Spatial distribution of tuberculosis in Mazandaran province-Iran: spatiotemporal modeling

ABSTRACT

Incidence of Tuberculosis [TB] in Golestan province is higher than its national incidence rate in Iran [about 13 in 100, 000]. Considering the proximity of Mazandaran to Golestan this survey was conducted to determine the high risk areas in Mazandaran province. This was an observational, longitudinal, ecological study conducted during the years 1999 to 2008. Our understudy cases were 2, 444 TB patients registered in the TB center of Mazandaran province. Collected data including patients' age, gender, type of disease and residential location were analyzed using descriptive statistical methods and Nested Poisson regression models. Of 2, 444 registered patients, 1, 283 [52.5%] were males and 1, 161[47.5%] were females; among which, 61% were urban and 39% were rural residents. A total of 96.4% of them were Iranian. No significant difference was observed in TB incidence between the two genders, but incidence of TB in the cities of Tonekabon and Behshahr was 30% higher than the mean incidence rate of this province [P<0.05]. Risk of contracting TB infection was 1.46 times greater in urban compared to rural areas [95% confidence interval=1.35-1.59]. No significant difference was detected between our study results and those of similar studies conducted in Gilan and Golestan provinces. Higher incidence of TB in Behshahr and Tonekabon compared to the mean incidence of the province is indicative of the spatial correlation of the disease. Lower incidence of TB in neighboring cities might be due to delayed detection of smear-positive pulmonary TB patients