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Original research
Association between work schedules and motivation for lifestyle change in workers with overweight or obesity: a cross-sectional study in Japan
  1. Yukihiro Tanikawa1,
  2. Miho Kimachi1,
  3. Minoru Ishikawa2,
  4. Tomoichiro Hisada2,
  5. Shunichi Fukuhara1,3,4,5,
  6. Yosuke Yamamoto1
  1. 1Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan
  2. 2Health Examination Centre, Urasoe General Hospital, Urasoe, Japan
  3. 3Section of Clinical Epidemiology, Department of Community Medicine, Kyoto University, Kyoto, Japan
  4. 4Centre for Innovative Research for Communities and Clinical Excellence, Fukushima Medical University, Fukushima, Japan
  5. 5Shirakawa STAR for General Medicine, Fukushima Medical University, Fukushima, Japan
  1. Correspondence to Dr Yosuke Yamamoto; yamamoto.yosuke.5n{at}


Objective To investigate the association between work schedules and motivation for behavioural change of lifestyle, based on the transtheoretical model (TTM) in workers with overweight or obesity.

Design A cross-sectional observational study.

Setting A healthcare examination centre in Japan.

Participants Between April 2014 and March 2016, we recruited 9243 participants who underwent healthcare examination and met the inclusion criteria, namely, age 20–65 years, body mass index (BMI) ≥25 kg/m2 and full-time workers.

Exposure Night and shift (night/shift) workers were compared with daytime workers in terms of motivation for behavioural change.

Primary and secondary outcome measures The primary outcome was action and maintenance stages of change (SOC) for lifestyle in TTM. In a subgroup analysis, we investigated interactions between characteristics, including age, sex, BMI, current smoking, alcohol habits, hours of sleep and working hours.

Results Overall, 1390 participants (15.0%) were night/shift workers; night/shift workers were younger (median age (IQR): 46 (40–54) vs 43 (37–52) years) and the proportion of men was lesser (75.4 vs 60.9%) compared with daytime workers. The numbers of daytime and night/shift workers in the action and maintenance SOC were 2113 (26.9%) and 309 (22.2%), respectively. Compared with daytime workers, night/shift workers were less likely to demonstrate action and maintenance SOC (adjusted OR (AOR): 0.85, 95% CI: 0.74 to 0.98). In a subgroup analysis that included only those with long working hours (≥10 hours/day), results revealed a strong inverse association between night/shift work and action and maintenance SOC (AOR: 0.65, 95% CI: 0.48 to 0.86). A significant interaction was observed between long working hours and night/shift work (P for interaction=0.04).

Conclusions In workers with overweight or obesity, a night/shift work schedule was associated with a lower motivation for behavioural change in lifestyle, and the association was strengthened in those with long working hours.

  • work schedule
  • behavioural change
  • the transtheoretical model (TTM)
  • obesity

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  • Contributors YT, MK, SF and YY designed the research. YT, MI and TH conducted the research. YT and YY analysed the data. YT, MK and YY prepared the manuscript. YT had primary responsibility for the final content. All the authors read and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval It adhered to the principles of the Declaration of Helsinki, and was approved by the ethics committee of the Kyoto University Graduate School and Faculty of Medicine (approval number: R-1345).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No additional data are available.

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