a1 Central Laboratory for Clinical Chemistry, University Hospital Groningen, Oostersingel 59, PO Box 30.001, 9700 RB Groningen, The Netherlands
a2 Retired Professor of Paediatrics, Rijksstraatweg 65, 9752 AC Haren, The Netherlands
a3 Department of Internal Medicine, University Hospital Groningen, The Netherlands
a4 Hoofdweg 86, 9761 EK Eelde, The Netherlands
a5 Department of Internal Medicine, St Elisabeth Hospital, Willemstad, Curaçao, The Netherlands Antilles
To study the effect on plasma 25-hydroxycholecalciferol (25(OH)D), 1,25-dihydroxycholecalciferol (1,25(OH)2D) and parathyroid hormone (PTH) we supplemented premenopausal (aged 30 (SD 7) years) and postmenopausal (aged 61 (SD 2) years) white women living in The Netherlands in late winter/early spring, and elderly black and white women (aged 75 (SD 6) years) living in Curacao (Dutch Antilles) with either 10 or 20µpg cholecalciferol/d for 4, 5 and 9 weeks respectively. Baseline plasma 25(OH)D concentration of Dutch women was lower than that of Curacao women. Postmenopausal Dutch women had a higher PTH concentration in plasma than premenopausal Dutch and postmenopausal Curaçao women. There were no differences in plasma 1,25(OH)2D. Cholecalciferol administration increased 25(OH)D in all groups, 1,25(OH)2D in postmenopausal Curaçao women and PTH in postmenopausal Curaçao women and premenopausal Dutch women. Serum and urinary Ca and phosphate concentrations did not change. There were no response differences between 10 and 20 µg doses. Oral cholecalciferol administration (either 10 or 20 µg/d) to women living at northern latitudes in late winter/early spring increased 25(OH)D levels to the baseline levels of elderly people living in the tropics.
(Received March 06 1995)
(Revised July 05 1995)
(Accepted August 08 1995)
* Professor Jonxis died on 26 July 1995.
† For reprints.