Abstract
PURPOSE: Chronotype can be used to describe individual's circadian preference in behavioral and circadian rhythm, representing the preferences for earlier or later sleep times. This study aimed to investigate the association of chronotype with hypertension and metabolic parameters in middle-aged and older adults. PATIENTS AND METHODS: A total of 945 participants were recruited from December 2023 to December 2024 at First Affiliated Hospital of University of Science and Technology of China. Chronotype was determined using the full Morningness-Eveningness Questionnaire, with higher scores indicating preference for morning chronotype. Chronotype was dichotomized at the median score in current cohort, classifying 447 participants as morning chronotypes and 498 as evening chronotypes. Anthropometric measurements and biochemical analyses were also conducted. Multivariable logistic, linear regression, and restricted cubic spline (RCS) analyses were employed to evaluate association between chronotype, metabolic parameters, and hypertension. RESULTS: After adjustment for covariates, evening chronotype was significantly associated with hypertension risk (OR = 1.60, 95% CI: 1.17-2.17), compared with morning chronotype. The RCS analysis suggested a significant nonlinearity association between chronotype score and hypertension (P for nonlinear = 0.047). Furthermore, higher chronotype score was significantly associated with decreased levels of total cholesterol [TC, β (95% CI): -0.12 (-0.19, -0.04)], low-density lipoprotein-cholesterol [LDL-C, β (95% CI): -0.21 (-0.33, -0.08)] and serum uric acid [SUA, β (95% CI): -0.09 (-0.18, -0.01)], but with increased levels of aspartate aminotransferase [AST, β (95% CI): 0.16 (0.05, 0.27)]. In discrimination model, chronotype was associated with hypertension independently of TC, SUA, alanine transaminase, and alkaline phosphatase, with model's AUC of 0.779 (95% CI: 0.749-0.808). CONCLUSION: In middle-aged and older adults, preference for morning chronotype was associated with decreased levels of TC, LDL-C, and SUA, but with increased levels of AST. Moreover, evening chronotype was significantly independently associated with increased risk of hypertension.