Seven participants had a diagnosis of dementia; the number of excluded participants differed based on different exclusion processes, and there was missing data of one participant with a dementia diagnosis. That is, one participant was excluded in the missing data before being excluded by the dementia diagnosis. Certification for long-term care in Japan occurs at the disability level, not at the frailty level [1,2]. Therefore, in many Japanese cohort studies, certification for long-term care is an exclusion criterion [3]. Also, in this study, participants who were already certified for long-term care were excluded from the discussion of the frailty state. There can be multiple causes of chronic pain that cannot be identified in a single community-based cohort study [4]. Further, in the current study, we did not explore the use of painkillers and, thus far, no discussion has taken place in this regard [5]. This is an aspect we would like to consider in future studies.
Author Contributions
Y.N. was responsible for study conceptualization and design, analysis and interpretation of data, and writing the manuscript. H.M. contributed to study conceptualization and design, subject recruitment, interpretation of data, and writing the manuscript. R.K., K.T., and Y.T. were instrumental in acquiring data and preparing the manuscript. T.K., T.T. and M.O. helped with recruitment, interpreting the data, and preparing the manuscript. All authors were involved in designing the study; all contributed to and approved the final manuscript. All authors have read and agreed to the published version of the manuscript.
Funding
This work was supported by AMED under Grant Number JP18dk0207027; Research Funding for Longevity Sciences (29-42) from the National Center for Geriatrics and Gerontology (NCGG) and JSPS KAKENHI (Grant-in-Aid for challenging Exploratory Research) Grant Number JP17K19870.
Conflicts of Interest
The authors declare no conflict of interest.
References
- 1.Alizargar J. Comment on Nakai, Y.; Makizako, H.; Kiyama, R.; Tomioka, K.; Taniguchi, Y.; Kubozono, T.; Takenaka, T.; Ohishi, M. Association between Chronic Pain and Physical Frailty in Community-Dwelling Older Adults. Int. J. Environ. Res. Public Health 2019, 16, 1330, doi:10.3390/ijerph16081330. Int. J. Environ. Res. Public Health. 2020;17:179. doi: 10.3390/ijerph17010179. [DOI] [Google Scholar]
- 2.Ministry of Health, Labour and Welfare Long-Term Care Insurance System of Japan. [(accessed on 1 July 2019)];J. Digit. Converg. 2016 Available online: https://www.mhlw.go.jp/english/policy/care-welfare/care-welfare-elderly/dl/ltcisj_e.pdf. [Google Scholar]
- 3.Shimada H., Makizako H., Doi T., Tsutsumimoto K., Suzuki T. Incidence of Disability in Frail Older Persons with or without Slow Walking Speed. J. Am. Med. Dir. Assoc. 2015;16:690–696. doi: 10.1016/j.jamda.2015.03.019. [DOI] [PubMed] [Google Scholar]
- 4.Treede R.-D., Rief W., Barke A., Aziz Q., Bennett M.I., Benoliel R., Cohen M., Evers S., Finnerup N.B., First M.B., et al. A classification of chronic pain for ICD-11. Pain. 2015;156:1003–1007. doi: 10.1097/j.pain.0000000000000160. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Wade K.F., Lee D.M., Mcbeth J., Ravindrarajah R., Gielen E., Pye S.R., Vanderschueren D., Pendleton N., Finn J.D., Bartfai G., et al. Chronic widespread pain is associated with worsening frailty in European men. Age Ageing. 2016;45:268–274. doi: 10.1093/ageing/afv170. [DOI] [PMC free article] [PubMed] [Google Scholar]