Knowledge of tuberculosis among female sex workers in Rajshahi city, Bangladesh: a cross sectional study

Background Tuberculosis (TB) is a major public health problem in developing countries like Bangladesh. Female sex workers (FSWs) and their clients are active sources for spreading TB. The purpose of this study was to assess the knowledge of TB among FSWs in Rajshahi city, Bangladesh. Methods It was a cross-sectional study with a sample size of 225 FSWs. The knowledge on TB was measured by six different questions. Chi-square test and multinomial logistic regression model were used in this study to find the associated factors of lack of general knowledge on TB among FSWs. Results Out of 225 FSWs, 43.1, 34.7 and 22.2% came from urban, rural and slum areas respectively. More than 41% FSWs perceived that TB is a non-communicable disease. A large number of FSWs (76.4%) did not know the spread of TB. It was found that more than 90% FSWs did not have knowledge on latent TB. The χ2-test demonstrated that FSWs’ education, monthly family income, age, currently marital status and sex trading place were significantly associated with their knowledge on TB. A remarkable number of FWSs (42.2%) had poor knowledge on TB. It was found that comparatively higher educated FWSs were more likely to have good or fair knowledge on TB than lower educated ones (p < 0.01). Conclusions This study revealed that near to half of FSWs in Rajshahi city, Bangladesh had poor knowledge on TB. Public health authorities should pay due attention and adopt policy for increasing the knowledge on TB among FSWs to reduce the incidence of TB in Bangladesh. Subsequently, advocacy, communication for social mobilization program is very urgent.


Background
Tuberculosis (TB) is still a burning issue in developing countries like Bangladesh, where favorable environment is available for the spread of TB. Female sex workers (FSWs) are most important vulnerable groups for getting and spreading TB, because they trade sex with their clients without any information of clients' TB status in Bangladesh [1]. It was estimated in 2009 that the number of FSWs was 63 to 74 thousand in Bangladesh [2]. Usually, FSWs in Bangladesh trade sex in street, hotel, residence and brothel. Hotel and residence based FSWs entertained an average of 61 clients per week in Bangladesh [2]. There are few brothels in Bangladesh, and Rajshahi is one of the cities where there is no brothel. As sex trade is illegal outside of brothel in Bangladesh and it is strongly considered as antisocial activities, it is a great challenge for FSWs in this country to run their trade. They are frequently bound to change their identities including their names, addresses, cell phone numbers etc. It was reported that the number of hotel and residence based FSWs in Rajshahi city was 40.5 and 39.0% respectively, and a remarkable number (20.5%) of FSWs trade sex in street [2]. Most of the sex trading places are unhygienic and favorable environment for TB. Besides, the street is comparatively a more vulnerable place for TB bacteria, and most of their clients are transport workers and rickshaw pullers [3]. Rajshahi is one of the biggest cities in Bangladesh, situated at the western border of Bangladesh, separated from India by a branch of Ganges River (Padma branch). Every day many people are travelling India legally or illegally for various purposes, and India is the first ranking country among 30 highly burden countries for TB in the world [4,5], also the highest prevalence of HIV/AIDS in India among SARC countries [6]. It is important to survey the knowledge on TB among FSWs who are trading sex in this border city. However, some studies have been conducted on TB with other populations such as, community people and key public [7,8], TB patients [9,10] and school students [11,12]. Some other studies were done with medical students, health care workers and people of other occupations [13][14][15]. Study on TB with medical, nursing and midwifery students were also conducted in other population [16,17]. According to world health organization 2016, Bangladesh is one of the most highly burden countries out of 30 highly TB burden countries and its rank is 7 with annual occurrence of 362,000 new TB cases [18]. About 73,000 people die annually due to TB in this country. Another important challenge is Multi Drug Resistance TB (MDR TB) -with an estimated 9, 700 MDR cases per year [18]. This type of study would be interested for improving policy to control TB in Bangladesh. Survey on knowledge about TB among nonmedical university students, industrial labors in Rajshahi have been done [19,20]. These studies neither identified FSWs nor focused on association of TB with them, and did not examine risks of the easy spread of TB by the FSWs. To the best of our knowledge there is no other report or study about the knowledge on TB among FSWs in Bangladesh, however one study has been done with FSWs in Rajshahi city to survey their knowledge on HIV/AIDS [2]. As association between the knowledge on TB among FSWs is very important because socioeconomic and demographic factors of them and as well as their clients, and eventually the community as a whole, are largely affected by TB. Though our study was conducted in Rajshahi city, it would explore some aspects of risks and help finding out measures to save the FSWs, their clients and the society as a whole from TB in Bangladesh.
The aim of the present study was to investigate the knowledge on TB and its associated factors of FSWs in Rajshahi city, Bangladesh.

Study design and population
It was a cross-sectional study. The sample consisted of 225 FSWs who traded sex at different places such as streets, residences and hotels in Rajshahi city, Bangladesh. This study was based on the complete good clinical procedures. FSWs' personal cell phone numbers were collected from the NGOs working for welfare of FSWs and their clients. Primarily we contacted the key personnel of the NGOs. They introduced us with their peer educators who themselves were FSWs and paid workers of the respective NGOs. These peer educators managed appointments and meetings for us with FSWs. With the help of peer educators we collected 300 FSWs' personal mobile phone numbers. We contacted 300 FSWs by using mobile phone. Out of them 243 FSWs were willingly agreed for interviews. Finally, 225 FSWs provided their written consent (Fig. 1). Selected FSWs were interviewed at their suggested venue. We followed the procedure which was used in previous study [2].

Data collection
Study data was collected in the period from July'2015 to December'2016. All of the respondents were street, hotel and residence based FSWs in Rajshahi city. The study design was to document the socio economic, demographic and sex trade practices related to TB knowledge of FSWs and particular attention was given to identify The following data were collected for the study: (i) general and specific information of TB, (ii) socioeconomic and demographic characteristics of FSWs, (iii) knowledge on TB. The data were collected by using a semi-structured questionnaire. The original questionnaire was prepared in English but it was translated to Bengali the mother language of Bangladeshi for easy understanding of the subjects. The original and translated questionnaires were reviewed by ten professional experts and volunteers, and a pilot study was conducted to validate the questionnaire. We also modified the questionnaire based on the results of the piloting to make it easier to comprehend and answer. To ensure strictly confidentiality the names of the respondents were not recorded to avoid link from data.

Outcome variables
The dependent variable in this study was knowledge on TB, which was measured by six dissimilar questions, namely: i) Is TB a communicable disease? ii) Have you ever heard about latent TB? iii) Do you know the main sign and symptom of TB? iv) Do you know how TB spread? v) Do you think is TB curable? vi) Do you know which part is mostly affected by TB? The overall level of knowledge on TB was measured on the basis of the number of correct answers of these six questions; (i) poor knowledge (0-2 correct answers), (ii) fair knowledge (3-4 correct answers) and (iii) good knowledge (5-6 correct answers).

Independent variables
In this study, theoretically pertinent socio-economic and demographic factors were included as independent variables. We classified age into two groups: a younger group (≤25 years), and an older age group (≥26 years). Education was classified based on the formal education system in Bangladesh: Illiterate (0 years), primary education (1-5 years), secondary and higher education (6 years or more). Marital status was categorized as unmarried and ever married. Place of residence was categorized as rural, urban and slum. Type of family was categorized as single and joint family. Types of clients were categorized as transport workers, small traders and service holder. Sex trade place was categorized as residence, hotel and street. Respondent's monthly income was categorized as < 8000 BDT and ≥ 8001 BDT.

Statistical analyses
Data were cross-checked for consistency before final data entry using Microsoft Excel. Descriptive analyses were conducted to determine the socio-economic and demographic factors related with knowledge on TB of the respondents. Chi-square test and Fisher's exact test (if the cell frequency less than 5) were used to find the association between two factors. Since the level of knowledge on TB among FSWs was of three categories; (i) poor, (ii) fair and (iii) good, it was an outcome variable, multinomial logistic model was selected to determine the effect of socio-economic and demographic factors on overall knowledge of TB. Analyses were performed using statistical package for social sciences (SPSS version 22 IBM). Significance for all analyses was set at p < 0.05.

Results
In this study, we assessed the knowledge on TB among FSWs in Rajshahi city, Bangladesh. Table 1 shows the socio-economic and demographic profile of FSWs. Out of the total sample population 225 FSWs, more than 54% were above 26 years of age. By education, 14.2% were illiterate, 48.9% were got primary  Table 2). A very few number of FSWs (9.8%) heard the term of latent TB, and the association between the knowledge on latent TB and education and monthly family income were statistically significant (p < 0.05) ( Table 3). It was found that more than 13% FSWs did not have idea any about the main sign and symptoms of TB. More than 87% FSWs believed that cough for 3 weeks or more was the main sign and symptom of TB. The association between the knowledge on sign and symptom of TB and FSWs marital status was significant (p < 0.05) ( Table 4). Only 23.6% FSWs knew about the spread of TB. On the knowledge of TB spreading, FSWs with secondary and higher education and sex trade at residence had higher percentage (36.1%) and (34.6%) than their counterparts and the association between the knowledge on mode of TB spreading and respondents' education (p < 0.01) and sex trade place (p < 0.05) were statistically significant (Table 5). More than 78% respondents strongly believed that TB was a curable disease, and younger and respondents with monthly income ≥8000 in taka had higher percentages (84.5%) (91.3%) than their counterparts and the association between the knowledge on curability of TB and respondents' age (p < 0.05) and monthly family income (p < 0.01) were statistically significant (Table 6). More than 81% FSWs did not know which parts of the body are mostly affected by TB. Regarding the knowledge on which parts of the body are mostly affected by TB, secondary and higher educated FSWs had higher percentage (28.9%) than their counterparts and the association between the knowledge of which parts of the body mostly affected by TB and education was statistically significant (p < 0.01) ( Table 7). It was observed that 42.2% FSWs had overall poor knowledge on TB while 7.8% had good knowledge. More than 50% FSWs had fair knowledge on TB (Table 8). It was found that the level of poor knowledge decreased with increasing FSWs' education level. However the level of fair and good knowledge increased with increasing their education level. The association between the level of the knowledge of FSWs and their education level was significant (p < 0.01). The other selected factors did not show significant association with the level of the knowledge on TB (Table 8).
Only significantly associated factor, education level was considered as independent variable in multinomial logistic model to find the effect of this factor on level of FSWs' knowledge about TB. This model demonstrated that secondary and higher educated FSWs were more likely to have fair knowledge than illiterate FSWs [OR = 0.075, 95%CI: 0.025-0.224; p < 0.01]. On the other hand,   studies. However, researchers found that 71% primary school students in Malawi had knowledge about the type of TB disease [21]. It was found that the general knowledge on HIV/AIDS among FSWs in Rajshahi city, Bangladesh was very poor [2]. Education and family status (family income) were the most important predictors of the lack of general knowledge on any disease. In this study, it was noted that more than 63% FSWs did not complete their primary education and more than 69% FSWs lived with poor family (monthly income≤8000 Taka). This study also found that the FSWs who had secondary and higher level of education and monthly income of ≥8000 BDT had more knowledge regarding communicable disease than their counterpart. Female sex trade is illegal in Bangladesh but its demand is very high in the society and most of the time FSWs are very busy so they have no enough time to gather knowledge about the risks of communicable diseases like TB. WHO (2018) estimated that 23% (about 1.7 billion people) of the world's population to have a latent TB infection. They are in the risk of developing active TB disease during their lifetime [22].  This latent TB has the chance of reactivation to active disease at any time when environment is favorable. In Chinese Immigrants in a Canadian a patient' knowledge about latent TB was 19.8% [23] but present study found that FSWs knowledge about latent TB was only 9.8%. Limitation of access to TB screening facilities is very poor for FSWs compared to general population, because in day time most of the FSWs take rest and there is no chance of having TB screening at night time. Knowledge about transmission of TB in Nigerian population was 57.8% [24] but present study showed that FSWs' knowledge on TB transmission was 23.6%. In Bangladesh, there is no special program of TB related issues exclusively for FSWs, though most of the respondents were known to have cough for 2 weeks or more, the main symptom of TB. Some study showed that most of the Indian students (86.0%) believed that TB was curable disease [25], this study demonstrated that 78.7% of the FSWs believed that TB was a curable disease. We found that the FSWs having secondary and higher level education and monthly income of ≥8000 BDT had more knowledge regarding TB is curable disease than their counterpart. The present study reported that FSWs' education level, sex trade place, monthly family income, marital status were the important risk factors for the lack of general knowledge on TB among FSWs in Rajshahi city, Bangladesh, most of these factors had been found for the lack of knowledge on HIV/AIDS and FSWs in the same region [2]. This suggests that the FSWs with education and working in better social environment had better opportunity to learn about TB. Many governments, donor and non-government organizations (NGOs) were working for advocacy, communication and social mobilization (ACSM) in this city for general population but FSWs are not given special attention in this regard. To make the FSWs aware of TB, special measures like sessions, meetings, workshops, and video shows etc. regarding TB should be arranged in a regular manner especially with them.

Study limitations
This study has some limitations. Firstly, the crosssectional observational design did not permit us to establish any absolute chronological associations for identifying between knowledge on TB and various sociodemographic and health seeking behavior related features. Additional longitudinal research is desirable to fully identify this complex relationship and understand the underlying mechanisms. Secondly, this study used the only quantitative survey to FSWs knowledge on TB. For the development of culture-sensitive communication strategies, qualitative studies are also necessary. However, these approaches couldn't be done due to time and resource constraints. We should consider this point in our future studies. Lastly, the idea of knowledge, which has several definitions, was hard to measure, especially using the questionnaire. However, this study measured the knowledge variables with several indicators which were used in some previous studies [21,[23][24][25].

Conclusions
In the present study, we surveyed the general knowledge on TB among FSWs in Rajshahi city, Bangladesh, and data were   collected from 225 randomly selected FSWs. Some questions were asked to FSWs for determining their general knowledge on TB, and it was observed that the knowledge of FSWs on TB was very poor. Moreover, we investigated the associated factors for lacking of TB knowledge among FSWs in Rajshahi city. It was observed that more than 42% FSWs had overall poor knowledge on TB while more than 50% had fair knowledge but only 7.6% FSWS had good knowledge on TB. It was found that comparatively more educated, living with rich family, currently unmarried, traded sex at residence, aged≥26 years FSWs were more knowledgeable than their counterparts. In conclusion, considering alarming situation revealed in this study regarding knowledge on TB of FSWs, the government and other concerned authorities should pay special attention to FSWs community as a vulnerable group. This study strongly recommends that advocacy, communication and social mobilization program is urgently needed for FSWs. It further suggests that access to TB screening and treatment facilities for the FSWs should be easy and immediately arranged.