title: Associations of blood pressure, sunlight, and vitamin D in community-dwelling adults.
abstract: Vitamin D deficiency/insufficiency is associated with hypertension. Blood pressure (BP) and circulating vitamin D concentrations vary with the seasons and distance from the equator suggesting BP varies inversely with the sunshine available (insolation) for cutaneous vitamin D photosynthesis.
  
  
  
  To determine if the association between insolation and BP is partly explained by vitamin D, we evaluated 1104 participants in the Reasons for Racial and Geographic Differences in Stroke study whose BP and plasma 25-hydroxyvitamin D [25(OH)D] concentrations were measured.
  
  
  
  We found a significant inverse association between SBP and 25(OH)D concentration and an inverse association between insolation and BP in unadjusted analyses. After adjusting for other confounding variables, the association of solar insolation and BP was augmented, -0.3.5 ± SEM 0.01 mmHg/1 SD higher solar insolation, P = 0.01. The greatest of effects of insolation on SBP were observed in whites (-5.2 ± SEM 0.92 mmHg/1 SD higher solar insolation, P = 0.005) and in women (-3.8 ± SEM 1.7 mmHg, P = 0.024). We found that adjusting for 25(OH)D had no effect on the association of solar insolation with SBP.
  
  
  
  We conclude that although 25(OH)D concentration is inversely associated with SBP, it did not explain the association of greater sunlight exposure with lower BP.
authors.affiliation: aNephrology Research and Training Center, Division of Nephrology, Department of Medicine, School of Medicine bDepartments of Biostatistics cEpidemiology, School of Public Health, The University of Alabama at Birmingham, Birmingham, Alabama dTruven Health Analytics, Ann Arbor, Michigan, USA *Current address: Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, Pennsylvania, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Rostand
authors.forename: Leslie A
authors.initials: LA
authors.lastname: McClure
authors.forename: Shia T
authors.initials: ST
authors.lastname: Kent
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Judd
authors.forename: Orlando M
authors.initials: OM
authors.lastname: Gutiérrez
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D044469:Racial Groups / Q000706:statistics & numerical data*; D013472:Sunlight; D014807:Vitamin D / Q000097:blood*
chemical_list: D014807:Vitamin D