1. by Sarah Steinmetz and Amber Brouillette
Change in DASH diet score and cardiovascular risk factors in youth with type 1 and type 2 diabetes mellitus: The SEARCH for Diabetes in Youth Study
by Sarah Steinmetz and Amber Brouillette

2. Background/Rationale
Observational studies and clinical trials have shown an association with adherence to DASH diet and improvement in CVD risk factors in adults and youth
SEARCH (a cross-sectional analysis) showed a DASH-like diet was inversely related to CVD risk factors, including: HTN, total cholesterol, LDL, LDL:HDL, and HbA1C
DASH diet:
emphasizes: fruits, vegetables, low-fat dairy, whole grains, fish/poultry/nuts, lean red meats, and limited sugar and sweets
low-saturated fat, cholesterol, total fat, and sodium
No prospective study has assessed the relationship between CVD risk factors and DASH diet adherence in youth with or without diabetes

3. Objective
To investigate whether a change in a DASH diet score was associated with change in CVD risk over multiple time points in youth with both type 1 and type 2 diabetes

4. Methods Used data per SEARCH protocol
data from baseline visit and 2 follow-up visits at 12 and 60 months
CV risk measures: DBP, SBP, HDL, LDL, TC, TAGs, HbA1C, waist circumference, and BMI (as z-score)
DASH adherence
measured by 85 point FFQ
each component with maximum score of 10 points: grains, vegetables, fruits, dairy, meat, nuts/seeds/legumes, fats/oils and sweets (80 points total)
Each person assessed for: diabetes duration, age, gender, race/ethnicity, income, study site, height, weight, waist circumference, and physical activity

5. Methods Sample Size: Inclusion criteria: Exclusion criteria:
youth with diabetes diagnosis in , >10 years old, had diabetes for at least 6 months at initial visit
had completed baseline FFQ
Exclusion criteria:
missing CVD related measures
those fasting for <8 hours at any visit
Sample Size:
797 total; 617 with T1DM, 180 with T2DM
The final sample consisted of 797 participants. Of the 617 youth with type 1 diabetes, 278 had a complete 12-month follow-up visit (i.e. including diet information) and 231 had a complete 60-month follow-up visit. A total of 65 and 53 participants, respectively, had complete follow-up visits of the 180 youth with type 2 diabetes.

6. Statistics Stratified by diabetes type
To assess the relationship between DASH score and CVD risk factors: longitudinal mixed-models with a random intercept to account for within-subject dependence
CVD risk factor measurements modeled as a function of baseline DASH scores and change in DASH scores from baseline
displayed relationship between:
baseline DASH score and outcome
if a change in DASH score was associated with longitudinal outcome
Models adjusted for: age, disease duration, race/ethnicity, sex, study site, income, height, BMI z-score, and waist circumference

7. Results Mean CVD risk factor values and change in DASH diet score:
Type 1 diabetes
no symmetrical change in DASH score over time (follow up 1: mean change of -0.18, SD=10.1; follow up 2: -0.41, SD=11.2)
increase in BP, total cholesterol, TAGs, and HbA1C
Type 2 diabetes
small overall mean change in DASH score (follow up 1: -0.36, SD=10.7; follow up2: 1.99, SD=11.4)
increase in HDL and HbA1C

9. Results
Longitudinal mixed-models separating the effect of diet at baseline from the effect of change in diet and included time-varying covariates per risk factor:
Type 1 diabetes
Inverse association between change in DASH diet score and HbA1C
10-point increase in DASH=0.20% decrease in HbA1C
Type 2 diabetes
Inverse association between DASH diet score and systolic BP
10-point increase in DASH=2.02mmHg decrease in SBP
Cross-sectional relationship between
baseline DASH score and LDL:HDL (B1=-0.14, p=0.0443); baseline DASH score and total cholesterol (B1=-7.78, p=0.0093)

11. Conclusion
Positive change in diet associated with improvements in HbA1C (T1DM) and systolic BP (T2DM)
Good quality dietary intake (DASH diet) can be beneficial in youth with type 1 and type 2 diabetes
Strengths:
longitudinal modeling for assessment of DASH diet changes
cross-sectional effect of baseline diet
Limitations:
small sample size (although modeling approach accounted for loss of follow-up by many time points)
no information on changes in macro/micronutrients provided