Social-life factors associated with participation in screening and further assessment of colorectal cancer: A nationwide ecological study in Japanese municipalities

The burden of colorectal cancer in developed countries is high, and it is a major public health concern in Japan. Improving the quality of evidence on colorectal cancer screening participation and further assessment participation rates is important to reduce this burden. This study examined the social-life factors that influence colorectal cancer screening programs in Japan, particularly the effects of the proportion of elderly people and social capital, using a municipality-level national database and existing health reports. Data from a national municipality-based study were analyzed to identify social-life factors associated with participation in colorectal cancer screening and further assessment. Administrative data on the Japanese municipal screening programs were drawn from the Report on Regional Public Health Services and Health Promotion Services 2017. Available data used as predictors of interest for all 1719 municipalities as of 2017 were from the national census, statistical reports on the land area by prefecture and municipality, municipal financial surveys, a survey of physicians, dentists and pharmacists, and other databases. The mean rate of participation in colorectal cancer screening was 13.8%, and that of further assessment was 73.6%. Multiple linear regression analyses of the two outcomes showed that the proportion of elderly people was most significantly positively associated with colorectal cancer screening programs (β = 0.51 for participation, β = 0.13 for further assessment participation), and the proportion of single-elderly-person households was most significantly negatively associated (β = −0.45 and −0.19, respectively). It is suggested that the health behaviors required for participation in colorectal cancer programs in Japanese elderly populations are greatly affected by family members.