Introduction
In many developed Western countries, there is a need to increase labour market participation due to amongst others longevity and several policies have already been developed and implemented (European Commission
2014). The Europe 2020 strategy targets at increasing the working population’s employment rate to at least 75 per cent (European Commission
2014). Besides policies at the EU level, many national policy measures focus on increasing labour participation of older employees. Employees from 45 years onwards are defined as older employees by the WHO (Ilmarinen
2005). For instance, The Netherlands implemented policy measures such as increasing the legal retirement age and abolishing early retirement schemes (Doekhie et al.
2014; Ybema et al.
2009). These policy measures have effectively increased the net labour participation of older Dutch employees over a 10-year time period (2008–2017). A major increase was specifically noticeable for employees aged 55–65 years (Statistics Netherlands
2017a,
2018): the net labour participation of men increased from 61.7 to 77.4% and for women from 39.6 to 59.2% in this period (Statistics Netherlands
2018).
Notwithstanding this increased labour participation, it is important to note that older employees still leave the labour market before the actual retirement age. For instance, in the Netherlands, this occurs via different routes such as unemployment or disability schemes. There is an increasing proportion of employees receiving work disability benefits according to the Work and Income by Work Capacity Act (Berendsen
2017). This proportion increased from 5.3 to 8.2% over 4 years (2012–2016) within the 60 plus age group (Berendsen
2017). Furthermore, although the net labour participation of Dutch employees is among the highest in Europe (Statistics Netherlands
2017b) the amount of working hours per week is among the least (Statistics Netherlands
2017b). The proportion of part-time employees in the EU is by far the highest in The Netherlands with nearly 47% (Eurostat
2018). For older male and female employees aged 60–64 the amount of working hours per week is respectively 24.4 and 22.2 h/week (European Commission
2016). This may suggest that older employees might adjust their work hours to be able to continue labour participation (Damman et al.
2013).
With ageing, the risk of having (one or more) chronic condition(s) substantially increases (Doekhie et al.
2014; Sociaal-Economische Raad
2016; Ybema et al.
2009). Additionally, due to declining health, the risk of work incapacity/disability increases (Berendsen
2017). Chronic conditions are considered as an important factor which could hinder older employees’ ability to continue labour participation until their retirement age. This raises the question if and under which conditions older workers with a chronic condition are able to continue to participate in the labour market.
Chronic conditions are not unambiguously to define. In general, mental and somatic chronic conditions are distinguished (Sociaal-Economische Raad
2016). Amongst mental chronic conditions, depressive complaints comprise the majority of mental health complaints. Depressive complaints comprise a depressed mood or relatively mild to moderate symptoms of depression. Moreover, depressive complaints might act as a precursor for (clinical) depression according to DSM criteria (Nuijen et al.
2018; Lexis et al.
2009). Depressive complaints contribute to an increase in societal costs and healthcare use (Kant et al.
2008; Lexis et al.
2009). In the general Dutch population the prevalence rate of depressive complaints is high and is expected to keep increasing. In 2017, respectively 8.3 and 15.1% of men and women had depressive complaints (Nielen et al.
2017; World Health Organization
2018). Depressive complaints are also highly prevalent among the working population (Harvey et al.
2009; Lexis et al.
2012). The first goal of this study is therefore to gain more insight into the impact depressive complaints might have on labour participation of older employees.
When studying the potential association between depressive complaints and labour participation among older employees, it is important to consider that labour participation is a broad concept which entails various outcome measures or indicators. Often studies considered one single indicator to comprise the concept labour participation such as retirement intentions or disability pension (Bültmann et al.
2008; Lahelma et al.
2015). To complement the concept labour participation, it is valuable to consider both objective (employment status) and subjective indicators representing labour participation. Therefore, this study will consider both these objective (such as employment status) and subjective indicators (such as retirement intentions, psychological disengagement, and general, mental and physical work ability) to complement the concept labour participation.
In this respect, the concept work ability is relevant since it concerns a (in)balance between work demands and an employees’ individual resources to meet these demands (Boschman et al.
2017; Ilmarinen et al.
1997). Good work ability can support employment whereas poor work ability might increase the risk of early retirement (Ilmarinen
2008). Second, retirement intentions can be relevant as these might affect the continuation of labour participation (European Commission
2012). Additionally, motivation can be conceptualized by psychological (dis)engagement levels since older employees often gradually disengage from work by reducing work investments, activities and motivation a couple of years before the actual retirement age (Damman et al.
2013).
The Conservation of Resources (COR) model is used as a theoretical framework (Hobfoll
1989) throughout this study to understand and explain the association between depressive complaints and indicators of labour participation. The COR theory offered fundamental insights that have guided research on amongst others coping with chronic illness (Holmgreen et al.
2017). The main proposition of this theoretical framework is that individuals strive to obtain, foster, and protect resources. Resources are things individuals centrally value such as health, self-esteem, or time (Grandey and Cropanzano
1999; Hobfoll
1989,
2018). Stress is a reaction to an environment in which there is an actual or perceived loss in resources (Grandey and Cropanzano
1999; Hobfoll
1989). With ageing there is an inevitable loss of resources which requests a rearrangement of available resources to compensate for failing ones (Hobfoll
2018). In our study, older employees with depressive complaints (may) have a loss in resources due to impaired health and ageing. This might cause stress and could affect an employees’ ability to cope with their (mental) chronic conditions while being involved in labour participation resulting in withdrawal or disengagement (Hobfoll
2018).
Most empirical studies so far have focused on the impact of depressive complaints on one single and particular outcome such as sickness absence or work disability (Andrea et al.
2004; de Graaf et al. 2012; Lexis et al.
2009; Bültmann et al.
2008; Lahelma et al.
2015; Mykletun et al.
2006). Moreover, most studies assessed specific defined occupational groups (Chevalier et al.
1996; Gommans et al.
2017; Lahelma et al.
2015; Stansfeld et al.
2013). Though many studies are prospective cohort studies with significant long follow-up periods (Bonde
2008), these studies were performed in different European countries (Bültmann et al.
2008; Mykletun et al.
2006). Due to differences in social insurance systems generalizations to other countries/settings may be hindered. Furthermore, research specifically into older employees with depressive complaints is lacking. Moreover, longitudinal studies to date often focused on (major) clinical depression (Kaila-Kangas et al.
2014; Knudsen et al.
2010; Mykletun et al.
2006) or common mental disorders (Knudsen et al.
2010; Lahelma et al.
2015) and did not specifically distinguish depressive complaints as exposure of interest. Focusing on depressive complaints instead of clinical depression in the work context is of particular interest since employees with a clinical depression might already left the labour market whereas employees with depressive complaints are often still actively involved in the labour market. Furthermore, it is valuable to study depressive complaints both continuously as well as categorically. Studying different categories of severity might explain stagnation or transition to a more severe category of depressive complaints over time (Nuijen et al.
2018). Conceptualizing depressive complaints on a continuum ranging from no/mild depressive complaints at one end of the spectrum to severe complaints at the other end (Cuijpers et al.
2004; Geiselman and Bauer
2000; Hjarsbech et al.
2011) encompasses the total range of complaints preceding the diagnosis of clinical depression (Hjarsbech et al.
2011; Lexis et al.
2009). Moreover, it is valuable to consider the presence of other mental/physical chronic condition(s) since this may lead to a less favorable course of depressive complaints (Nuijen et al.
2018) and consequently also affect labour participation.
The understanding of the association between depressive complaints and indicators of labour participation of older employees may be further advanced by taking into account factors from the work context. It is valuable to study the impact of work-related factors in this relation as this might reveal facilitating and/or hindering factors for labour participation of older employees with depressive complaints and as such give insight how the work context can be optimized for workers with depressive complaints. According to our theoretical framework, other available resources such as employment conditions may counteract individual reactions to stress (Grandey and Cropanzano
1999). This is also supported by previous empirical research. A favorable work context consisting amongst others of low physical work demands, experiencing decision latitude (Stynen et al.
2017), or support from supervisor(s) and co-worker(s) (Ilmarinen
2008) could buffer the adverse impact of depressive complaints. Moreover, employees are less likely to report having early retirement intentions (Stynen et al.
2017) and are more likely to report good work ability (Ilmarinen
2008). Contrary, an unfavorable work context consisting amongst others of high physical work demands and stressful work demands might elevate employees’ risk of being out of employment (Gommans et al.
2016; Lund et al.
2001). Moreover, employees are likely to report limited work ability (Ilmarinen
2008). These studies have shown that high psychological job demands, low decision latitude, high emotional demands, number of working hours and overtime work, are related with (an elevated risk of) depressive symptoms (Andrea et al.
2004; Bonde
2008; Driesen et al.
2010; Niedhammer et al.
2004). However, these studies often assessed work-related factors as risk factors for the occurrence of depressive complaints. To date little is known about the potential facilitating/hindering impact of the work context on the relation between depressive complaints and indicators of labour participation among older employees. The second goal of this study is therefore to acquire more in-depth insight into how older employees with depressive complaints could better facilitate their labour participation. This by assessing potential facilitating and/or hindering impact of factors from the work context such as physically demanding work, working hours, overtime work, decision latitude, psychological job demands, and emotional demands when studying the relation between depressive complaints and indicators of labour participation.
To conclude, our study aims to firstly assess associations between depressive complaints and indicators of labour participation among older employees cross-sectionally and longitudinally over a 2-year time period. Secondly, this study aims to assess the potential facilitating and/or hindering impact of factors from the work context in the relation between depressive complaints and indicators of labour participation.
Results
Descriptive results
The characteristics of the study population (
n = 1253) and separately for the three categories of depressive complaints at 2012 baseline are reported in Table
1. Statistically significant differences were observed between the categories of depressive complaints regarding demographic and private factors (educational level and living alone). As for the work-related factors, statistically significant differences in mean scores for psychological job demands, decision latitude, co-worker social support, supervisor social support, emotional demands, and physically demanding work were observed between the different categories of depressive complaints. No statistically significant differences were observed for working hours. As for health factors, the percentage of employees having one or more mental/physical chronic condition(s) was significantly higher for employees with moderate/severe depressive complaints compared to employees without depressive complaints (85.3% vs 48.0). As for the indicators of labour participation, all outcome measures showed statistically significant differences in mean scores between the different categories of depressive complaints. At article baseline, a strong cross-sectional association between the severity of depressive complaints and retirement intentions was observed. Over 18 per cent of employees without depressive complaints indicated having strong retirement intentions compared to nearly 30% of employees with moderate/severe depressive complaints.
Table 1
Description of and mean depressive complaints scores of the study population (n = 1253) at article baseline (2012) according to demographic—and private, work and health factors (%)
Demographic and private factors |
Age (years) Mean (SD) | 54.60 (4.95) | 54.60 (4.92) | 54.28 (5.46) | 55.15 (5.01) | 0.695 |
Sex | | | | | |
(%)Male (%)Female | 70.2 29.8 | 70.0 30.0 | 69.3 30.7 | 79.4 20.6 | 0.491 |
Educational level | | | | | |
(%) Low (%)Medium (%) High | 5.3 23.0 71.7 | 4.9 23.2 71.9 | 4.1 21.6 74.3 | 21.9 18.8 59.4 | 0.001* |
Living alone |
(% Yes) | 10.6 | 9.8 | 22.7 | 9.1 | 0.002* |
Health factors |
HAD-D score (mean, SD)\presence other chronic condition(s) | 2.78 (3.08) | 2.08 (2.05) | 8.91 (.79) | 12.85 (2.22) | < 0.0001* |
(% Yes) | 50.3 | 48.0 | 68.1 | 85.3 | < 0.0001* |
Work-related factors |
Working hours |
(%)Part-time (%) Full-time | 29.8 70.2 | 29.8 70.2 | 32.4 67.6 | 24.2 75.8 | 0.694 |
Physically demanding work (% Yes) | 13.7 | 12.8 | 18.6 | 32.4 | 0.002* |
Mean (SD) |
Psychological job demandsa | 31.02 (5.64) | 30.85 (5.54) | 32.51 (6.29) | 33.56 (6.38) | 0.001* |
Decision latitudeb | 75.00 (10.30) | 75.42 (10.19) | 71.73 (9.59) | 68.00 (12.08) | < 0.0001* |
Emotional demandsc | 1.05 (1.24) | 0.99 (1.20) | 1.44 (1.45) | 2.06 (1.46) | < 0.0001* |
Co-worker social supportd | 12.10 (1.51) | 12.15 (1.49) | 11.88 (1.53) | 10.81 (1.53) | < 0.0001* |
Supervisor social supportd | 10.95 (2.19) | 11.03 (2.14) | 10.27 (2.51) | 9.76 (2.56) | < 0.0001* |
Indicators of labour participation |
Work ability |
Mean (SD) Generale Physicalf Mentalf | 7.71 (1.17) 4.20 (.55) 4.04 (.57) | 7.83 (1.05) 4.23 (.53) 4.10 (.52) | 6.48 (1.63) 3.93 (.70) 3.54 (.67) | 6.53 (1.44) 3.79 (.69) 3.29 (.63) | < 0.0001* < 0.0001* < 0.0001* |
Retirement intentions (% Strong) | 19.8 | 18.8 | 30.7 | 29.4 | 0.02* |
Psychological disengagement Mean (SD) | 12.70 (4.17) | 12.43 (4.07) | 15.51 (3.98) | 15.35 (4.90) | < 0.0001* |
Cross-sectional and longitudinal associations between depressive complaints and indicators of labour participation
Cross-sectional and longitudinal associations between depressive complaints and indicators of labour participation at article baseline and over a two-year follow-up period are presented in respectively Tables
2 and
3. Only fully adjusted models are discussed. For the longitudinal analyses, prevalent cases for the respective indicator of labour participation at baseline were excluded.
Table 2
Cross-sectional associations between depressive complaints scores/categories and indicators of labour participation
HAD-D continuous (0–21) | 1.30 (1.24–1.37)* | 1.26 (1.20–1.33)* | 1.26 (1.20–1.33)* | 1.30 (1.21–1.39)* | 1.27 (1.17–1.37)* | 1.24 (1.15–1.35)* | 1.45 (1.37–1.55)* | 1.41 (1.32–1.51)* | 1.40 (1.31–1.50)* | 1.10 (1.05–1.15)* | 1.09 (1.04–1.14)* | 1.09 (1.03–1.14)* | 1.21 (1.14–1.27)* | 1.14 (1.07–1.21)* | 1.13 (1.06–1.20)* |
Depressive complaints |
Noa | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Mild | 6.69 (3.69–12.11)* | 5.67 (3.08–10.47)* | 5.54 (3.00–10.23)* | 5.96 (2.86–12.42)* | 5.22 (2.40–11.35)* | 4.55 (2.07–9.97)* | 6.15 (3.50–10.81)* | 4.86 (2.69–8.77)* | 4.57 (2.52–8.29)* | 2.21 (1.27–3.86)* | 2.00 (1.14–3.52)* | 1.97 (1.12–3.47) * | 2.85 (1.47–5.49)* | 2.09 (1.04–4.20)* | 1.95 (0.97–3.94) |
Moderate/severe | 5.93 (2.57–13.69)* | 3.76 (1.56–9.06)* | 3.57 (1.47–8.64)* | 7.92 (3.11–20.15)* | 4.90 (1.73–13.83)* | 3.82 (1.35–10.87)* | 17.38 (7.85–38.45)* | 9.49 (3.98–22.60)* | 8.11 (3.36–19.56)* | 1.52 (0.66–3.52) | 1.23 (0.51–2.95) | 1.19 (0.49–2.87) | 4.38 (1.87–10.26)* | 2.21 (0.87–5.57) | 1.91 (0.76–4.84) |
Table 3
Longitudinal associations between depressive complaints and indicators of labour participation over 2-year follow-up period
HAD-D continuous (0–21) | 1.09 (1.03–1.16)* | 1.08 (1.00–1.15)* | 1.07 (1.00–1.15)* | 1.09 (1.00–1.19)* | 1.08 (0.99–1.19) | 1.08 (0.98–1.18) | 1.26 (1.18–1.35)* | 1.22 (1.13–1.31)* | 1.21 (1.12–1.31)* | 1.00 (0.94–1.07) | 0.96 (0.89–1.03) | 0.96 (0.89–1.03) | 1.08 (1.02–1.14)* | 1.07 (1.01–1.14)* | 1.07 (1.01–1.13)* | 1.03 (1.00–1.07) | 1.03 (0.99–1.06) | 1.02 (0.99–1.06) |
Depressive complaints |
Noa | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Mild | 1.91 (0.78–4.70) | 1.67 (0.66–4.23) | 1.66 (0.66–4.19) | 2.49 (0.87–7.09) | 2.26 (0.77–6.61) | 2.22 (0.76–6.50) | 3.94 (1.84–8.43)* | 2.85 (1.28–6.37)* | 2.60 (1.14–5.92)* | 1.24 (0.54–2.86) | 0.97 (0.41–2.28) | 0.97 (0.41–2.28) | 2.52 (1.32–4.81)* | 2.38 (1.22–4.62)* | 2.35 (1.21–4.57)* | 1.33 (0.87–2.03) | 1.28 (0.83–1.96) | 1.26 (0.82–1.94) |
Moderate/severe | 2.23 (0.70–7.12) | 1.92 (0.56–6.59) | 1.79 (0.52–6.20) | 2.03 (0.46–8.93) | 1.58 (0.34–7.20) | 1.53 (0.33–6.98) | 8.76 (3.00–25.58)* | 4.66 (1.43–15.21)* | 4.22 (1.27–14.00)* | 0.78 (0.19–3.20) | 0.50 (0.12–2.17) | 0.50 (0.12–2.16) | 1.03 (0.25–4.21) | 0.94 (0.22–3.95] | 0.91 (0.22–3.86] | 1.23 (0.67–2.26] | 1.09 (0.58–2.06] | 1.07 (0.56–2.03] |
General, mental and physical work ability
At article baseline, a one-point increase in HAD-D score was statistically significantly associated with higher odds for poor general, physical, and mental work ability (respectively OR 1.26, 95% CI 1.20–1.33; OR 1.24, 95% CI 1.15–1.35; and OR 1.40, 95% CI 1.31–1.50) after controlling for confounding factors. Employees with mild and moderate/severe depressive complaints had statistically significantly higher odds for poor general work ability (respectively OR 5.54, 95% CI 3.00–10.23; and OR 3.57, 95% CI 1.47–8.64) and poor physical work ability (respectively OR 4.55, 95% CI 2.07–9.97; and OR 3.82, 95% CI 1.35–10.87) compared to employees without depressive complaints. Furthermore, employees with mild and moderate/severe depressive complaints had statistically significantly higher odds for poor mental work ability (OR 4.57, 95% CI 2.52–8.29; and OR 8.11, 95% CI 3.36–19.56) compared to employees without depressive complaints. At follow-up measurement, a one-point increase in HAD-D was borderline statistically significantly associated with a higher risk for poor general work ability (HR 1.07, 95% CI 1.00–1.15], after controlling for confounding factors. Moreover, a one-point increase in HAD-D was substantially and statistically significantly associated with a higher risk for poor mental work ability (HR 1.21, 95% CI 1.12–1.31). Employees with mild and moderate/severe depressive complaints had substantial and statistical significant higher risks for poor mental work ability (respectively HR 2.60, 95% CI 1.14–5.92; and HR 4.22, 95% CI 1.27–14.00) over time compared to employees without depressive complaints. No statistically significantly associations were found for poor physical work ability.
Retirement intentions
At article baseline, a one-point increase in HAD-D score was statistically significantly associated with higher odds for strong retirement intentions (OR 1.09, 95% CI 1.03–1.14). Employees with mild depressive complaints had higher odds for strong retirement intentions (OR 1.97, 95% CI 1.12–3.47) compared to employees without depressive complaints. At follow-up measurement, a one-point increase in HAD-D was not statistically significantly associated with a higher risk for strong retirement intentions. Either, employees with mild and moderate/severe depressive complaints had no statistical significant higher risk for strong retirement intentions over time, compared to employees without depressive complaints.
Psychological disengagement
At article baseline, a one-point increase in HAD-D was statistically significantly associated with higher odds for high psychological disengagement levels (OR 1.13, 95% CI 1.06–1.20). At follow-up measurement, a one-point increase in HAD-D was statistically significantly associated with a higher risk for high psychological disengagement levels (HR 1.07, 95% CI 1.01–1.13). Employees with mild depressive complaints had a substantial and statistical significant higher risk for high psychological disengagement levels (HR 2.35, 95% CI 1.21–4.57) over time compared to employees without depressive complaints. However, no statistical significant associations were found for employees with moderate/severe depressive complaints.
Employment status
No cross-sectional associations were assessed since all employees were in (paid) employment at article baseline. When assessing the risk of not being in employment at follow-up measurement, fully adjusted models showed no statistical significant higher risk, while the first model (solely adjusted for demographic and private factors) showed that a one-point increase in HAD-D was borderline statistically significantly associated with a higher risk of not being in employment (HR 1.03, 95% CI 1.00–1.07) over time. No statistical significant associations were found for employees with mild and moderate/severe depressive complaints.
Association between depressive complaints and indicators of labour participation over-time: stratification for potentially hindering and/or facilitating work-related factors.
To explore the potential facilitating and/or hindering impact of work-related factors on the strength of the association between depressive complaints and indicators of labour participation over time, stratified analyses were performed for the following six factors: physically demanding work, working hours, overtime work, decision latitude, psychological job demands, and emotional demands (Table
4). Depressive complaints were only assessed as a continuum. Prevalent cases for the respective indicator of labour participation at baseline were excluded.
Table 4
Associations between depressive complaints and indicators of labour participation over 2-year follow-up period: stratification for potentially facilitating/hindering work-related factors
HAD-D continuous (0–21) |
Physically demanding work |
Yes | 1.12 (0.94–1.34) | 1.07 (0.87–1.32) | 1.09 (0.88–1.35) | 1.17 (1.02–1.35)* | 1.18 (0.99–1.41) | 1.23 (1.01–1.50)* | 1.23 (1.05–1.43)* | 1.44 (1.06–1.96)* | 1.44 (1.05–1.97)* | 0.88 (0.73–1.07) | 0.82 (0.67–1.00) | 0.82 (0.67–1.01) | 1.14 (0.99–1.30)* | 1.15 (0.98–1.35) | 1.14 (0.97–1.34) | 1.03 (0.96–1.12) | 1.04 (0.96–1.13) | 1.04 (0.95–1.13) |
No | 1.08 (1.01–1.16)* | 1.07 (0.99–1.16) | 1.06 (0.99–1.15) | 1.05 (0.93–1.17) | 1.04 (0.92–1.18) | 1.05 (0.93–1.19) | 1.27 (1.17–1.37)* | 1.21 (1.11–1.32)* | 1.21 (1.10–1.32)* | 1.02 (0.95–1.10) | 0.99 (0.92–1.07) | 0.99 (0.91–1.07) | 1.07 (1.00–1.14)* | 1.07 (1.00–1.14)* | 1.07 (1.00–1.14)* | 1.03 (0.99–1.07) | 1.02 (0.98–1.06) | 1.02 (0.98–1.06) |
Working hours |
Full-time | 1.11 (1.04–1.19)* | 1.08 (1.00–1.17)* | 1.08 (1.00–1.16)* | 1.14 (1.03–1.26)* | 1.09 (0.97–1.22) | 1.09 (0.97–1.22) | 1.29 (1.20–1.39)* | 1.22 (1.11–1.33)* | 1.20 (1.09–1.32)* | 1.00 (0.93–1.08) | 0.96 (0.88–1.05) | 0.95 (0.88–1.04) | 1.06 (0.99–1.14) | 1.05 (0.98–1.13) | 1.05 (0.98–1.13) | 1.02 (0.98–1.07) | 1.01 (0.97–1.06) | 1.01 (0.97–1.06) |
Part-time | 1.00 (0.84–1.20) | 1.02 (0.85–1.24) | 1.02 (0.84–1.23) | 0.98 (0.81–1.19) | 1.00 (0.82–1.23) | 1.00 (0.81–1.22) | 1.18 (1.01–1.37) | 1.25 (1.04–1.50)* | 1.26 (1.04–1.52)* | 0.99 (0.87–1.13) | 0.94 (0.81–1.09) | 0.95 (0.82–1.11) | 1.17 (1.04–1.31)* | 1.22 (1.06–1.40)* | 1.21 (1.06–1.39)* | 1.05 (0.99–1.11) | 1.05 (0.99–1.12) | 1.05 (0.99–1.13) |
Overtime work |
Yes | 1.10 (1.00–1.21)* | – | – | 1.09 (0.92–1.29) | – | – | 1.30 (1.17–1.45)* | – | – | 0.99 (0.88–1.11) | – | – | 1.10 (0.99–1.22)* | – | – | 1.02 (0.95–1.08) | 1.01 (0.94–1.08) | 1.00 (0.93–1.08) |
No | 1.08 (1.00–1.18)* | 1.07 (0.98–1.18) | 1.06 (0.97–1.16) | 1.08 (0.98–1.19) | 1.09 (0.98–1.21) | 1.09 (0.98–1.21) | 1.25 (1.15–1.37)* | 1.25 (1.13–1.39)* | 1.24 (1.11–1.38)* | 1.01 (0.93–1.09) | 0.99 (0.91–1.08) | 0.99 (0.90–1.08) | 1.06 (0.99–1.14) | 1.06 (0.99–1.14) | 1.06 (0.99–1.14) | 1.04 (1.00–1.08)* | 1.03 (0.99–1.08) | 1.04 (0.99–1.08) |
Decision latitude |
Low | 1.05 (0.96–1.14) | 1.05 (0.95–1.15) | 1.04 (0.95–1.14) | 1.10 (0.99–1.23) | 1.09 (0.96–1.24) | 1.09 (0.96–1.24) | 1.31 (1.19–1.45)* | 1.28 (1.15–1.42)* | 1.27 (1.14–1.41)* | 0.98 (0.90–1.06) | 0.96 (0.88–1.05) | 0.96 (0.87–1.05) | 1.06 (0.98–1.15) | 1.05 (0.97–1.14) | 1.05 (0.96–1.14) | 1.04 (1.00–1.08)* | 1.03 (0.99–1.08) | 1.04 (0.99–1.08) |
Middle/high | 1.13 (1.03–1.23)* | 1.13 (1.02–1.25)* | 1.13 (1.02–1.25)* | 1.12 (0.96–1.31) | 1.10 (0.94–1.29) | 1.09 (0.93–1.29) | 1.20 (1.07–1.34)* | 1.16 (1.02–1.32)* | 1.17 (1.02–1.34)* | 1.01 (0.91–1.13) | 0.99 (0.88–1.12) | 0.99 (0.88–1.12) | 1.10 (1.01–1.20)* | 1.14 (1.05–1.25)* | 1.15 (1.05–1.25)* | 1.04 (1.00–1.08)* | 1.03 (0.99–1.08) | 1.04 (0.99–1.08) |
Psychological job demand |
High | 1.13 (1.02–1.25)* | 1.10 (0.99–1.24) | 1.10 (0.98–1.24) | 1.19 (1.02–1.38)* | 1.15 (0.97–1.37) | 1.14 (0.95–1.36) | 1.24 (1.11–1.38)* | 1.16 (1.03–1.33)* | 1.15 (1.01–1.32)* | 0.97 (0.86–1.08) | 0.88 (0.77–1.00) | 0.86 (0.75–.99) | 1.13 (1.00–1.29)* | 1.08 (0.92–1.26) | 1.07 (0.91–1.24) | 0.98 (0.90–1.06) | 0.96 (0.88–1.05) | 0.96 (0.87–1.05) |
Low/middle | 1.06 (0.98–1.16) | 1.06 (0.96–1.16) | 1.06 (0.96–1.16) | 1.03 (0.91–1.17) | 1.05 (0.92–1.20) | 1.05 (0.92–1.20) | 1.25 (1.15–1.37)* | 1.28 (1.16–1.42)* | 1.29 (1.16–1.44)* | 1.01 (0.93–1.10) | 0.99 (0.91–1.08) | 1.00 (0.91–1.09) | 1.07 (1.01–1.14)* | 1.06 (1.00–1.14)* | 1.06 (1.00–1.14)* | 1.05 (1.01–1.08)* | 1.03 (0.99–1.07) | 1.03 (0.99–1.07) |
Emotional demands |
High | 1.08 (1.01–1.17)* | 1.08 (0.99–1.17) | 1.08 (0.99–1.17) | 1.09 (0.99–1.19) | 1.10 (0.99–1.22) | 1.09 (0.98–1.21) | 1.22 (1.13–1.32)* | 1.23 (1.13–1.33)* | 1.23 (1.13–1.33)* | 1.01 (0.94–1.09) | 0.99 (0.91–1.08) | 1.00 (0.91–1.09) | 1.09 (1.02–1.16)* | 1.07 (1.00–1.15)* | 1.08 (1.00–1.16)* | 1.02 (0.98–1.07) | 1.02 (0.98–1.07) | 1.02 (0.98–1.07) |
Low/middle | 1.11 (0.98–1.26) | 1.06 (0.93–1.21) | 1.06 (0.92–1.21) | 1.07 (0.86–1.34) | 1.08 (0.85–1.36) | 1.07 (0.85–1.36) | 1.31 (1.11–1.56)* | – | – | 0.96 (0.84–1.11) | .91 (0.79–1.06) | 0.91 (0.78–1.05) | 1.06 (0.95–1.19) | 1.05 (0.94–1.18) | 1.05 (0.94–1.18) | 1.03 (0.97–1.09) | 1.02 (0.96–1.08) | 1.02 (0.96–1.08) |
Physically demanding work
Among employees reporting to perform physically demanding work, results showed substantial and statistical significant associations between depressive complaints and poor physical (HR 1.23, 95% CI 1.01–1.50) and mental (HR 1.44, 95% IC 1.05–1.97) work ability over time. No statistical significant associations were found with between depressive complaints and other indicators of labour participation. Among employees reporting not to perform physically demanding work, a substantial and statistical significant association was found between depressive complaints and poor mental work ability (HR 1.21, 95% CI 1.10–1.32) over time, and a borderline significant association was found between depressive complaints and high psychological disengagement levels (HR 1.07, 95% CI 1.00–1.14) over time.
Working hours
Among full-time workers, results showed a borderline statistically significant association between depressive complaints and poor general work ability (HR 1.08, 95% CI 1.00–1.16) over time. Also, among full-time workers, results showed a substantial and significant association between depressive complaints and mental work ability (HR 1.20, 95% CI 1.09–1.32) over time. Among part-time workers, results showed a statistically significant association between depressive complaints and poor mental work ability (HR 1.26, 95% CI 1.04–1.52) and a substantial and statistically significant association between depressive complaints and high psychological disengagement levels (HR 1.21, 95% CI 1.06–1.39) over time.
Overtime work
Among employees reporting to work overtime, no statistically significant results were obtained. Among employees reporting not to work overtime, results showed a significant association between depressive complaints and poor mental work ability (HR 1.24, 1.11–1.38) over time.
Decision latitude
Among employees reporting low decision latitude, results showed a substantial and statistically significant association between depressive complaints and poor mental work ability (HR 1.27, 95% CI 1.14–1.41) over time. No statistically significant associations between depressive complaints and other indicators of labour participation were observed. Among employees reporting middle/high decision latitude, results showed a statistically significant association between depressive complaints and poor general work ability (HR 1.13, 95% CI 1.02–1.25) and high disengagement levels (HR 1.15, 95% CI 1.05–1.25) over time.
Psychological job demands
Among employees reporting high psychological job demands, results showed a borderline statistically significant association between depressive complaints and poor mental work ability (HR 1.15, 95% CI 1.01–1.32) over time. No statistical significant associations were found between depressive complaints and poor general and physical work ability. Among employees reporting low/middle psychological job demands, results showed a substantial and statistical significant high risk for poor mental work ability (HR 1.29, 95% CI 1.16–1.44) over time.
Emotional demands
Among employees reporting high emotional demands, results showed a borderline statistical significant association between depressive complaints and high psychological disengagement levels (HR 1.08, 95% CI 1.00–1.16) over time. Also, among employees reporting high emotional demands, results showed a substantial association between depressive complaints and poor mental work ability (HR 1.23, 95% CI 1.13–1.33) over time. No statistical significant associations between depressive complaints and other indicators of labour participation were observed. Among employees reporting low/middle emotional demands, results showed no statistically significant associations between depressive complaints and indicators of labour participation over time.
Discussion
The aim of this prospective study was to examine associations between depressive complaints and indicators of labour participation among older employees and to explore the possible facilitating and/or hindering impact of several work-related factors from the work context on this relation.
Cross-sectional results show that depressive complaints as a continuum were significantly associated with elevated odds of poor general, physical, mental work ability, strong retirement intentions, and high psychological disengagement levels among older employees even after controlling for confounding factors. Employees with mild and moderate/severe depressive complaints had substantial and significantly higher odds for poor general, physical, and mental work ability compared to employees without depressive complaints. In addition, employees with mild depressive complaints had significantly higher odds for strong retirement intentions compared to employees without depressive complaints.
Longitudinal results show that depressive complaints as a continuum were associated with a higher risk of reporting poor general and mental work ability as well as higher psychological disengagement levels over time. Employees with mild and moderate/severe depressive complaints had a substantial statistical significant higher risk for poor mental work ability over time compared to employees without depressive complaints. The observed results are in line with the COR theory. Employees with mild and moderate/severe depressive complaints might have or perceive a loss of resources in terms of health. This loss of resources affects employees rapidly and thus might lead to negative outcomes such as withdrawal or disengagement from work activities (Hobfoll
2018) affecting labour participation. Additionally, the COR theory explains that ageing is accompanied with an inevitable loss of resources. This may explain the strong associations observed in this study since our study population consists of older employees. Previous studies also support the strong associations observed between depressive complaints and high psychological disengagement levels. Declining health might accelerate the work disengagement process (Damman et al.
2013; Ilmarinen
2008). Additionally, results indicate substantial associations between depressive complaints and poor mental work ability over time. This might be explained by depressive complaints being considered a potential precursor for depression. Previous research already showed the negative affect of clinical depression on labour participation outcomes such as a decreased work ability and productivity loss (Ilmarinen
2008; Lagerveld et al.
2010). Despite being a precursor for depression, depressive complaints thus also appear to substantially negatively affect labour participation outcomes. No statistically significant associations were found between depressive complaints and strong retirement intentions and not being in employment over time.
Analyses furthermore explored the potential facilitating and/or hindering role of factors from the work context on the relation between depressive complaints and indicators of labour participation. The observed results show that the work context plays an important role in (the strength of) the adverse association between depressive complaints and indicators of labour participation over time among employees reporting to perform physically demanding work or having high psychological job demands. Results show that older employees reporting to perform physically demanding work, having high psychological job demands, having low decision latitude, or having high emotional demands, were at higher risk to report having poor mental work ability over time. These findings are supported by previous studies which also state that diseases, in general, have a detrimental effect on work ability. These detrimental effects are most apparent among workers performing physically demanding work (Ilmarinen
2008). Previous research also shows that high job demands negatively affect employees’ physical and mental health (Karasek
1979; Stansfeld et al.
2013). Furthermore, the observed results show that employees reporting having high emotional demands were at higher risk to report high psychological disengagement levels over time. According to the COR theory ageing is accompanied by an inevitable loss of resources such as impaired health (Hobfoll
2018). However, various (individual) resources might minimize these losses due to variations in self-esteem or skills (Grandey and Cropanzano
1999). Perhaps employees with high emotional demands in our study do at the same time have sufficient job resources such as more skills or a higher self-esteem. Consequently, these employees are thus not that affected by the loss of resources such as health. These employees might be able to cope with depressive complaints in their working life. Among part-time workers, a substantial-high risk was found between depressive complaints and high psychological disengagement levels over time. The strength of this association was lower and not significant among full-time workers. Perhaps employees previously involved in full-time employment yet experiencing (mild) depressive complaints reduced their working hours to part-time employment before article baseline to remain (actively) involved in paid employment. We cannot rule out a potential healthy-worker effect due to various selection processes. The impact of these (potential) selection processes on the interpretation of our study results will be explained more in-depth in the internal validity paragraph.
Internal validity
The internal validity of this study is strengthened amongst others due to the use of the validated HAD-D scale (Zigmond and Snaith
1983). Although the HAD-D was initially designed to detect depressive complaints in a nonpsychiatric hospital setting, the validity of the HAD-D scale is also warranted in other settings such as primary care patients, in the general population (Bjelland et al.
2002) and among employees (Andrea et al.
2004). The validity of the HAD-D among employees is additionally substantiated by the distribution of employees indicating to be currently under treatment by doctor/caregiver for depressive complaints at article baseline, which increases with increasing severity of depressive complaints (specific data not presented). The HAD-D scale allowed to measure depressive complaints both as a continuum and categorical. This provided more in-depth insights within different categories of severity of depressive complaints. Also, the continuous HAD-D score could indicate a transition and/or increase in indicators per one-point increase in HAD-D. Another major advantage of this study is the prospective and large cohort design. This prospective design enables us to assess cause and effect and to study longitudinal associations between depressive complaints and indicators of labour participation over time while taking into account confounding factors. Despite this longitudinal design, various selection processes and healthy worker effects (Neophhytou et al.
2014) cannot be ruled out. At article baseline, a potential healthy worker effect might have occurred due to selective participation. Perhaps employees experiencing (more severe) depressive complaints might have already left the labour force or have adjusted their work situation by reducing the amount of working hours and/or (perhaps) enrolled in part-time work due to their health problems already earlier. This might also explain the relatively small proportion of employees with moderate/severe depressive complaints (
n = 34). Unfortunately, information about the duration of (a) depressive (episode) complaints is lacking at article baseline. We should interpret these results carefully since this might be a selected population of employees being still actively employed despite having severe depressive complaints. Results are thus likely to be an underestimation of the true impact of depressive complaints on these indicators of labour participation. Moreover, mean HAD-D score at article baseline was statistically significantly higher for the non-responders (
n = 174) compared to the responders (
n = 1,079) at follow-up measurement (specific data not shown). This selective loss to follow-up over time may have attenuated the results regarding the impact of depressive complaints on indicators of labour participation over time. Moreover, in both the cross-sectional and longitudinal analyses, several adjustments were made for important demographic, work-related, and health factors. These confounding variables could potentially bias or modify the relation between depressive complaints and indicators of labour participation. In general, ORs and HRs moderately decreased after an additional adjustment was made. After additionally controlling for the presence of other mental/physical chronic condition(s) HRs showed a small decrease. The presence of one or more other chronic condition(s) was highly prevalent among the study population and especially among employees with moderate/severe depressive complaints (85.3%). Perhaps controlling for the presence of other chronic condition(s) led to an underestimation of the true strength of the associations. In the longitudinal analyses, the strength of the association substantially decreased after additionally controlling for work-related factors. This illustrated a potential impact from the work context when studying this relation. Moreover, the observed differences between cross-sectional and longitudinal findings might be (partially) attributable to the duration and frequency of the follow-up period.
External validity
Within our study, we aimed to complement the concept labour participation by assessing both objective and subjective outcome measures. The generalizability in our study is strongly affected by the chosen outcome measure. For instance, the generalizability of the observed results in terms of employment status and retirement intentions may be restricted to employees in the Netherlands since these outcomes are also determined by external factors such as social security systems. However, (general, physical, and mental) work ability and psychological (dis)engagement are universal outcome measures which are not country-specific. These observed results are thus readily generalizable to other European countries. In contrast, having (strong) retirement intentions is highly affected and influenced by the social insurance systems within a specific country. This makes the observed results with regards to strong retirement intentions less generalizable to other settings.
Recommendations further research
Employees without depressive complaints were classified as reference group in which results showed substantial and significant differences compared to, respectively, employees with mild depressive complaints and employees with moderate/severe depressive complaints. For further research, it might be interesting to test differences between employees with mild depressive complaints and moderate/severe depressive complaints. By exploring a (potential) difference in the severity of depressive complaints, preventive measures might be tailored specifically for the severity of depressive complaints.
Furthermore, within this study various objective and subjective indicators were used to complement the concept labour participation. This is specifically valuable when studying older employees since (declining) health status not only affects work ability but might also affect retirement intentions. A more comprehensive understanding is obtained which might contribute to developing tailored preventive measures and thus optimize labour participation of older employees. However, it should be acknowledged that this study was not intended to be exhaustive in examining all (possible) indicators of labour participation. Further research might for instance explore indicators of labour participation in further detail by assessing the underlying reasons for not being in employment. The exit route from paid employment through for instance disability schemes or unemployment benefits could be explored. While this study explored the potential role of six work-related factors from the work context when studying the relation between depressive complaints and indicators of labour participation, it should be noted that the stratified analyses were based on single work-related factors from the work context and thus not exhaustive. Further research should aim to gain more in-depth insight into the role of other work-related factor(s) from the work context, such as task variety or competencies when studying this relation.
Despite the longitudinal study design being a major prerequisite to assess a causal association over time between depressive complaints and indicators of labour participation, no measurements have taken place in the meantime. Further research should consider more frequent measurements during follow-up to detect more cases of (mild) depressive complaints.
Our goal was to assess whether there is an association between depressive complaints and indicators of labour participation among older employees over time. To increase this study internal validity a more homogenous group of older employees was assembled. Results show substantial results amongst these employees involved in daywork. However, it is also valuable to assess this association in other settings. Therefore, further research should investigate this association in other groups of older employees working for instance irregular working hours or being involved in night and/or shift work.
Overall, this study indicates strong, adverse associations between increasing depressive complaints and indicators of labour participation over time. Moreover, different work contexts revealed various negative associations between depressive complaints and indicators of labour participation. However, these results were not unambiguous since we found differential effects indicating the important role of the work context when studying this relation.
To prevent the transition from depressive complaints to clinical depression, work organizations/employers should aim to monitor depressive complaints among employees. Uniform preventive measures and/or interventions for all older employees are difficult since a one-size fits-all measure is probably ineffective considering the impact of different work contexts. In line with the COR theory, preventive measures or interventions might focus on enhancing resources to compensate for the losses in other resources such as health (Hobfoll
2018). Work organizations/employers should focus on balancing job demands and job resources (such as more autonomy) since this could have a beneficial impact on labour participation indicators among older employees. In addition, it is valuable to consider the role of the work context since the strength of these associations substantially differs within various work contexts. In practice, these study findings may serve as valuable input when considering the development of preventive measures and/or interventions aiming to prolong older employees’ working life.
In sum, further research on the relation between depressive complaints and indicators of labour participation should further explore the underlying reason(s) of (early) labour market exit. In addition, more in-depth insights into other factors from the work context is necessary when studying this relation, to optimize labour participation of older employees in a sustainable way.
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