Between 1920 and 1950, Jamaicans added life expectancy at one of the most rapid paces attained in any country.
It is not just Kerala, today Jamaicans live nearly as long as do Americans. James C. Riley wrote Poverty and Life Expectancy: The Jamaica Paradox to tell us why. For the most part he credits public health institutions, most of all education about individual disease hazards.
Recommended, the book is also readable, though the $60.00 price is steep.