| Zero-inflated part (ZI) | Negative binomial part (NB) | |||
| Coefficient | OR (95 CI) | Coefficient | MR (95 CI) | |
| Baseline (odds for ZI, mean for NB) | 0.54 | 0.58 (0.37 to 0.91) | 1.73 | 5.67 (4.12 to 7.80) |
| Male blue-collar | 2.02 | 7.53 (4.76 to 11.90) | 0.34 | 1.40 (1.04 to 1.88) |
| Male white-collar (reference) | 0 | 1 | 0 | 1 |
| Female white-collar | 1.44 | 4.24 (2.24 to 8.00) | 0.26 | 0.77 (0.52 to 1.15) |
| Age (years) | ||||
| 1839 (reference) | 0 | 1 | 0 | 1 |
| 4044 | 0.37 | 0.69 (0.40 to 1.21) | 0.11 | 0.90 (0.68 to 1.17) |
| 4561 | 0.72 | 0.49 (0.31 to 0.75) | 0.12 | 0.89 (0.72 to 1.10) |
| Musculoskeletal impairment due to work (per 1 unit; scale 010) | 0.13 | 1.13 (1.02 to 1.26) | 0.13 | 1.14 (1.09 to 1.19) |
| Insufficient sleep (per hour) | 0.32 | 1.38 (1.14 to 1.66) | 0.09 | 0.92 (0.86 to 0.98) |
| Predicted work ability | ||||
| Able | 0 | 1 | 0 | 1 |
| Uncertain | 0.11 | 1.12 (0.63 to 1.98) | 0.69 | 2.00 (1.53 to 2.62) |
| Not able | 0.63 | 1.87 (0.50 to 6.99) | 1.13 | 3.09 (1.89 to 5.05) |
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Estimated model coefficients, odds ratios (OR) and mean ratios (MR) with 95 CI from fitting a zero-inflated negative binomial regression Model 3 including age, occupational grade, gender, musculoskeletal impairment, insufficient sleep and self-rated future working ability as covariates.
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The estimate of the dispersion parameter was 0.62.
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Zero-inflated part refers to the model component for predicting membership to the subpopulation A with high propensity to zero absence, and negative binomial part to the component predicting the days on sick leave among the susceptible subpopulation B. To facilitate interpretation, for the zero-inflation part we have provided the ORs associated with the complementary propensity to having any sickness absencethat is, inclusion in subpopulation B.
