A prospective study of plasma Selenoprotein P and lung cancer risk among low-income adults.
BACKGROUND
Epidemiologic studies have shown increased risks of lung cancer among adults with low blood levels of selenium, although evidence is inconsistent. In the United States, the incidence of lung cancer is higher and mean serum selenium levels lower among Blacks than Whites, but prior studies have not assessed the selenium-lung cancer association among Blacks.


METHODS
From the prospective Southern Community Cohort Study, we identified 372 participants who provided blood samples and subsequently developed lung cancer. Selenoprotein P (SEPP1), the most abundant selenoprotein in plasma and a biomarker of selenium nutriture, was measured in the plasma from these individuals and from 716 matched controls.


RESULTS
Mean SEPP1 levels were significantly (P < 0.0001) lower among Blacks than Whites. Conditional logistic regression models accounting for smoking revealed a significant trend of increasing OR of lung cancer with decreasing SEPP1 tertiles among Blacks (P = 0.0006) but not Whites (P = 0.69; Pinteraction = 0.10). The ORs and corresponding 95% confidence intervals of lung cancer risk among those with lowest versus highest tertile levels of SEPP1 were 2.4 (1.5-3.0) among Blacks and 1.1 (0.6-2.1) among Whites.


CONCLUSIONS
Among a mostly low-income population in the southeastern United States, lower levels of SEPP1 were associated with an increasing risk of lung cancer among Blacks but not Whites.


CONCLUSIONS
The combined findings of higher prevalence of low selenium status and higher lung cancer risk associated with low status raise the possibility that selenium deficiency may contribute to observed racial disparities in lung cancer incidence.
Authors' Affiliations: Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center and Vanderbilt-Ingram Cancer Center; meira.epplein@vanderbilt.edu.
Meira
M
Epplein
Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine;
Raymond F
RF
Burk
Authors' Affiliations: Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center and Vanderbilt-Ingram Cancer Center;
Qiuyin
Q
Cai
Department of Internal Medicine, Meharry Medical College, Nashville, Tennessee; and.
Margaret K
MK
Hargreaves
Authors' Affiliations: Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center and Vanderbilt-Ingram Cancer Center; International Epidemiology Institute, Rockville, Maryland.
William J
WJ
Blot
D000328:Adult; D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D051149:Selenoprotein P / Q000097:blood*; D015144:Southeastern United States / Q000453:epidemiology
D051149:Selenoprotein P