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

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

NIOSH/OSHA Report higher rates for larger companies

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 MSD is under-reported Occupational disease is primarily MSD Better recordkeeping? Less fear of reporting?

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

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

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)

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

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

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

CT BLS Repetitive trauma rates also increase by size of business

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%)

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

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)

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

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

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

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

Logistic Regression MSD case on Size : OR=0.91 CI Doctor called MSD on Size OR=0.88 CI

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

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

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

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

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