Sunshine exposure and serum 25-hydroxyvitamin D concentrations in exclusively breast-fed infants

J Pediatr. 1985 Sep;107(3):372-6. doi: 10.1016/s0022-3476(85)80509-6.


The relationship between serum 25-hydroxyvitamin D (25-OHD) concentrations and sunshine exposure in 61 term, exclusively breast-fed infants younger than 6 months of age was investigated. Sunshine exposure was quantitated using a sunshine and clothing diary, which was verified by infant-adapted ultraviolet dosimetry. By multiple regression techniques, infant serum 25-OHD concentrations were significantly related to UV exposure and maternal serum 25-OHD concentrations. Infant 25-OHD concentrations correlated with sunshine exposure in infants whose mothers had low (less than 35 ng/ml) or high (greater than 35 ng/ml) serum concentrations of 25-OHD (r = 0.70, P less than 0.001 and r = 0.53, P = 0.004, respectively). Estimates were made to determine sunshine exposure conditions necessary to maintain serum 25-OHD concentrations above the lower limit of the normal range (11 ng/ml). A conservative estimate would be 30 minutes per week wearing only a diaper or 2 hours a week fully clothed without a hat.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Breast Feeding*
  • Calcitriol / blood*
  • Calcitriol / radiation effects
  • Female
  • Humans
  • Infant
  • Mothers
  • Rickets / prevention & control
  • Seasons
  • Socioeconomic Factors
  • Sunlight*
  • Time Factors
  • Ultraviolet Rays


  • Calcitriol