Michel Fuss

Prevalence of zinc deficiency and its clinical relevance among hospitalised elderly

Zinc is an essential trace element, and constituent of many metallo-enzymes required for normal metabolism. Age may be associated with altered metallothionein metabolism related to changes in zinc metabolism. The objectives of this study were: (i) to assess the prevalence of zinc deficiency among hospitalised elderly patients; (ii) to define the social, functional, pathological and nutritional characteristics of zinc deficient elderly hospitalised patients; and (iii) to assess the relationship between the zinc status and humoral immune function among hospitalised elderly patients. Fifty consecutive patients underwent comprehensive geriatric assessments included evaluations of the medical (index of the severity of the disease(s)), psychiatric (Geriatric depression scale (GDS)), therapeutic, social, functional (Katzs scale), and nutritional problems (Mini Nutritional Assessment (MNA) and biochemical markers (zinc, albumin, prealbumin (PAB), cholesterol) before their discharge. Fourteen patients (28%) presented a zinc concentrations lower than 10.7 micromol/l, this value is usually considered as the cut-off level below which a zinc deficient status is possible. Higher proportions of respiratory infections, cardiac failure, and depression were observed among zinc deficient patients as compared with the group of patients with normal zinc status. The other parameters of comprehensive geriatric assessment did not allow to discriminate the zinc deficient patients. The only slight differences (which remained unsignificant) concerned the prealbumin levels which tended to be higher in the group of patients presenting normal zinc status than in the group with poor zinc status (0.208+/-0.062 versus 0.171+/-0.068 g/l respectively, P=0.06), and the IgG2 levels which tended to be lower in the group of patients with normal zinc status than in the group presenting poor zinc status (2.77+/-1.91 versus 4.06+/-2.56, respectively, P=0.057). A negative correlation was observed between the Zn concentrations and the IgG2 levels (Spearman R=-0.311, P=0.028). To the best of our knowledge, this is the first study presenting zinc status according to a comprehensive geriatric assessment among European hospitalised geriatric patients. We decided to perform this study to known whom of our patients needed to be supplemented with zinc administration. Considering the low energy intake of hospitalised patients (confirmed here in regards of the nutritional assessment), and the insufficient trace element density in European foods, the relevance of providing medical supplements or enriched foods to this population has to be evaluated. Although most of the current diseases may be relevant to long-term interactions between nutrition and ageing, certain states observed in the elderly, like impaired immune and cognitive functions, could still benefit from an appropriate nutritional supplementation.

Calcium and vitamin D metabolism in granulomatous diseases

SummaryOverproduction of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D) has been described in sarcoidosis and other granulomatous diseases. High circulating concentrations of 1,25(OH)2D lead to increased intestinal absorption of calcium, possibly to enhanced bone resorption, and may result in hypercalcaemia and/or hypercalciuria. Data obtained in vivo and in vitro demonstrated that the unregulated production of 1,25(OH)2D lies within the granulomatous tissue and is controlled by glucocorticoids. This abnormal production of 1,25(OH)2D seems to be a general phenomenon of granulomatous processes, which is not exceptional in sarcoidosis, but appears seldom in tuberculosis. These abnormalities, however, are not pathognomonic of granulomatous processes, since they have been described in other diseases such as lymphomas.

CORRECTION OF LOW CIRCULATING LEVELS OF 1,25-DIHYDROXYVITAMIN D BY 25-HYDROXYVITAMIN D DURING REVERSAL OF HYPOMAGNESAEMIA

The effect of 25‐hydroxyvitamin D (250HD), given orally during the reversal of hypomagnesaemia, was studied in five patients with hypomagnesaemic hypocalcaemia and low serum levels of 25OHD and 1,25‐dihydroxyvitamin D (1,25(OH)2D). The results were compared to those obtained in five other patients with similar initial levels of magnesium, calcium, 25OHD and 1,25(OH)2D who did not receive 25OHD. Serum levels of 1,25(OH)2D in the ten hypomagnesaemic patients were lower than in ten control subjects with low serum levels of 25OHD. The reversal of hypomagnesaemia was similar in the two groups of patients and elicited a similar increase of circulating iPTH levels. The expected increase of circulating 25OHD was observed in patients supplemented with 25OHD; their circulating 1,25(OH)2D rose within 48 h to normal levels, contrasting with the delayed and poor increase of 1,25(OH)2D in patients receiving no 25OHD. The evolution of serum calcium was however identical in the two groups. Our results suggest that vitamin D deficiency was a significant factor leading to low circulating levels of 1,25(OH)2D in hypomagnesaemic hypocalcaemic patients. The biological consequences of low serum 1,25(OH)2D in these patients remain unclear, but clearly, normal levels of 1,25(OH)2D are not essential for the correction of hypomagnesaemic hypocalcaemia.

Parathyroid Hormone Plasma Level in Untreated Chronic Renal Failure and in Hemodialyzed Patients

In 42 untreated patients at various stages of chronic renal failure, plasma level of parathyroid hormone was directly proportional to the degree of renal failure and inversely proportional to the serum calcium level. Plasma parathyroid hormone levels were frequently elevated in 21 patients undergoing regular dialysis treatment, in spite of normal levels of serum total calcium and magnesium. Serum-ionized calcium levels measured in dialyzed patients were usually reduced and inversely correlated with the creatinine levels. Parathyroid hormone levels were correlated with the creatinine levels, but the inverse relationship with ionized calcium was not significant.

Parathyroid Hormone and Calcium Blood Levels in Acute Renal Failure

Parathyroid hormone (PTH), creatinine, calcium and phosphate blood levels were repeatedly measured in 5 patients with acute renal failure. 1 patient developed hypercalcemia during the recovery phase o

Paget's disease of bone: five regimens of pamidronate treatment.

SummaryThe efficacy of five therapeutic regimens using (3-amino-1-hydro-xypropylidene)-1,1-bisphosphonate (APD or pamidronate) was assessed in patients with Pagets disease of bone. These regimens were as follows: (a) pamidronate 600 mg/day given orally during six months; (b) iv infusion of 20 mg daily for 10 days; (c) iv infusion of 40 mg daily for 5 days; (d) iv infusion of 10 mg daily for 4 days and (e) a single iv infusion of 10 mg. Six months after the initiation of therapy, urinary excretion of hydroxyproline and serum alkaline phosphatase activity (expressed as percent of their initial value) were: Group a: 30±10 (mean±SE) and 30±6, Group b: 55±8 and 46±6, Group c: 54±7 and 57±6, Group d: 53±7 and 69±4, and Group e: 85±10 and 98±4 respectively. Oral route was accompanied by digestive intolerance. On the contrary, except for rare and transient “flu-like syndromes”, the iv treatment was not associated with any serious secondary effect. Intravenous infusion of pamidronate, 20 mg for 10 days or 40 mg for 5 days, appears as an interesting alternative to the oral route in the treatment of Pagets disease of bone.

Comparison between the fractional isotopic calcium absorption and an oral calcium tolerance test

SummaryIn 27 subjects with several disorders of calcium metabolism, the fractional intestinal absorption of47CaCl2 was rather poorly correlated with the urinary output of calcium or with the maximal increase of serum calcium after an oral calcium load. Conversely, a good correlation was observed with the product of these parameters. We propose that this product be used as an estimate of intestinal calcium absorption when a radioisotopic method is not available.

Evolution of parathyroid hormone and calcitonin plasma levels during haemodialysis and following renal transplantation.

SummaryCreatinine, calcium (Ca), phosphate, immuno-reactive parathyroid hormone (i PTH) and calcitonin (i CT) blood levels were measured before and after haemodialysis (HD) in 24 patients submitted to regular dialysis treatment, and in the days following successful renal transplantation (RT) in other patientsi PTH and i CT levels were elevated before HD; the rise of plasma Ca following HD was accompanied by a decrease in i PTH (P < 0.001), whereas i CT was increased, though not significantly.The levels of i PTH and i CT, elevated before RT, returned to normal after RT, together with creatinine and P levels; a rejection after some days in 2 patients was followed by a rapid increase in i PTH and i CT levels. One patient who underwent subtotal parathyroidectomy 281 days after RT because of persistent hypercalcaemia and high i FTH levels is also presented.