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

0

50

100

150

1-10 11-49 50-249 250-999 1,000+

Incidence Rates for Occupational Illness, 1997, OSHA, NIOSH

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?

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 0.58-1.24%) doctor-

called incident cases 10.6-21.0% 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

0

20

40

60

0-10 11-49 50-249 250-999 1000+

Repetitve Trauma by Size of Business, 1996, CT OSHA/BLS

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-.078 (p=.001)

Stress/computer risk factor and business size .120 correlation (p<.001)

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

7542733092934151157N =

company size code

1000+250-99950-24911-491-10Missing

95%

CI w

ork

-re

late

d c

ase

.18

.16

.14

.12

.10

.08

.06

.04

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

MSD CaseTotal % Low CI Upper CI1-10 43 415 10.4 7.4% 13.3%11-49 35 293 11.9 8.2% 15.7%50-249 24 309 7.8 4.8% 10.8%250-999 32 273 11.7 7.9% 15.5%1000+ 55 754 7.3 5.4% 9.2%Missing 103 1157 8.9 7.3% 10.5%Total 292 3201 9.1 8.1% 10.1%

% MSD by Size and Industry, CUSP, CT, 1996

0.05.0

10.015.0

20.025.0

30.035.0

1-10 11-49 50-249 250-999 1000+

ag,mine, const

manuf

govt

service

fin insur re

0.0

5.0

10.0

15.0

1-10 11-49 50-249 250-999

1000+

MSD CUSP Prev and BLS Incid, CT 1996

CUSP

BLS

0

2

4

6

8

1-10 11-4950-249 250-999

1000+

MSD CUSP Dr. Called Prev and BLS Incid, 1996, CT

BLS

CUSP Dr.

0.0

10.020.0

30.040.0

50.060.070.0

Push-pull Reach Bent wrist Tools

Risk factors by company size, CT, CUSP, 1996

1-10

11-49

50-249

250-999

1000+

0.010.020.030.040.050.060.070.080.0

Stress Computer

Risk factors by company size, CT, CUSP, 1996

1-10

11-49

50-249

250-999

1000+

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

0.0

5.0

10.0

15.0

20.0

25.0

1-10 11-49 50-249 250-999 1000+

MSD Prev

Phys Risk rate

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

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; 0.81-1.00)

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