An empirical analysis was performed to obtain information on the reasons of the poverty situation of mother-children households by estimating poverty rates and searching their determinants. On the basis of the open data of household numbers in income classes of the Housing and Land Survey, the poverty rates of mother-children households in 47 prefectures were estimated, and the disparity of the poverty situation of mother-children households in local areas was discussed. Determinants of poverty rates were searched by applying a nonlinear regression analysis to the estimated poverty rates in prefectures as an objective variable, and many related factors mainly relevant to working conditions of single mothers as explanatory variables. Seven determinants were obtained: mothers’ employment rates as manufacturing process workers, professional and engineering workers, sales workers and service workers, rates of temporary employees, rates of high school graduates as final educational background and rates of households with children under 6 years of age. It is newly found that mothers’ employment rates by occupation significantly affect the poverty rates of mother-children households.

An infant disorder, so-called meningitis in infancy (SCMI), was reported by Sukehiko Itoh et al. in the 28th year of Meiji Era (1895) in Japan. Twenty-eight years later, Ikutaro Hirai, a professor at Kyoto University, clarified in the 12th year of Taisho Era (1923) that SCMI was a chronic lead-poisoning disease caused by white lead included in the mothers’ cosmetic powder. Then, regulation of white lead was stipulated in the 5th year of Showa Era (1930) and came into force in the 10th year of Showa Era (1935). In the present study, we examined the outline of SCMI research in this period from the perspective of clinical and laboratory findings including those by blood tests, physiological function tests, biochemical tests and X-ray examinations of bones and teeth.