Changes in bone mineral density and markers of bone remodeling during lactation and postweaning in women consuming high amounts of calcium.
A randomized clinical intervention trial to determine effects of lactation and 1 g of calcium (Ca) on bone remodeling was conducted in 15 women (calcium = 7, placebo [P] = 8) consuming 1.3-2.4 g of Ca/day from diet + prenatal supplement. Study periods were baseline, < or = 2 weeks postpartum; lactation, 3 months lactation; and postweaning, 3 months postweaning. Bone mineral density (BMD) corrected for body weight was determined by dual-energy X-ray absorptiometry (DXA). Indicators of calcium metabolism, bone turnover, and lactation were measured: calcium metabolism, parathyroid hormone (PTH), 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH]2D); bone turnover, formation, procollagen I carboxypeptides (PICP), osteocalcin, and bone alkaline phosphatase (B-ALP), resorption, tartrate resistant acid phosphatase (TRAP); and lactation, prolactin (PRL). Mean BMD changes differed by site: baseline to lactation -4.3% (P) (p < 0.04) and -6.3% (Ca) (p < 0.01) at the lumbar spine (L2-L4) and 5.7% gains of the ultradistal (UD) radius (Ca) (p < 0.04); lactation to postweaning, -6% to -11% at all sites of the radius and ulna (Ca, P) (p < 0.04) +3% at L2-L4 (Ca) (p < 0.03); baseline to postweaning, (UD) radius -5.2% (P) (p < 0.03), UD radius + ulna -6% to -8% (Ca, P) (p < 0.04) but no significant loss of L2-L4 or total body. Bone turnover markers were higher at lactation than postweaning: PICP (+34%, p < 0.001), osteocalcin (+25%, p < 0.01), TRAP (+11%, p < 0.005) as well as PRL (+81%, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Cross
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NA
Department of Food Science and Human Nutrition, University of Missouri, Columbia, USA.
Hillman
L S
LS
Allen
S H
SH
Krause
G F
GF
D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000737:chemistry; D015519:Bone Density / Q000187:drug effects*; D016723:Bone Remodeling / Q000187:drug effects*; D002118:Calcium / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007774:Lactation / Q000187:drug effects*; D009752:Nutritional Status; D014886:Weaning
D015415:Biomarkers; D002118:Calcium