Endocrine Abstracts

If calcium intake and absorption are insufficient plasma calcium is maintained but bone loss ensues. The relationship between calcium intake and parathyroid hormone (PTH) levels in serum of 186 women (mean age 62.4 years) with bone mineral density >2.5 SD below the young adult value and 586 age-matched controls with normal bone mineral density was studied.

The approximate calcium intake from dairy products was assessed by a simple questionnaire. All 772 women were tested for intact serum PTH by Elecsys immunometric assay (all PTH results are ng/L).

86.6% of the osteoporotic women had a low calcium intake compared with 32.8% of the control women.

The low and moderate intake osteoporotic patients had significantly higher PTH levels, mean 58.7 and 50.2 respectively than the high intake osteoporotic patients 45 and the control patients, low intake 42, moderate intake 38, high intake 39.

14 out of 586 (2.4%) of the control group have PTH above the reference range compared with 40 out of the 186 (21.5%) of the osteoporotic group (reference range for the assay 12-72ng/L).

Conclusion: PTH was raised in osteoporotics with low or moderate intake of dairy products. No significant relationship was shown between dairy product consumption and PTH levels in women with normal bone mineral density.

Secondary hyperpararthyroidism was common in this osteoporotic population. This was associated with a low calcium intake which was demonstrated by a simple questionnaire.