Changing dynamics of tuberculosis incidence in Northwest Iran (East Azerbaijan): 15-Year joinpoint time trend...

Tuberculosis remains a major public health challenge in Iran due to changing demographic and epidemiological patterns. Understanding these trends is essential for disease control. We used Joinpoint regression to analyze tuberculosis trends in northwest Iran during 2005-2019.

All tuberculosis cases from East Azerbaijan Province (2005-2019) were extracted from the national TB surveillance database. Population data were obtained from the national census, with inter-census years estimated by linear interpolation. Temporal incidence trends were assessed using Joinpoint regression, yielding annual percent change and 95% confidence intervals. Analyses were stratified by age and sex to examine incidence differences.

Between 2005 and 2019, 3,827 tuberculosis cases were reported in East Azerbaijan Province, with women comprising 53% of cases and a median patient age of 55 years. The age-standardized incidence rate increased until 2012 (APC: +2.6%, 95% CI: 1.2-4.1), then declined significantly (APC: - 6.4%, 95% CI: - 8.1 to - 4.7), reaching 2.8 per 100,000 by 2019. The most marked decreases were observed in men aged 15-34 years (APCs: - 11.6% and - 23.3%), with similar reductions among women in this age group. Trends among older adults were more variable, but after the joinpoint, the decline became significantly steeper among women (APC: - 7.7%, P < 0.001).

The decline in tuberculosis incidence since 2012, especially among younger groups, indicates progress in local TB control. However, rising rates among older men highlight new demographic concerns. Continued surveillance and targeted interventions are crucial to sustain gains and further reduce tuberculosis in the province.