Race and ethnicity are ascertained using the 1990 U. S. Census questions. Measures of socioeconomic status include education and occupation. Birth addresses were linked to 1920 census data to determine early-life socioeconomic status [31]. Age 40 addresses were linked to 1960 census data to determine mid-life socioeconomic status. Other indicators of early life socioeconomic status include parental education and occupation.
