Occupational history associates with ALS survival and onset segment

Abstract

Objective

To identify associations between occupational settings and self-reported occupational exposures on amyotrophic lateral sclerosis (ALS) survival and phenotypes.

Methods

All patients seen in the University of Michigan Pranger ALS Clinic were invited to complete an exposure assessment querying past occupations and exposures. Standard occupational classification (SOC) codes for each job and the severity of various exposure types were derived. Cox proportional hazards models associated all-cause mortality with occupational settings and the self-reported exposures after adjusting for sex, diagnosis age, revised El Escorial criteria, onset segment, revised ALS Functional Rating Scale (ALSFRS-R), and time from symptom onset to diagnosis. Multinomial logistic regression models with three categories, adjusted for age, assessed the association between occupational settings and exposures to onset segment.

Results

Among the 378 ALS participants (median age, 64.7 years; 54.4% male), poorer survival was associated with work in SOC code “Production Occupations” and marginally with work in “Military Occupation”; poor survival associated with self-reported occupational pesticide exposure in adjusted models. Among onset segments: cervical onset was associated with ALS participants having ever worked in “Buildings and Grounds Cleaning and Maintenance Occupations,” “Construction and Extraction Occupations,” and “Production Occupations”; bulbar onset with self-reported occupational exposure to radiation; and cervical onset with exposure to particulate matter, volatile organic compounds, metals, combustion and diesel exhaust, electromagnetic radiation, and radiation.

Conclusion

Occupational settings and self-reported exposures influence ALS survival and onset segment. Further studies are needed to explore and understand these relationships, most advantageously using prospective cohorts and detailed ALS registries.

Keywords:

• Amyotrophic lateral sclerosis
• occupation
• survival
• phenotype

Acknowledgements

The authors are indebted to the study participants that provided information. We thank Blake Swihart, Adam Patterson, Jayna Duell, RN, Daniel Berger, Amanda Williams, and Scott Dent for the study support. We thank Stacey Sakowski, PhD for assistance with figures.

Author contributions

S.A. Goutman, MD, MS: Drafting/revising the manuscript for content, study concept and design, analysis and interpretation of data.

J. Boss, MS: Drafting/revising the manuscript for content, analysis and interpretation of data.

C. Godwin, DDS, PhD: Drafting/revising the manuscript for content, analysis and interpretation of data.

B. Mukherjee, PhD: Analysis and interpretation of data, drafting/revising the manuscript for content.

E.L. Feldman, MD, PhD: Drafting/revising the manuscript for content, study concept and design, analysis and interpretation of data.

S. Batterman, PhD: Drafting/revising the manuscript for content, study concept and design, analysis and interpretation of data.

Declaration of interest

SAG served on a DSMB. The other authors declare they have no competing interests.

Data availability statement

Sharing of non-identifiable data will be considered at the reasonable request of a qualified investigator.

Additional information

Funding

This work was supported by the National ALS Registry/CDC/ATSDR (1R01TS000289); National ALS Registry/CDC/ATSDR CDCP-DHHS-US (CDC/ATSDR 200-2013-56856); NIEHS K23ES027221; NIEHS R01ES030049; NIEHS P30ES017885.