Relationship between Whole- Grain Intake, Chronic Disease Risk Indicators, and Weight Status among Adolescents Laura Simonitch B.S. University of Nebraska-Lincoln Dietetic Intern, MS Student University of Kansas Medical Center

Introduction Whole grains: dietary fiber, phytoestrogens, minerals, antioxidants, vitamin E, folate 1, 2 Past studies contradictory 3 Little data for adolescents Inverse association between whole-grain intake and BMI 4 Failed to account for other dietary factors 1,5,6

Introduction Increased prevalence of obesity –Type 2 diabetes, CVD risk factors 7,8,9 Future public health efforts about whole grain intakes for adolescents 7. Ogden et al (2010) 8. Tybor et al (2011) 9. Freedman eta l (1999)

Research Question What is the relationship among chronic disease risk factors, weight status, and whole-grain intake among adolescents ages years by sex? Reicks et al. Relationship between whole-grain intake, chronic disease risk indicators, and weight status among adolescents in the National Health and Nutrition Examination Survey, Journal of the Academy of Nutrition and Dietetics. 2012;112:46-55.

Study Methods Cross-sectional data from the National Health and Nutrition Examination Survey from years (NHANES) Stratified, multistage probability sample of the non-institutionalized US population NHANES surveys from , , and combined

Participants Age 12 to 19 years old Boys and girls of various ethnicities and anthropometrics 6,418 adolescents screened 2,495 boys 2,433 girls 4,928 adolescents included

Exclusion Criteria Extreme energy intakes Currently breastfeeding or pregnant Taking insulin, oral medication for diabetes, or medication for hypertension Missing data for disease risk factors, C- reactive protein, systolic blood pressure, total cholesterol, HDL cholesterol, serum folate, or homocysteine

Data Collection Dietary Intake: –NHANES and data sets based on a single 24-hour dietary recall –NHANES data based on 2 days of dietary recall

Data Collection Anthropometrics –Height –Weight –Waist, arm, and thigh circumferences –Subscapular skinfold thickness –BMI and BMI z scores

Data Collection Chronic disease risk factors/laboratory measures –Blood and urine samples –complete blood count and pregnancy analyses –standard clinical assays –Friedewald formula –Fluorescence polarization immunoassay –Mercury sphygmomanometer –CDC used standard assay procedures

Data Collection Whole grain intake –MyPyramid Equivalents Database for USDA Survey food codes show food group information: total grain whole-grain non-whole grain total vegetables, fruits, milk, and meat and beans

Results Dietary Intake –52% boys and 50% girls did not consume whole grains on days that intake was measured –Fiber intake below recommendations for boys and girls –Positive association between whole-grain intake and daily energy intake for boys and girls

Dietary Intake Significance level: P < 0.05

Results Anthropometric Measures –Whole-grain intake inversely related among boys with BMI, BMI z score, weight, and waist, thigh, and arm circumferences –Only a significant inverse association between whole-grain intake and arm circumference in boys once adjusted for food group intake in the second set of models

Anthropometric Parameter

Results Chronic disease risk factors/laboratory measures –Fasting insulin levels inversely related to whole-grain intake for boys –C-peptide inversely related to whole-grain intake for girls –Positive association between whole-grain intake and HDL levels for girls –Boys had an inverse association between homocysteine levels and whole-grain intake.

Chronic disease risk factors/laboratory measures –Boys and girls had a positive association between serum and red blood cell folate levels and whole-grain intake –Inverse association between whole-grain intake and fasting insulin levels in girls –C-reactive protein levels were higher for girls who had low whole-grain intake compared to those with no or high intake Results

Chronic disease risk factors/laboratory measures BoysGirls NoneLowHighP valueNoneLowHighP value 1 st set of models Homocysteine (µmol/L) 6.8 ± ± ± ± ± ± Folate, serum (ng/mL) 12.5 ± ± ± 0.3< ± ± ± 0.5< Folate, red blood cell (ng/mL) 236 ± 3248 ± 4259 ± 6< ± 5244 ± 6269 ± 6< nd set of models Folate, serum (ng/mL) 12.6 ± ± ± 0.3< ± ± ± 0.4< Folate, red blood cell (ng/mL) 237 ± 3249 ± 4256 ± 5< ± 5244 ± 6266 ± 5< 0.001

Discussion/Implications Whole-grain intake was not found to be associated with BMI in the second set of models (adjusted for food group intake) Positive results between whole-grain intake, nutrient intake, and chronic disease risk indicators for protection against chronic disease in the second set of models

Sex differences may be due to differences in body composition, weight-gain patterns, hormone involvement in growth Inconsistent results from very low overall whole-grain intake Overall, this study supports current recommendations that promote high whole grain intake for adolescents Discussion/Implications

Study Limitations Missing data in non-fasting blood samples Self-reported 24-hour and 2-day dietary recalls High category scoring misconception

Thank you! Questions? Laura Simonitch B.S. University of Nebraska-Lincoln Dietetic Intern, MS Student University of Kansas Medical Center