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Prevalence of type 2 diabetes by age, sex and geographical area among two million public assistance recipients in Japan: a cross-sectional study using a nationally representative claims database
  1. Tami Sengoku1,
  2. Tatsuro Ishizaki2,
  3. Yoshihito Goto1,
  4. Tomohide Iwao3,
  5. Shosuke Ohtera3,4,
  6. Michi Sakai1,5,
  7. Genta Kato3,
  8. Takeo Nakayama1,
  9. Yoshimitsu Takahashi1
  1. 1 Department of Health Informatics, Kyoto University School of Public Health, Kyoto, Japan
  2. 2 Human Care Research Team, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan
  3. 3 Kyoto University Hospital, Kyoto, Japan
  4. 4 National Institute of Public Health, Wako, Japan
  5. 5 Comprehensive Unit for Health Economic Evidence Review and Decision Support, Ritsumeikan University, Kyoto, Japan
  1. Correspondence to Dr Tami Sengoku, School of Public Health, Kyoto University, Kyoto, Japan; sengoku.tami.5{at}


Background Recognising the importance of the social determinants of health, the Japanese government introduced a health management support programme targeted at type 2 diabetes (T2D) for public assistance recipients (PAR) in 2018. However, evidence of the T2D prevalence among PAR is lacking. We aimed to estimate T2D prevalence by age and sex among PAR, compared with the prevalence among health insurance enrollees (HIE). Additionally, regional differences in T2D prevalence among PAR were examined.

Methods This was a cross-sectional study using 1-month health insurance claims of both PAR and HIE. The Fact-finding Survey data on Medical Assistance and the National Database of Health Insurance Claims data were used. T2D prevalence among PAR and HIE were assessed by age and sex, respectively. Moreover, to examine regional differences in T2D prevalence of inpatients and outpatients among PAR, T2D crude prevalence and age-standardised prevalence were calculated by prefecture. Multilevel logistic regression analysis was also conducted at the city level.

Results T2D crude prevalence was 7.7% in PAR (inpatients and outpatients). Among outpatients, the prevalence was 7.5% in PAR and 4.1% in HIE, respectively. The mean crude prevalence and age-standardised prevalence of T2D (inpatients and outpatients) among 47 prefectures were 7.8% and 3.9%, respectively. In the city-level analysis, the OR for the prevalence of T2D by region ranged from 0.31 to 1.51.

Conclusion The prevalence of T2D among PAR was higher than HIE and there were regional differences in the prevalence of PAR. Measures to prevent the progression of diabetes among PAR by region are needed.

  • health inequalities
  • morbidity
  • nutritional sciences
  • social inequalities

Data availability statement

No data are available. The raw data of the FSMA and NDB-SD were not shared. Application for MHLW should be required to obtain the data.

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Data availability statement

No data are available. The raw data of the FSMA and NDB-SD were not shared. Application for MHLW should be required to obtain the data.

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  • Contributors YT conceived and designed the study, acquired the funds and supervised the project. TS, YG and YT contributed to data acquisition. TIwao contributed to formal data preparation. TS carried out the analysis. TS, TIshizaki, YG, SO, MS, GK, TN and YT contributed to the interpretation of the results. TS and YT wrote the manuscript. YT is the guarantor. All authors provided substantial critical work on the manuscript and approved the final version of the manuscript.

  • Funding This work was supported by the Japan Society for the Promotion of Science KAKENHI (16K15372 and 20H01594) and by the Ministry of Health, Labour and Welfare in Japan (H28 Tokubetsu-Shitei-031 and H29-Seisaku-Shitei-007).

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  • Competing interests None declared.

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

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