title: Unexpected long-term effects of calcium supplementation in pregnancy on maternal bone outcomes in women with a low calcium intake: a follow-up study.
abstract: BACKGROUND
  Calcium supplementation of pregnant Gambian women with a low calcium intake results in lower maternal bone mineral content in the subsequent lactation.
  
  
  OBJECTIVE
  The objective was to investigate whether the lower bone mineral content persists long term.
  
  
  METHODS
  All women in the calcium supplementation trial (International Trial Registry ISRCTN96502494) who had been scanned with dual-energy X-ray absorptiometry at 52 wk of lactation (L52; n = 79) were invited for follow-up when neither pregnant nor lactating for ≥3 mo (NPNL) or at 52 wk postpartum in a future lactation (F52). Bone scans and anthropometric and dietary assessments were conducted.
  
  
  RESULTS
  Sixty-eight women participated (35 at both NPNL and F52 and 33 at only one time point): n = 59 NPNL (n = 31 calcium, n = 28 placebo) and n = 44 F52 (n = 24 calcium, n = 20 placebo). The mean (±SD) time from L52 was 4.9 ± 1.9 y for NPNL and 5.0 ± 1.3 y for F52. Size-adjusted bone mineral content (SA-BMC) was greater at NPNL than at L52 in the placebo group (P ≤ 0.001) but not in the calcium group (P for time-by-group interaction: lumbar spine, 0.002; total hip, 0.03; whole body, 0.03). No significant changes in SA-BMC from L52 to F52 were observed in either group. Consequently, the lower SA-BMC in the calcium group at L52 persisted at NPNL and F52 (P ≤ 0.001): NPNL (lumbar spine, -7.5 ± 0.7%; total hip, -10.5 ± 1.0%; whole body, -3.6 ± 0.5%) and F52 (lumbar spine, -6.2 ± 0.9%; total hip, -10.3 ± 1.4%; whole body, -3.2 ± 0.6%).
  
  
  CONCLUSIONS
  In rural Gambian women with a low-calcium diet, a calcium supplement of 1500 mg/d during pregnancy resulted in lower maternal bone mineral content in the subsequent lactation that persisted long term. This trial was registered at www/controlled-trials.com/mrct/ as ISRCTN96502494.
authors.affiliation: Medical Research Council Keneba, Keneba, The Gambia.
authors.forename: Landing M A
authors.initials: LM
authors.lastname: Jarjou
authors.forename: Yankuba
authors.initials: Y
authors.lastname: Sawo
authors.forename: Gail R
authors.initials: GR
authors.lastname: Goldberg
authors.forename: M Ann
authors.initials: MA
authors.lastname: Laskey
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
authors.forename: Ann
authors.initials: A
authors.lastname: Prentice
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000009:adverse effects* / Q000172:deficiency; D002136:Calcium, Dietary / Q000009:adverse effects* / Q000627:therapeutic use; D003677:Deficiency Diseases / Q000517:prevention & control; D004032:Diet; D019587:Dietary Supplements / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D005714:Gambia; D006615:Hip; D006801:Humans; D007774:Lactation / Q000187:drug effects* / Q000378:metabolism; D008159:Lumbar Vertebrae; D011247:Pregnancy; D011248:Pregnancy Complications / Q000517:prevention & control; D055815:Young Adult
chemical_list: D002136:Calcium, Dietary; D002118:Calcium
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