The causal pathways from social determinants of health to health outcomes can be numerous and complex. Though some factors (like smoking) are directly related to health, others (like education or income) relate to health in a variety of indirect ways.
These facts are conveyed by the chart below from the WHO’s Global Health Risks.
The chart includes a number of social determinants of ischaemic heart disease: education, income, and health behaviors like smoking, alcohol use, physical activities and eating habits (fat intake).
Education, income, and age do not directly cause ischaemic heart disease. But, they affect a number of other factors in a causal chain that does lead to the disease. For example, someone with greater education is less likely to smoke or consume alcohol. Because education is not a direct cause of the disease, it is said to be further upstream or distal.