This study offers projections for future healthcare expenditures based on the anticipated demographic shift towards older Americans through 2050.  Using age ratios the authors estimate that per capita costs of mental health, substance abuse, pregnancy, and infertility will decline while per capita costs of congestive heart failure, coronary heart disease and diabetes will increase. 

Garrett, N., & Martini, E. M. (2007). The boomers are coming: a total cost of care model of the impact of population aging on the cost of chronic conditions in the United States. Disease Management, 10(2), 51-60. 1 Apr. 2007. DOI: 10.1089/dis.2006.630.  http://www3.interscience.wiley.com/journal/117996526/abstract

Authors: Nancy Garrett, E. Mary Martini