Secular trends in physiological capital: implications for equity in health care.

Over the past three centuries, there has been a rapid accumulation of physiological capital in Organisation for Economic Cooperation and Development (OECD) countries. Enhanced physiological capital is tied to long-term reduction in environmental hazards and to the conquest of chronic malnutrition, since both nutritional status and the quality of the external and intrauterine environments appear to be linked to the quality of organ development and to the onset of chronic diseases later in life. Data on heights and birth weights suggest that physiological capital has become more equally distributed, thereby reducing socioeconomic disparities in the burden of disease. These developments have a number of health care policy implications: (1) enhanced physiological capital has done more to reduce inequities in health status than has wider access to health care; (2) the main contribution of more advanced medical treatment so far has been to retard depreciation in individuals' physiological capital; (3) prenatal and early childhood care and environmental issues are key for interventions aimed at enhancing physiological capital and at affecting its rate of depreciation; (4) lifestyle change is the most important issue affecting health equity in rich countries; and (5) greater access to clinical care should be promoted through aggressive outreach, since expanded insurance coverage by itself is inadequate.