Public health improvements and historical mortality declines


Human capital accumulation and public health environment have been closely interrelated throughout the course of economic development. Historical improvement in the disease environment, captured by the decline in mortality rates, has been associated with increases not only in the stature of human beings but also in the socioeconomic outcomes. In fact, the United Nations has now set the access to improved safe water sources by 2030 as one of the most important Sustainable Development Goals. However, waterborne infectious diseases still result in considerable global burden. Therefore, developing countries still need efficient water-supply facility planning to mitigate the risk of infection from waterborne diseases.

A growing body of literature shows the mitigating effects of water-supply systems on the mortality rates in large cities. However, the heterogeneities in the effects remain understudied. Our projects fill the gap in existing literature by providing evidence for non-linearity in the effects of clean water using semiparametric fixed effects approach with nationwide city-level longitudinal dataset between 1922 and 1940, which covers more than 90% of total city population in Japan. We found heterogeneities in the improving effects of clean water, with regard to the coverage of tap water among citizens and external meteorological environment of cities. Our projects also explore the validity of the Mills–Reincke phenomenon—observed both in Europe and the US states—that the purification of polluted water can reduce not only typhoid deaths but also those because of other infectious diseases. For each additional typhoid death, we found approximately two deaths because of tuberculosis and pneumonia.


  1. Tatsuki Inoue, Kota Ogasawara.
    Chain effects of clean water: The Mills-Reincke phenomenon in early twentieth-century Japan.
    Economics & Human Biology, forthcoming.
  2. Kota Ogasawara, Yukitoshi Matsushita.
    Public health and multiple-phase mortality decline: Evidence from industrializing Japan.
    Economics & Human Biology 29, 2018, 198-210.
  3. Kota Ogasawara, Yukitoshi Matsushita.
    Heterogeneous treatment effects of safe water on infectious disease: Do meteorological factors matter?
    Cliometrica 13, 2019, 55-82.
  4. Kota Ogasawara, Shinichiro Shirota, Genya Kobayashi.
    Public health improvements and mortality in interwar Tokyo: A Bayesian disease mapping approach.
    Cliometrica 12, 2018, 1-31.

Funding acknowledgements