Pandemic influenza and gender imbalance: Mortality selection before births.

This study uses data from the 1918-1920 influenza pandemic in Japan along with newly digitized and complete census records on births and infant deaths to analyze mortality selection in utero. I find that fetal exposure to the influenza pandemic during the first trimester of the pregnancy decreases the proportion of males at birth. The results from mechanism analysis suggest that this decline in male births is associated with the deterioration of fetal and infant health. This result supports a wide range of existing literature on the long-run adverse effects of pandemic influenza.

The long-run heterogeneous effects of a cholera pandemic on stature: Evidence from industrializing Japan.

The recent COVID-19 pandemic poses the general question on how infectious diseases can persistently affect human health. A growing body of literature has found a significant amount of evidence on the long-term adverse effects of infectious diseases, such as influenza, typhoid fever, and yellow fever. However, we must be careful about the fact that little is known about the long-term consequences of the acute diarrheal disease pandemic cholera - Vibrio cholerae bacillus - which still threatens the health of the population in many developing countries. To bridge this gap in the body of knowledge, we utilized unique census-based data on army height at age 20 in early 20th-century Japan, with a difference-in-differences estimation strategy using regional variation in the intensity of cholera pandemics. We found that early-life exposure to a cholera pandemic had heterogeneous stunting effects on the final height of men; the magnitude of the stunting effects increased as the intensity of exposure increased.

Particulate air pollution, birth outcomes, and infant mortality: Evidence from Japan's automobile emission control law of 1992.

This study investigates the impacts of the Automobile NOx Law of 1992 on ambient air pollutants and fetal and infant health outcomes in Japan. Using panel data taken from more than 1500 monitoring stations between 1987 and 1997, we find that NOx and SO2 levels reduced by 5% and 11%, respectively in regulated areas following the 1992 regulation. In addition, using a municipal-level panel data set from Japan's Vital Statistics Survey and a difference-in-differences approach, we find that the regulation explains most of the improvements in the fetal death rate after the regulation came into effect. This study provides evidence on the positive impacts of this large-scale automobile regulation policy on fetal health.

Chain effects of clean water: The Mills-Reincke phenomenon in early 20th-century Japan.

This study explores the validity of chain effects of clean water, which are known as the "Mills-Reincke phenomenon," in early 20-century Japan. Recent studies have reported that water purifications systems are responsible for huge contributions to human capital. Although some studies have investigated the instantaneous effects of water-supply systems in pre-war Japan, little is known about the chain effects of these systems. By analyzing city-level cause-specific mortality data from 1922 to 1940, we find that a decline in typhoid deaths by one per 1000 people decreased the risk of death due to non-waterborne diseases such as tuberculosis and pneumonia by 0.742-2.942 per 1000 people. Our finding suggests that the observed Mills-Reincke phenomenon could have resulted in the relatively rapid decline in the mortality rate in early 20-century Japan.

Early-life exposure to weather shocks and child height: Evidence from industrializing Japan.

In this study, we estimate the long-run effects of early-life exposure to weather shocks on the height of primary school children. To estimate the global impacts on almost the entire child population in an industrializing country, we utilize both a unique nationwide multi-dimensional longitudinal dataset of Japanese children aged 6-11 and official monthly statistics on meteorological conditions in the 1920s. We observe that the exposure to cold waves in early-life exerted stunting effects on both the boys and girls. In the coldest regions in the northeastern area of Japan, the stunting effects of cold weather shocks on the boys and girls are estimated to be approximately 0.8 and 0.6 cm, respectively. Our observation indicates that prenatal (postnatal) exposure is important for the boys (girls). Our results suggest that the marginal effects of cold waves are stronger in the warmer regions than in the colder regions.

The long-run effects of pandemic influenza on the development of children from elite backgrounds: Evidence from industrializing Japan.

This study estimates the lingering effects of fetal exposure to the 1918 influenza pandemic on the development of secondary school and girls' high school students in industrializing Japan. In order to refine the verification of the fetal origins hypothesis, we tried not only to focus on children from elite schools but also to construct the continuous influenza mortality measure using monthly variations in the number of births and influenza deaths. By utilizing a nationwide multidimensional physical examination dataset, we found that fetal exposure to influenza in the pandemic years reduced the heights of boys and girls by approximately 0.3 cm and 0.1 cm, respectively. While the strongest negative magnitude was observed in the pandemic period, the lingering relapses in the post-pandemic period still had considerable adverse effects on height. In relation to the lowest decile group which experienced normal influenza mortality in non-pandemic years, the heights of the boys and girls who experienced pandemic influenza in the womb are approximately 0.6 and 0.3 cm lower. The lingering influenza relapse in the post-pandemic period has an adverse effect on the boys' height, accounting for roughly 80% of the maximum pandemic effect.

Public health and multiple-phase mortality decline: Evidence from industrializing Japan.

A growing body of literature shows the mitigating effects of water-supply systems on the mortality rates in large cities, yet the heterogeneities in the effects have been understudied. This study fills in the gap in existing knowledge by providing evidence for non-linearity in the effects of clean water using semiparametric fixed effects approach with city-level nationwide longitudinal dataset between 1922 and 1940, which covers 91% of total city population. According to our baseline estimate, the clean water accounts for approximately 27% of the decrease in the crude death rate in this period. Our results also indicate the heterogeneities in the improving effects of clean water with respect to the coverage of tap water among citizens. We found evidence that the installation of the water-supply system itself decreased waterborne infections and infant mortality but did not substantially improve the overall mortality rate in the initial phase. However, the subsequent expansion of tap water could result in a continuous decline in the overall risk of deaths in the second phase.

Long-run effects of early childhood exposure to cholera on final height: Evidence from industrializing Japan.

Pandemic cholera is one of the most topical and urgent issues in many developing countries. However, although a growing body of research has shown the negative long-run effects of infectious disease exposure on human health, the long-run influences of early childhood exposure to cholera have thus far been understudied. To bridge this gap in the body of knowledge, we draw both on new data describing adult height from 1899 to 1910 from comprehensive official Japanese army records and on data recording the regional variation in the intensity of cholera pandemics. By using a difference-in-differences estimation strategy, we find that exposure to pandemic cholera had stunting effects on the final height of men at that time. Our estimates also suggest that early-infancy exposure to cholera seems to have a stronger long-run effect on adult height than late-infancy exposure.

Persistence of pandemic influenza on the development of children: Evidence from industrializing Japan.

In this study, we estimate the persistent effects of fetal exposure to the 1918-1920 influenza pandemic of Japan on the physical development of primary school children. By using a unique nationwide longitudinal physical examination dataset of children aged 6-13 in units of 47 prefectures between 1929 and 1939, this study is the first to adopt the bilateral-specific fixed effects approach to identify the impact of fetal influenza exposure on the physical development of children. We find that the children born in 1919-1920 were shorter than those in surrounding cohorts. Our result from the specification using regional heterogeneities in the timing and severity of the influenza pandemic also implies that the persistency of fetal exposure to shocks on children's development could vary by gender.

Cationic cellulose hydrogels cross-linked by poly(ethylene glycol): Preparation, molecular dynamics, and adsorption of anionic dyes.

Cationic cellulose hydrogels (CCGs) were prepared from quaternized celluloses with degrees of substitution (DS) of 0.56, 0.84, and 1.33, by the cross-linking reaction with poly(ethylene glycol) diglycidyl ether as a cross-linker. The CCGs exhibited swelling behavior in aqueous solutions, which was not affected by pH and temperature of the solution because of the presence of quaternary ammonium groups in their structures. The CCGs showed adsorption ability toward anionic dyes in aqueous solution, which increased with increasing DS. The dye adsorption was found to follow the pseudo-second order kinetic model and the equilibrium isotherm data can be described by the Langmuir adsorption model. In addition, the CCGs could be regenerated and proved to be recyclable adsorbents for wastewater treatment.