Labor income inequality in Japanese corporations and employee health: Evidence from Japanese health insurance society data

This study investigates the relationship between labor income inequality and employee health in Japanese corporations based on a nationwide survey - that is, the monthly reports of health insurance societies, which cover the majority of Japanese employees working in major Japanese companies and industries. The authors calculate the mortality rate and the rate of sickness and injury leave using the public medical insurance benefit data. Labor income inequality is calculated using the labor income distribution data, which is also used for calculating insurance premiums. The paper finds a significant association between intra-company labor income inequality and the mortality rate after controlling for certain confounding factors, such as the average age, average labor income, and ratio of women. These data show that intra-company labor income inequality is associated with the health of employees in major Japanese companies and industries.