Social epidemiology is the branch of epidemiology that studies the social distribution and determinants of health. It examines how social factors influence health outcomes, including social inequalities, health behaviors, material and economic conditions, life course, social biology, and ecological perspectives. Social epidemiology contrasts with individualistic approaches by focusing on the broader social structure and its impact on health. The field has evolved by posing new research questions, using innovative methods, and influencing public policy. The social determinants of health refer to the conditions in which people are born, grow, live, work, and age. These determinants are shaped by the distribution of money, power, and resources at various levels of society. Social inequalities in health are well-documented, with individuals from lower socioeconomic backgrounds experiencing poorer health outcomes and shorter life expectancies, even in wealthy countries. For example, in the Whitehall study, men in lower administrative grades had significantly higher mortality rates than those in higher grades. Research in social epidemiology seeks to understand the pathways linking social structures to health. The Commission on Social Determinants of Health (CSDH) 2008 proposed a model illustrating these pathways, emphasizing the role of socioeconomic factors in shaping health. The field also focuses on improving measures of social exposures, health outcomes, and the associations between social structures and health. These efforts aim to inform public policy and reduce health inequalities.Social epidemiology is the branch of epidemiology that studies the social distribution and determinants of health. It examines how social factors influence health outcomes, including social inequalities, health behaviors, material and economic conditions, life course, social biology, and ecological perspectives. Social epidemiology contrasts with individualistic approaches by focusing on the broader social structure and its impact on health. The field has evolved by posing new research questions, using innovative methods, and influencing public policy. The social determinants of health refer to the conditions in which people are born, grow, live, work, and age. These determinants are shaped by the distribution of money, power, and resources at various levels of society. Social inequalities in health are well-documented, with individuals from lower socioeconomic backgrounds experiencing poorer health outcomes and shorter life expectancies, even in wealthy countries. For example, in the Whitehall study, men in lower administrative grades had significantly higher mortality rates than those in higher grades. Research in social epidemiology seeks to understand the pathways linking social structures to health. The Commission on Social Determinants of Health (CSDH) 2008 proposed a model illustrating these pathways, emphasizing the role of socioeconomic factors in shaping health. The field also focuses on improving measures of social exposures, health outcomes, and the associations between social structures and health. These efforts aim to inform public policy and reduce health inequalities.