Socioeconomic inequalities in coronary heart disease risk in older age: contribution of established and novel coronary risk factors.

S.E Ramsay,R.W Morris,A Rumley,S.G Wannamethee,G Lowe,P.H Whincup,L Lennon,O Papacosta

doi:10.1111/j.1538-7836.2009.03602.x

Abstract

Background:Evidence on socioeconomic inequalities in coronary heart disease (CHD) and their pathways in the elderly is limited. Little is also known about the contributions that novel coronary risk factors (particularly inflammatory/hemostatic markers) make to socioeconomic inequalities in CHD. Objectives:To examine the extent of socioeconomic inequalities in CHD in older age, and the contributions (relative and absolute) of established and novel coronary risk factors. Methods:A population-based cohort of 3761 British men aged 60–79 years was followed up for 6.5 years for CHD mortality and incidence (fatal and non-fatal). Social class was based on longest-held occupation recorded at 40–59 years. Results:There was a graded relationship between social class and CHD incidence. The hazard ratio for CHD incidence comparing social class V (unskilled workers) with social class I (professionals) was 2.70 [95% confidence interval (CI) 1.37–5.35; P-value for trend = 0.008]. This was reduced to 2.14 (95% CI 1.06–4.33; P-value for trend = 0.11) after adjustment for behavioral factors (cigarette smoking, physical activity, body mass index, and alcohol consumption), which explained 38% of the relative risk gradient (41% of absolute risk). Additional adjustment for inflammatory markers (C-reactive protein, interleukin-6, and von Willebrand factor) explained 55% of the relative risk gradient (59% of absolute risk). Blood pressure and lipids made little difference to these estimates; results were similar for CHD mortality. Conclusions:Socioeconomic inequalities in CHD persist in the elderly and are at least partly explained by behavioral risk factors; novel (inflammatory) coronary risk markers made some further contribution. Reducing inequalities in behavioral factors (especially cigarette smoking) could reduce these social inequalities by at least one-third.

Highlights

Coronary heart disease (CHD) is an important cause of morbidity and mortality; the incidence and prevalence of CHD both rise steeply with increasing age [1]
We investigated the extent to which established behavioral [cigarette smoking, alcohol consumption, body mass index (BMI) and physical activity] and biological coronary risk factors [15], and novel coronary risk factors [C-reactive protein (CRP), interleukin-6 (IL-6), and von Willebrand factor (VWF)] [10,16], contribute to socioeconomic differences in CHD in older men in both relative and absolute terms
Socioeconomic inequalities in CHD risk are present at older ages

Summary

Introduction

Coronary heart disease (CHD) is an important cause of morbidity and mortality; the incidence and prevalence of CHD both rise steeply with increasing age [1]. Some reports suggest that the relative differences in overall and CHD mortality between socioeconomic groups may decrease with increasing age [3,6,7]. In middle age, established coronary risk factors, including smoking, physical inactivity, obesity, and hypertension, make appreciable, limited, contributions to socioeconomic inequalities in CHD risk [8,9]. Novel risk factors, including inflammatory and hemostatic markers, are known to be associated with increased risk of coronary disease [10] Some of these inflammatory markers, such as C-reactive protein (CRP), are reported to be higher in lower socioeconomic groups, and are increasingly hypothesized to be possible contributors to the association between socioeconomic position and CHD [11,12,13]. A study in middle-aged subjects has suggested that inflammatory markers such as fibrinogen can contribute to

Objectives

Methods

Results

Discussion

Conclusion