Participants needed for the Night Shift Work and Gut Microbiome

Eligibility criteria:

  • Between 18 and 65 years of age
  • Live and work in British Columbia
  • Be a night shift or day shift worker
    • Night shift worker primarily works night shifts (at least three nights per week of ≥7 hours ending no earlier than 6am) and does not work from home for the past 6 months or more
    • Day shift worker works only day shifts (at least three days per week of ≥7 hours ending no later than 6pm) and does not work from home for the past 6 months or more
  • No personal history of cancer or diagnosed sleep disorder (e.g., sleep apnea, narcolepsy)
  • No trans-meridian travel in the past month 
  • Not currently using melatonin supplements
  • Not antibiotic prescription in the past month
  • Not currently pregnant 

An overview of the study

Participants needed for the Melatonin, Nightshift Work and DNA Damage (MEND) Study


Melatonin suppression in nightshift workers is associated with reduced ability to repair DNA damage, which may contribute to increased risks of cancer. Dr. Parveen Bhatti is leading a research study to determine if melatonin supplementation can reverse these effects in nightshift workers.

Who can participate? 

  • 18- 50 years of age
  • BMI within the range of 18.5- 30
  • Live and work in the Greater Vancouver area
  • Primary work nightshifts at least 7 hours in duration ending no earlier than 6 AM, at least 2-3 nights per week over the past 6 months 
  • Sleep at least 4 hours each day after completing a nightshift

Who should not participate in this study?

  • Are currently using melatonin supplements
  • Have a personal history of hormonal disorders, seizure disorders or chronic medical condition
  • Have been diagnosed with sleep disorders 
  • Are currently using illicit drugs
  • Are currently pregnant or breast feeding
  • For more details, please read the informed consent page 3

What's involved?

  • Complete questionnaires
  • Donate urine samples
  • Wear a watch-like device to measure sleep quality

What do I do if I am interested?

Complete a 5 minutes screening to interview to determine eligibility

To learn how to volunteer, or set up a screening interview, call 1.604-675.8056 or email at

For those that participate in the study, a token of appreciation for your time will be offered.

Click on the link below to find out more about the eligibility criteria and informed consent. 

Participants informed consent form

An overview of the study

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