The comparison of two temporally separated populations in Emmet County, Michigan: higher survivorship in Caucasian than Native American females.

Abstract

Demography is a division of ecology that provides statistical information for a population of interest. Demography uses life tables to display how a population is age-structured and survivorship curves to compare rates of mortality between populations. The populations in interest in this study are Caucasian and Native American females. The purpose of this experimental study was to determine if there is a difference in mortality rates in Native American and Caucasian females in two time periods, 1900-1945 and 1946-2000, in Emmet County, northern lower Michigan, USA. I surveyed five cemeteries in Emmet County and recorded the year of death and age of death for Caucasian and Native American females. I divided the data into two time intervals and constructed life table and survivorship curves for each ethnic group in each time period. I performed Chi-squared Tests of Independence and t-tests on the mean age-specific mortality rates. The survivorship rates are statistically significantly different for Native American and Caucasian females in the 1900-1945 interval (X2 = 39.71, df = 2, P<0.05) and in the 1946-2000 interval (X2 = 17.21, df = 2, P<0.05). Female Native Americans were found to have a higher mortality rate than Caucasian females in the 1900-1945 period and in the 1946-2000. The mean age-specific mortality rate for Caucasian females in 1900-1945 is greater than in 1946-2000 (t = 1.363325, df = 42, P<0.05). The mean age-specific mortality rate for Native American females in the 1900-1945 was also greater than in 1946-2000 (t = 0.933101, df=42, P<0.05). There are several health factors that can explain the trend of lower survivorshiop of Native American females in relation to Caucasian females, such as their higher rates of chronic diseases, excessive consumption of alcohol and tobacco, poor health care system, and a high rate of infant mortality.