FIGURE 2.

Differences in serum concentrations of LDL cholesterol and HDL cholesterol comparing the 80th (137.7 ng/mL) with the 20th (111.4 ng/mL) percentile of the serum selenium distribution. Differences (95% CI in parentheses) in concentrations of serum LDL cholesterol and HDL cholesterol were derived from multiple linear regression models that included serum selenium concentrations as a continuous variable. Differences were adjusted for age, sex, race-ethnicity, education, family income, postmenopausal status for women, cigarette smoking, serum cotinine, alcohol consumption, physical activity, body mass index, cholesterol-lowering medication use, vitamin-mineral supplement use, glomerular filtration rate, C-reactive protein, diabetes mellitus, thyroid-stimulating hormone, and thyroxine. The area of each square is proportional to the inverse of the variance. Horizontal lines represent 95% CIs. None of the P values for the interactions was statistically significant at the 0.05 level, except for the interaction of serum selenium and sex on serum HDL cholesterol (P < 0.001) and the interaction of serum selenium and race on serum HDL cholesterol (P = 0.03). Although we used a comparison between the 80th and 20th percentiles, the statistical significance of these analyses would be the same if we had used other percentiles for comparison.