Abstract Body: Introduction: High intake of added sugars (>10% total energy) is associated with major cardiovascular risk factors and cardiovascular disease (CVD). Less is known about the effects on cardiovascular health (CVH) that could result from free-sugar restriction, particularly in adolescence, a critical period of CVH loss.

Hypothesis: An 8-week low free-sugar diet will improve CVH more than a usual diet in adolescent boys with metabolic dysfunction-associated steatotic liver disease MASLD (formerly NAFLD).

Methods: This is a secondary analysis of data from a randomized controlled open-label trial designed to test the effects of a diet that restricted free-sugar intake on hepatic steatosis (NCT02513121). Boys aged 11–16 years old with a diagnosis of MASLD (n=40) were randomized to an 8-week, study-provided low free-sugar diet (<3% of daily calories from sugar) or their usual diet in a 1:1 ratio. CVH was measured using the AHA Life’s Essential 8 (LE8) criteria to estimate a continuous score (range: 0-100) and a categorical variable (high: 80-100, moderate: 50-79, low: 0-49) by averaging the scores from 4 CVH metrics (blood pressure, BMI, non-HDL cholesterol, and glucose). Intention-to-treat mixed model analyses were employed, adjusting for age, study site (Emory or UCSD) and total energy intake. Analyses were performed in SAS (v.9.4) with significance evaluated two-sided at 0.05.

Results: All 40 randomized participants (mean (SD) age 13.0 (±1.8) years; 95% Latinx) completed the study. At baseline, the mean LE8 scores were 63.0 ±14.6, and 10% of boys had high, 75% moderate, and 15% low CVH. From baseline to 8-weeks, the mean CVH scores of boys in the low free-sugar diet (n=20) significantly improved by 8 points (mean difference (MD) 8.27; 95% Confidence Interval (CI), 2.9, 13.7; P=0.003) from 62.7 ±13.5 to 67.7 ±11.7. Among boys in the usual diet (n=20), the mean CVH scores had a non-significant decrease of MD=1.15 points (95% CI, -6.6, 4.3) from 63.4 ±15.8 to 62.2 ±13.6 (P=0.68). After 8 weeks, the mean changes in CVH scores for the free-sugar diet were not significantly different from those of the usual diet (MD=4.98, 95% CI, 0.6, 10.6; P=0.08).

Conclusion: In this small sample of adolescents, a low free-sugar diet was associated with improvements in CVH after only 8-weeks, but outcomes were not statistically different from the usual diet. Further research is needed to determine if a free-sugar diet can support the maintenance of CVH in youth with and without MASLD.