title: Time series cross-correlation analysis of HIV seropositivity and pulmonary tuberculosis among migrants entering Kuwait.
abstract: BACKGROUND
  There is a paucity of published data on burden and pattern of dual infection with Mycobacterium tuberculosis and HIV among migrants from South Asia, South-east Asia and sub-Saharan Africa entering the Middle-East, particularly Kuwait. Therefore, this study assessed the overall prevalence of HIV infection and pulmonary tuberculosis (TB) and evaluated the ecological relationship between them.
  
  
  METHODS
  Time series cross-correlation analysis was used to determine the ecological time-lagged relationship between the monthly proportions (per 100,000) of HIV seropositive and pulmonary TB cases among migrant workers that entered Kuwait between January 1, 1997 and December 31, 2006.
  
  
  RESULTS
  During the study period, overall prevalence (per 100,000) of HIV seropositivity and pulmonary TB among the migrants was 21 (494/23,28,582) (95% CI: 19-23), and 198 (4608/23,28,582) (95% CI: 192-204), respectively. Estimated cross-correlation function revealed a significant positive correlation (0.292±0.093) at lag -3 representing a positive relationship between the proportions of HIV seropositive (per 100,000) migrants tested 3 months earlier and the proportion of pulmonary TB (per 100,000) cases detected among migrants in a given month. Thus, the peak in proportion of pulmonary TB cases preceded the peak in proportion of HIV seropositive migrants indicating a direct time-lagged association between HIV seropositivity and the prevalence of pulmonary TB among migrants.
  
  
  CONCLUSIONS
  HIV infection seemed to have played a significant role in the re-activation of latent M. tuberculosis infection in this migrant population. While currently less evident, in near future, however, TB and HIV/AIDS control programmes in the countries of origin of migrants may face a crucial challenge. Knowledge of serious consequences of association between HIV infection and pulmonary TB allows the promotion of public heath education to reduce the exposure to these infections. Future studies may focus on evaluating the impact of public health education programs on this dual burden of HIV infection and pulmonary TB in migrants.
authors.affiliation: Department of Community Medicine and Behavioural Sciences, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait. Electronic address: saeed.akhtar@hsc.edu.kw.
authors.forename: Saeed
authors.initials: S
authors.lastname: Akhtar
authors.affiliation: Ports and Borders Health Division, Ministry of Health, P.O. Box 32830, Rumaithiya 25410, Kuwait.
authors.forename: Hameed Gh H
authors.initials: HG
authors.lastname: Mohammad
keywords: Cross-correlation; HIV; Kuwait; Migrants; Pulmonary tuberculosis