Determinants of health are factors that influence health status and determine health differentials or health inequalities. They are many and varied and include, for example, natural, biological factors, such as age, gender and ethnicity; behaviour and lifestyles, such as smoking, alcohol consumption, diet and physical exercise; the physical and social environment, including housing quality, the workplace and the wider urban and rural 67 See Section 3.2.2 for more information on the public health functions in a public health classification. environment; and access to health care (Lalonde 1974 , Labonté 1993 . All of these are closely interlinked and differentials in their distribution often lead to health inequalities (WHO 1998a).