The hypothesis that healthcare-seeking behaviours of foreign migrant workers in Thailand differ among different occupational groups was supported. Nevertheless, in all three occupations, self-medication was the most common way of dealing with most illnesses, including the development of TB-suspicious symptoms. Only for GI symptoms and obstetric problems did migrant workers commonly seek healthcare at modern healthcare facilities. The predominance of self medication has been similarly noted in a review of health service utilization among ethnic minorities
 as well as in many other studies of international migrants in developed countries
[10, 11] and of internal migrants in China
. In UK, self-medication was described as one of the main barriers hindering migrants from accessing primary healthcare services, even though the respondents there were well educated
, in contrast to those in our study, who mostly had no more than middle-school education, being low-skilled workers.
For GI problems, workers of all three occupations made greater use of modern healthcare facilities, although not to the exclusion of self-medication. Private facilities were greatly preferred over government health services by FW and RT but government facilities were preferred by CW. Easy access and short waiting time were reasons for using, and economic constraints reasons for not using, private clinics. An earlier study in Thailand reported similar reasons for the preference of migrants for private clinics, namely convenience in terms of time, legal status and transportation
. Among the information provided by our respondents was the observation that private service providers never asked them for their identification card or about their background so that they did not need to worry about their legal status.
By contrast, for obstetric problems, especially delivery, government health facilities were overwhelmingly preferred over private facilities by female migrants in all three occupations, although half of the female FWs returned to their home country when they were about to give birth. Qualitative information obtained in our study suggests that the FW commonly returned to their home country for delivery because they were forced to quit their job when they became pregnant, but could get their job back after their delivery.
Unlike RT and CW, FW employed in large factories were able to attend in-factory clinics to obtain treatment for minor ailments, while for more severe illnesses the factory would arrange for them to attend at large private clinics with which they had pre-existing arrangements. Thus, there was little need for FW to attend government hospitals or clinics. RT also made little use of government healthcare services, as their generally wealthier status meant that the higher cost at private clinics did not outweigh the added convenience of rapid service and freedom from worry over their often precarious legal status. CW shared neither the higher economic status of the RT nor the accessibility of a work-place clinic or factory-arranged referral to a private clinic, and this probably explains their relatively greater utilization of government healthcare providers for GI problems. The differential was shown clearly after adjustment for confounding variables in the regression models, in which CW were much more likely than workers in the other occupations to avail themselves of government services and far less likely than RT to utilize private hospitals or clinics. Economic constraints have similarly been reported in other migrant populations to be determinants of healthcare behaviour
[9, 12, 14]. Affordability may also explain the greater preference of female than of male and of married than of single migrant workers to utilize government healthcare services. Our qualitative information indicated that female workers were more concerned about saving money, while married workers may have higher expenses for daily living.
The proportion of workers reporting having experienced TB-suspicious symptoms during their stay in Thailand, around 30%, is likely to be an underestimate of the true proportion. Most of the migrant workers were seemingly reluctant to answer admit to having had such symptoms. A review of the TB situation compiled by the Government of Thailand and WHO mentions that less than 50% of the estimated number of TB cases were notified even among the indigenous population
. In fact, the migrant population is likely to be at greater risk of tuberculosis because most of the workers were young (median age of 25.6) and male (69%), and tuberculosis has been reported to be more likely to occur among males of 15–54 yrs of age
. Furthermore, tuberculosis is deeply rooted in populations where human rights and dignity are limited
Our estimates of the one-year period prevalence of TB-suspicious symptoms following the last annual health checkup indicate a considerably higher prevalence among CW and RT than among FW. The difference might be explained by the generally poorer conditions of the accommodation of RT and CW, a finding that has also been reported among both migrants and non-migrants in other settings
[9, 17]. However, the high prevalence of TB-suspicious symptoms among CW might also be attributed partly to the unfavourable dusty environment of construction sites, which may render CW vulnerable to cough or expectoration.
As with most other health problems, self medication of TB-suspicious symptoms was extremely common, and the drugs used were inappropriate. Such workers preferred to use prepackaged western medicines over traditional medicines. This practice mirrors that reported among TB suspects in other studies
[18, 19], including a survey among Myanmar migrant workers in different region of Thailand, in which around half of the workers failed to get any treatment until their health deteriorated considerably
Overall, only about 1 in 4 workers with these symptoms visited a modern health facility, usually a private or factory clinic. CW were the least likely to visit a modern healthcare facility for these symptoms, even after adjusting for the possession of a health card and/or labour card. It was surprising that having an education above middle school was associated with a lower probability of attending a modern healthcare facility when TB-suspicious symptoms developed. No satisfactory explanation has been found.
Undetected TB cases could be present among these TB suspects. The common practice of self-medication for symptoms suggestive of TB without seeking any treatment at an appropriate healthcare service is likely to prevent cases being diagnosed correctly as pulmonary TB. This could affect the case finding of the National TB Programme. Indeed, high prevalences of pulmonary TB have been reported among TB suspects who had suspicious symptoms in other settings
Workers in our study frequently bought prepackaged western medicine from vendors of the same nationality. Drug stores are often the first and only, or preferred, source of healthcare outside home for a majority of patients in developing countries
[21, 22]. It was striking in our survey that 41% of the workers having low grade fever took prepackaged packets containing sulphadoxine-pyrimethamine to relieve their fever. Sulphadoxine-pyrimethamine is in fact an antimalarial drug. Misuse of antimalarial drug can result in drug resistance to malaria and frustrate measures to effectively manage the disease as drug resistance will lead to treatment failure
[23, 24]. The problem may be greatest among CW, who were found to have a high prevalence of TB-suspicious symptoms and yet utilized modern health care facilities the least.
Inappropriate use of glucocorticosteroids in multidrug packets was also investigated among the workers having cough for more than two weeks. When they went to the vendors for cough, they were given the specific combination containing dexamethazone, which is a kind of glucocorticosteroid. Because glucocorticoids are commonly used immunosuppressive agents, their impact on the risk of tuberculosis is important. In one study in UK, patients who were exposed to a glucocorticoid had an approximately 5-fold increased risk for developing new tuberculosis, independent of other risk factors
. Amongst patients with systemic sclerosis on dexamethazone-pulse therapy, it was concluded that there was an increased risk of tuberculosis
. Therefore, the respondents of our survey with cough for more than 2 weeks, a well-known TB-suspicious symptom, could progress from subclinical tuberculosis to active disease because of using dexamethazone inappropriately. Workers usually took these dexamethazone-containing packages two to three times a day for at least five days continuously to relieve their prolonged cough.
The reasons given by our respondents for using self medication and not trying to seek professional treatment for their TB-suspicious symptoms were variable. All three types of worker in our survey similarly thought that these symptoms were not serious enough to seek professional treatment. They were waiting to see whether or not their symptoms would become severe. Other studies also found that TB suspects preferred to wait and see whether their symptoms would become serious as they did not want to pay high healthcare costs out of pocket unnecessarily
[18, 19]. RT in our study did not worry about spending money as they earned more than FW and CW, but they were also the busiest workers and could less readily afford the time to attend at a modern healthcare facility. They worked at night and had to sleep in the daytime. A WHO report similarly notes that people with a full time job are usually too busy to seek professional healthcare, especially when they think their symptoms are not severe enough to justify stopping their work and seeking treatment
Our study has a number of strengths. The respondents were interviewed in their own language by interviewers of the same nationality, thereby facilitating rapport. Within each camp, the subjects were selected randomly and with a constant sampling fraction within each camp so that, despite the snowball sampling technique to choose the camps, the study sample should have been well representative of the chosen camps within each occupational group. The migrant workers were interviewed at their own residence so that they felt safe and could respond well to the questions.
Nevertheless, the study also has some limitations. Firstly, snowball sampling to locate and select workers’ camps for inclusion could potentially lead to a sample that is not fully representative of the population in general. Unfortunately, in the absence of complete enumeration lists of migrant workers, particularly those who have questionable legal status, we could not avoid using this non-random method as the first stage of sampling. Snowball technique is the simplest approach to reach hidden populations. Secondly, the healthcare-seeking behaviours of the workers in the same camp were likely to be similar as they lived very close to one another. This problem was minimized by using mixed effects regression modeling in the analysis, which adjusted the estimates of coefficients for clustering on camp. Thirdly, the information on history of illness and healthcare-seeking behaviour was based on recall and perception of the interviewees and not independently verified with data from the formal healthcare facilities. Thus, the data obtained may not have been a totally valid representation of actual illness and healthcare-seeking behaviour. Nevertheless, the aim was to identify healthcare-seeking behaviours of the migrants when they perceived themselves to be ill so, in this context, their actual health status was not the prime concern. Lastly, it is not certain to what extent the healthcare-seeking behaviours described in the study are attributable to migrant status per se, as a comparison group of similar host country workers or of workers in the country of origin was not included. As migrant workers in the three occupations included have almost replaced host country workers and access to study workers in the migrants’ home country was not permitted, no comparable group was available.