The Roseto effect is the phenomenon by which a close-knit community experiences a reduced rate of heart disease.
The Roseto effect was first noticed in 1961 when the local Roseto doctor encountered Stewart Wolf, then head of Medicine of the University of Oklahoma, and they discussed, over a couple of beers, the unusually low rate of myocardial infarction in the Italian American community of Roseto compared with other locations.
As the original authors had predicted, as the Roseto cohort shed their Italian social structure and became more Americanized in the years following the initial study, heart disease rates increased, becoming similar to those of neighboring towns.
They smoked unfiltered stogies, drank wine "with seeming abandon" in lieu of milk and soft drinks, skipped the Mediterranean diet in favor of meatballs and sausages fried in lard with hard and soft cheeses.
The men worked in the slate quarries where they contracted illnesses from gases and dust.