John Z. Ayanian is site principal investigator on this project. Debby Collins is the project contact: 617-432-3467. 

The first MIDUS investigation, funded by the John D. and Catherine T. MacArthur Foundation, was conducted in 1994–95 with a sample of over 7,000 Americans, aged 25 to 74. In 2002, the National Institute on Aging provided funding to the University of Wisconsin, Madison, to conduct a longitudinal follow-up study of these participants (MIDUS II). The purpose of the original study was to investigate the role of behavioral, psychological, and social factors in understanding age-related differences in physical and mental health. The study was innovative for its broad scientific scope, its diverse samples (which included twins and siblings of participants), and the creative use of “satellite” studies to obtain in-depth assessments in key areas such as daily stress and cognitive functioning. 
   
The MIDUS II project is assessing the role of behavioral and psychosocial factors as key mediators of changes in physical and mental health and socioeconomic and racial disparities in health. To explore these effects, the MIDUS team has collected a second wave of data on the MIDUS I cohort. A new cohort of approximately 400 African-Americans was also enrolled from the Milwaukee, Wisconsin, area. Data collection for this second study repeated numerous assessments from the first project and gathered new information in select areas such as optimism and coping, stressful life events, and caregiving. 

The Harvard research team for this study has linked the 1994–95 cohort to the National Death Index to identify subjects in the original cohort who have died between 1995 and 2005. Using the extensive data collected in the original and follow-up surveys during 1994–95 and 2004–05, respectively, we are analyzing the relative importance of health status and numerous health behaviors and risk factors, sociodemographic factors, and psychosocial factors as predictors of mortality through 2005 in this nationally representative cohort of adults. The specific aims of these analyses are to: 

• assess the relative importance of sociodemographic factors, psychosocial factors, and health status and behaviors as predictors of mortality;
  
  
• evaluate individuals’ experiences of stressful daily events as predictors of mortality, controlling for other study variables;
  
  
• determine the degree to which health variables and sociodemographic and psychosocial factors account for socioeconomic gradients and racial differences in mortality.