Introduction: The Period 3 (Per3) gene is associated with individual differences in several sleep
and circadian functions. Shift workers experience sleep restriction and exposure to
wakefulness during an adverse circadian phase. Workers who carry genetic polymorphisms
in the Per3 gene may experience particularly high levels of sleepiness during the
night shift, which can lead to the development of various diseases. They may also
be at greater risk for automotive or occupational accidents when assigned to work
hours that do not align with their chronotype profile. We hypothesize that the Morningness
and Eveningness Questionnaire, also known as the AutoMEQ, developed by Horne and Östberg
in 1976 (HO), may not be sufficient for defining work schedules in companies. It would,
therefore, be necessary to include the evaluation of Per3 gene polymorphism to make
more accurate decisions.
Methods: Our study aimed to investigate the genetic profile of night and shift workers, as
well as whether they present differences between the circadian preference results
from the HO questionnaire and their genetic chronotype. For this study, DNA extracted
from archived buccal cell samples was obtained from randomly selected subjects participating
in the Brazilian mining companies, average age 43.7 years, and we applied a validated
MEQ containing 19 questions about the sleep and activity preferences by Horne and
Ostberg 1976, Brazilian version. Chronotype was assessed according to the formula
provided in the instruction for MEQ score interpretation.
Results: We detected significant discrepancies in the HO questionnaire when compared with
the genetic results of workers, especially among 1.9% of workers who self- identified
as evening types according to the HO questionnaire but had a genetic chronotype of
38.1% classified as eveningness. Unexpectedly, 77.9% of workers reported being morning
types, which agreed with their genetic profile in only 12.1% of cases.
Conclusion: Our data serves as a warning for companies to assess the genetic profiles of their
employees to avoid misinterpretations regarding circadian preference, which could
contribute to poor work performance, harm worker health, and increase the risk of
accidents. Support: UFMG, UNIFESP, FEPE, CEPE, CEMSA, CAPES, CNPq.
