title: Does degree of baldness influence vitamin D status?
abstract: OBJECTIVE
  To determine the association, if any, between male-pattern hair loss (baldness) and serum 25-hydroxyvitamin D (25-OHD) levels.
  
  
  METHODS
  A cross-sectional study of 296 healthy middle-aged and older men.
  
  
  METHODS
  Degree of baldness was independently assessed by two researchers using the Hamilton-Norwood scale and serum 25-OHD was measured in all men.
  
  
  RESULTS
  Classification of the degree of baldness by the two researchers showed a high level of agreement (kappa = 0.93). Forty-eight per cent of men had no hair loss or mild frontotemporal recession, 15% had predominant vertex loss, and 37% had significant scalp and vertex loss. After data were adjusted for potential confounding factors - including age, month of 25-OHD measurement, exercise levels, use of sunscreen, skin type and frequency of outdoor hat wearing - no significant differences in 25-OHD levels between these groups was detected (P = 0.60).
  
  
  CONCLUSIONS
  The degree of baldness does not appear to influence serum 25-OHD levels. The high prevalence of baldness in older men does not explain sex differences in 25-OHD levels. Other novel hypotheses are required to help determine whether baldness serves any physiological purpose.
authors.affiliation: Department of Medicine, University of Auckland, Auckland, New Zealand. m.bolland@auckland.ac.nz
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Bolland
authors.forename: Ruth W
authors.initials: RW
authors.lastname: Ames
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Grey
authors.forename: Anne M
authors.initials: AM
authors.lastname: Horne
authors.forename: Barbara H
authors.initials: BH
authors.lastname: Mason
authors.forename: Greg D
authors.initials: GD
authors.lastname: Gamble
authors.forename: Ian R
authors.initials: IR
authors.lastname: Reid
mesh_terms: D000328:Adult; D000505:Alopecia / Q000097:blood* / Q000145:classification; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D