Metabolic bone disease and the elderly: current approach to diagnosis and therapy

Serum concentration and dietary intake of Mg and Ca in institutionalized elderly people

We determined the serum levels and the dietary intake of Mg and Ca in 93 institutionalized elderly people (24 men and 69 women) in Granada (Spain). The serum samples had mean concentrations of 21.39 +/- 2.08 mg/l magnesium and 93.39 +/- 9.24 mg/l calcium. No significant differences were found in the serum levels of the two minerals as regards the sex of the subjects. Application of linear regression analysis to the serum Mg and Ca levels showed a statistically significant positive correlation (P < 0.05). A low vitamin D intake of these subjects (51.8% of the recommended dietary allowance) was observed. The intakes of Ca and Mg correlated positively together, as well as with the intakes of energy, protein, fibre (in the case of Mg only), iron and phosphorus (P < 0.05). The Ca and energy intake were adequate to their current recommendations, as too was the Ca:P ratio, whereas the diet had a poor supply of fibre, vitamin D and Mg.

Endurance training and bone loss in calcium-deficient and ovariectomized rats

We examined interactions among physical training, estrogen deficiency, and calcium deficiency with respect to the maintenance of femoral bone in five groups of 10 to 11-month-old female Fischer 344 rats: sedentary intact, sedentary ovariectomized, trained intact, trained ovariectomized, and control. All rats, except controls, were maintained on a calcium-deficient diet (0.02%) for 8 weeks, and had lower femoral weight, density, ash weight, and ash weight/volume than control rats. Ovariectomy combined with calcium deficiency decreased bone density more than did calcium deficiency alone. Treadmill training for 8 weeks resulted in an increase in maximal functional capacity, endurance time, heart weight and heart/body weight and attenuated the decrease in femoral density observed when ovariectomy and calcium deficiency both were present such that it was similar to that observed in calcium deficiency alone. We concluded that calcium-deficient ovariectomized rats undergo some of the bone changes characteristic of osteoporosis, and of these changes, a decrease in femoral density was attenuated by endurance training.