Midnight salivary cortisol secretion associated with high systolic blood pressure in type 1 diabetes

OBJECTIVE: To explore associations between high midnight salivary cortisol (MSC) secretion and high blood pressure (BP) in type 1 diabetes (T1D). METHODS: Cross-sectional study of 196 adult patients with T1D (54% men). Associations between high MSC (≥9.3 nmol/L) and high systolic BP (>130 mmHg), and high diastolic BP (>80 mmHg) were explored for all patients, users and non-users of antihypertensive drugs (AHD). Adjustments were performed for age, sex, diabetes-related variables, p-creatinine, smoking, physical inactivity, depression and medication. RESULTS: The prevalence of high MSC differed between patients with high and low systolic BP in all 196 patients: 39 vs 13% (P = 0.001); in 60 users of AHD: 37 vs 12% (P = 0.039), and in 136 non-users of AHD: 43 vs 13% (P = 0.012). Significant associations with high systolic BP were for all patients: physical inactivity (adjusted odds ratio (AOR) 6.5), high MSC (AOR 3.9), abdominal obesity (AOR 3.7), AHD (AOR 2.9), age (per year) (AOR 1.07), and p-creatinine (per µmol/L) (AOR 1.03); for 60 users of AHD: high MSC (AOR 4.1) and age (per year) (AOR 1.11); for 136 non-users of AHD: abdominal obesity (AOR 27.4), physical inactivity (AOR 14.7), male sex (AOR 9.0), smoking (AOR 7.9), and age (per year) (AOR 1.08). High MSC was not associated with high DBP. CONCLUSIONS: In adult patients with T1D, high systolic BP was associated with physical inactivity, high MSC secretion, abdominal obesity, p-creatinine, age, and AHD, the latter indicating treatment failure.