Health profile of workers from different industries in Singapore

Abstract

Introduction:

Workplace safety and health are interrelated — a worker who is not healthy may cause safety lapses at the workplace; conversely, safety lapses could affect the health of the workers. This study was part of a larger Total Workplace Safety and Health (WSH) programme run by the Workplace Safety and Health Council, Singapore. The objectives were to obtain a baseline health profile of workers across four major industries and identify important health risks for targeted workplace interventions.

Methods:

Five service providers (SPs) were appointed to run the Total WSH programme. As part of the programme, SPs conducted an anonymous basic health survey among workers of participating companies.

Results:

The responses of 6,373 respondents from the cleaning, construction, manufacturing, and transport and storage industries were studied. The overall response rate was 62%. Key health issues identified were high rates of obesity (22%) and smoking (24%) and low prevalence of regular exercise and healthy dietary habits. Chronic disease rates were similar to population self-reported rates (hypertension 15%, high lipid 12% and diabetes mellitus 6%). The workers reported high work stress (13%).

Conclusion:

Health issues are prevalent in the workforce and may affect work and employee safety. It is increasingly important for employees’ health to be considered in risk assessments and prioritised in workplace safety and health management systems and strategies. Health promotion interventions should be targeted, and multilevel and multicomponent initiatives should be integrated with pre-existing occupational safety programmes.

INTRODUCTION

Good physical condition and absence of chronic illness are factors that have been observed to be associated with low occupational injury rates.[1,2,3] Workers with certain adverse health risk factors are more likely to sustain injuries than those without such risks. Among these factors are obesity, sleep deprivation, poorly controlled diabetes mellitus, smoking and impairment caused by certain prescription medications.[1,4]

With a rapidly ageing population and tight labour market, workers in Singapore are working longer and retiring later. Hence, it has become increasingly important for the workplace to be a strategic partner in the prevention and management of chronic diseases. If the chronic diseases of workers are well managed, employers can mitigate against the risk of high sickness absenteeism, increased healthcare costs, and poor employee working capacity and motivation.[4]

Traditionally, occupational safety and health protection has focused on protecting workers from harms arising from work, while health promotion seeks to reduce health risks from individual behaviour. These two functions at the workplace are divorced from each other and operate independently. However, there is increasing evidence that the integration of occupational safety and health protection with health promotion activities brings synergistic benefits.[5]

Total Workplace Safety and Health (WSH) is a comprehensive and integrated approach to mitigating workplace safety and health risks, together with health promotion. It encompasses a comprehensive risk management approach, which includes the consideration of individual risk factors.[6] In 2019, the Ministry of Manpower, Singapore, piloted the Total WSH programme in 20 companies across four industries. As part of the programme, a basic health survey (BHS) was conducted to understand the health profile of workers and to identify the health risks and concerns. This would form part of a needs assessment and contribute towards prioritisation of health risks for targeted workplace interventions.

The objectives of this study were to obtain the baseline health profile of workers across four prioritised industries and identify important safety and health risks for targeted workplace interventions.

METHODS

The BHS is a tool adapted from existing validated tools in the literature, such as the 36-Item Short Form Survey and Standardised Nordic Questionnaire. A primary resource for the development of BHS was the National Population Health Survey (NPHS) by the Ministry of Health and the Health Promotion Board (HPB), Singapore, which has been validated and designed for use in the local setting. The BHS is a health needs assessment tool to capture the baseline health status of employees.[5] Data across the following domains were collected: demographics, shift work, work ability, chronic health conditions, body pain, lifestyle and nutrition, tobacco and alcohol consumption, physical activity, health screening, stress and work environment. In 2015, BHS was successfully used to capture the baseline health status of more than 9,285 employees from 30 local and multinational companies.[7]

As the risk for cardiovascular diseases and diabetes mellitus starts at a lower body mass index (BMI) for Asian populations, the World Health Organization expert consultation has recommended additional classification of BMI by risk categories. The recommended risk categories were used in our analysis (low risk 18.5–22.9, moderate risk 23.0–27.4, high risk ≥27.5).[8] For dietary habits, we surveyed the respondents on the frequency and quantity of sugar-sweetened beverages, fruits and vegetables. The availability of healthier food options at the workplace was also surveyed. For physical activity, the respondents were asked if they had performed any physical activity outside work in the past 7 days. Moderate-intensity physical activities were listed as examples in the question. The cumulative duration of physical activity over the past 7 days was also collected. We considered sufficient physical activity to be meeting HPB’s guideline of 150 min of moderate-intensity physical activity a week. Chronic health conditions were defined to be generally progressive diseases that had been diagnosed by a western trained doctor. Presence of body pain and its interference with work was surveyed via an adaptation of the Standardised Nordic Questionnaire. Levels of general and work stress were graded by the respondents using a five-point scale. Further questions on potential stressors in work organisation and social factors at work were included. The respondents were also asked to report days of sickness absence from work over the last 12 months and the most common clinical symptoms and conditions leading to absenteeism. The respondents were surveyed on organisational safety culture through questions on safety attitudes at the workplace and worker satisfaction.

Five service providers (SPs) were appointed to run the Total WSH programme in the cleaning, construction, manufacturing, and transport and storage industries. These four industries were prioritised, as they were overrepresented in terms of workplace injury rate based on the data collated by the Ministry of Manpower.[9] Workers from 20 companies were invited to participate in the study between January 2019 and November 2019. The BHS was translated into Chinese, Malay, Tamil and Bengali, and participants completed the survey either online or on hardcopy in the language that they were most proficient in. Participation was on a voluntary basis, and implied informed consent was sought in the completion and return of the survey. Ethics approval was obtained from the Saw Swee Hock School of Public Health Department Ethics Review Committee.

Data were coded and analysed using Microsoft Excel analytical tools and IBM SPSS Statistics version 27 (IBM Corp, Armonk, NY, USA). Categorical variables were reported as counts and percentages, whilst continuous variables were reported as means with standard deviations. Chi-square and Fisher’s exact tests were used to assess the statistical significance of categorical variables, while Student’s t-test was employed for continuous variables. Logistic regression was used to adjust for possible confounders when adjusted odd ratios (OR) were reported.

RESULTS

Respondent demographics

A total of 6,373 workers from 20 companies across four industries participated in the study [Table 1]. The overall response rate was 62%. Seventy-four percent of participants were male, with more males in the older age groups compared to females. Relative to the 2018 resident population in Singapore, the cleaning and manufacturing industries featured a greater proportion of workers aged ≥60 years (22.5% vs. 39.4% and 31.8%, respectively).[10]

Table 1.

Companies by industries and size of workforce that participated in the project.

Industry and company	n (%)
Cleaninga	1,400 (22.0)
A	526 (28.8)
B	116 (68.6)
C	260 (63.7)
D	40 (57.1)
E	458 (67.4)
Constructiona	1,999 (31)
F	143 (61.1)
G	157 (98.1)
H	356 (67.2)
I	144 (72.7)
J	144 (75.8)
K	66 (82.5)
L	638 (63.8)
M	351 (100)
Manufacturinga	1,551 (24.0)
N	600 (20.0)
O	951 (29.9)
Transport & storagea	1,423 (22.0)
P	224 (76.7)
Q	132 (57.4)
R	413 (45.8)
S	269 (67.2)
T	385 (26.0)
Total	6,373 (61.5)

^aAverage response rates for the cleaning, construction, manufacturing, and transport & storage industries are 57.1%, 77.7%, 25.0% and 54.6%, respectively

BMI risk categories

Sixty percent of all the respondents were in the moderate (38%) or high (22%) BMI risk category. The cleaning industry and transport and storage industry recorded the highest prevalence of respondents in the high BMI risk category (27% and 25.5%, respectively) [Table 2]. This was higher than the national prevalence of 20.7% in the high BMI risk category as reported in NPHS 2020.[11]

Table 2.

Distribution of age groups, BMI and work stress by industry.

Variable	n (%)
	Cleaning	Construction	Manufacturing	Transport & storage	Totala
Age (years)
≤25	63 (15.5)	155 (38.1)	81 (19.9)	108 (26.5)	407 (100.0)
26–45	548 (16.4)	1410 (42.2)	571 (17.1)	811 (24.3)	3340 (100.0)
46–59	450 (25.3)	358 (20.1)	637 (35.7)	337 (18.9)	1782 (100.0)
≥60	309 (39.4)	63 (8.0)	250 (31.8)	163 (20.8)	785 (100.0)
Asian classification of BMI risk category
Low risk	473 (20.6)	709 (30.9)	628 (27.4)	481 (21.0)	285 (100.0)
Moderate risk	519 (21.4)	820 (33.8)	544 (22.5)	540 (22.3)	2423 (100.0)
High risk	382 (27.1)	343 (24.4)	324 (23.0)	359 (25.5)	1408 (100.0)
Work stress
Not stressed	385 (25.9)	553 (37.3)	271 (18.3)	275 (18.5)	1484 (100.0)
A little stressed	347 (23.3)	393 (26.4)	421 (28.3)	326 (21.9)	1487 (100.0)
Moderately stressed	426 (21.5)	586 (29.5)	596 (30.0)	378 (19.0)	1986 (100.0)
Highly stressed	104 (16.9)	213 (34.6)	179 (29.1)	120 (19.5)	616 (100.0)
Very highly stressed	25 (13.1)	69 (36.1)	55 (28.8)	42 (22.0)	191 (100.0)

^aNumbers may not add up to 6373 as there are some missing values in some of the groups. BMI: body mass index

Lifestyle habits

The prevalence of smoking in our study was 24.4%, which was almost double the national prevalence of 13.1% recorded in NPHS 2020.[10] A high proportion of respondents (64%) consumed sweet drinks on a daily/weekly basis. Seventy-eight percent of respondents consumed vegetables daily, but only 52% of them consumed fruits on a daily basis. Seventy-nine percent of respondents reported the availability of healthy food and drink options at/near the workplace. However, one-third (29%) of the respondents rarely purchased healthier food and drinks. There were no recently reported population-level data on dietary habits available for comparison. Only 21.0% of respondents reported sufficient total physical activity. This was significantly lower than the 76.4% recorded for persons aged 18–78 years in NHPS 2020.[11] The respondents who did not engage in any physical activity in the past week were likely to be from the cleaning industry, aged 46–59 year and male.

Self-reported health conditions

The most common self-reported chronic health conditions were hypertension (14.6%) and musculoskeletal (14.6%) conditions, followed by high lipids (11.7%) and diabetes mellitus (6.2%). The prevalence of self-reported hypertension, high lipids and diabetes mellitus was similar to that reported in NPHS 2019 (15.6%, 13.6% and 6.9%, respectively).[10] Seventy-five percent of respondents with diabetes mellitus and 76% of those with high blood pressure were either overweight or obese. Out of the respondents who reported having chronic health conditions, 31.8% had one chronic disease and 14.2% had two or more chronic diseases.

Eight percent of respondents had experienced significant body pain that interfered with work over the last 4 weeks . Thirteen percent of respondents reported experiencing a ‘high’ or ‘very high’ level of mental stress at work.

Risk factors for high work stress

Risk factors for high work stress included Chinese ethnicity (OR 1.28, confidence interval [CI] 1.01–1.63), age ≤ 25 years (OR 1.91, CI 1.28–2.87) and working in the construction industry (OR 1.46, CI 1.13–1.87). Groups that recorded the lowest levels of high stress were made the reference groups, and each risk factor was adjusted for possible confounding variables. All odds reported were statistically significant [Table 3].

Table 3.

Risk factors for high stress — ethnic group, age group, industry.

Parameter	Odds ratio	95% CI
Ethnic groupa
Chinese	1.28	1.01–1.63
Indian	0.77	0.59–1.01
Malay	0.83	0.60–1.16
Others	Reference
Ageb (years)
≤25	1.91	1.28–2.87
26–45	1.89	1.42–2.52
46–59	1.70	1.26–2.28
≥60	Reference
Industryc
Construction	1.46	1.13–1.87
Manufacturing	1.40	1.10–1.77
Transport & storage	1.31	1.01–1.69
Cleaning	Reference

^aOdds ratio adjusted for industry and age with ‘others’ as reference. ^bOdds ratio adjusted for industry and ethnic group with ‘age (≥60 years)’ as reference. ^cOdds ratio adjusted for age and ethnic group with ‘cleaning industry’ as reference. CI: confidence interval

The prevalence of healthy lifestyle habits such as regular exercise (62% vs. 67.4%), daily fruit consumption (45.4% vs. 51.1%) and daily vegetable consumption (74.6% vs. 78.3%) was lower in the high-stress group compared to the low-stress group. The differences were all statistically significant.

In comparison to respondents with low work stress, there was a higher prevalence of ‘unrealistic time pressures’ (20.7% vs. 3.7%) and ‘exposure to interpersonal conflict at work’ (20.4% vs. 9%) reported by those with high work stress. There was also a lower prevalence of encouragement received from the direct supervisor (36.1% vs. 50.6%). Compared to the low-stress group, respondents in the high-stress group reported being less satisfied with their working environment (32.8% vs. 46.1%) and feeling less safe working at their workplaces (34.8% vs. 45.5%). The high-stress group reported being less able to balance the demands of work and home life (23.5% vs. 31.3%) and recorded lower rates of being proud to work for their company (36.8% vs. 45.7%).

Effects of high work stress

Using ‘No pain made worse by work’ as the reference group, the odds of having pain were significantly higher for those in high work stress groups [Table 4]. There was a significant association between high work stress and body pain made worse by work.

Table 4.

Risk factors for high stress — site of pain.

Site of pain	Odds ratioa	95% CI
Neck pain	2.99	2.49–3.58
Shoulder pain	2.31	1.92–2.78
Elbow/forearm	2.62	2.01–3.42
Wrist/hand	2.35	1.86–2.97
Upper back	2.38	1.92–2.94
Lower back	2.64	2.19–3.18
Thigh/hip	2.70	2.06–3.54
Knee/lower leg	2.50	2.02–3.11
Ankle/feet	2.28	1.80–2.89

^aOdds ratio adjusted for age, ethnic group and industry with ‘no pain in body part’ as reference. CI: confidence interval

Absenteeism — sick leave

The average number of days of sick leave for manufacturing (4.9 days per year) was higher compared to other industries. The most common cause for taking sick leave was ‘cough and cold’, with 44.2% of those who had taken sick leave indicating this.

DISCUSSION

The BHS is a tool for the assessment of general well-being of the individual and provides the management team with information on the overall health status of their workers. An understanding of the workforce’s current stage of health, safety and perception of work contributes to the identification of gaps in the company’s Total WSH strategy and provides valuable information for improvement.[6]

Companies that participated in our study took the first step in understanding individual health risks through BHS. Based on the Assessment, Intervention, Monitoring and Evaluation approach,[5] implementation of targeted interventions would be the next step, followed by monitoring and evaluation of progress in improvement of workers’ health status.

Another important application of the findings would be in preplacement, periodic medical and fitness to work examinations. Relevant screening questionnaires or investigations for early detection and management of health conditions that may affect work capacity and safety may be introduced as part of the medical consultation. Medical examinations specific to health risks can help in overall risk reduction. A Cochrane review found that pre-employment examinations that are specific to certain job tasks or health risks may be effective in reducing occupational disease, injury or sick leave by either denying the job or by adequately mitigating the job risk on the health of the worker.[12]

Twenty workplaces participated in the study with over 6,000 respondents, and an overall response rate of 62% was achieved. More than half of the workforce surveyed was at moderate- or high-risk BMI. Considered in tandem with low levels of physical activity and poor dietary habits, it indicates a workforce that is at high risk of chronic diseases and their associated adverse health outcomes.

Since the workplace presents a captive audience, there is a strong case for workplace health promotion to fight the growing obesity and chronic disease pandemic. Workplace health promotion can also benefit ‘hard-to-reach’ target groups such as those of lower socio-economic status, who are unlikely to engage in preventive health behaviours outside of the workplace. Given that the vast majority of workplaces were reported to offer healthier food options (79%), intervention efforts to encourage healthy eating behaviours could target intrapersonal and interpersonal factors. Complementary organisational-level interventions could include replacement of high sugar content drinks with lower sugar options in vending machines and restriction of catering options to providers offering healthier foods.

Regular physical activity was reported by only 21.0% of respondents. This is significantly lower than the proportion of Singapore residents engaging in sufficient total physical activity as reported in NPHS 2020.[11] This may be due to the different survey methodology (i.e. household face-to-face interviews) and the more extensive questions on physical activities in all domains employed in NPHS 2020. Nevertheless, there remains an opportunity for improvement in physical activity levels both at and beyond the workplace and for raising awareness about the need for an active lifestyle. Given that the respondents were largely in physically demanding jobs, they could have assumed that exercise would not be required and activity at work would be more than sufficient. This is a misconception, and workers should be encouraged to make a distinction between occupational and leisure time physical activity.

Smoking rates in our respondents were almost twice the prevalence in the population. It would be worthwhile for organisations to consider introducing workplace interventions aimed at the individual worker (e.g. counselling or pharmacological treatment)[13] while working towards the institution of a smoke-free workplace policy.[14]

The prevalence of chronic diseases in the workforce was somewhat lower compared to the prevalence reported in NPHS 2019.[10] A separate unpublished study of 944 workers from six construction sites (from the same cohort) found the self-reported prevalence of hypertension, high lipids and diabetes mellitus to be 5.2%, 3.5% and 1.9%, respectively. However, the prevalence of the same chronic conditions was found to be several times higher during health screening (27.6%, 28.8% and 8.2%, respectively). Therefore, the lower prevalence of chronic diseases in our surveyed workforce may be due to underreporting, as the respondents may be unaware or undiagnosed. Health screening is critical for secondary prevention and should be actively offered to workers as part of workplace safety and health efforts. Mitigating the effects of chronic disease on the worker directly contributes to safety at the workplace and impacts workplace productivity and health costs.[7]

Dueñas et al. reported a reduction in the efficiency and productivity of workers with chronic pain at work. This effect was amplified as the intensity of pain increased.[15] Chronic pain is also associated with increased concentration problems[16] and could result in safety lapses leading to injuries or fatalities at the workplace. In our study, a significant 8.3% of respondents experienced significant body pain that interfered with work over the past 4 weeks. With an increasing prevalence of work-related musculoskeletal disease and our ageing workforce, chronic pain is no longer a personal issue, but an organisation’s health and safety priority. Eliminating potential hazards and introducing workplace ergonomic interventions should be prioritised.

The Health and Safety Executive defined work-related stress, depression or anxiety as a harmful reaction people have to undue pressures and demands placed on them at work.[17] Although our study was conducted in 2019 before the additional stressors of dealing with the coronavirus disease 2019 (COVID-19) pandemic, it showed that a significant proportion of respondents was already experiencing a high or very high level of stress at work (12.7%). As stress causes poor attention, fatigue and errors in judgement, work injuries and accidents become more frequent. In our study, workers in the construction, manufacturing, and transport and storage industries were up to 1.46 times more stressed than workers in the cleaning industry. Mental stress at the workplace is a priority to tackle in these safety-critical industries, as its impact could result in severe consequences.

Higher work stress was reported in younger workers from the construction industry [Table 3]. A possible explanation could be that they belong to the ‘sandwich generation’. These workers are sandwiched between raising children and caring for elderly family members. Hence, they face competing demands from home, work and the social front. Understanding the contributory external stressors of this at-risk population would be useful in designing targeted programmes to meet their practical and mental health needs. Examples include offering talks on child/eldercare and training in stress and time management and relaxation techniques. Our study also reported lower rates of healthy behaviours such as regular exercise and daily fruit consumption in the high-stress group. A complex and bidirectional relationship exists between stress and health behaviours. Stress may impair efforts to be physically active. Hence, organisations should consider a multidimensional approach to reap synergistic effects when planning programmes for employees.[18]

Most of the causes of work stress concern the way work is designed and organisations are managed.[19] In our study, respondents with high or very high work stress reported stressors like ‘unrealistic time pressures’ and ‘less support from direct supervisors at the workplace’. They also reported being less satisfied with their working environment and feeling less safe working at their workplaces. Hence, interventions at the team/department and organisational level are pertinent to effectively reduce work stress. Examples include recalibrating work demands and promoting a supportive organisational culture.[19,20] In addition, we found a significant association between high work stress and body pain made worse by work (OR 2.28–2.99) [Table 4]. It is recognised that chronic pain in workers is associated with severe job stress, and increased job stress worsens the state of chronic pain.[21] Hence, interventions to address work stress will complement strategies to deal with chronic pain at the workplace.

Given that upper respiratory symptoms were the primary reasons for absenteeism, influenza could have been a possible occurrence in a proportion of workers reporting sick. Organisations could consider providing influenza vaccination annually or per season as recommended under the National Adult Immunisation Schedule.[22] Vaccination has been repeatedly reported as an effective and cost-saving preventive measure.[23]

We have alluded to the close and dynamic relationships between health behaviours earlier and the need for multilevel and multicomponent workplace health intervention programmes. Integrating workplace health promotion and occupational health and safety may increase programme participation and effectiveness for high-risk workers.[24]

There are several limitations to this study. Firstly, this study was conducted by means of a questionnaire and collected self-reported data. Although the questionnaires were translated into Chinese, Malay, Tamil and Bengali, there remained workers unfamiliar with these languages. For those workers, supervisors translated or read out the questions before completing the questionnaire on their behalf. Recall and social desirability biases were possible but minimised, as the survey was conducted anonymously. Also, as companies were invited and not randomly selected to participate in the study, selection bias is possible. Lastly, generalisability of the study could be limited, as the companies were primarily from four industries. Nevertheless, a good overall response rate of 62% was achieved, allowing for potential generalisation of the findings across the industries surveyed.

In conclusion, this study profiled the health status of 6,373 workers across the cleaning, construction, manufacturing, transport and storage industries. Significant health issues identified included a higher than population prevalence of smoking and high-risk BMI among the workers, and a lower than population prevalence of regular exercise. Dietary habits were suboptimal, and a significant proportion of workers experienced high or very high work stress. More research is required to validate this observation. More research is required to validate this observation, and a possible tool is iWorkhealth.[25]

Organisations should actively consider multilevel and multicomponent interventions to (a) reduce the prevalence of smoking, (b) encourage healthier dietary habits, (c) promote regular exercise, (d) increase regular health screening and vaccination rates, (e) introduce workplace ergonomic interventions and (f) actively reduce psychosocial risks at the workplace by prioritising mental well-being. It is necessary for organisations to move beyond tackling traditional safety issues to optimising employee health and well-being. Workplace safety and health management strategies should consider the impact of health in risk assessments. Health promotion interventions should be targeted, and multilevel and multicomponent initiatives should be integrated with pre-existing occupational safety programmes.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

This projected was funded by Health Promotion Board and the Workplace Safety and Health Council.