title: Cortisol:brain-derived neurotrophic factor ratio associated with silent ischaemia in a black male cohort: the SA BPA study.
abstract: OBJECTIVE
  Emotional distress has been associated with cardiovascular disease (CVD) in Africans. Cortisol and brain-derived neurotrophic factor (BDNF), as markers of emotional distress, increase cardiometabolic risk. We therefore aimed to investigate associations between cardiometabolic risk markers and the cortisol-to-BDNF ratio (cortisol:BDNF).
  
  
  METHODS
  A cross-sectional study included a bi-ethnic gender cohort (n = 406) aged 44.7 ± 9.52 years. Ambulatory blood pressure (ABPM), ECG, fasting serum cortisol and BDNF levels and cardiometabolic risk markers were obtained.
  
  
  RESULTS
  Africans had increased incidence of hyperglycaemia and 24-hour silent ischaemic events, and elevated 24-hour blood pressure (BP) and cortisol:BDNF ratios compared to Caucasians. Forward stepwise linear regression analysis underscored a similar trend with associations between hyperglycaemia, 24-hour BP [Adj R20.21-0.29; β 0.23 (0.1-0.4); p = 0.01], silent ischaemia [Adj R20.22; β 0.40 (0.2-0.6); p < 0.01] and cortisol:BDNF levels in Africans, mostly in the men.
  
  
  CONCLUSIONS
  Attenuated cortisol levels in this group may be indicative of emotional distress and if chronic, drive the cortisol:BDNF ratio to desensitise BDNF. Desensitised cortisol:BDNF may sustain cardiometabolic risk and induce neurodegeneration in African men via silent ischaemia. Compensatory increases in blood pressure to increase perfusion and maintain homeostasis may increase coronary artery disease risk.
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom Campus, South Africa.
authors.forename: Christiaan E
authors.initials: CE
authors.lastname: Schutte
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom Campus, South Africa. Email: Leone.Malan@nwu.ac.za.
authors.forename: Leoné
authors.initials: L
authors.lastname: Malan
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom Campus, South Africa.
authors.forename: Jacobus D
authors.initials: JD
authors.lastname: Scheepers
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom Campus, South Africa.
authors.forename: Woudri
authors.initials: W
authors.lastname: Oosthuizen
authors.affiliation: Statistical Consultation Services, North-West University, Potchefstroom Campus, South Africa.
authors.forename: Marike
authors.initials: M
authors.lastname: Cockeran
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom Campus, South Africa.
authors.forename: Nicolaas T
authors.initials: NT
authors.lastname: Malan
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases; D015415:Biomarkers / Q000097:blood; D044383:Black People; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002545:Brain Ischemia / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D006943:Hyperglycemia / Q000097:blood / Q000208:ethnology; D006973:Hypertension / Q000208:ethnology / Q000503:physiopathology; D015994:Incidence; D016014:Linear Models; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D013019:South Africa; D013315:Stress, Psychological / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D044465:White People
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human; D006854:Hydrocortisone