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Osteoporosis International

, Volume 13, Issue 1, pp 83–88 | Cite as

Relationships Between Intestinal Calcium Absorption, Serum Vitamin D Metabolites and Smoking in Postmenopausal Women

  • A. G. Need
  • A. Kemp
  • N. Giles
  • H. A. Morris
  • M. Horowitz
  • B. E. C. Nordin
Original Article

Abstract:

Smoking has been associated with low bone density, fractures and poor intestinal calcium absorption. Calcium absorption is a critical factor in calcium balance in postmenopausal women but the mechanisms causing decreased absorption efficiency in postmenopausal smokers are controversial and poorly defined. We performed a cross-sectional study of 405 postmenopausal women attending a clinic for the management of osteoporosis to compare intestinal calcium absorption efficiency, serum vitamin D metabolites and parathyroid hormone levels in postmenopausal women who had never smoked, who were smokers previously or who were current smokers, to examine the relationships between these variables in smokers. Two hundred and fifty-two of the women had never smoked, 79 had smoked previously and 74 were current smokers. The hourly fractional rate of calcium absorption was similar in non-smokers and those who had previously smoked. Radiocalcium absorption was less in the 74 smokers compared with the 331 non-smokers [0.60 (0.29 SD) vs 0.71 (0.27); p= 0.004], as were serum calcitriol (p<0.001) and parathyroid hormone (PTH) (p<0.01). There was no difference in the relationship between calcium absorption and serum calcitriol between smokers (r= 0.38) and non-smokers (r= 0.28); hence the impaired calcium absorption in the smokers was almost entirely attributable to suppression of the PTH–calcitriol endocrine axis. In postmenopausal women smoking is associated with a reduction in calcium absorption efficiency due to suppression of the PTH–calcitriol axis. This impairment of calcium absorption could lead to accelerated bone loss and limit the usefulness of dietary calcium supplementation.

Key words:Calcium absorption – Parathyroid hormone – Postmenopausal women – Serum calcitriol – Smoking – Vitamin D 

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Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2002

Authors and Affiliations

  • A. G. Need
    • 1
  • A. Kemp
    • 3
  • N. Giles
    • 3
  • H. A. Morris
    • 2
  • M. Horowitz
    • 3
  • B. E. C. Nordin
    • 1
  1. 1.The Division of Clinical BiochemistryAU
  2. 2.Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide,AU
  3. 3.Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, AustraliaAU

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