title: Relationship between Vitamin D Status and Autonomic Nervous System Activity.
abstract: Vitamin D deficiency is associated with increased arterial stiffness. However, the mechanisms underlying this association have not been clarified. The aim was to investigate whether changes in autonomic nervous system activity could underlie an association between 25 hydroxy vitamin D and arterial stiffness. A total of 49 subjects (age = 60 ± 8 years, body mass index = 26.7 ± 4.6 kg/m², 25 hydroxy vitamin D = 69 ± 22 nmol/L) underwent measurements of pulse wave velocity (PWV) and augmentation index (AIx), spontaneous baroreflex sensitivity, plasma metanephrines and 25 hydroxy vitamin D. Subjects with 25 hydroxy vitamin D ≤ 50 nmol/L were restudied after 200,000 International Units 25 hydroxy vitamin D. Plasma metanephrine was positively associated with AIx (p = 0.02) independent of age, sex, smoking and cholesterol and negatively associated with 25 hydroxy vitamin D (p = 0.002) independent of age, sex and season. In contrast, there was no association between baroreflex sensitivity and 25 hydroxy vitamin D (p = 0.54). Treatment with vitamin D increased 25 hydroxy vitamin D from 43 ± 5 to 96 ± 24 nmol/L (p < 0.0001) but there was no significant change in plasma metanephrine (115 ± 25 vs. 99 ± 39 pmol/L, p = 0.12). We conclude that as plasma metanephrine was negatively associated with 25 hydroxy vitamin D and positively with AIx, it could mediate an association between these two variables. This hypothesis should be tested in larger interventional studies.
authors.affiliation: Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, SA 5041, Australia. morton.burt@sa.gov.au.|School of Medicine, Flinders University, Adelaide, SA 5042, Australia. morton.burt@sa.gov.au.
authors.forename: Morton G
authors.initials: MG
authors.lastname: Burt
authors.affiliation: Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, SA 5041, Australia. Brenda.Mangelsdorf@sa.gov.au.
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Mangelsdorf
authors.affiliation: Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, SA 5041, Australia. Steve.Stranks@sa.gov.au.|School of Medicine, Flinders University, Adelaide, SA 5042, Australia. Steve.Stranks@sa.gov.au.
authors.forename: Stephen N
authors.initials: SN
authors.lastname: Stranks
authors.affiliation: School of Medicine, Flinders University, Adelaide, SA 5042, Australia. Arduino.Mangoni@sa.gov.au.|Department of Clinical Pharmacology, Flinders Medical Centre, Adelaide, SA 5042, Australia. Arduino.Mangoni@sa.gov.au.
authors.forename: Arduino A
authors.initials: AA
authors.lastname: Mangoni
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000187:drug effects*; D017704:Baroreflex / Q000187:drug effects; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008676:Metanephrine; D008875:Middle Aged; D059289:Vascular Stiffness / Q000187:drug effects; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; D008676:Metanephrine; C104450:25-hydroxyvitamin D
keywords: 25 hydroxy vitamin D; augmentation index; baroreflex sensitivity; metanephrine; pulse wave velocity