Key points from article :
Longevity gap between high-income and low-income Americans has been widening sharply.
Life expectancy difference for top/bottom 50% earners has increased from 1.2 years in 1970s to 5.8 years in 2001.
Difference between top 10% and bottom 10% income now 14 years.
Greater declines in smoking among the affluent and educated may partly explain the difference.
More complicated relationship for obesity, prescription drugs and access to health care.
The studies were published in the PubMed Central and Health Reports journals.
