Selective migration from deprived areas in Northern Ireland and the spatial distribution of inequalities: implications for monitoring health and inequalities in health

Much of the evidence suggesting that inequalities in health have been increasing over the last two decades has come from studies that compared the changes in relative health status of areas over time. Such studies ignore the movement of people between areas. This paper examines the population movement between small areas in Northern Ireland in the year prior to the 1991 census as well as the geographical distribution of migrants to Northern Ireland over the same period. It shows that deprived areas tended to become depopulated and that those who left these areas were the more affluent residents. While immigrants differed a little from the indigenous population, the overall effect of their distribution would be to maintain the geographical socio-economic status quo. The selective movement of people between areas would result in the distribution of health and ill-health becoming more polarized, i.e. produce a picture of widening inequalities between areas even though the distribution between individuals is unchanged. These processes suggest potential significant problems with the area-based approaches to monitoring health and inequalities in health.

Significance of peroxisome proliferator-activated receptors in the cardiovascular system in health and disease.

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear transcription factors that belong to the nuclear receptor superfamily. Three isoforms of PPAR have been identified, alpha, delta and gamma, which play distinct roles in the regulation of key metabolic processes, such as glucose and lipid redistribution. PPARalpha is expressed predominantly in the liver, kidney and heart, and is primarily involved in fatty acid oxidation. PPARgamma is mainly associated with adipose tissue, where it controls adipocyte differentiation and insulin sensitivity. PPARdelta is abundantly and ubiquitously expressed, but as yet its function has not been clearly defined. Activators of PPARalpha (fibrates) and gamma (thiazolidinediones) have been used clinically for a number of years in the treatment of hyperlipidaemia and to improve insulin sensitivity in diabetes. More recently, PPAR activation has been found to confer additional benefits on endothelial function, inflammation and thrombosis, suggesting that PPAR agonists may be good candidates for the treatment of cardiovascular disease. In this regard, it has been demonstrated that PPAR activators are capable of reducing blood pressure and attenuating the development of atherosclerosis and cardiac hypertrophy. This review will provide a detailed discussion of the current understanding of basic PPAR physiology, with particular reference to the cardiovascular system. It will also examine the evidence supporting the involvement of the different PPAR isoforms in cardiovascular disease and discuss the current and potential future clinical applications of PPAR activators.