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Temporal dynamics of tuberculosis incidence in Piauí, northeast Brazil, 2010-2024: a time-series and decomposition
José Mário Nunes da Silva1,2,3, Ivone Venâncio de Melo3,4, Walter Massa Ramalho1
1Centre for Tropical Medicine, School of Medicine, University of Brasília, Campus Universitário Darcy Ribeiro, S/N, Brasília, DF 70910-900, Brazil.
Background:
Tuberculosis (TB) remains a major public health challenge in Brazil, characterised by marked regional heterogeneity. This study aimed to analyse the temporal dynamics of TB in a state of northeast Brazil.
Methods:
This was an ecological time-series study using official TB surveillance data on newly reported TB cases from 2010 to 2024. Age-standardised incidence rates (ASIRs) were analysed through seasonal-trend decomposition by Loess (STL) and Joinpoint regression models. Furthermore, the rates were decomposed to quantify the contributions of population ageing, population growth and epidemiological changes.
Results:
A total of 10 690 TB cases were reported. Time-series analysis revealed consistent seasonality, with peaks occurring in March-May and October-November. The ASIR declined from 25.8 per 100 000 in 2010 to 22.6 in 2024 (average annual percentage change -1.51 [95% confidence interval -2.50 to -0.38). The decline was most pronounced among women and individuals ages 50-79 y, whereas incidence increased among younger age groups. Decomposition analysis indicated that epidemiological improvements offset demographic effects until 2015. However, from 2023 onwards, population ageing and growth became the predominant drivers, leading to a net increase in incidence.
Conclusions:
Although TB incidence declined overall, recent resurgence highlights the growing impact of demographic dynamics and persistent regional disparities.
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