Open Access Research article

Japan Diabetes Outcome Intervention Trial-1(J-DOIT1), a nationwide cluster randomized trial of type 2 diabetes prevention by telephone-delivered lifestyle support for high-risk subjects detected at health checkups: rationale, design, and recruitment

Naoki Sakane1*, Kazuhiko Kotani1, Kaoru Takahashi12, Yoshiko Sano1, Kokoro Tsuzaki1, Kentaro Okazaki1, Juichi Sato3, Sadao Suzuki4, Satoshi Morita5, Kazuo Izumi67, Masayuki Kato6, Naoki Ishizuka8, Mitsuhiko Noda679 and Hideshi Kuzuya110

Author Affiliations

1 Division of Preventive Medicine, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto, Japan

2 Hyogo Health Service Association, Hyogo, Japan

3 Department of General Medicine/Family & Community Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan

4 Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan

5 Department of Biostatistics and Epidemiology, Yokohama City University, Yokohama, Japan

6 Office of Strategic Outcomes Research Program, Japan Foundation for the Promotion of International Medical Research Corporation, Tokyo, Japan

7 Department of Diabetes and Metabolic Medicine, National Center for Global Health and Medicine, Tokyo, Japan

8 Biostatistics, Biostatistics & Programming Clinical Sciences & Operation Research & Development, Sanofi K.K, Tokyo, Japan

9 Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan

10 Koseikai Takeda Hospital, Kyoto, Japan

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BMC Public Health 2013, 13:81  doi:10.1186/1471-2458-13-81

Published: 29 January 2013



Lifestyle modifications are considered the most effective means of delaying or preventing the development of type 2 diabetes (T2DM). To contain the growing population of T2DM, it is critical to clarify effective and efficient settings for intervention and modalities for intervention delivery with a wide population reach.

The Japan Diabetes Outcome Intervention Trial-1 (J-DOIT1) is a cluster randomized controlled trial to test whether goal-focused lifestyle coaching delivered by telephone can prevent the development of T2DM in high-risk individuals in a real-world setting. This paper describes the study design and recruitment of the study subjects.


For the recruitment of study subjects and their follow-up annually over 3 years, we employed health checkups conducted annually at communities and worksites. Health care divisions recruited from communities and companies across Japan formed groups as a cluster randomization unit. Candidates for the study, aged 20-65 years with fasting plasma glucose (FPG) of 5.6-6.9 mmol/l, were recruited from each group using health checkups results in 2006. Goal-focused lifestyle support is delivered by healthcare providers via telephone over a one-year period. Study subjects will be followed-up for three years by annual health checkups. Primary outcome is the development of diabetes defined as FPG≥7.0 mmol/l on annual health checkup or based on self-report, which is confirmed by referring to medical cards.


Forty-three groups (clusters), formed from 17 health care divisions, were randomly assigned to an intervention arm (22 groups) or control arm (21 clusters) between March 2007 and February 2008. A total of 2840 participants, 1336 from the intervention and 1504 from the control arm, were recruited. Consent rate was about 20%, with no difference between the intervention and control arms. There were no differences in cluster size and characteristics of cluster between the groups. There were no differences in individual characteristics between the study arms.


We have launched J-DOIT1, a nation-wide trial to prevent the development of T2DM in high-risk individuals using telephone-delivered intervention. This trial is expected to contribute to evidence-based real-world preventive practices.

Trial registration