Potential Risk Factors for Work-Related Musculoskeletal Pain to Hired Crop

Workers in the U.S.

John R. Myers and Larry A. Layne

National Institute for Occupational Safety and Health

The findings and conclusions in this Presentation are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

National Agricultural Workers Survey National survey of hired crop workers in the

U.S.

U.S. Department of Labor, Employment Training Administration

Began in 1989

Main focus: crop worker labor force stability, demographics, work histories, and economics

National Agricultural Workers Survey

1999-2004 NIOSH occupational health supplemental modules

Injury: 1999, 2002-2004 Musculoskeletal pain: 1999-2004 Dermatitis: 1999-2003 Health conditions: 1999-2004

asthma, diabetes, high blood pressure, tuberculosis, heart disease, urinary tract infections

Methods

Methods: NAWS

Retrospective, cross sectional study Survey of the Continental U.S.--Excludes

Hawaii and Alaska Personal interview in worker’s primary

language Conducted in a location chosen by worker Core questionnaire and supplemental modules All hired crop workers eligible Complex sampling weights

Methods

Demographic information on hired crop workers:

General: Age, Sex, Race/Ethnicity, Education, Language

Time of interview: Region, Migration pattern, US farm work experience, Health problems, Type of crop, Type of work, Socio-economic information

Chart TitleGeographic Regions Used by NAWS

East

Southeast

Midwest

Southwest

Northwest

California

Methods

Musculoskeletal pain module: Number of self-reported complaints of

pain during the past year Farm work-related events only

Methods Modeling using SAS Proc Surveylogistic

Outcome = incidence of musculoskeletal complaints divided by weeks of farm work (adjusted range to be 0 - 1)

34 statistically significant independent variables from univariate models (α=0.05)

Multivariate model of these 34 variables Backwards elimination approach

Results

Basic Survey Results

Survey response: Operator participation rate: 69% Crop worker participation rate: 94%

Number of interviewed hired crop workers just over 20,000

Musculoskeletal Pain, 1999-2004 Musculoskeletal pain complaints (MPC):

Weighted estimate = 4,021 complaints Crude incidence = 43.3 MPC/100 FTEWB

Chart TitleMultivariate Logistic Model Results

23 independent variables were associated with the incidence of musculoskeletal pain (α=0.05)

8 demographic, 5 employment , 10 socio-economic

Chart TitleMultivariate Logistic Model Results

Demographic variables: Age Sex Education Marital status Region Years of farm work in U.S. Health conditions English speaking skills

Chart TitleMultivariate Logistic Model Results

Demographic: Health conditions

Demographic: Sex

Illnesses ORadj L95% U95%

2 ≥ illnesses 2.13 1.78 2.551 illness 1.58 1.36 1.72No illnesses 1.00 --- ---

Sex ORadj L95% U95%

Female 1.66 1.47 1.87Male 1.00 --- ---

Chart TitleMultivariate Logistic Model Results

Demographic: Education

Demographic: Education

Formal Education ORadj L95% U95%

None 1.51 1. 20 1.90Any education 1.00 --- ---

Region ORadj L95% U95%

California 1.50 1.22 1.85Southeast 1.40 1.13 1.74Southwest 1.32 0.99 1.75

Midwest 1.27 1.02 1.57West 1.26 0.99 1.60

East 1.00 --- ---

Chart TitleMultivariate Logistic Model Results

Employment variables: Workers’ compensation coverage Crop currently harvesting Task currently doing Employer provided tools/equipment Employer provided clean drinking water

Chart TitleMultivariate Logistic Model Results

Employment: Workers’ compensation

Employment: Current crop worked on

Known Coverage ORadj L95% U95%

None 1.83 1.58 2.13Medical or indemnity 1.43 1.26 1.63

Medical & indemnity 1.00 --- ---

Crop ORadj L95% U95%Multiple 1.60 1.22 2.10Fruit & nuts 1.54 1.29 1.85Vegetables 1.53 1.29 1.82Field crops 1.51 1.24 1.83Horticultural 1.00 --- ---

Chart TitleMultivariate Logistic Model Results

Socio-economic variables: Migrant type Farm work income Home ownership US owned assets Housing arrangements Used unemployment insurance past year Used U.S. healthcare past 2 years Healthcare payment method Number of Social services used Below minimum wage

Chart TitleMultivariate Logistic Model Results

Socio-economic: Used U.S. health care

Socio-economic: Healthcare payment method

Used healthcare ORadj L95% U95%

Yes 1.96 1.20 3.43No 1.00 --- ---

How paid ORadj L95% U95%

Did not pay 1.99 1.36 2.91Employer/WC 1.17 1.00 1.37None used 1.19 0.68 2.07

Other insurance 1.00 --- ---

Chart TitleMultivariate Logistic Model Results

Socio-economic: Farm work income

Socio-economic: Migrant type

Income ORadj L95% U95%

None 2.18 1.63 2.91< $15,000 1.09 0.97 1.22

≥ $15,000 1.00 --- ---

Migrant type ORadj L95% U95%

Shuttle 1.72 1.44 2.06Settled 1.12 0.95 1.33

Follow the crop 1.00 --- ---

Summary

Summary The average incidence of musculoskeletal

pain complaints was even higher—43.3 complaints/100 FTEWB.

Twenty-three of 34 independent variables were significantly associated with incidence of musculoskeletal pain in multivariate model

Mixture of demographic, employment, and socio-economic variables.

Summary

Workers reporting responsible employment practices had lower odds of musculoskeletal complaints:

Told about workers’ compensation coverage

Provided fresh drinking water/cups Provided tools and equipment

Summary

Some variables suggest young/new workers have higher odds of musculoskeletal pain:

<20 years old highest adjusted odds ratio

≤ 1 year U.S. farm work No previous farm work income

Summary

Other key potential risk factors: Female worker No reported education Shuttle migrant Reporting other health issues

Future Work Work with NIOSH Ag centers, employers,

and farm worker groups to address factors associated with work-related musculoskeletal pain

Need to focus on female farm workers and new hired crop workers

Approaches need tailored to low income workers with little formal education

Limitations Cross-sectional survey Self-reported pain by farm workers Small number of farm workers covered by

the survey in some regions

Questions?