Page:Scientific Monthly, volume 14.djvu/102

 By LOUIS I. DUBLIN, Ph. D., Statistician

METROPOLITAN LIFE INSURANCE COMPANY, NEW YORK

Y interest in this subject arose in connection with another study. Some eight years ago, I began to investigate the reasons for the increasing mortality of the American people after age 45. The mortality figures for the previous decade had shown that, while there had been very marked declines in the mortality rates of our population in infancy, in childhood, and in early adult life, that beginning with the age period 45 and continuing well into old age, there had been a slight increase in mortality. This was very puzzling because such conditions did not appear in England, in Germany, or in the Scandinavian countries for which comparable data were at hand. This was evidently a condition characteristic of America. Why should there be such an adverse change in the death rate during a period of extraordinary activity in public health and when so much was being done to improve the sanitary conditions of the country? Living and working conditions were undoubtedly getting better all the time for the great mass of the population. But these improvements were not being reflected in the facts of the death rate for middle life and beyond. After much labor on this problem, it finally occurred to me that the facts could, perhaps, be explained very simply as the result of the character of our recent immigration. My hypothesis was that, if the foreign stocks that had been coming into the country in increasing numbers actually had a higher death rate than the native stock at the older ages of life, that the very fact of their coming would be sufficient to account for the increase in mortality of the whole population.

To test this hypothesis, it was necessary to construct tables of mortality for the several race stocks, including the native born of native parentage, the native born of foreign or mixed parentage and the foreign born. For the last group, it was necessary also to prepare a table for each one of the important foreign nativity classes. I turned to the data for the State of New York where there was a large representation of the three groups of the population, where registration of deaths was