Table 4.
Adjusted injury case status and significant covariates for poor functioning at follow-up within the GROW Study Cohort
| Characteristic | Lowest quartile SF-12 PCS (N = 664) | Lowest quartile work effectiveness (N = 621) | 2+ lost workdays in past 4 weeks (N = 621) | Changed site or not working (N = 664) |
| OR (95% CI) | OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| Case (versus ref) | 1.4 (0.9–2.2) | 0.9 (0.6–1.4) | 0.7 (0.5–1.2) | 1.5 (0.9–2.4) |
| Age at follow-up (per 10 years) | 1.3 (1.1–1.6)** | 1.0 (0.8–1.2) | 0.9 (0.8–1.1) | 0.9 (0.7–1.2) |
| SES quintile | ||||
| 1 (scores 2–3) | 2.0 (1.0–4.0)* | 1.0 (0.5–2.2) | 1.5 (0.7–2.9) | 2.5 (1.1–5.8)* |
| 2 (score 4) | 1.2 (0.6–2.4) | 1.7 (0.9–3.4) | 1.4 (0.7–2.6) | 1.6 (0.7–3.5) |
| 3 (score 5) | 1.5 (0.8–2.6) | 1.4 (0.8–2.5) | 1.5 (0.8–2.5) | 1.5 (0.7–3.1) |
| 4 (score 6) | 1.8 (1.0–3.4)* | 1.8 (1.0–3.2) | 1.4 (0.8–2.4) | 1.2 (0.6–2.6) |
| 5 (scores 7–8) (ref) | 1.0 (–) | 1.0 (–) | 1.0 (–) | 1.0 (–) |
| Co-morbid hypertension | 1.7 (1.1–2.6)* | 1.5 (1.0–2.5) | 1.2 (0.8–1.9) | 0.7 (0.4–1.2) |
| Co-morbid diabetes | 2.2 (1.0–4.7)* | 0.6 (0.2–1.8) | 0.8 (0.3–2.1) | 1.9 (0.8–4.5) |
| Job strain/ERI | ||||
| Above median: ERI ratio only | 0.7 (0.4–1.4) | 1.3 (0.7–2.3) | 0.8 (0.4–1.5) | 0.9 (0.4–1.9) |
| Above median: job strain only | 1.5 (0.9–2.6) | 1.3 (0.7–2.3) | 1.1 (0.6–1.8) | 1.4 (0.7–2.8) |
| Above median: both | 1.7 (1.1–2.7)* | 2.6 (1.6–4.2)*** | 1.0 (0.7–1.6) | 1.2 (0.7–2.2) |
| Above median: neither (ref) | 1.0 (–) | 1.0 (–) | 1.0 (–) | 1.0 (–) |
Predictors in multivariable models included age, gender and race/ethnicity, SES quintile, co-morbid hypertension and diabetes and combined effort–reward and job strain measure. Poor functioning defined as lowest functioning quartile over both assessments for the referents subsample for SF-12 PCS and work effectiveness. For lost workdays, poor functioning defined as >2 days lost in the past 4 weeks. N's for outcomes applicable only to individuals working at following are based on rounded number of individuals with an actual or imputed value of working at follow-up. N = 13 cases and n = 29 controls were not working at follow-up, which is due to rounding error and does not add up to the N = 43 who were not working when cases and referents are pooled. SES = quintile SES, created by adding together one point each for higher levels of education and income shown in Supplementary Table 1 and grouping into quintiles, from lowest (1) to highest (5). Job strain/effort–reward ratio created by recoding each variable into above-median (binary) equivalent and then testing each simultaneously to yield four categories. *P < 0.05; **P < 0.01; ***P < 0.001.