Int Arch Occup Environ Health (2011) 84:705–712 Table 3 Univariate and multi- variate associations of individual characteristics and work-related factors with productivity loss among 10,542 workers * p < 0.05 Table 4 Interaction between work ability and work-related factors in the association with productivity loss at work among 10,542 workers RERI relative excess risk due to interaction * p < 0.05, adjusted for age and sex Variable Age category 18–39 years (Ref) 40–49 years 50–68 years Female worker Psychosocial work demands Lack of job control Poor skill discretion High work demand Physical work demands Manual materials handling Awkward back postures Static working postures Repetitive movements Bending or twisting upper body Model 1: WAI and job control Good WAI and high job control Good WAI and lack of job control Decreased WAI and high job control Decreased WAI and lack of job control Model 2: WAI and skill discretion Good WAI and high skill discretion Good WAI and poor skill discretion Decreased WAI and high skill discretion Decreased WAI and poor skill discretion Model 3: WAI and work demand Good WAI and low work demand Good WAI and high work demand Decreased WAI and low work demand Decreased WAI and high work demand OR 1.00 0.83* 0.81* 0.91* 1.38* 1.28* 1.30* 1.11 1.13* 1.09* 1.09* 0.94 OR 1.00 1.23* 2.25* 3.11* 1.00 1.18* 2.51* 2.93* 1.00 1.22* 2.73* 2.89* 95% CI 0.76–0.91 0.74–0.89 0.85–0.99 1.28–1.50 1.18–1.40 1.20–1.40 0.95–1.30 1.01–1.26 1.01–1.18 1.01–1.17 0.87–1.02 1.13–1.34 1.87–2.70 2.75–3.52 1.07–1.30 2.02–3.14 2.58–3.34 1.12–1.34 2.29–3.26 2.55–3.27 Univariate model Multivariate model seems to act as a buVer in the association between decreased work ability and productivity loss at work. Some limitations must be considered in this study. First of all, the cross-sectional design of the study does not per- mit further explanation of the causal relationship between determinants and productivity loss at work. The results of this study do not indicate whether productivity loss at work was a result of decreased work ability or decreased work ability was a result of lack of productivity. The cross-sec- tional design also limits insight into the ‘lag time’ between decreased work ability and productivity loss at work. It could be that recent decreased work ability has a stronger eVect on productivity loss at work because a worker with a longer period of decreased work ability could have changed working tasks or found coping techniques to remain pro- ductive despite decreased work ability. Secondly, a subjective measure of productivity loss at work was used. Since objective measures of productivity at work are rarely available or diYcult to access, self-reports to estimate the decrease in productivity are more common (Koopmanschap et al. 2005; Burdorf 2007). One study showed signiWcant correlations between self-reported pro- ductivity and objective work output (r = 0.48) among Xoor layers (Meerding et al. 2005). Nevertheless, the current 123 OR 1.00 0.83* 0.82* 0.87* 1.32* 1.20* 1.28* – – – – – 709 95% CI 0.75–0.91 0.74–0.90 0.81–0.95 1.22–1.43 1.10–1.32 1.18–1.39 95% CI RERI 95% CI 0.63* 0.11–1.16 0.24 ¡0.31 to 0.79 ¡0.07 ¡0.65 to 0.51