In "The Health Gap" reading, the author compares the life expectancy of the Upton Druid area of Baltimore - where the median household income is $17,000- against that of India, where the average income per person in India is $3,000. He points out that the male life expectancy in India is nearly 2 years longer than in Upton Druid, meaning that the poor of Baltimore are richer compared to the average Indian, but have worse health. What is the author's argument for why this might be?