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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Effect of shift work on human health and metabolism; a preliminary study
Scientific title
shift workers and non-shift workers; their gut bacteria and metabolites
Secondary ID [1] 286008 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gut disorders due to disruption of sleep schedule 293971 0
Condition category
Condition code
Oral and Gastrointestinal 294270 294270 0 0
Normal oral and gastrointestinal development and function
Metabolic and Endocrine 294457 294457 0 0
Normal metabolism and endocrine development and function

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Observational study to evaluate gut microbiota and metabolism of shift workers and non- shift workers.
At the Initial screening participants will fill out two questionnaires.
1. Pittersburg Sleep Quality Index (PSQI)
2. Gut health questionnaire
The duration of the observation will be 7days, where participants of both groups (shift workers and non-shift workers) will maintain a sleep log (7 days) as well as a diet record (only for the last 3 days of the observational period). Participants will fast overnight on the 7th day and will provide a faecal, a urine and a blood sample on the following morning.
Intervention code [1] 290987 0
Not applicable
Comparator / control treatment
Comparator group will be non-shift workers.
Control group

Primary outcome [1] 294092 0
Quantification of blood and urinary chemical metabolites by liquid chromatography-mass spectrometry
Timepoint [1] 294092 0
On the Day 8; after 8 hour fasting
Primary outcome [2] 294243 0
Changes in faecal bacteria by next generation gene sequencing
Timepoint [2] 294243 0
On the Day 8; after 8 hour fasting
Primary outcome [3] 294244 0
Quantification of circadian markers in blood by gene expression
Timepoint [3] 294244 0
On the Day 8; after 8 hour fasting
Secondary outcome [1] 312502 0
Assessing sleep quality by 7 day sleep log used by Sleep Wake Research Institute/Massey University
Timepoint [1] 312502 0
Each day during the observational period (7 days)
Secondary outcome [2] 312865 0
Dietary intake using 3 day Diet record used by Plant and Food Research
Timepoint [2] 312865 0
During the 3 days (i.e. days 5,6, and 7) before the sample donation day
Secondary outcome [3] 313243 0
Gut health assessment using a gut health questionnaire used by Plant and Food Research designed by Plant and Food Research with input from external collaborators.
Timepoint [3] 313243 0
At the initial screening

Key inclusion criteria
Adult (18-65 years) with a BMI between 18.5-29 will be considered.
For the purpose of this study, shift workers are defined as people who have undertaken shift work duties for at least 1 year on permanent night or rotating shifts with at least 2 nights per week. Night shift is defined as at least 3 hours work between midnight and 5am.
Non-shift workers are defined as people who are on permanent work schedules during the day time with no shift work history over the last 1 year and do not suffer from sleep disruption on a regular basis (no more than 1 sleep disruption episode during one week).

Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Candidates who suffer from chronic disease (cancer, diabetes, cardiovascular or gastrointestinal disorders, neurological conditions (e.g. multiple sclerosis, spinal cord injury, and stroke).
Women who are pregnant or breastfeeding will also be excluded.

Study design
Natural history
Defined population
Statistical methods / analysis
There is no published data available regarding the effect of shift work on intestinal microbiome or blood and urinary metabolites in humans. However, quantitative changes in gut microbiome in two individuals before, during and after jet lag has been reported (Thaiss et al., 2014). This is an acute study with only one episode of sleep disruption, unlike our proposed trial which studies the long term effects of sleep disruption. In another study, the shiftworkers were found to consume significantly lower percentage of carbohydrate and higher percentage of fat than non-shiftworkers, with changes in proteins that are linked to fat metabolism and inflammation (Crispim et al., 2012). There is no other study on long term changes in the gut microbiome or metabolites of shiftworkers as compared to non-shiftworkers, so we are unable to perform power calculations. Therefore our study is a preliminary study to investigate long term effects of shift work on gut microbiome and metabolic patterns.

Thaiss, Christoph A., Zeevi, D., Levy, M., Zilberman-Schapira, G., Suez, J., Tengeler, Anouk C., Abramson, L., Katz, Meirav N., Korem, T., Zmora, N., Kuperman, Y., Biton, I., Gilad, S., Harmelin, A., Shapiro, H., Halpern, Z., Segal, E., Elinav, E., 2014. Transkingdom Control of Microbiota Diurnal Oscillations Promotes Metabolic Homeostasis. Cell 159, 514-529. DOI 10.1016/j.cell.2014.09.048.

Crispim, C.A., Padilha, H.G., Zimberg, I.Z., Waterhouse, J., Dattilo, M., Tufik, S., de Mello, M.T., 2012. Adipokine Levels Are Altered by Shiftwork: A Preliminary Study. Chronobiology International 29, 587-594. DOI 10.3109/07420528.2012.675847.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 6605 0
New Zealand
State/province [1] 6605 0
Country [2] 6640 0
New Zealand
State/province [2] 6640 0

Funding & Sponsors
Funding source category [1] 290615 0
Name [1] 290615 0
The New Zealand Institute for Plant and Food Research
Address [1] 290615 0
Private bag 11 600, Palmerston North, 4442
Country [1] 290615 0
New Zealand
Primary sponsor type
The New Zealand Institute for Plant and Food Research
Private bag 11 600, Palmerston North, 4442
New Zealand
Secondary sponsor category [1] 289301 0
Name [1] 289301 0
Address [1] 289301 0
Country [1] 289301 0
Other collaborator category [1] 278299 0
Name [1] 278299 0
Sleep Wake Research Institute, Massey University, Wellington
Address [1] 278299 0
Drummond Street, Mount Cook, Wellington 6021
Country [1] 278299 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 292245 0
Heath and Diabaility Ethics commitee
Ethics committee address [1] 292245 0
Ministry of Health
No 1 The Terrace
PO Box 5013
Ethics committee country [1] 292245 0
New Zealand
Date submitted for ethics approval [1] 292245 0
Approval date [1] 292245 0
Ethics approval number [1] 292245 0

Brief summary
Circadian rhythm or body clock refers to the 24 hour cycle that controls physiological functions such as sleep/wakefulness, eating, hormonal and metabolic functions. When we sleep for 7 to 10 hours, our bodies get adequate rest resulting in stabilisation of our metabolic pattern and immune defenses. Irregular sleep patterns are increasingly common in industrialised countries and many years of shift work increases the chances of metabolic disorders by about 50 to 60%. Shift work disorder may result in excessive sleepiness or insomnia associated with reduction of total sleep time and it may affect 10-38% of shift workers.

Irregular exposure to light or disruption of sleep as commonly experienced in shift work or jetlag results in circadian disruption with behavioural consequences such as disturbed sleep patterns, increased food intake, and the hormonal system is unable to cope with excessive nutrients resulting in metabolic shifts towards diabetes and obesity. Gut health can also be compromised with a higher prevalence of Irritable Bowel Syndrome among rotating shift workers, which was directly associated with disruption of the circadian clock. Also, evening shift and widely varying work start and end times may increase risks for gastrointestinal disturbances.

Gut microbial balance is known to play an important role in metabolism of food, gut health and obesity. A recent study with just two volunteers showed an increase in faecal Firmicutes following jet lag, which was then reversed to normal pattern after 2 weeks.

Our hypothesis is that shiftwork, especially over a prolonged period of time, may disrupt circadian rhythm, resulting changes in metabolism and the gut microbial balance.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 54146 0
Dr Shanthi Parkar
Address 54146 0
Plant and Food Research
Private Bag 11600
Palmerston North
Country 54146 0
New Zealand
Phone 54146 0
(+64) 6 9537737
Fax 54146 0
(+64) 6 3517050
Email 54146 0
Contact person for public queries
Name 54147 0
Dr Christine Butts
Address 54147 0
Plant and Food Research
Private Bag 11600
Palmerston North
Country 54147 0
New Zealand
Phone 54147 0
(+64) 4 3556147
Fax 54147 0
(+64) 4 3517050
Email 54147 0
Contact person for scientific queries
Name 54148 0
Dr Shanthi Parkar
Address 54148 0
Plant and Food Research
Private Bag 11600
Palmerston North
Country 54148 0
New Zealand
Phone 54148 0
(+64) 6 9537737
Fax 54148 0
(+64) 6 3517050
Email 54148 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary