Trends in Aging
Over the past 25 years. the U.S. population has been aging. The median age (the age at which half the people are younger and half are older) has increased by slightlymore than 6 years-from se in 1980 t? 36.4 in 2006 (U.S. Census Bureau, 2009). 111is change was partly a result of the Baby Boomers (people born between 1946 and 1964) moving into middle age and partly a result of more people living longer. As shown in ~ figure 12.1a. the number of older persons-age 65 and above-increased ignificantly between 1980 and 2000. The population over .lge 85 has been growing especially fast.When new ce,ISUSdata for the 2 10 census are available.we will no doubt learn of additional changes in the age composition of the U.S. population.An increase in the number of older people living in the United States and other high-income nations resulted from an increase in life expectancy (greater longevity) combined with a stabilizing of birth rates (Atchley and Barusch, 2004). Life expectancy is the average number of years ,!Jhat a group of people born
in the same year could expect to live. Based on thedeath rates- in the year of birth, life expectancy shows the average length of life of a cohort=« group of people born within a specified period of time. Cohorts may be established on the basis of onc-, five-, or tenyearintervals; they may also be defined by events taking place at the time of their birth, such as Depressionera babies or Baby Boomers (Moody. 2002). 1’01’ the cohort born in 2004, as an example. life expectancy at birth was 77.9 years for the overall u.s. population- 75.2 for males and 80.4 for females. However. as Figure J 2. J b shows. there arc significant racial-ethnic and sex differences in life expectancy. Although the life expectancy of people of color has improved over the past 50 year§,. higher rates of illness and disabilily-attributed to poverty, inadequate health care, and greater exposure to environmental risk factors-still persist. Today, a much larger percentage of the u.s. population is over age 65 than in the past. One of the fastest-growing segments of the population is made “1′- of people age 85 and above. 111is cohorl is expecte-i to almost double in size between 2000 and 2025 (loS. Census Bureau. 2009); by the ycar 2050. the Census Bureau predicts that the number of pe”~’1I1Sage .over will have increased to about 20 million (almost 5 percent of the population). Even more astonishing is the fact that the number of centenarians (persons 100 years of age and above) in this country will increase more than 12 times. from 66.000 in,,1999 to ‘about 834,000 in 2050 (L. Ramirez, 1999). TIle current distribution of the u.s. population is depicted in the “age pyramid” in Figure 12.1d.lf, every year, the same number of people are born as in the previous year and a certain number die in each age group, the rendering of the population distribution should be pyramid shaped. As you will note, however, Figure 12.1 d is not a perfect pyramid, but instead reflects declining birth rates among post-Baby Boomers.