1. ABSTRACT CONCLUSION RESULTSBACKGROUND Decreased High Density Lipoprotein Cholesterol in a Cohort of 6th-grade Children: Association with Cardiovascular Risk Factors and Lifestyle Behaviors 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. 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. RESULTS OBJECTIVE We sought to determine the prevalence of low HDL-C in a cohort of 6 th -grade students and to explore potential associations between low HDL-C levels and other markers of cardiovascular health. METHODS Chi-squared analyses and unpaired t-tests were used to compare the two cohorts. P-Values <0.05 were considered significant. STATISTICAL METHODS We analyzed data from 1104 6 th -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 <5 th percentile, Normal: ≥5 th percentile and <85 th percentile, Overweight: ≥85 th percentile and <95 th percentile and Obese: ≥95 th percentile. VariableN HDL-C ≤ 40 mg/dL HDL-C > 40 mg/dL P Value Number of subjects (%) 1104 177 (16.0%) 927 (84.0%) * Female gender (%)1096 103 (58.9%) 458 (49.7%) 0.027 Age (years)- mean1096 11.61 ±0.46 11.55 ±0.40 0.073 Race (%) 0.489 Caucasian636 107 (60.8%) 529 (57.6%) * African American180 21 (11.9%) 159 (17.3%) * Asian134 20 (11.4%) 114 (12.4%) * Hispanic52 11 (6.3%) 41 (4.5%) * * No significant differences (P<0.05) were found in mean age or racial composition between the two cohorts. Figure 1: Mean HDL-C by BMI Percentile Table 1: Baseline Characteristics P-value for trend = 0.001 Table 2: Physiologic Parameters and Self-Reported Lifestyle Behaviors HDL-C (mg/dL) % 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. VariableN HDL-C ≤ 40mg/dL HDL-C > 40mg/dL P Value N(%)1104 177 (16.03) 927 (83.97) BMI (kg/m 2 )-mean1099 22.93 ±5.05 19.54 ±3.70 0.001 BMI>85 th percentile (%)1090 105 (60.3) 264 (28.8) 0.001 Systolic BP (mmHg)- mean 1101 110.88 ±11.47 107.98 ±11.16 0.002 Diastolic BP (mmHg)- mean 1101 66.01 ±8.90 63.67 ±7.74 0.001 Resting HR (beats/min)- mean 1101 84.34 ±11.30 80.22 ±10.81 0.001 Recovery HR (beats/min)-mean 1040 110.72 ±18.13 103.39 ±17.38 0.001 Triglycerides (mg/dL)- mean 1064 175.01 ±102 111.88 ±67.16 0.001 Low density lipoprotein cholesterol (mg/dL)-mean 1000 93.53 ±27.32 87.90 ±24.72 0.009 # days strenuous exercise/week-mean 1025 4.02 ±2.13 4.53 ±2.01 0.004 # days moderate exercise/week-mean 1029 2.99 ±2.39 3.41 ±2.29 0.019 Shannon Flynn, Roopa Gurm, 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 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/dL vs 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