How does the altitude at which beans are grown affect the final roast? In what way does the altitude at which coffee beans are grown affect the flavor of the final roast?

I often see coffees labeled with marketing materials such as "contains only beans grown above x thousand feet." Does the altitude at which the beans are grown actually affect the final flavor of the coffee? If so, what are the mechanisms which cause this, and what does it do to the actual flavor of the final product?
Based on the study entitled Effects of Altitude, Shade, Yield and Fertilization on Coffee Quality (Coffea arabica L. var. Caturra) produced in Agroforestry
Systems of the Northern Central Zones of Nicaragua the summary describes following on the altitude subject:


  ...
  
  Altitude had the strongest influence on coffee physical
  characteristics, biochemical composition and organoleptic quality.
  Shade influenced significantly the physical characteristics and
  biochemical composition of coffee beans; nonetheless, the organoleptic
  quality was significantly enhanced by shade only in the altitudinal
  range of 950-1255 m. Fertilization and yield influenced positively
  physical characteristics of the coffee beans as well as their
  biochemical composition. The organoleptic quality was influenced by
  fertilization, but not by yield. Biochemical compounds showed strong
  relationships with organoleptic characteristics.