The study aimed to describe the temporal trend of tuberculosis cases according to gender and age group and to make predictions considering the current context in an endemic municipality of northeast Brazil. The study also showed a curious fact, that is, although tuberculosis most commonly affects men of the economically active and older adult age groups, there was a high incidence of the disease in women in the 15 to 59 years age group, an unusual phenomenon, compared with other studies carried out in Brazil and internationally [15-20].
The majority of the tuberculosis cases occurred in men, especially in the 15 to 59 years age group, that is, people classified as economically active. This may have a negative impact on their lives and those of their families, as the disease in these people may result in removal from their workplaces, which may compromise their income and/or that of their family and contribute to the emergence or worsening of poverty [9,21-23]. These data indicate a warning situation, as they may signify a high transmission of the disease in the population.
This can also be associated with delays in diagnosis, social factors that make diagnosis and control difficult and with areas lacking sufficient screening measures [24]. Furthermore, this high incidence among men may be related to behavioral factors, such as the fact that they do not frequently seek medical attention when symptoms appear, as well as operational issues related to difficulties in accessing health services in a timely manner due to incompatibility between men’s working hours and those of health facilities, lack of a health policy directed toward men, and restricted access to health information [20].
In addition to these issues, the influence of socioeconomic and cultural factors, include the consumption of alcohol, tobacco and other drugs and having Diabetes mellitus or lung cancer, which are known risk factors for tuberculosis and are more common in the male population [24,25].
There also was a high incidence of tuberculosis in the female population in Imperatriz, especially in the 15 to 59 years age group (Figure 1F), demonstrating a feminization of tuberculosis, a phenomenon that is particularly present in the North and Northeast regions of Brazil [26]. This phenomenon may be related, not to the fact that they have difficulty in accessing health services, but, contrary to what is verified in the male population, they are more likely to abandon treatment [27,28]. Another possible explanation for this high incidence of tuberculosis, especially in the city of Imperatriz, concerns the educational level or the lack of knowledge of this population about tuberculosis, especially in relation to the symptoms, diagnosis of the disease and treatment.
Regarding education, according to data from DATASUS, referring to the female population of Imperatriz, in the 15 to 59 years age group, 22.7% were classified as uneducated/incomplete 1st fundamental cycle; 20.0% had complete 1st fundamental cycle/incomplete 2nd fundamental cycle; while 57.3% reported having completed the 2nd fundamental cycle or more [28].
There is also an association of high incidences of tuberculosis in the female population with the processes of autonomy and decision-making; the domestic work burden, postponement of seeking healthcare; low levels of education; high unemployment rates; informal work; low income and/or residing in rural areas, where distances make access to diagnostic and treatment services difficult, and lead to a higher proportion abandoning treatment [27,29,30-33]. Despite the fact that tuberculosis treatment is offered free of charge in Brazil, through the Brazilian Nation Health System (Sistema Único de Saúde - SUS), financial resources are often needed to get to the health care units, as well as expenses with food and lost working days, which make it untenable to continue treatment [34,35]. Furthermore, women working in the informal sector need to work long hours to earn their income, not having time to respond to their health needs in a timely manner and being more likely to visit health facilities only when they are seriously ill [26].Regarding the cases of tuberculosis in the population over 59 years of age in the city of Imperatriz, the present study showed a high incidence in both genders, especially in the initial years of the study (Figure 1D and 1G). This result is in line with other studies that found that older adults are more susceptible to falling ill, since they present a decline in immunity, as well as having other comorbidities [16,26,33,36,37].
The results of the study also showed, especially in the trend graphs (Figure 1), that there was a decrease in the cases of tuberculosis in the years 2003, 2008, 2013, 2015, 2017 and 2019, demonstrating a pronounced decrease in cases. This reduction in cases is consistent with the temporal trend of tuberculosis in Brazil, showing a fall in its incidence in the country’s geopolitical regions [26,38,39].
The reduction in tuberculosis cases in the early 2000s in the study scenario may be a reflection of the actions implemented in the National Plan for the Control of Tuberculosis (Plano Nacional para Controle da Tuberculose - PNCT), created in 1998, in which the program coverage was extended to 100% of the municipalities, with directly observed treatment (DOT) [40,41). In addition, this plan also aimed to integrate tuberculosis control with primary care, including the Community Health Agents Program (Programa de Agentes Comunitários de Saúde - PACS) and the Family Health Program (Programa de Saúde da Família - PSF), to ensure effective expansion of access to diagnosis and treatment [41].
In 2009, there were changes in national policies regarding active case finding, monitoring and treatment of tuberculosis in Brazil, which resulted in the reduction of new cases [39]. The other reductions in cases in Imperatriz, especially in the years 2013, 2015, 2017 and 2019 may also be the result of measures implemented by the Brazilian government, such as, for example, the Regional Strategy for Tuberculosis Control for 2005-2015, with the expansion and the strengthening of the DOTS Strategy; the Strategic Plan for the Control of Tuberculosis between 2007-2015; the National Tuberculosis Control Program in 2010 [42] and the implementation of Active Case Finding for Respiratory Symptomatic Patients; the National Tuberculosis Control Program in 2017 [5] and implementation of the National Plan for the End of Tuberculosis as a Public Health Problem, having, among other goals, the aims of ending tuberculosis as a public health problem by 2035 [39].
Considering the forecasts, despite the decrease in the detection of the disease, the municipality under study will continue to present cases of tuberculosis, according to the forecasts for the quadrennium 2019 to 2022, as the forecasts indicate a curve with a stationary trend. This, in a way, imposes challenges for public managers with regard to more effective and efficient strategies of active case finding and directly observed treatment, as well as improvements in the laboratory network for quality diagnoses with the results delivered rapidly and treatment started as early as possible. From this perspective, the findings of this study lead to a discussion on the behavior of the disease in the context of the scenario studied, revealing that the trends found in this study period and in the forecasts, indicate that the male and female population, in the 15 to 59 years age group will still be the most affected by this disease.
Regarding the temporal modeling stage, the ARIMA models selected for the total detection and rates according to gender presented adequate fits, providing efficacy in the models to capture the data dependency structure, that is, they effectively described the variability of the detection rates over time.
Limitations of the study related to the characteristic bias of ecological studies should be highlighted, in which the findings of this investigation cannot be inferred on a case by case basis, being only representative for the populations. Furthermore, the acquisition of information through secondary data can lead to errors or flaws inherent in the notification or recording of data and possible bias in the investigation, such as, for example, underreporting, with the potential presence of ignored or incomplete data.
It should be highlighted that the pandemic scenario was not considered, which may influence the incidence of tuberculosis in the coming years, however, as in other aspects, there are no concrete affirmations that can consider the specificities of the Brazilian territory. In general, the findings showed the problem of tuberculosis in the city of Imperatriz, over the years, where, prior to this study, statistical resources of temporal analysis had not been used as a tool to identify this problem.
It is believed that the evidence gathered in the study can contribute to tuberculosis control actions in the municipality, through the public agents, indicating measures to improve the population’s health, as well as being an instrument for articulation with the FHS teams, guiding their health promotion actions in the municipality.
In conclusion, the study showed that men and women in the socioeconomically active age group are those most commonly affected by tuberculosis. The study demonstrated a decreasing trend in tuberculosis, however, at a rate below WHO expectations, and, according to the forecasts, TB will remain at levels of hyperendemicity until 2022, which indicates that the elimination of the disease is more distant than it appears.