Does Size Count? Incidence and Reporting of Occupational Disease by Size of Company

1. Does Size Count? Incidence and Reporting of Occupational Disease by Size of Company Tim Morse, Ph.D. ErgoCenter UConn Health Center

2. Collaborators • Charles Dillon, NHANES • Joseph Weber, CT Labor Dept. • Nick Warren, UCHC • Heather Bruneau, UCHC • Rongwei Fu, UCHC

3. NIOSH/OSHA Report higher rates for larger companies

4. Reasons for Correlation? • Increased risk vs. better reporting • Increased risk? • Biersner and Winn, 1998 • More repetition in larger companies? • Connected to industry segment or other co-variate such as worker age? • Better reporting? • Oleinick, et al. 1995 • MSD is under-reported • Occupational disease is primarily MSD • Better recordkeeping? • Less fear of reporting?

5. Why do we care? • How do you best target industries? • Grants for small employer training • Prioritize OSHA inspections • Other policy issues • Recordkeeping by small employers • What is source of problem? • Repetition, stress, other risk factors • Need for and focus of internal training for companies • Under-estimate of Occupational Disease if under-reporting

6. Under-reporting • CUSP (CT Upper-Extremity Surveillance Project) Data • 9.1% of population with likely work-related prevalent MSD • 0.78% (95% CI 0.58-1.24%) doctor-called incident cases • 10.6-21.0% had filed workers’ compensation claims

7. Correlates of under-reporting (CUSP) • Severity of MSD • Surgery (OR 3.5) • Time off work (OR 4.5) • Doctor diagnosis (OR 13.7) • Psycho-social factors • Management cares (OR 2.0) • Fear of reporting • Union (OR 4.1) • Industry/Occupation • Manufacturing, transport, trade higher • Hourly wage workers (OR 2.8)

8. Population-based telephone survey (CUSP) • Random sample of 3,200 CT workers • 78% interview response rate • % with likely work-related MSD • % of cases reported to workers’ comp • Compare to BLS MSD figures by size of company • Size of company coded by CT Labor Dept; additional coding by InfoUSA

9. Statistical methods • Data reduction of risk factors by factor analysis • Tabular analysis of MSD by size of company • Partial correlations and Logistic regression

10. ConnOSHA/BLS Survey • Connecticut, 1996 • Repetitive Trauma • 61.6% of occupational illnesses • 3.6% of all injuries and illnesses • 3,711 cases of repetitive trauma • 28.8 per 10,000 workers

11. CT BLS Repetitive trauma rates also increase by size of business

12. Results: Coding for Size • Only 64% of respondents could be coded for size • No major differences between coded and uncoded for gender, age, and ethnicity • Minor differences in education • 33% (uncoded) vs. 27% (coded) High school grad • 13% vs 20% for post-graduate • Differences in industry • government (5.2% uncoded vs. 20.1% coded) • service (60.2% vs. 50.7%) • construction (8.1% vs. 4.1%)

13. Demographic characteristics by company size • No difference in gender distribution • Higher education in larger companies • chi-square=110.3, sig<.001 • Blacks and Hispanics over-represented in larger companies • chi-square=39.6, sig=.006 • Older workers in very large and very small companies • chi-square=72.7, sig<.001

14. Risk Factors • Factor analysis • Physical risk factor (push/pull,reach above, wrist bent, tool use) • Stress/computer factor (job stress, computer use) • Correlations with business size • physical risk factor (r= -.14) • stress/computer factor (.14)

15. Partial correlations • Controlling for gender, race, marriage, age, and education. • Physical risk factor and Business size -.078 (p=.001) • Stress/computer risk factor and business size • .120 correlation (p<.001)

16. MSD % Prevalence by Company Size, CUSP, CT, 1996

17. MSD by Company Size, CUSP, CT, 1996Chi-square=9.4, sig=.052

23. Physical risk by MSD prevalence, by firm size, CUSP, CT, 1996

24. Logistic Regression • MSD case on Size : • OR=0.91 • CI 0.83-1.00 • Doctor called MSD on Size • OR=0.88 • CI 0.78-0.99

25. Logistic Regression • Entered: Company size, gender, age, industry, occupation, married, race • Backward conditional regression

26. Logistic regression • MSD • Stay in equation: Gender, age, race, occupation • Size marginally significant (OR=0.90; 0.81-1.00) • Larger companies have lower rates • Doctor called: • Stay in regression: occupation, gender, race • Size not significantly related to MSD

27. Cautions and limitations • Self-reported data • Prevalence, not incidence • Just MSD • Only 64% could be coded for size • Likely that sample under-represented smaller companies • Demographics similar between coded and uncoded • Not likely to systematically affect rate of MSD by size

28. Conclusions • Business size is only weakly related to MSD, in negative direction (in contrast to BLS reports) • Risk factors vary somewhat by size; largest companies have: • Lowest physical risks, • Highest stress and computer risks

29. Under-reporting • Strong positive correlation in BLS reports between MSD and company size most likely due to better reporting in larger companies • Appears to be large under-reporting for smaller companies