Evening meal timing irregularity is associated with higher depressive symptoms in Iranian adults: A cross-sectional study.

BACKGROUND: This study aimed to examine the association between irregular meal timing and symptoms of depression, anxiety, and stress among Iranian adults. METHODS: This cross-sectional study included 450 apparently healthy adults (aged 20-59 years; 53.8% female) recruited via convenience sampling. Dietary data were collected using three non-consecutive 24-h recalls to assess meal timing irregularity, defined as day-to-day variability and deviation from participants' habitual meal timing, using composite phase deviation (CPD) scores for breakfast, lunch, and dinner. Mental health outcomes were measured with the Depression Anxiety Stress Scales short form. Covariates included sleep quality (Pittsburgh Sleep Quality Index), chronotype (Morningness-Eveningness Questionnaire), physical activity (International Physical Activity Questionnaire), anthropometrics, and sociodemographics. Associations were examined using multivariable logistic regression for binary outcomes and linear regression for continuous scores, adjusting for confounders. Linear regression analyses included participants with complete data for all model variables (n = 404). RESULTS: No significant associations emerged between meal timing irregularity tertiles and binary mental health outcomes (all adjusted P-trend>0.05). However, in linear regression models, dinner irregularity was independently associated with higher depressive symptom scores (B = 1.08, 95% CI 0.32-1.85, P = 0.006), but not stress (P = 0.336) and anxiety (P = 0.388). Breakfast and lunch irregularities showed no significant associations. CONCLUSIONS: Dinner timing irregularity may be associated with higher depressive symptom scores in this sample of Iranian adults. Future prospective and intervention studies are needed to clarify temporality and underlying mechanisms.