Objectives:

To investigate the relationship between body mass index (BMI) and blood pressure (BP) circadian rhythm in patients with essential hypertension, and to analyze differences in lipid profiles and carotid plaque prevalence across different dipping patterns.

Methods:

A total of 443 patients with essential hypertension were enrolled from the Department of Cardiology, the Second Affiliated Hospital of Anhui Medical University, between July 1, 2024, and July 30, 2025. Based on 24-hour ambulatory BP monitoring (ABPM), they were categorized into four groups: dippers (n = 79), nondippers (n = 224), reverse-dippers (n = 127), and extreme-dippers (n = 13). Clinical data were collected to analyze the associations between BP circadian rhythm, BMI, blood lipid profiles, and carotid plaque formation.

Results:

Significant differences were observed among the four groups in BMI (P = 0.038, η² = 0.019), total cholesterol (P = 0.040, η² = 0.019), low-density lipoprotein cholesterol (LDL-C) (P = 0.028, η² = 0.021), and triglyceride levels (P = 0.025). The prevalence of carotid intima-media thickening (P < 0.05, Cramer’s V = 0.265) and carotid plaque formation (P < 0.05, Cramer’s V = 0.303) also significantly differed among the groups. The reverse-dipper group had a higher detection rate of carotid intima-media thickening (85, 66.9%) than the dipper (27, 34.2%) and nondipper (90, 40.2%) groups. The detection rate of carotid plaque formation in the reverse-dipper group (80, 63%) was higher than in the other three groups. BMI levels were significantly higher in the nondipper group (26.43 ± 4.30) and the reverse-dipper group (26.25 ± 4.41) compared with the dipper group (24.82 ± 4.48) (P < 0.05). Total cholesterol levels were significantly higher in the nondipper group (4.89 ± 1.09) than in the dipper group (4.52 ± 1.03) (P = 0.006). LDL-C levels were significantly elevated in the nondipper group (3.06 ± 0.84) and the extreme-dipper group (3.38 ± 0.93) compared with the dipper group (2.77 ± 0.82) (P < 0.05). Triglyceride levels were significantly higher in the nondipper group (1.79 [1.38, 2.53]) than in the dipper group (1.44 [0.95, 2.36]) (P = 0.015). Logistic regression analysis indicated that BMI and the presence of carotid plaque were independent risk factors for an abnormal BP circadian rhythm (P < 0.05). Advanced age, an abnormal BP circadian rhythm, and comorbid coronary heart disease were identified as risk factors for carotid plaque formation (P < 0.05).

Conclusion:

In patients with essential hypertension, elevated BMI levels and carotid plaque formation may be associated with abnormal circadian BP rhythms. Patients with abnormal circadian BP rhythms exhibit varying degrees of elevated blood lipid levels, which may also be correlated with carotid plaque formation.