of TB in Turkey.

The mean incidence of TB in 56 Turkish cities was measured as n/100,000 population between 1999 and 2005. The mean altitude of each city was recorded in metres.

The incidence of TB was lower in cities located at high altitude (P=0.000) and higher in cities with a high population density (P=0.000). Multivariate analysis showed that the incidence of TB in low altitude cities was 3.28-fold higher than in high altitude cities (P=0.000). In cities with a population density >80 people/km(2), the incidence of TB was 4.18-fold higher than in cities with a lower population density (P=0.000) Other factors found to affect the incidence of TB were having a social insurance card and a low annual income.

There was a strong negative correlation between altitude and the incidence of TB, and population density was significantly associated with the incidence of TB. Possession of a social insurance card and fertility rate were also risk factors for TB. The authors believe that altitude has a stronger influence on the incidence of TB than the other factors. The effect of altitude on TB may reveal new data, but further studies need to be undertaken to assess the effects of potential factors on the incidence of TB.