International Shortfall Inequality in Life Expectancy in Women and in Men, 1950-2010/inegalite Internationale De L'esperance De Vie Des Femmes et Des Hommes, Mesuree En Termes D'ecart, 1950-2010/desigualdad Internacional En la Desviacion En la Esperanza De Vida En Mujeres Y En Hombres, 1950-2010

Article excerpt

Introduction

Life expectancy at birth has long been recognized as a summary measure of mortality that allows inequality levels and trends to be compared within and across societies. (1) The second half of the 20th century saw large and sustained increases in life expectancy at birth throughout the world; between 1950-1955 and 2005-2010, global average life expectancy at birth rose from 48 to 70 years in women and from 45 to 65 years in men. (2) However, global averages mask considerable variation across countries. (1) International inequalities in life expectancy fell sharply between 1950 and 1990 primarily because of rapid decreases in mortality in developing countries. (3,4) These improvements were associated with increased access to safe water and sanitation, childhood immunization and improved public health infrastructure, as well as improved child and maternal nutrition and declining fertility. (3) Life expectancy trends closely mirror reductions in mortality among male and female children less than 5 years of age, which is hardly surprising given that life expectancy estimates are strongly influenced by under-five mortality. (5) On the other hand, the last decade of the 20th century was a period of stagnation, and inequalities in overall life expectancy increased largely because of the decline in life expectancy in sub-Saharan Africa caused by the epidemic of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). (6,7) Consequently, this region is key to understanding between-country health inequality in the late 20th century.

Research on international inequalities in life expectancy has traditionally focused on overall mortality, (3,6,8) but there are well known gender differences in mortality trends across countries, (9-11) and within-country inequalities in life expectancy also vary by gender. (12-14) This suggests that the pattern of international inequality in life expectancy could differ by gender, but no known studies have compared international trends in inequalities in life expectancy separately for women and men. We used a "shortfall" measure of inequality, a method that should be distinguished from measures of total inequality (8,15) and akin to the notion of "shortfall" inequality discussed by Sen and others) (16-19) The shortfall method compares life expectancy in a given country with some maximum or selected norm to identify inequality. For example, in the assessment of gender inequality in life expectancy, shortfalls in longevity for males and females have been compared with their respective biological maxima. (20) This differs from traditional measures of inequality that use the population average rate as the reference value.

The aims of this study are to assess international shortfall inequalities in life expectancy among women and men and to quantify how much specific geographic regions and country income groups contribute to them.

Methods

We used estimates of life expectancy at birth by sex from the United Nations Population Division's World population prospects, 2008 revision. The life expectancy estimates are for the 12 five-year periods between 1950-1955 and 2005-2010. We also extracted population estimates for the midpoints of each period (1952, 1957, 1962, etc.). (2) Data for life expectancy at birth by sex were available for 179 of the 193 Member States of the World Health Organization (WHO) (as of 2010). We excluded 14 countries with very small populations that accounted for less than 0.01% of the world's population in 2007. Countries were organized into World Bank income groups for 20102 (21) and into WHO regions. (22)

International shortfall inequality

Global life expectancy is simply defined as the weighted average of countries' life expectancy, with the weight being each country's population size. We defined international shortfall in life expectancy in the same way--as the weighted average of the deviation of each country's average life expectancy from the highest attained life expectancy for each time period, and we used each country's population size as the weight. …