Work ability of Thai older Workers in Southern Thailand: a comparison of formal and informal sectors

Thai society is moving towards becoming an ageing society. The population aged 60 years and over has been slowly increasing. In 2019, older people comprised 17.5% of the nation’s population, which is considered an ageing society, as defined by the United Nations [1, 2]. Thai society will become a completely aged society when the proportion of older people increases to approximately 20%, which is expected to happen in 2022 [1]. The number of older workers has increased yearly, from 3.10 million people in 2010 to 4.70 million in 2020 [3]. The World Health Organisation (WHO) and European countries define older workers as workers aged 45 years and over [4]. The International Labour Organisation (ILO) describes older workers as those who are beginning to have difficulty with their employment and/or occupation due to increasing age [5]. Thailand has identified older workers as those aged 60 years and older who are still working and able to perform their duties [3]. However, based on physical deterioration or physiological changes that affect an individual’s working potential, some people may be considered older workers at the age of 45 years.

The 2nd National Plan for the Elderly 2002–2021 indicated that 67% of independent older people need to continue to work after retirement [6]. The main reasons for working in old age are the workers’ health and his or her family income [7]. Evidence suggests that older people will remain in the workforce for longer periods in response to several social and economic drivers [8, 9]. The vast majority of Japanese workers aged 60 years and over remain in the labour force to maintain their standard of living and for economic reasons. Five factors contribute to the differences in the labour force participation rates of older workers in the United States and Japan: 1) economic need; 2) type of employment; 3) cultural values; 4) policy factors; and 5) health [10]. In Thailand, informal workers continue to work in old age to generate income and security because unlike civil servants or formally employed workers, informal workers do not receive a pension. Legally, informal workers do not have the right to receive the same benefits as formal workers [11, 12].

Older workers’ productivity depends on their health and work-related health, which can be compromised by injuries due to long-term strain, backaches, hearing loss, eye strain, and mental illness. Moreover, ageing- and work-related conditions—such as disease history, behavioural health, work hazards and health care access— are two main factors that threaten their work ability and can cause decreases in work opportunities, productivity and income stability [13].

The increasing trend of older workers in the community thus presents significant issues for worker health. The health needs of older workers comprise physical function, fitness and the working ability needed to perform any job. The Work Ability Index (WAI) is an instrument used in clinical occupational health and research to assess working ability during health examinations and workplace surveys. The index comprises work demands and the worker’s health status and resources, making it an appropriate tool for assessing older worker’s health needs [14]. The assessment results can help community occupational health services to support older workers’ health.

A number of studies have been conducted among different populations to determine the relation between individual and work-related factors and the WAI [15‐18]. However, the WAI has not been used for comparative studies of informal and formal older workers in Thailand. The differences between these two groups in terms of socioeconomic and work-related factors, health status, healthcare experience, and WAI have not been studied. Nonetheless, there is a need to improve work ability given the expected increase in the number of older workers in the near future. This study explored work ability and its related factors among Thai older workers in formal and informal sectors in southern Thailand. To achieve this objective, a survey was conducted in Nakhon Si Thammarat province, the southern Thailand province with the largest population. The study’s findings can be used to support occupational health protection and health promotion programmes that can increase the work ability of older workers by extending their working years and improving their well-being.

This study was conducted mainly to explore the differences in the WAI between formal and informal sector workers and the relationship between sociodemographic, health- and work-related factors and the WAI and its domains. The multivariate analysis showed that age group was associated with the WAI and its domains, including the perceived working ability, health status and mental resources of the study sample. Workers in the oldest age group (55 years and over) were at risk of poor to moderate work ability. The presence of NCDs was also negatively associated with WAI and health status, while safe working practices were positively associated with WAI.

The mean total WAI score of the formal workers was 40.6, while that of the informal workers was 37.5. The overall proportion of workers with good to excellent work ability was 66.7%. A higher proportion of formal workers than informal workers reported good to excellent work ability. Demographic factors were associated with higher WAI scores among the worker groups. The proportions of younger workers (less than 55 years of age), workers without NCDs and safe working practices were higher among the formal workers than among the informal workers. The study of Yingratanasuk (2015) focused on informal older workers aged over 60 years and found that 43.4% had good to excellent work abilities. Most of the workers were general labourers and merchants [16]. Moreover, Rattanapunya (2019) studied work ability among informal older workers aged over 45–80 years and found that 13% had a good to excellent WAI [18]. Most of the workers in that study were home-based workers in urban areas, which differed from our study. The previous studies showed a higher mean age of informal workers than our study did. These factors probably affected the lower proportion of good to excellent WAI scores. In contrast, the study by Kaewboonchoo (2011) of the WAI scores of formal workers in small- and medium-sized enterprises found a mean worker age of 34 years and a mean total WAI score of 40 [15]. Our study had a similar mean total WAI score, although the formal workers in our study had a higher mean age. Our study categorised worker age into two groups: Less than 55 years and 55 years and older. The age group was associated with the WAI and its three domains. The risk of a poor to moderate WAI was 1.45 times higher in participants aged 55 years and older. Age was significantly associated with work ability. The direction of this association is consistent with many studies showing that age is significantly and negatively associated with WAI in various occupational sectors [28‐31]

However, our results revealed that gender and working ability were not significantly associated in the multivariable analysis [21, 27]. Two factors must be considered for older workers [32, 33]: The first is the workers’ health, and the second is job productivity and performance. A larger number of older workers implies, for example, an increasing number of people working with minor and major health problems that occur more frequently after 55 years of age [34]. Approximately 52% of the workers in both sectors in this study were older than 55 years, and half had NCDs. Age and the presence of NCDs were the predominant factors affecting older workers’ productivity. The results also indicate that the presence of NCDs has strong and positive association with poor to moderate WAI, especially in the health status domain (adj. OR = 6.42). The causal factors of NCDs are complex and have been described as the interaction of work-related risk factors and lifestyle risk factors [35]. Our data show that hypertensive disease accounted for the highest proportion of NCDs (48.2%), and approximately 60% of the workers were overweight or obese, in line with other reports [20, 21, 36‐38]. The rates did not differ between the two sectors. Physical health is one of the intermediate determinants of individual lifestyle. It directly affects workers’ health status and functional activity, which are fundamental factors for work ability [39, 40]. Moreover, more than half of the workers (59%) reported that they did not regularly exercise. Therefore, the increasing risk of NCDs among older workers may be due to a decline in physical capability and increased obesity. These factors have a negative impact on older workers’ work ability. Other risk factors, including smoking and alcohol consumption, are not associated with WAI [36]. Therefore, formal workers must engage in NCD prevention and health promotion activities for adult workers before they reach old age. This approach is promoted by the total worker health (TWH) concept, which is a platform for promoting disease and injury prevention efforts in the workplace by developing innovative methods, techniques and approaches for dealing with occupational safety and health problems [41]. Additionally, primary healthcare centres should coordinate with occupational health protection activities aimed at preventing NCDs among community informal workers before they enter old age [42].

We explored personal hygiene, safety inspections, personal protective equipment (PPE) usage, simple work improvements, rest duration and housekeeping as working conditions. The study results demonstrated that workers who were exposed to unsafe practices had a higher probability of a poor to moderate WAI (adj. OR = 2.11). They also showed that workers in the formal sector were more likely to engage in safe work practices than those in the informal sector. The WAI is composed of four dimensions: Health and functional capacity, occupational competence, attitude and motivation, and working conditions. Working conditions comprise the top floor of the four main dimensions; if the individual’s resources (floors 1–3) are able to support the top floor, the individual’s work ability is good [39, 40]. Tuomi et al. (2001) showed that work environment factors, such as poor ergonomics, a distracting work environment, poor physical climate, tool failure and dissatisfaction work rooms, were strongly associated with poor working ability [20]. On the other hand, improvements in work and tasks, work environments and tools positively influenced work ability [20]. Therefore, our results demonstrate that working conditions are among the crucial occupational health factors that can improve the work ability of older workers. The study also found a difference in working practices between the formal and informal sectors. This difference may be related to legal protections for employments and access to occupational health services. In Thailand, informal workers utilise healthcare services provided by the Universal Health Coverage Scheme (UCS). It provides healthcare for people who have no employment benefits, such as agricultural and home-based workers. However, the services do not include occupational health services, which are necessary to help older informal workers improve their work ability. The improvement of worker health to support work ability is complex and requires a holistic approach, especially for older workers. Occupational health service arrangements for older workers should be initiated at the early phase of physical and mental deterioration, as indicated by a decline in the WAI score. The work ability model is appropriate for an older workforce and is based on the self-assessment of subjective experiences regarding personal resources, work context, and work-life interface [39, 40]. The structure of an individual’s work ability changes throughout his or her life and career [43]. Therefore, the implementation of work ability assessments in occupational health programmes for older workers will provide measures to improve work ability in both workplaces and healthcare services centres [44‐46].

There are several limitations of this study. First, the cross-sectional design in which exposure and outcome were measured concurrently does not support causal relationships. In epidemiological studies, an association between exposures and outcomes is causal only if the study’s plausibility is explored. Second, self-reported measurements of the study variables—including working ability and occupational hazards—may lead to recall and information bias. Workers’ awareness of occupational hazards could affect the accuracy of the measurements. The workers in the formal sector are familiar with their work conditions and can recognise occupational hazards in their workplace, while informal workers may not be able to do so. Finally, we focused on the working abilities of older workers residing in suburban and rural communities for reasons of access, and this population may not be representative of workers elsewhere in different settings. Therefore, generalisations of the results beyond the study population should consider this limitation.

In conclusion, this study determined the association between work ability and the determinants, health-related factors, sociodemographic characteristics and work environment of formal and informal older workers. Most of the older workers had good to excellent work ability. Older age group and the presence of NCDs were negatively associated with good to excellent work ability. There was a strong negative association between NCDs and the health status of workers. This result suggests that older workers with poor health due to NCDs require more intensive healthcare if they are to extend their working years. In addition, safe working practices improved older workers’ work ability. The work ability of older workers is a very important background factor if workers are to continue to work throughout their lifespan. According to the concept of TWH, formal workers’ organisations could integrate occupational health protections with NCD prevention for workers beginning in the early stages of ageing. Similarly, primary healthcare programmes for NCD prevention in the community should cooperate with occupational health protection services to promote longer healthy lives among informal workers. For further study, a longitudinal study of various occupations and programme interventions is required to determine and compare the factors associated with improved work ability in formal and informal workers.