Background and Objectives: Chronotype and sleep quality are related but non-identical dimensions of sleep health. We examined whether later chronotype is associated with subclinical visceral adiposity and atherogenic dyslipidaemia independently of perceived sleep quality, and whether this association differs by sex, in adults without previously diagnosed chronic disease. Materials and Methods: This single-centre cross-sectional study included 282 adults without previously diagnosed chronic disease or regular medication use. Chronotype was assessed with the Morningness-Eveningness Questionnaire (MEQ) and sleep quality with the Pittsburgh Sleep Quality Index (PSQI). Composite cardiometabolic indices were calculated from routine anthropometric and biochemical data. Primary dependent variables were log-transformed Visceral Adiposity Index (log[VAI]) and Atherogenic Index of Plasma (AIP). Multivariable linear models used heteroscedasticity-consistent type 3 (HC3) robust standard errors and adjusted for age, sex, education, physical activity, and PSQI; body mass index (BMI) was additionally included in the AIP model. Sex × MEQ interactions, false-discovery-rate (FDR) correction, and glycaemic sensitivity analyses were performed. Results: Median age was 28.0 years; 50.4% were women, 25.9% were evening type, and 51.8% had poor sleep quality. Higher MEQ score (greater morningness) was independently associated with lower log(VAI) (B = -0.0096; 95% confidence interval (CI), -0.0159 to -0.0033; β = -0.190; p = 0.003) and AIP (B = -0.0035; 95% CI, -0.0063 to -0.0008; β = -0.160; p = 0.011), whereas PSQI was not independently associated with either outcome. Sex × MEQ interactions were nominally significant and estimates were stronger in women, but interaction terms did not survive FDR correction. Associations persisted after excluding diabetes-range glycaemia but attenuated in strictly normoglycaemic participants. Conclusions: Later chronotype was associated with a less favourable subclinical adiposity-atherogenic profile independently of perceived sleep quality. Findings are cross-sectional, and the sex-specific pattern is hypothesis-generating. Prospective studies with objective circadian, sleep, dietary-timing, behavioural, and hormonal measures are required.
