Diet Quality Is Not Associated with Malnutrition, Low Muscle Mass and Sarcopenia During Lung Cancer Treatment: A Cross-Sectional Study

<b>Background/Objectives</b>: Studies evaluating the impact of diet quality on nutrition- and muscle-related outcomes in cancer are limited. This study aimed to understand the diet quality of people with lung cancer and its cross-sectional associations with malnutrition, low muscle mass and (probable)-sarcopenia. <b>Methods</b>: Three-day food records were collected from 47 adults (mean ± SD age 70.6 ± 8.6 years; 58% male) with lung cancer prior to, or within one week, of curative-intent (chemo)radiotherapy. Dietary Guidelines Index (DGI-2013) and Mediterranean Diet Score (MDS) estimated diet quality, reflecting established healthy eating patterns. Malnutrition was determined using Patient Generated Subjective Global Assessment (PG-SGA). Low muscle mass was estimated using diagnostic third lumbar vertebra computed tomography (CT) images. (Probable)-sarcopenia was determined using the revised European Working Group for Sarcopenia in Older People definition, including low muscle (grip) strength, muscle mass and impaired function. Multivariate adjusted logistic regression analyses estimated odds ratios (OR) and 95% confidence intervals (CI) for associations between diet quality and outcomes. <b>Results</b>: Prevalence of malnutrition, low muscle mass and (probable)-sarcopenia were 36.2%, 50.0% and 13.6%, respectively. Mean ± SD DGI-2013 score was 53.0 ± 13.0. Adherence to the DGI-2013 was not significantly associated with malnutrition (OR, 0.67 [95%CI 0.35, 1.28]), low muscle mass (0.90 [95%CI 0.47, 1.70]) or (probable)-sarcopenia (0.73 [95%CI 0.29, 1.80]). Mean ± SD MDS was 3.6 ± 1.5. Adherence to the MDS was not significantly associated with malnutrition (0.75 [95%CI 0.37, 1.49]), low muscle mass (0.98 [95%CI 0.51, 1.88]) or (probable)-sarcopenia (1.82 [95%CI 0.72, 4.85]). <b>Conclusions</b>: Diet quality was not associated with malnutrition, low muscle mass or (probable)-sarcopenia. Given that overall diet quality was poor, it remains unclear whether high diet quality may be associated with nutritional status or muscle-related outcomes. Further research is needed to determine whether diet quality should be considered in nutritional interventions during lung cancer treatment.