Upload
rodney-marshall
View
220
Download
0
Tags:
Embed Size (px)
Citation preview
OLSON, M.L . , ET AL
Vitamin D Deficiency in Obese Children an Its Relationship to
Glucose Homeostasis
J CL IN ENDOCRINOL METAB, 97 , 279 -285 , 2012
Researchers
5.967 Impact FactorInternal MedicinePediatric Endocrinology
Background
Obesity has tripled in U.S. children since 1980 19% of 6-19yr olds are obese
The rise in obesity has paralleled increases in childhood hypertension, hyperlipidemia, and Type 2 Diabetes.
Childhood obesity is associated with increase prevalence of cardiovascular events and Type 2 Diabetes in adulthood.
Supporting Evidence
Hypovitaminosis D in obese children and adolescents: relationship with adiposity, insulin sensitivity, ethnicity, and season Metabolism 57:183-91
Prevalence of vitamin D insufficiency in obese children and adolescents J Clin Endocrinol Metab 92:2017-29
Objectives
The aim of this study was to examine the relationship between dietary habits and 25(OH)D status in obese children.
Examine the relationship between 25(OH)D and glucose homeostasis.
Cross-sectional observational study
Selection of Subjects
411 obese children (BMI >95th percentile for age group) ages 6-16 Recruited from Center of Obesity and its
Consequences on Health in Dallas, Texas89 non overweight children
Recruited from Endocrinology Center after being treated for hypothyroidism or GH deficiency, but otherwise healthy
Exclusion criteria: use of anticonvulsant, vitamin D supplement more than 400 IU/day, other relevant disorders
Calculating Pediatric BMI
Data collected
Age, sex, ethnicity, height, weight, blood pressure, dietary habits
Laboratory data Serum 25(OH)D HbgA1C Fasting glucose and insulin OGTT HOMA-IR
Statistical Analysis
Prevalence of Vit D insufficiency determined for obese and non-overweight populations within each ethnic group and season Data collected in summer, fall, winter, spring Sufficiency: 75 nmol/L Insufficiency: < 75 nmol/L Deficiency: < 50 nmol/L χ squared to determine prevalence rate
Statistical Analysis cont.
Two way ANOVA to compare 25(OH)D between groups and assess interaction btw obesity and season; gender and ethnicity
Pearson coefficients used to determine relationship btw 25(OH)D and: 2h glucose HbbA1c HOMA-IR Blood pressure
Study Subject Analysis
Study Subject Analysis
Study Subject Analysis
Results
Results
Vitamin D deficiency + inadequacy
Results
Results
Discussion
Study Objective
To compare prevalence of vitamin D deficiency in obese versus non-overweight children.
Examine relationships between: Dietary habits and serum 25(OH)D levels Abnormal glucose metabolism and obesity in children
Cross-sectional observational study- no intervention was implemented
Subjects
411 obese and 89 non-overweight children (aged 6-16 years) residing in North Texas Grouping based on BMI percentile-for-age: Obese= >95th
percentile, non= <85th percentile Adequate sample size, but could have included more non-
overweight to better compare Convenience sample of non-overweight subjects from
Endocrinology Center for Hyperthyroidism No known relationship between thyroid and vitamin D status
Same exclusion criteria for both groups Meds: anticonvulsant, glucocorticoid, and/or vitamin D
supplement Health Status: Hepatic dz, renal dz, malabsorptive disorder,
bone metabolism disorder, hypothalamic dz, genetic predisposition to obesity
Accounted for multiple subject characteristics
AgeBMIGenderEthnicitySeasonDietary practices
Test Procedures
Used common, standard procedures determined to be reliable and valid: Serum 25(OH)D Diabetes Risk Factors (validated by Amer Diabetes Assoc)
OGTT Fasting plasma glucose and insulin HgbA1C HOMA-IR (insulin resistance and beta-cell function)
All measurements taken in same way in both groups
Result evaluation based to gender, race, and season in both groups
Study Design- valid
Used standardized, accurate measures of glucose metabolism and vitamin D status
Included variety of subjects: different genders, races, ages
Matched non-overweight subjects to obese based on age, race, and season more accurate comparison
Author’s Conclusions
Study results show a negative relationship between vitamin D status and BMI in children
Glucose metabolism is related to vitamin D status
Limitation: unable to account for physical activity or sun-light exposure Could aid in better understanding differences in
vitamin D status between the 2 groups
Relevant Outcomes
Obese had less seasonal variation in vitamin D status (p<0.03)
Breakfast skipping and high soda intakes were associated with lower vitamin D status (p<0.001)
When adjusted for age and BMI, vitamin D status negatively correlated with HOMA-IR and OGTT (p=0.001 and p=0.04) Lower vitamin D status is associated with T2D risk
factors in obese children
Implications for Practice
Nutrition Professionals: Raise awareness of dietary factors negatively affecting
vitamin D status in children (breakfast skipping, soda consumption)
Highlight need for early dietary interventions
Clinical Professionals: Suggests need for further study of vitamin D
supplementation as a potential treatment for conditions such as insulin resistance