Polymorphism: The occurrence in a population of two or more genotypes; i.e. the existence of two or more genetic variants. Genetic polymorphims can have opposite relations with different diseases.
The Seven Countries Study
The Seven Countries Study (SCS for short) is the first major study to investigate diet and lifestyle along with other risk factors for cardiovascular disease, across contrasting countries and cultures and over an extended period of time. Read more about this study.