Serum Lycopene Concentration Is an Independent Predictor of Cardiovascular Disease Risk

Lycopene is an unsaturated carotenoid that provides fruits and vegetables with a natural red pigment. Lycopene is predominately found in tomatoes, watermelon, papaya, and grapefruit. Lycopene has eleven linear conjugated bonds allowing it to oxidize free radicals. Lycopene’s antioxidative capacity are suggestive to have protective effects against chronic disease. Serum lycopene concentrations are inversely associated with cardiovascular disease risk. Purpose: To use data from the National Health and Nutrition Examination Survey (NHANES), 2003-2004 and 2005-2006 cycles, to investigate the relationship between elevated serum lycopene concentrations and demographic, socioeconomic, and lifestyle factors (Aim 1), as well as cardiovascular disease risk profiles (Aim 2). Methods: Females and males >20 yrs. who completed the 2003-2004 or 2005-2006 NHANES cycles were used in the current analysis (n=4442). Participants were excluded from the analysis if they were pregnant, had a previous cardiac event (i.e., heart attack, stroke, heart failure), or fasted < 8 hrs before the blood draw. An analysis of variance (ANOVA) was conducted modeling serum lycopene concentration as the dependent variable and demographic (age, sex, race) and socioeconomic factors as independent variables (education, and income). A multivariate one-way ANOVA was used to determine which demographic and socioeconomic factors were independently associated with serum lycopene concentrations. Cardiovascular risk profiles were calculated by totaling the number of risk factors between -1 and 12. Each participant received a +1 risk factor if the participant met a given risk factor criteria: <40 mg/dL serum HDL cholesterol, >130 mg/dL serum LDL-cholesterol, > 200mg/dL serum cholesterol, HDL to cholesterol ratio > 5, currently taking cholesterol medication, >130 mmHg systolic blood pressure, >90 mmHg diastolic blood pressure, currently taking blood pressure medication, HbA1C >7%, currently taking insulin, BMI > 30 kg/m2, or currently taking a diuretic [1] [2] . Each participant received a -1 risk factor if the participant had >60 mg/dL serum HDL cholesterol [1]. A linear regression model of total CVD risk and serum lycopene was conducted controlling for age (35-50, 51-69, >70 yrs), race (Non-Hispanic-Black, Mexican American, Other Hispanic, Other Race), education (Less than High School (HS) Education, High School Graduate or GED, Some College or AA Degree), socioeconomic status (SES, <100%, 100-199%, 200-299% poverty income guidelines), < 150 min moderate physical activity per week, smoking, and serum lycopene concentrations. Results: Serum lycopene concentrations were lower in participants aged 51-69 (40.4 ± 20.1 µg/dL , p-value = .001) and >70 yrs. (33.0 ± 18.8 µg/dL)p-value = .000) compared to participants 20-34 yrs. Females (40.2 ± 18.6 µg/dL) had reduced concentrations of serum lycopene compared to men (43.5 ± 19.4 µg/dL)(p-value = .000). Other Hispanics (44.7 ± 19.5 µg/dL) had significantly higher concentrations of serum lycopene compared to Non-Hispanic Whites (42.5 ± 18.9 µg/dL) (p-value = .015). Individuals with education status below a College Degree (45.6 ± 19.4 µg/dL) had significantly lower levels of serum lycopene compared to College Degree and Above [less that HS education (36.8 ± 18.7 µg/dL, p-value = .000), High School Grad or GED, (41 ± 18.7 µg/dL, p-value = .001), Some College or AA degree, (43 ± 18.9 µg/dL, p-value = .001)]. There were no differences between SES and serum lycopene concentrations when compared to income >300% (47.2 ± 20 µg/dL) of poverty guidelines [<100% poverty guidelines (39.8 ± 20.7 µg/dL, p-value = .160), 100-199% poverty guidelines (40.8 ± 22.8 µg/dL, p-value = .515), 200-299% poverty guidelines, (43.7 ± 21.2 µg/dL, p-value = .542). Serum lycopene concentrations (p-value .000) were a significant positive predictor of CVD risk profile score. In addition, age [35-49 yrs. (p-value .000), 50-69 yrs. (p-value .000), >70 yrs. (p-value .000)], sex [female (p-value .000)], Non-Hispanic Black (p-value .036), education [Less than HS Education ( p-value .008), High School Grad or GED (p-value .001), Some College or AA Degree (p-value .007)], socioeconomic status [<100% (p-value .045), 100-199% (p-value .011)], and physical activity [physical activity (p-value .002)] were significant predictors of CVD risk profile score. Race [Mexican American (p-value .912), Other Hispanic (p-value .405), Other Race (p-value .256)], socioeconomic status 200-299% (p-value .0539), and smoking (p-value .875) were not associated with CVD risk profile scores. Conclusion: In this cross-sectional study of the U.S. population, age, sex, race, education, and income were significant determinants of serum lycopene concentration. However, after multivariate analysis, age (>50 yrs ), females, Hispanics, Non-Hispanic Black, and education less than a college degree were found to be negatively associated with serum lycopene concentrations. Age, education, 100-199% SES, physical activity, and serum lycopene concentrations were positively associated with CVD risk factor scores. The positive association between CVD risk factor score and serum may have occurred due to underlying determinants such as serum LDL and cholesterol levels.