ABSTRACT

1. Decreased High Density Lipoprotein Cholesterol in a Cohort of 6th-grade Children: Association with Cardiovascular Risk Factors and Lifestyle Behaviors Shannon Flynn, RoopaGurm, Jean DuRussel-Weston, Susan Aaronson, Lindsey Gakenheimer, Joe Smolarski, Daniel Simhaee, Nicole Corriveau, Cathy Fitzgerald, Taylor Eagle, Ravi Rao, Kim A. Eagle, Caren Goldberg, Elizabeth A. Jackson, University of Michigan Health System, Ann Arbor, MI ABSTRACT BACKGROUND RESULTS RESULTS • In light of the recent childhood obesity epidemic, there is heightened interest in identifying children and adolescents at increased risk for cardiovascular disease. • High density lipoprotein cholesterol (HDL-C) has been shown to be inversely associated with coronary heart disease risk in adults through anti-atherogenic, anti-thrombotic, and anti-inflammatory mechanisms. • The role of HDL-C in children and adolescents is not well understood, though the process of atherogenesis has been shown to begin early in life. Table 2: Physiologic Parameters and Self-Reported Lifestyle Behaviors Table 1: Baseline Characteristics Background: High density lipoprotein cholesterol (HDL-C) levels are inversely associated with coronary heart disease risk in adults due to anti-inflammatory, anti-atherogenic, and anti-thrombotic mechanisms. Atherogenesis starts early in life, but the significance of low HDL-C in children and adolescents has scarcely been explored. We determined the prevalence of low HDL-C (≤ 40mg/dL) in a population of 6th-grade students to assess associations between low HDL-C and cardiovascular risk factors and lifestyle behaviors. Methods: Data from 1104 participants in Project Healthy Schools, a school-based intervention program in southeast Michigan, were collected, including lipid and glucose levels, body mass index (BMI), blood pressure, heart rate and a standardized questionnaire assessing dietary, exercise and sedentary habits. Chi-squared analyses and unpaired t-tests were used to compare the two cohorts. Results: Low HDL-C was prevalent in the study population, with 16.06% of participants having an HDL-C of ≤ 40 mg/dL. HDL-C was inversely associated with BMI (P=0.001), and females comprised a higher percentage of the low HDL-C group than the high HDL-C group (58.9% vs. 49.7%, P=0.027). Compared to students in the high HDL-C group, those in the low HDL-C group had higher mean low-density lipoprotein cholesterol (93.53±27.32 mg/dL vs. 87.90±24.72 mg/dL, P=0.009), higher mean triglycerides (175.01±102 mg/dLvs 111.88±67.16 mg/dL, P=0.001), higher mean systolic and diastolic blood pressure (110.88±11.47 mmHg vs. 107.98±11.16 mmHg, P=0.002 and 66.01±8.90 mmHg vs. 63.67±7.74 mmHg, P=0.001), higher resting heart rate (84.34±11.30 beats/min vs. 80.22±10.81 beats/min, P=0.001), and higher recovery heart rate (110.72±18.13 beats/min vs. 103.39±17.38 beats/min, P=0.001). Additionally, students in the low HDL-C group engaged in fewer days of strenuous and moderate physical activity per week (4.02±2.13 vs. 4.53±2.01, P=0.003 and 2.99±2.39 vs. 3.41±2.29, P=0.032). Conclusion: We found a high prevalence of low HDL-C in our population, which tended to cluster with inactive, overweight, less fit girls with high triglycerides and higher blood pressure. Our findings suggest that there may be a large population of youth already at risk for adverse health events; thus lipid screening in children and adolescents may have significant value. Disclosures: None OBJECTIVE We sought to determine the prevalence of low HDL-C in a cohort of 6th-grade students and to explore potential associations between low HDL-C levels and other markers of cardiovascular health. *No significant differences (P<0.05) were found in mean age or racial composition between the two cohorts. METHODS Figure 1: Mean HDL-C by BMI Percentile • We analyzed data from 1104 6th-grade students participating in Project Healthy Schools (PHS), a UMHS-community collaborative that seeks to educate middle school students about diet, exercise, and healthy lifestyles in order to decrease cardiovascular risk factors. • Data collected and analyzed included lipid and glucose levels, body mass index (BMI), blood pressure, heart rate and a standardized questionnaire assessing dietary, exercise and sedentary habits. • Weight categories were defined using 2000 CDC Growth Charts for United States (all BMI’s adjusted for age and gender). Underweight: BMI <5th percentile, Normal: ≥5th percentile and <85th percentile, Overweight: ≥85th percentile and <95th percentile and Obese: ≥95th percentile. • No significant differences were found in total cholesterol, glucose, fruit and vegetable intake, or television and computer time between the two cohorts. • Of the 177 students in the low HDL-C cohort, 90 (50.8%) had at least two additional criteria for metabolic syndrome in adolescents, as defined by the National Cholesterol Education Program. HDL-C (mg/dL) % P-value for trend = 0.001 CONCLUSION • We found a high prevalence of low HDL-C in our population, which tended to cluster with inactive, overweight, less fit girls with high triglycerides and higher blood pressure. • Our findings suggest that there may be a large population of youth already at risk for adverse health events; thus lipid screening in children and adolescents may have significant value. STATISTICAL METHODS • Chi-squared analyses and unpaired t-tests were used to compare the two cohorts. • P-Values <0.05 were considered significant.