Introduction: Circadian misalignment has been proposed as a potential determinant of cardiometabolic risk. Chronotype, as an expression of individual circadian organization, has been associated with unfavorable metabolic profiles; however, the role of total and central adiposity as potential mediating mechanisms in this relationship remains incompletely understood. Objective: This study aimed to analyze the association between chronotype and cardiometabolic risk in adults and to evaluate the potential mediating role of body fat percentage (BF%) and waist-to-height ratio (WHtR). Methods: An observational study was conducted in 1462 adults from the general population. Chronotype was assessed using the Morningness–Eveningness Questionnaire (MEQ), and cardiometabolic risk was evaluated using a continuous cardiometabolic risk score (CMRS) derived from waist circumference (WC), systolic blood pressure (SBP), triglycerides (TG), fasting blood glucose (FBG), and total cholesterol (TC). Multiple linear regression models adjusted for covariates were used to examine the association between chronotype and CMRS, and hierarchical regression was performed to estimate the incremental contribution of adiposity indicators. Mediation analysis was conducted using the PROCESS macro (Model 4) with 95% bootstrap confidence intervals. Results: Chronotype was independently associated with CMRS after adjustment for covariates (β = 0.055; p = 0.030), although the effect size and explained variance were small. In hierarchical regression analysis, the inclusion of chronotype explained a small but significant increase in CMRS variance (ΔR² = 0.003; p = 0.030). The addition of adiposity indicators significantly increased the explained variance (ΔR² = 0.014; p < 0.001), with WHtR emerging as the most relevant predictor in the final model. Bootstrap mediation analysis did not reveal significant indirect effects of BF% or WHtR on the relationship between chronotype and CMRS. In sensitivity analyses excluding waist circumference from the CMRS, the association between chronotype and cardiometabolic risk was no longer significant (β = −0.001; p = 0.974). Conclusions: Chronotype showed a modest association with cardiometabolic risk in the primary analysis. However, sensitivity analyses indicated that this association may partly depend on the inclusion of waist circumference within the composite cardiometabolic risk score. These findings highlight the central role of abdominal adiposity in cardiometabolic health and suggest that the relationship between chronotype and cardiometabolic risk should be interpreted with caution.

Mercury exposure associated with fish consumption remains a significant public-health concern in the Amazon Basin. Here, we quantified total mercury (T-Hg) in muscle of five fish species from the Alto Nanay River (Loreto, Peru) across wet and dry seasons to characterize contamination patterns and implications for human consumers. Across all species, T-Hg ranged from 0.16 to 3.79 mg kg⁻¹. The highest mean burdens occurred in piscivores: Pseudoplatystoma punctifer (2.63 ± 1.03 mg kg⁻¹, 1.60–3.66; n = 6) and Cichla monoculus (2.43 ± 0.26 mg kg⁻¹, 2.17–2.69; n = 6), exceeding a widely used food-safety guideline (0.5 mg kg⁻¹). Mean concentrations were higher in the wet season (1.68 ± 0.94 mg kg⁻¹; n = 15) than in the dry season (1.31 ± 0.54 mg kg⁻¹; n = 15), with a difference of 0.37 mg kg⁻¹ (≈28% increase). Linear regression analyses indicated low–moderate size-dependence of T-Hg (standard length R² = 0.19; total length R² = 0.20; total weight R² = 0.12; all p < 0.05). These findings show that two piscivorous species from the Alto Nanay frequently exceed recommended limits for safe human consumption and highlight the need for continuous monitoring and species- and size-specific fish-consumption advisories to protect Amazonian riverine communities.