Work Hours and Cognitive Function: The Multi-Ethnic Study of Atherosclerosis

Luenda E. Charles, Desta Fekedulegn, Cecil M. Burchfiel, Kaori Fujishiro, Adina Zeki Al Hazzouri, Annette L. Fitzpatrick, Stephen R. Rapp

Research output: Contribution to journalArticlepeer-review


Background: Cognitive impairment is a public health burden. Our objective was to investigate associations between work hours and cognitive function. Methods: Multi-Ethnic Study of Atherosclerosis (MESA) participants (n = 2,497; 50.7% men; age range 44–84 years) reported hours per week worked in all jobs in Exams 1 (2000–2002), 2 (2002–2004), 3 (2004–2005), and 5 (2010–2011). Cognitive function was assessed (Exam 5) using the Cognitive Abilities Screening Instrument (version 2), a measure of global cognitive functioning; the Digit Symbol Coding, a measure of processing speed; and the Digit Span test, a measure of attention and working memory. We used a prospective approach and linear regression to assess associations for every 10 hours of work. Results: Among all participants, associations of hours worked with cognitive function of any type were not statistically significant. In occupation-stratified analyses (interaction p = 0.051), longer work hours were associated with poorer global cognitive function among Sales/Office and blue-collar workers, after adjustment for age, sex, physical activity, body mass index, race/ethnicity, educational level, annual income, history of heart attack, diabetes, apolipoprotein E-epsilon 4 allele (ApoE4) status, birth-place, number of years in the United States, language spoken at MESA Exam 1, and work hours at Exam 5 (β = –0.55, 95% CI = –0.99, –0.09) and (β = –0.80, –1.51, –0.09), respectively. In occupation-stratified analyses (interaction p = 0.040), we also observed an inverse association with processing speed among blue-collar workers (adjusted β = –0.80, –1.52, –0.07). Sex, race/ethnicity, and ApoE4 did not significantly modify associations between work hours and cognitive function. Conclusion: Weak inverse associations were observed between work hours and cognitive function among Sales/Office and blue-collar workers.

Original languageEnglish (US)
Pages (from-to)178-186
Number of pages9
JournalSafety and Health at Work
Issue number2
StatePublished - Jun 2020
Externally publishedYes


  • Cognitive abilities screening instrument
  • Digit Symbol Coding
  • Global cognitive function
  • Occupation
  • Work schedule

ASJC Scopus subject areas

  • Safety, Risk, Reliability and Quality
  • Safety Research
  • Public Health, Environmental and Occupational Health
  • Chemical Health and Safety


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