Abstract
INTRODUCTION: Health-related quality of life (HRQoL) is a key outcome in the long-term management of celiac disease, yet many adults report persistent limitations despite adherence to a gluten-free diet. Evidence on the independent contribution of socioeconomic, lifestyle, and psychological factors to HRQoL at the population level remains limited. METHODS: We conducted a national cross-sectional study including 1,050 adults with celiac disease living in Spain, recruited through patient associations. Sociodemographic characteristics, lifestyle factors, mental health, and disease-related variables were collected using an online questionnaire. HRQoL was assessed using the disease-specific Celiac Disease Quality of Life questionnaire (CD-QOL), and adherence to a gluten-free diet was measured with the Celiac Dietary Adherence Test (CDAT). Multivariable linear regression models were used to estimate independent associations with overall and domain-specific HRQoL scores. RESULTS: The mean overall HRQoL score was 59.9 ± 20.1, with the lowest scores observed in the limitations domain. After adjustment, higher income level (>4,000 € vs. < 1,000 €: MD 9.22; 95% CI 3.96-14.48; p = 0.001), older age (MD 0.43 per year; 95% CI 0.14-0.71; p = 0.003), daily physical activity (MD 4.00; 95% CI 0.43-7.57; p = 0.028), and the absence of anxiety (MD 4.90; 95% CI 1.79-8.00; p = 0.002) and depression (MD 5.40; 95% CI 0.62-9.45; p = 0.025) were independently associated with better HRQoL. In contrast, poorer adherence to a gluten-free diet was consistently associated with worse quality-of-life outcomes across all domains (MD -1.77 per point; 95% CI -2.10 to -1.43; p < 0.001). Time since diagnosis and years on a gluten-free diet were not independently associated with HRQoL. DISCUSSION: These findings indicate that, beyond dietary treatment, HRQoL in adults with celiac disease is primarily shaped by socioeconomic, behavioral, and psychological factors. Population-based strategies that integrate nutritional support with mental health care, physical activity promotion, and measures to reduce socioeconomic barriers may be essential to improve wellbeing and reduce inequalities in this population.