This study evaluates the effects of a Combined Lifestyle Intervention Program (CLIP) on sleep, lifestyle behaviors, obesity risk and health in night-shift workers. The primary objective is to assess the effect of the CLIP on objectively measured sleep duration. Secondary objectives include behavioral outcomes related to sleep, diet, physical activity, and stress, as well as body weight and metabolic outcomes, . It is hypothesized that CLIP participants will show a greater increase in sleep duration than controls, alongside favorable changes in lifestyle and health outcomes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
400
The 24-week lifestyle intervention is structured in four 6-week blocks focusing on sleep and stress management or diet and physical activity. Lifestyle advice and behavior change techniques are delivered via a mobile application, complemented by workshops.
Uni Bremen
Bremen, Germany
RECRUITINGTTZ
Bremerhaven, Germany
NOT_YET_RECRUITINGErasmus Medical Centre
Rotterdam, Netherlands
RECRUITINGWageningen University & Research
Wageningen, Netherlands
RECRUITINGLodz
Lodz, Poland
NOT_YET_RECRUITINGSleep duration
Total sleep time (min/24h)
Time frame: From enrollment to the end of intervention (24 weeks)
Body weight
(kg)
Time frame: From enrollment to end of intervention (24 weeks)
BMI
(kg/m2)
Time frame: From enrollment to end of intervention (24 weeks)
Objective sleep quality
Wake after sleep onset (min spent awake/main sleep episode), derived from actigraphy data
Time frame: From enrollment to end of intervention (24 weeks)
Overall diet quality
Diet quality score: Eetscore™, a 55-item FFQ which is scored with the Dutch Healthy Diet 2015-index to evaluate adherence to the Dutch food-based dietary guideline; resulting in a total score between zero (no adherence) and 100 (complete adherence).
Time frame: From enrollment to end of intervention (24 weeks)
Physical activity level
Light, moderate, vigorous activity (min), Sedentary time (min) as measured with an actigraphy (Motionwatch)
Time frame: From enrollment to end of intervention (24 weeks)
Perceived stress
Perceived stress score (PSS-10), a 10-item validated questionnaire assessing the extent to which individuals perceive their lives as unpredictable, uncontrollable, and overloaded. Items are rated on a 5-point Likert scale referring to experiences over the past month; higher score mean more stress.
Time frame: From enrollment to end of intervention (24 weeks)
Subjective sleep quality (Insomina)
Insomnia severity (0-28): a 7-item self-administered questionnaire validated in shift workers as a proxy for sleep quality. Items assess the severity of insomnia symptoms, including difficulties with sleep onset, maintenance, and early awakening. Each item is scored 0-4, with total scores ranging from 0 to 28; higher scores indicate more severe insomnia
Time frame: From enrollment to end of intervention (24 weeks)
Subjective leep quality (pattern)
Shift Work Disorder Questionnaire (SWDQ): a 4-item questionnaire assessing sleep patterns, excessive sleepiness, and functional impairment related to shift work (53). Each item is scored 1-4, yielding a total score of 4-16, with higher scores reflecting greater symptom severit
Time frame: [Time Frame: From enrollment to end of intervention (24 weeks)]
Chrono-nutrition patterns
Meal timing, frequency, regularity; using the Chrono nutrition Questionnaire for Shift Workers (CNQ-Shift). The questionnaire contains 20-23 questions, five questions each for morning, afternoon, and night shifts, three split shifts questions (if applicable), and two questions for work-free days.
Time frame: From enrollment to end of intervention (24 weeks)
Food preferences
FFPQ (liking/wanting scores): Participants rate "how pleasant it would be to try a bite of this food," using a 100-point visual analogue scale (explicit liking). A forced choice procedure is then carried used to assess which food participants would "most like to eat now" (implicit wanting).
Time frame: From enrollment to end of intervention (24 weeks)
Occupational physical activity
OSPAQ (min)
Time frame: From enrollment to end of intervention (24 weeks)
Work-related sense of coherence
Work-related sense of coherence Work-Soc (5-point Likert scale), a 9-scale assessing individuals' perceived comprehensibility, manageability, and meaningfulness at work.
Time frame: From enrollment to end of intervention (24 weeks)
Satisfaction With Life
Satisfaction With Life Scale (SWLS): a 5-item questionnaire evaluating global life satisfaction (66). Items are rated on a 7-point scale
Time frame: [Time Frame: From enrollment to end of intervention (24 weeks)]
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