As defined by Friis and Sellers (1999), psychosocial epidemiology can be more broadly conceptualized to include psychosocial, behavioral, and social factors. That is, the determinants of health or disease studied in psychosocial epidemiology are not single agents such as specific bacteria or chemicals, but a host of less tangible human factors.

Psychosocial determinants such as stress, alcohol consumption, dietary practice, and smoking habit are almost of little or no direct concern to regulatory agencies. However, this type of epidemiologic studies usually offers invaluable information regarding the adverse health effects caused by toxic agents of regulatory concern. For example, there are interactive and synergistic effects of smoking and occupational exposures to asbestos, nickel, and chromium.

Another example is the information gained on dietary practice in a population. The relationship between diet and cancer or coronary heart disease has long been the subject of investigation on nutrient toxicity. A food additive is a substance used to facilitate some part of the processing of a foodstuff, or deliberately added to a foodstuff to effect a particular characteristic such as taste, smell, or color. Both the toxicology of food additives and the pesticide residues in food are of regulatory concern to the U.S. Food and Drug Administration (Slide 17 of Lecture 2). Assessment of the intake of these food contaminants requires information on a population’s dietary pattern, which to a great extent is culture-bound and economics-based.