Circadian blood pressure dipping patterns, hypertension, and cortisol metabolism across the weight spectrum

BACKGROUND: Blood pressure (BP) exhibits a circadian rhythm with a nocturnal decline, dipping. Alterations in cortisol metabolism have been linked to hypertension and nondipping patterns. This study aimed to examine associations between 24-h BP patterns, hypertension, and cortisol levels. METHODS: In this cross-sectional study, 426 participants (329 with BMI ≥30 kg/m2; 97 with BMI 18.5-29.9 kg/m2) underwent 24-h ambulatory BP monitoring and assessments of 24-h urinary cortisol/cortisone ratio (F/E ratio), serum corticosteroid-binding globulin, and serum F/E ratio. Dippers were defined by at least 10% nocturnal BP fall; nondippers as less than 10% BP fall; and risers as a nocturnal BP increase. RESULTS: Participants with BMI 18.5-29.9 kg/m2 (BMI 24.8 ± 2.7 kg/m2) compared to participants with BMI at least 30 kg/m2 (BMI 40.9 ± 6.8 kg/m2), were older (47.6 ± 8.2 vs. 43.9 ± 10.9, P = 0.002), had lower 24-h mean SBP (119 ± 11 vs. 131 ± 12 mmHg, P < 0.001), and were less frequently nondippers (50.5 vs. 66.6%, P = 0.004). No significant difference was observed in cortisol metabolism when comparing nondippers and dippers (sex-stratified). In a multivariable regression analysis, female sex, BMI at least 30 kg/m2, being normotensive, or receiving antihypertensive treatment were all significantly associated with a lower 24-h urinary F/E ratio. Among nondippers with BMI 18.5-29.9 kg/m2, urinary F/E ratio was positively associated with 24-h mean SBP (r = 0.46, P < 0.001). CONCLUSION: Associations between cortisol biomarkers and BP variation were limited in participants with BMI at least 30 kg/m2, but appeared stronger in individuals with BMI 18.5-29.9 kg/m2 with nondipping BP.