In 2018, we reported an epidemiological study on disease-preventive effects of habitual hot spa-bathing in the elderly in Beppu city, which has the highest number of hot spring sources in the world. In this analysis, women with diabetes mellitus were observed more often as hot spa-bathers than non-spa-bathers [odds ratio (OR): 1.238, confidence interval (CI): 1.011-1.517]. To see whether there is an apparent harmful effect of spa-bathing, complicated background diseases of women with diabetes mellitus were investigated in this study. We compared background diseases of women complicated with diabetes mellitus in spa-bathers and non-spa-bathers. Compared with non-spa-bathers, female spa-bathers with diabetes mellitus revealed a higher occurrence of cancer history (OR: 2.626, CI 1.517-4.545). The occurrence of diabetes mellitus in women with no cancer history was not significantly different between habitual spa-bathers and non-spa-bathers (OR:1.041, CI 0.837-1.293). The observed odds ratios suggest that spa-bathing associated cancer surviving promotion leads to an increasing number of diabetic women with a past history of cancer and contributes to more women with diabetes mellitus in spa-bathers rather than habitual spa-bathing promoting the pathogenesis of diabetes mellitus.