Socioeconomic deprivation and cardiovascular disease

Socioeconomic deprivation (SED) is inversely associated with mortality. The most deprived are at a higher risk of all cause mortality and cardiovascular mortality. However, only limited study of the relationship between SED and non-fatal cardiovascular disease has been previously undertaken. In those studies that have examined the relationship between SED and non-fatal cardiovascular disease, analyses have been limited to one form of cardiovascular disease (CVD), such as myocardial infarction or stroke and often prevalent disease. Furthermore, these studies have often failed to examine the association between SED and CVD whilst adjusting analyses for cardiovascular risk factors which are more prevalent in the most deprived. The aim of this work was to examine the association between SED and a number of cardiovascular outcomes after adjusting for the traditional cardiovascular risk factors of age, sex, smoking, blood pressure, diabetes mellitus and cholesterol. To determine is SED is in fact a risk factor for CVD after adjustment for these other risk factors, the relationship between SED and a number of fatal and non-fatal cardiovascular outcomes was examined. A number of forms of CVD were examined, including all coronary heart disease, myocardial infarction, stroke and heart failure A cohort of over 15,000 men and women who participated in the Renfrew Paisley cohort study was examined. These individuals were enrolled between 1974 and 1976 and underwent comprehensive screening for cardiorespiratory risk factors. They have since been followed for hospitalisations and deaths for 28 years. SED was measured using the Registrar General’s social class system and the Carstairs Morris index of deprivation. Rates of fatal and non-fatal outcomes were calculated, as were a number of composite outcomes. Adjusted analyses using multivariable regression were conducted to account for the risk factors of age, sex, smoking, blood pressure, diabetes and cholesterol. Further adjustment for the risk factors of lung function as measured by forced expiratory volume in 1 second, cardiomegaly on chest x-ray, body mass index, and a history of bronchitis was also made. The association between SED and the risk of recurrent cardiovascular hospitalisations, the burden of cardiovascular disease, as well as mortality and premature mortality was assessed for SED. I found that SED was associated with higher rates of hospitalisation for CVD disease in men and women irrespective of the measure of SED, either social class or the area based score of the Carstairs Morris index. This association persisted after adjustment for the traditional cardiovascular risk factors of age, sex, smoking, systolic blood pressure and diabetes and cholesterol. Further adjustment for lung function, the presence of bronchitis, body mass index and cardiomegaly on a chest x-ray did not explain the relationship between SED and each outcome. This risk was long lasting and persisted to the end of follow up. The strength of association of SED with coronary heart disease, myocardial infarction and stroke and all cause mortality was similar. The risk of a recurrent CVD hospitalisation was not higher in the most deprived after adjustment for CVD risk factors. However, I observed that SED was associated with higher mortality following an admission to hospital with CVD, before and after adjustment for cardiovascular risk factors of age, sex, smoking, systolic blood pressure, cholesterol and diabetes and after adjusting for the year of first developing cardiovascular disease. All cause mortality and cardiovascular mortality was highest in the most deprived. Again this association persisted after adjustment for cardiovascular risk factors. The most deprived also experienced longer hospital stays than the least deprived for a number of cardiovascular diseases including myocardial infarction and stroke. As a result the costs associated with cardiovascular disease admissions to hospital were highest in the most deprived despite their higher risk of dying during follow up. The cost differential was also explained by the finding that the most deprived experienced a higher number of admissions per person. Finally, the population attributable risk associated with SED is comparable to that of other traditional cardiovascular risk factors. In conclusion, I have found that the risk of CVD in the most deprived is higher even after adjustment for a number of cardiovascular risk factors. The numbers of hospitalisations, costs and mortality are also highest in the most deprived. Efforts are required to redress this imbalance. This can be achieved at the level of the individual through health care interventions to reduce the absolute burden of cardiovascular risk factors and to treat disease. However, societal level interventions are also required to tackle this problem as SED exerts complex effects on health that seem to also be independent of risk factors.