CURRENT DIET DOES NOT RELATE TO BONE-MINERAL DENSITY AFTER THE MENOPAUSE

The influence of dietary Ca on peak bone mass and on subsequent bone l oss is controversial. Despite this an assessment of nutritional status is often included in the clinical evaluation of osteoporosis risk. To assess the value of this we investigated the relationship between cur rent diet and bone mineral density (BMD) in 426 postmenopausal women, aged 45-69 years, who were enrolled into an international multi-centre trial of alendronate for the prevention of postmenopausal osteoporosi s. BRID of the lumbar spine and proximal femur was measured on two occ asions approximately 2 weeks apart by dual-energy X-ray absorptiometry . Serum osteocalcin was measured by immunoradiometric assay and serum 25-hydroxycholecalciferol by radioimmunoassay. Dietary assessment was performed by analysis of a 3 d unweighed dietary record, using Salford University's Microdiet software. BMD at both the lumbar spine and fem oral neck correlated significantly with BMI, age, and average serum os teocalcin concentration. We therefore corrected for these variables in subsequent analyses. Dietary Ca intake ranged from 223 to 2197 mg/d ( median 852 mg/d). Neither dietary Ca intake nor any other nutritional variable correlated significantly with BMD. There was a weak, but sign ificant correlation between Ca intake and serum osteocalcin. We conclu de that current diet does not correlate with BMD in early postmenopaus al women. However, present diet may affect the rate of change of BMD, and this is supported by the finding of a significant relationship bet ween dietary Ca and serum osteocalcin, a marker of bone formation rate .