Does tuberculosis have a seasonal pattern among migrant population entering Iran?
BACKGROUND
There are few quantitative documents about the seasonal incidence of tuberculosis (TB) among immigrant populations. Concerning the significant role of recognizing seasonal changes of TB in improving the TB control program, this study determines the trend and seasonal temporal changes of TB among immigrants entering Iran.


METHODS
In this longitudinal study, data from the Iranian TB register Program (from 2005 to 2011) was used. The aggregated number of monthly and seasonal TB cases was obtained by adding the daily counts. Data was analyzed by Chi-square, Independent T-test, ANOVA, and Poisson regression using Stata 11 and SPSS 20 software.


RESULTS
Among 74,155 registered patients with TB, 14.3% (10,587) were non-Iranian who had immigrated to Iran from 29 different countries. The highest aggregated number of seasonal and monthly incidence of TB in immigrants was observed in spring (2824, P= 0.007) and in May (1037, P< 0.001). The number of non-Iranian patients with TB increased significantly over the years (β= 0.016, P= 0.001).


CONCLUSIONS
This study shows that immigrants constitute a significant portion of TB patients recorded in Iran and this trend is increasing. Also, the peak incidence of this disease is the second month of the spring.
Mazandaran University of Medical Sciences, Sari, Iran. ; Department of Biostatistics and Epidemiology, Faculty of Health, Kerman University of Medical Sciences, Kerman, Iran.
Mahmood
M
Moosazadeh
Neurology Research Center, Shafa Hospital, Kerman University of Medical Sciences, Kerman, Iran.
Narges
N
Khanjani
Department of Biostatistics and Epidemiology, Faculty of Health, Kerman University of Medical Sciences, Kerman, Iran.
Abbas
A
Bahrampour
Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
Mahshid
M
Nasehi
Iran; Migrant; Seasonality; Tuberculosis (TB)