Of the 10568 eligible participants, 48.0% (n = 5020) were men. The mean age was 44.1 years overall, 43.5 years in men and 44.8 years in women (p = 0.063). With regard to education 52.5% (n = 4022) of the participants had completed more than high school, 25.6% (n = 2178) had completed high school, while 21.7% (n = 3248) had completed less than high school. White (non-Hispanic) represented 70.4% (n = 4864) of the participants, African-Americans - 10.9% (n = 2103) and Mexican-Americans - 6.9% (n = 2690). Overall, 20.8% were current smokers (24.8% of the men and 16.6% of the women). The mean and standard error of mean (SEM) for the TL in the overall sample was 1.08±0.015 (1.07±0.014 in men and 1.08±0.016 in women).