Exposure to environmental hazards and effects on chronic disease

There are numerous hazards that people are exposed to in everyday life: at home, at work, and in other locations (microenvironments). Between exposure and health effect there are a large number of modifying risk factors, as embodied in the concept of the exposome. Exposures to other hazards, genetics, and society all play a role in whether and how an exposure results in an adverse effect. The timing of exposure is also an important factor. In utero and early life exposures may be of particular importance for initiating some types of diseases that manifest later in life. Chronic diseases such as cardiovascular and respiratory disease are important contributors to the global burden of disease. These diseases are a result of the interplay of several risk factors, which include environmental exposures. The exposomic approach is therefore particularly applicable to the study of environmental causes of chronic disease. Rather than take a pollutant-by-pollutant focus, this chapter will examine two common chronic diseases which research has shown to have multiple contributing environmental risk factors. The proposed diseases are cardiovascular disease and non-malignant respiratory disease (particularly asthma). The chapter will cover both acute and chronic effects, including a discussion of the evidence for some hazards where exposures in childhood or before birth can potentiate future disease.