| Racial Differences in Paraoxonase-1 (PON1): A Factor in the Health of Southerners? Kimberly A. Davis,1 J. Allen Crow,1 Howard W. Chambers,2 Edward C. Meek,1 and Janice E. Chambers1 1Center for Environmental Health Sciences, College of Veterinary Medicine, and 2Department of Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi, USA Abstract
Background: The southern United States (excluding Florida) has the highest age-adjusted rate of cardiovascular disease (CVD) in the country, with African Americans having a higher prevalence of CVD than Caucasians. Paraoxonase-1 (PON1) , an enzyme associated with high-density lipoprotein particles, participates both in the hydrolysis of oxidized lipids (thus protecting against atherosclerosis) and in the hydrolysis of organophosphates. Higher paraoxonase activity has been associated with lower risk of atherosclerosis. Objectives: In this study we characterized the distribution of the functional PON1Q192R polymorphisms (PON status as assessed by diazoxonase to paraoxonase ratios) and the PON1 activity levels in 200 adult males and females of both races (50 in each race/sex class) from the southern United States from commercially obtained blood bank serum samples. Methods: We used spectrophotometric methods with serum to determine PON1 status, arylesterase activities (phenyl acetate hydrolysis) , and levels of cotinine and C-reactive protein (CRP) . Results: African Americans had higher paraoxonase activities but lower diazoxonase activities than did Caucasians, consistent with African Americans having a lower proportion of the functional genotype QQ (QQ 15%, QR 34%, RR 44%, 7% indeterminate) , than did Caucasians (QQ 60%, QR 31%, RR 7%, 2% indeterminate) . Cotinine levels indicated that all samples came from nonsmokers and that CRP levels were higher in African Americans than in Caucasians and higher in females than in males. CRP levels showed no association with paraoxonase activities. Conclusions: These data present initial observations for use in characterizing the poorer cardiovascular health status of the population in the southern United States and more specifically southern African Americans. Key words: atherosclerosis, cardiovascular disease, C-reactive protein, health disparities. Environ Health Perspect 117:1226–1231 (2009) . doi:10.1289/ehp.0900569 available via http://dx.doi.org/ [Online 12 March 2009]
Address correspondence to J.E. Chambers, College of Veterinary Medicine, 240 Wise Center Dr., Mississippi State University, Mississippi State, MS 39762-6100 USA. Telephone: (662) 325-1255. Fax: (662) 325-1031. E-mail: chambers@cvm.msstate.edu We thank S. Givaruangsawat for the statistical analyses. This research was supported in part by National Institutes of Health grant R21 ES015107 and by the Center for Environmental Health Sciences and the College of Veterinary Medicine, Mississippi State University. This is Center for Environmental Health Sciences publication 123 and Mississippi Agricultural and Forestry Experiment Station publication J-11545. The authors declare they have no competing financial interests. Received 14 January 2009 ; accepted 11 March 2009.
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