Lactose absorption, milk consumption, and fasting blood glucose concentrations in women with idiopathic osteoporosis.

Lactose tolerance tests were performed in 33 women with osteoporosis and 33 control women matched for age. A questionnaire was used to elicit any history of milk intolerance and the subjects' daily intake of calcium derived from milk and dairy products. Eleven patients and four controls gave a history of milk intolerance (p less than 0.01); 13 patients had lactose malabsorption compared with four controls (p less than 0.01). The daily intake of calcium derived from milk was significantly lower in patients (125 (SEM 20) mg v 252 (43) mg; p less than 0.05). Curves of blood glucose concentrations during the lactose tolerance test in subjects with lactose malabsorption were significantly flatter in patients than controls (p less than 0.05). The fasting blood glucose concentration was higher (5.44 (0.17) mmol/l (98 (3) mg/100 ml) in the patients than the controls (4.88 (0.11) mmol/l (88 (2) mg/100 ml); p less than 0.05), although body weight was significantly lower (61.6 (2.2) kg v 66.3 (1.6) kg; p less than 0.05). Absorption of lactose is significantly impaired in women with "idiopathic" osteoporosis; this combined with low consumption of milk and a subclinical disorder of glucose metabolism may be a major factor in the development of idiopathic osteoporosis in women.