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. Author manuscript; available in PMC: 2014 Dec 6.
Published in final edited form as: J Occup Environ Med. 2013 Mar;55(3):318–324. doi: 10.1097/JOM.0b013e31827943c6

Appendix.

Non-Significant Bivariate Associations (P ≥ 0.10) of Baseline Variables with Clinically Significant Weight Gain (7%) by One Year after Initial Occupational Back Injury

Domain and variables No significant weight gain N=1089 Significant weight gain N=174 Odds ratio^ 95% CI P-value
Sociodemographic
Age, years (ref= 35-44 years) 339 53 0.14
    ≤24 years 94 17 1.16 0.64 – 2.09
    25 – 34 years 244 50 1.31 0.86 – 1.99
    45 – 54 years 289 43 0.95 0.62 – 1.47
    ≥ 55 years 123 11 0.57 0.29 – 1.13
Region of worker residence † (ref=urban) 633 97 0.64
    Suburban 184 33 1.17 0.75 – 1.80
    Large town 124 22 1.14 0.68 – 1.89
    Rural 115 20 1.12 0.66 – 1.90
Race/ethnicity (ref=White non-Hispanic) 798 122 0.34
    Hispanic 142 30 1.35 0.86 – 2.11
    Other 149 22 0.88 0.54 – 1.45
Education (ref=high school) 364 58 0.68
    Less than high school 120 14 0.73 0.39 – 1.36
    Vocational or some college 495 84 1.05 0.73 – 1.52
    College 110 18 1.00 0.56 – 1.78
Marital status (ref=married/living with partner) 748 114 0.78
    Other 340 60 1.05 0.74 – 1.48
Employment-related
Worker's industry ‡ (ref=trade/transportation) 285 39 0.57
    Natural resources 49 6 0.97 0.38 – 2.43
    Construction 201 27 1.11 0.65 – 1.89
    Manufacturing 83 8 0.75 0.34 – 1.68
    Management 192 26 0.96 0.56 – 1.64
    Education and health 155 36 1.25 0.73 – 2.14
    Hospitality 124 32 1.56 0.92 – 2.65
Heavy lifting (ref=not at all/rarely/occasionally) 510 83 0.42
    Frequently 363 51 0.90 0.61 – 1.32
    Constantly 215 39 1.19 0.78 – 1.83
Whole body vibration (ref=not at all/rarely) 708 127 0.46
    Occasionally/frequently 254 34 0.94 0.61 – 1.46
    Constantly 125 13 0.74 0.40 – 1.39
Physical demands (ref=sedentary/light) 211 43 0.49
    Medium 357 47 0.69 0.44 – 1.09
    Heavy 257 44 0.99 0.61 – 1.59
    Very heavy 258 39 0.85 0.52 – 1.40
Excessive amount of work (ref=strongly disagree/disagree) 871 134 0.21
    Strongly agree/agree 218 40 1.12 0.94 – 1.32
Enough time to do job (ref=Strongly agree/agree) 796 117 0.26
    Strongly disagree/disagree 293 57 1.22 0.86 – 1.73
Very hectic (ref=Strongly disagree/disagree) 313 39 0.60
    Agree 494 85 1.30 0.86 – 1.96
    Strongly agree 279 49 1.12 0.70 – 1.78
Supervisor listens to my work problems (ref=agree) 622 101 0.25
    Strongly disagree/disagree 205 40 1.03 0.69 – 1.56
    Strongly agree 248 30 0.67 0.43 – 1.04
Satisfaction with job (ref=Somewhat or very satisfied) 944 149 0.30
    Not at all or not too satisfied 142 25 1.02 0.64 – 1.64
Co-worker relations (0 – 10 scale, ref=10, get along extremely well) 570 90 0.87
    8 – 9 394 67 1.07 0.75 – 1.51
    0 – 7 121 16 0.86 0.48 – 1.53
Job type at time of injury (ref=full-time) 992 158 0.26
    Part-time 97 15 0.71 0.39 – 1.29
Seasonal job at injury (ref=no) 1020 167 0.35
    Yes 68 7 0.68 0.30 – 1.52
Temporary job at injury (ref=no) 1024 163 0.55
    Yes 62 11 1.23 0.63 – 2.41
Job duration ≥ 6 months 865 135 0.67
    < 6 months 222 39 1.09 0.73 – 1.62
Employer offered job accommodation (ref=Yes) 517 75 0.15
    No 561 94 1.28 0.92 – 1.79
Pain and function
Number pain sites (ref=0-2 sites) 528 70 0.21
    3 – 4 sites 403 74 1.37 0.96 – 1.97
    5 – 8 sites 158 30 1.29 0.80 – 2.09
Pain intensity, past week (0= no pain, ref= 0–3)40 291 41 0.79
    4 – 5 289 43 0.99 0.62 – 1.58
    6 – 7 286 48 1.07 0.68 – 1.68
    8 – 10 223 42 1.24 0.77 – 1.99
Pain interference with work, past week (0=no interference, ref=0-3)40 405 52 0.32
    4 – 5 189 29 1.20 0.74 – 1.97
    6 – 7 192 33 1.35 0.84 – 2.18
    8 – 10 300 59 1.52 1.00 – 2.29
Roland questionnaire € (0=no disability) (ref=0-8)42 326 47 0.23
    9 – 16 386 53 0.95 0.62 – 1.45
    17 – 24 377 74 1.30 0.87 – 1.95
SF-36 v2 Physical Function (ref=>50)39 276 39 0.26
    41 – 50 209 27 0.93 0.55 – 1.57
    30 – 40 279 42 1.03 0.64 – 1.66
    < 30 325 66 1.40 0.90 – 2.18
SF-36 v2 Role Physical (ref=>50)39 239 37 0.11
    30 – 50 469 63 0.82 0.53 – 1.28
    < 30 381 74 1.22 0.79 – 1.90
Pain change since injury (ref=better) 762 111 0.49
    Same 198 42 1.36 0.92 – 2.02
    Worse 120 19 1.00 0.59 – 1.71
Clinical status
Injury severity †† (ref=mild strain/sprain)11 594 91 0.31
    Major strain/sprain with substantial immobility but no evidence of radiculopathy 215 36 1.07 0.70 – 1.63
    Evidence of radiculopathy or abnormalities 273 47 1.15 0.78 – 1.70
Pain radiates below knee (ref=no) 791 119 0.27
    Yes 298 55 1.22 0.86 – 1.74
Previous similar back injury (ref=no) 568 101 0.73
    Yes 521 73 0.94 0.67 – 1.32
Previous injury (any type) with ≥ 1 month off work (ref=no) 791 128 0.49
    Yes 295 46 1.14 0.78 – 1.67
Number of self-reported worker's compensation claims before current injury (ref=0) 402 64 0.40
    1 328 49 1.06 0.70 – 1.60
    2 – 3 236 40 1.31 0.84 – 2.04
    ≥ 4 115 18 1.33 0.74 – 2.39
Work days missed because of back, previous year (ref=0) 720 114 0.34
    1 – 10 269 39 0.92 0.62 – 1.37
    > 10 87 16 1.31 0.73 – 2.33
Work days missed because of other health problems, previous year (ref=0) 458 56 0.20
    1 – 10 536 98 1.34 0.94 – 1.91
    > 10 78 14 1.26 0.66 – 2.40
Number other major medical problems (ref=0) 906 147 0.99
    ≥ 1 182 27 1.00 0.63 – 1.60
General health, year prior to injury (ref=excellent) 262 33 0.23
    Very good 415 62 1.16 0.74 – 1.83
    Good 320 58 1.39 0.88 – 2.21
    Fair/poor 90 21 1.71 0.93 – 3.13
Opioid Rx within 6 weeks of injury (ref=no) 703 109 0.64
    Yes 359 59 1.07 0.76 – 1.52
Health care
Health care provider recommended exercise (ref=yes) 768 126 0.66
    No 319 48 0.92 0.64 – 1.33
Health insurance (ref=yes) 787 119 0.32
    No 301 54 1.13 0.79 – 1.62
Administrative/legal
Time from injury to first medical visit for injury ◇ (ref=0-6 days) 845 123 0.12
    7 – 13 days 119 26 1.66 1.03 – 2.66
    ≥ 14 days 96 18 1.33 0.77 – 2.30
Health behavior
Tobacco use (ref=no) 591 92 0.63
    Occasionally/frequently 166 23 0.90 0.55 – 1.48
    Daily 332 59 1.14 0.80 – 1.63
Alcohol Use Disorder Identification Test-Consumption (AUDIT-C)^^ (ref=negative, AUDIT-C score of 0 – 3 for males, 0 – 2 for females)41 755 129 0.30
    Positive (4 – 12 for males, 3 – 12 for females) 331 44 0.77 0.53 – 1.12
Baseline Body Mass Index (BMI) (ref=<25) 318 57 0.89
    25 – 29 (overweight) 443 63 0.92 0.62 – 1.37
    ≥ 30 (obese) 328 54 1.00 0.67 – 1.51
Psychological
Blame for injury39 (ref=work) 527 91 0.41
    Self 230 27 0.72 0.45 – 1.14
    Someone/something else 151 30 1.11 0.70 – 1.75
    Nothing/no one 160 21 0.80 0.48 – 1.33
Work fear-avoidance (ref= <3, very low)◇◇ 214 28 0.31
    Low-moderate (>3 – <5) 358 51 1.11 0.68 – 1.82
    High (5 – 6) 517 95 1.37 0.87 – 2.15

Missing, “don't know,” and refusal responses for each variable were combined into one response for each variable (results not shown)

Ref indicates reference group.

All measures were obtained from worker baseline interviews except where noted

^

All odds ratios were adjusted for age and gender, except for age

†

By residential zip code, using the Washington State guidelines classifications at http://www.doh.wa.gov/Data/Guidelines/RuralUrban

‡

Derived from Standard Industrial Codes (SIC)

€

Roland-Morris Disability Questionnaire assesses overall back disability42-44

Scores from the Short-Form-36 version 2 (SF-36v2) Physical Function and Role Physical scales; higher scores indicate better functioning39

††

Rated by trained nurses based on medical records early in the claim

◇

From worker's compensation database

^^

The AUDIT-C score is a screening test for problematic alcohol usage41

◇◇

Mean of responses to two questions from the Fear-Avoidance Beliefs Questionnaire work scale46