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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vertebral mineral density, measured by computerized axial tomography, radiocalcium absorption, serum dehydroepiandrosterone (DHA), and serum cortisol (C) were measured in 98 postmenopausal women aged 56-70 yr. On the basis of spine radiographs and fracture history, the women were classified into 49 normal subjects (mean age, 60.5 yr) and 49 with osteoporosis (mean age, 63.1 yr). Vertebral mineral density (VMD), radiocalcium absorption (alpha), serum DHA, and the ratio of DHA to cortisol (DHA/C) were all significantly lower in the osteoporotic than in the normal subjects. DHA was significantly related to C in both groups but the regression was significantly flatter in the osteoporotic than in the normal subjects. Calcium absorption did not fall significantly with age in either group. In the normal group VMD, DHA, and DHA/C fell with age but VMD was not related to alpha, DHA, or DHA/C. In the osteoporotic group, VMD did not fall significantly with age but was significantly related to alpha and DHA/C. Stepwise regression analysis showed that in the normal subjects, age was the only variable significantly related to VMD (P less than 0.05). In the osteoporotic group, calcium absorption was the main determinant of VMD, with age and DHA/C contributing much less to the variance. Discriminant function analysis showed a theoretical misclassification of 45% of cases using DHA, 39% using DHA/C, 32% using alpha, and 18% when alpha and DHA or DHA/C were both taken into account. It is concluded that malabsorption of calcium is a significant risk factor for postmenopausal osteoporosis, probably because of a secondary increase in bone resorption to maintain serum calcium. The severity of the osteoporosis is directly related to the severity of the calcium malabsorption. Low serum DHA appears to represent a further risk factor, either because of its role as estrogen precursor or (possibly) because it promotes bone formation. However, the severity of the osteoporosis was not related to the serum DHA level and only weakly to the DHA/C ratio.
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PMID:The relation between calcium absorption, serum dehydroepiandrosterone, and vertebral mineral density in postmenopausal women. 315 44

Fractures of the proximal femur are the most dangerous complications of type-II-osteoporosis with a high rate of disability and mortality. In contrast to type-I-osteoporosis, men are affected rather frequently (ratio 1:3). We report on a 79-year old man who was completely in need of care after bilateral fractures of the humerus after having survived a previous pertrochanteric fracture of the left femur. Diagnostic procedures revealed that in this case an intestinal malabsorption has to be taken into consideration as a pathogenetic factor of this severe osteopathy. Bone biopsy confirmed a combination of osteoporosis and osteomalacia. Partial gastrectomy, which had been performed 10 years before, was obviously the reason for malabsorption having caused furthermore pernicious anemia, severe malnutrition and exsiccosis.
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PMID:[Disabling senile osteoporosis]. 323 54

Metabolic bone disease, particularly osteoporosis, is a complication of advanced primary biliary cirrhosis, but the extent of the problem is unclear. We present 33 patients who were investigated for bone disease at the time of diagnosis of their liver disease and who had received no prior treatment likely to influence their bones. Iliac crest bone biopsy showed no patient with osteoporosis, and mild osteomalacic changes in 1 patient. Slight elevations in appositional rate, osteoid volume, and resorption surface were compatible with a state of high bone turnover. Photon absorptiometry revealed a low forearm bone mineral content in 3 of 25 patients, calcium absorption was below normal in 14 of 24 patients, and there was evidence of fat malabsorption in 11 of 25 patients. Five patients also had low serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D. Thus, little evidence of significant metabolic bone disease was found in this group by these methods, but abnormalities were seen, such as poor calcium absorption, that may predispose to its later development.
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PMID:Metabolic bone disease in primary biliary cirrhosis at presentation. 333 17

A premenopausal woman with severe osteoporosis was found to have impaired calcium absorption, without other evidence of intestinal malabsorption. Although circulating levels of 25-OH-vitamin D and 1,25-(OH)2-vitamin D were normal, calcium absorption improved markedly following two weeks of treatment with synthetic 1,25-(OH)2-vitamin D. This suggests that a partial intestinal resistance to the actions of 1,25-(OH)2-vitamin D contributed to the development of her osteoporosis. This case report demonstrates the feasibility of using the calciuric response to a standard oral calcium load to screen for impaired calcium absorption in osteoporotic patients.
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PMID:Premenopausal osteoporosis associated with vitamin D-responsive calcium malabsorption. A case report. 366 94

The incidence of lactase deficiency, evaluated by means of a lactose absorption test with blood glucose measurements, was compared in a group of 58 women suffering from postmenopausal osteoporosis and a control group of 51 normal women of the same age and ethnic origin. In the patients suffering from osteoporosis, the examination was completed by a glucose-galactose absorption test and in the control group by a hydrogen breath test. The prevalence of lactase deficiency is of approximately the same magnitude in the two groups (25.8% and 33.3% respectively). Dietary investigations showed a calcium intake superior to 1 g per day in only 40% of the osteoporotic patients, this deficiency being more important in cases where lactase deficiency was observed than in those showing normal lactose absorption. The influence of lactose malabsorption on the calcium balance, and the role of the latter in the pathogenesis of osteoporosis, are discussed.
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PMID:[Incidence of lactase deficiency in patients with involution osteoporosis and in normal subjects. Its effect on the nutritional intake of calcium and phosphorus]. 368 31

Although calcium supplements are widely used to reduce bone resorption in osteoporosis, their beneficial effect is not conclusively established. We have studied the acute (after 12 h) effects of an oral calcium load (1 g) in a group of 35 osteoporotic postmenopausal women, comprising 19 subjects with normal absorption and 16 subjects with malabsorption of calcium. In the subjects with normal calcium absorption the fasting urinary total hydroxyproline/creatinine ratio fell from 0.021 to 0.017 (p less than 0.001), but in those with malabsorption of calcium it did not change significantly. This difference between the two groups was significant (p less than 0.01). These results indicate that an oral calcium load rapidly suppresses bone resorption in osteoporotic subjects with normal absorption of calcium, but not in those with malabsorption of calcium.
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PMID:Biochemical effects of a calcium supplement in osteoporotic postmenopausal women with normal absorption and malabsorption of calcium. 369 89

This chapter reviews the pathogenesis of disordered divalent mineral and bone metabolism in alcoholism, emphasizing the role of impaired vitamin D physiology. Normally, vitamin D metabolites are derived principally from cholecalciferol, which is synthesized in the skin via the energy of sunlight. Most alcoholics have subnormal levels of 25-hydroxyvitamin D [25(OH)D]. Those with Laennec's cirrhosis also have low levels of vitamin D binding protein due to impaired hepatic protein synthesis and as a result, have low serum concentrations of total, but not free, 1,25-dihydroxyvitamin D. The causes of 25(OH)D deficiency in alcoholics include reduced hepatic 25-hydroxylase activity, lack of sun exposure, inadequate dietary intake, and malabsorption. Hypomagnesemia and hypophosphatemia, which are very common in hospitalized alcoholics, result from deficient intake, malabsorption, excessive renal losses, and cellular uptake of both ions. Hypocalcemia in alcoholics is caused primarily by hypoalbuminemia but can result also from deficient intake, malabsorption, hypomagnesemia, and renal calcium wastage. Low vitamin D activity may contribute significantly to the calcium and phosphate deficiencies. Osteoporosis is extremely common in alcoholics whereas osteomalacia is exceptional. However, both bone disorders respond well to vitamin D therapy. Thus, alcoholics should be screened periodically for vitamin D deficiency and osteopenia, and when either is detected they should receive vitamin D supplements.
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PMID:Disorders of divalent ions and vitamin D metabolism in chronic alcoholism. 375 48

To investigate the pathogenesis of osteoporosis in male hypogonadism we have investigated a heterogeneous group of 13 men with hypogonadism: 7 men (median age 60, range 31-79) with two or more vertebral crush fractures and 6 men (median age 61.5, range 28-76) without vertebral fractures. The group with crush fractures had trabecular and cortical osteoporosis as assessed by Singh grade, iliac crest trabecular bone volume, and metacarpal cortical area/total area. This was accompanied by an altered trabecular architecture with a reduction in number of trabeculae but no change in trabecular width, which contrasts with age-related bone loss in men where there is no reduction in trabecular number but thinning of trabeculae. The fracture group had significantly lower plasma 1,25-dihydroxyvitamin D [1,25(OH)2D] concentrations than the nonfracture group, and this was associated with malabsorption of calcium. Irrespective of the presence or absence of osteoporosis, treatment with testosterone led to a significant increase in total and free plasma 1,25(OH)2D and an improvement in calcium absorption measured with radiocalcium and by balance techniques. In addition, urine biochemistry, metabolic balance studies, and bone biopsy suggest that skeletal retention of calcium and bone formation are increased by testosterone treatment. We conclude that male hypogonadism causes both cortical and trabecular osteoporosis and altered trabecular architecture. A major risk factor for the development of osteoporosis is reduction in plasma 1,25(OH)2D, leading to malabsorption of calcium and reduced bone formation.
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PMID:Osteoporosis in hypogonadal men: role of decreased plasma 1,25-dihydroxyvitamin D, calcium malabsorption, and low bone formation. 376 4

The prevalence of lactase deficiency and the relationship between lactose and calcium malabsorption in postmenopausal osteoporosis has been assessed in 46 subjects. Malabsorption of lactose occurred in 25 (54%) of the subjects and was associated with a significantly lower milk intake. Malabsorption of calcium occurred in 11 (44%) of the lactase-deficient subjects and in 11 (52%) of normal lactose absorbers. There was no relationship between lactose and calcium malabsorption. Vertebral and forearm mineral densities were not significantly different between normal lactose absorbers and lactase-deficient subjects.
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PMID:Lactose and calcium absorption in postmenopausal osteoporosis. 382 31

We have studied some effects of small doses of 1,25-dihydroxycalciferol (calcitriol) and calcium, either combined or separately, in 45 patients with osteoporosis and malabsorption of calcium. In 24 patients on 0.25 micrograms/d of calcitriol the hourly fractional rate of radiocalcium absorption rose from 0.37 +/- 0.02 to 0.55 +/- 0.04 (p less than 0.001) and in 21 patients on 0.50 micrograms/d it rose from 0.36 +/- 0.02 to 0.69 +/- 0.05 (p less than 0.001). These responses were seen within 5 days and were not increased further at 6 weeks to 3 months. The combined therapy significantly reduced the fasting urinary hydroxyproline/creatine ratio (OHPr/Cr) and plasma alkaline phosphatase activity (ALP) in 6-12 weeks, the smaller dose of calcitriol (0.25 micrograms/d) being as effective as the larger one (0.50 micrograms/d) in this respect. Calcium alone (1 g/d) had no effect and calcitriol alone (0.25 mcg/d) had a lesser effect on both OHPr/Cr and ALP than the combined therapy. The falls in OHPr/Cr and ALP tended to be greatest in the cases with the highest initial levels but constituted only partial suppression of these variables towards the theoretical non-bone components. These results suggest that treatment with calcitriol and calcium suppresses bone resorption in osteoporosis associated with malabsorption of calcium and is more effective than calcium or calcitriol given alone.
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PMID:1,25-Dihydroxycalciferol and calcium therapy in osteoporosis with calcium malabsorption. Dose response relationship of calcium absorption and indices of bone turnover. 383 58


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