Letter by Wexler and Feldman Regarding Article, “Socioeconomic Position, Race/Ethnicity, and Inflammation in the Multi-Ethnic Study of Atherosclerosis”
We read with great interest the research by Ranjit et al1 in the November 20, 2007, issue of Circulation. The link between socioeconomic position (SEP) and cardiovascular disease (CVD), especially in blacks, is well documented.2,3 As discussed by Ranjit et al,1 what is less clear is whether inflammation is linked to SEP and CVD. Should it become possible to explain the linkage between SEP, CVD, and inflammation, it would then theoretically become possible to target multipart interventions designed to address these various factors.
Ranjit et al1 studied the association between 2 SEP markers, education and income, and their relationship to inflammation. Education and income were directly linked and inversely associated with the inflammatory markers studied. In addition, as income and educational levels increased, smoking use and psychosocial stress decreased. They concluded that education and income were linked to inflammation, and that in blacks and whites, smoking and adiposity helped to explain this association.
We do not dispute these findings, and given what we know about SEP, CVD, education, and income, this is not surprising. That they were able to take the next step and link inflammation to SEP is an important step in our understanding of the interplay between SEP, inflammation, and CVD, and their role in cardiovascular health disparities. However, we would suggest that the linkage of education and income to SEP and inflammation as reported in this research is not as clear as it would appear.
We have recently completed analysis of a survey of 285 patients with hypertension about their opinions on lifestyle modification to treat blood pressure.4 Eighteen percent had a history of heart disease, and 43% were black. The educational level did not differ between groups. Thirty percent of both black and white patients were high school graduates. Rates of those achieving higher education also did not differ, with 11% of blacks having completed college compared with 12% of whites. The discrepancy in income, however, was striking. Blacks were more likely to earn less than $25 000 per year (35% versus 23%) and were less likely to earn more than $75 000 (11% versus 19%).
Our findings that education and income are not linked in blacks to the same degree seen in whites suggests that there are as of yet unknown factors that impact the interplay between education, income, SEP, CVD, and inflammation. It is possible that these factors play a significant role in cardiovascular health disparities. As such, further research in the areas of social epidemiology, cardiovascular disease, and health disparities is necessary to more fully explain the associations between inflammation, SEP, and CVD.
Dr Wexler is the recipient of a Pfizer Health Disparity Fellowship. Dr Feldman reports no conflicts.
Ranjit N, Diez-Roux AV, Shea S, Cushman M, Ni H, Seeman T. Socioeconomic position, race/ethnicity, and inflammation in the Multi-Ethnic Study of Atherosclerosis. Circulation. 2007; 116: 2383–2390.
Denvir MA, Lee AJ, Rysdale J, Walker A, Eteiba H, Starkey IR, Pell JP. Influence of socio-economic status on clinical outcomes and quality of life after percutaneous coronary intervention. J Epidemiol Community Health. 2006; 60: 1085–1088.
Wexler R, Feldman D, Larson D, Sinnott LT, Jones LA, Miner J. Adoption of exercise and readiness to change differ between Whites and African Americans with hypertension. J Am Board Fam Med. In press.