Risk Factors for Cardiovascxular
Disease and Cancer
A risk factor is a trait that places a person at higher risk of developing a disease and is generally considered to have a causal link to that disease. Risk factors may be behavioral, psychosocial, physiologic, or biochemical. Well-known examples for cardiovascular disease are high-serum LDL cholesterol, hypertension, diabetes mellitus, cigarette smoking, physical inactivity, and lack of social support.
This book is of course largely concerned with the effects of diet on chronic disease. Since any effects of diet are probably mediated by physiologic and biochemical mechanisms, it would strengthen the evidence that a vegetarian diet protects against CHD and cancer if this diet were found to change physiologic and biochemical risk factors in ways that are generally thought to reduce risk. Then there would not only be a statistical association between a vegetarian's dietary habits and risk of disease but also some evidence of the mechanism that underlies the reduced risk. An understanding of mechanisms is one way to strengthen causal inference.
Hypertension, diabetes mellitus, and obesity are not only risk factors for CHD but disorders in their own right. The evidence that a vegetarian diet may affect the risk of these disorders among Adventists was considered separately in Chapter 8. In this chapter, studies of non-Adventist vegetarian groups only are described in relation to the risk of these factors. For other risk factors, studies of both Adventist and non-Adventist vegetarians are included here. Results from similar studies of vegan vegetarians are discussed separately in Chapter 13.