the patients had had pathological fractures. All patients except one had a daily calcium intake of less than 50 mg daily, and a dietary vitamin D intake ofless than 50 IU daily. One patient was taking regular supplements of vitamin D. All had plasma urea and creatinine concentrations within the normal range for our laboratory. Seventeen age and sex matched healthy volunteers were also studied as controls. All controls had body weights within 10% of the average body weight appropriate for height (Geigy Scientific Tables).A fasting venous blood sample was collected from each patient without stasis. Blood was allowed to clot and centrifuged immediately at 4°C. Serum was aliquoted and stored a -20°C for PTH, 25 OHD, and 1,25(OH)2D assays. Plasma calcium and albumin concentrations, and phosphate, and alkaline phosphatase activities were measured by a SMAC Technicon autoanalyser (Technicon, Baskingstoke, UK).Serum 25 OHD was measured by the method described by Preece et al 'and PTH was measured by a radioimmunoassay with an antibody directed against the mid molecular fragment of PTH as described by Roos et al 4; 17f estradiol was measured by a double antibody radioimmunoassay. 1,25(OH)2D was measured by the method described by Reinhardt et al.5

SUMMARY.Plasma calcium, serum 25 hydroxyvitamin 0 [25(OH)D], 1,25 dihydroxyvitamin D[I,25(OH)2D] and parathyroid hormone (PTH) have been measured in pregnant and newborn Caucasians and Asians. Calcium and 25(OH)D concentrations were lower in Caucasian than in Asian women at all four stages (three trimesters and during labour) of pregnancy. PTH concentrations were greater in Asian than in Caucasian women during the three trimesters, but not at labour, and increased in both groups through pregnancy, without a concomitant change in plasma calcium concentrations. There was a significant inverse correlation between calcium and PTH, as well as 25(OH)D and PTH, concentrations. These data demonstrate the presence of progressive 'hyperparathyroidism' during pregnancy in Caucasian and Asian women. The higher PTH concentrations in Asian women may reflect the necessity of maintaining adequate plasma calcium concentrations through PTH-induced osteolysis in the face of vitamin 0 deficiency. Relative hyperparathyroidism in Asians may contribute to net loss of calcium from the skeleton and osteopenia in Asian women. Calcium, 25(OH)D and 1,25(OHhD concentrations were lower, and those of PTH higher, in Asian newborns compared with Caucasian newborns. Serum 1,25(OHhD concentrations in the Asian newborn, though lower than respective maternal levels, were comparable with normal adult levels, indicating that 1,25(OHhD biosynthesis is stimulated in the Asian newborn to compensate for the low serum 25(OH)D concentrations.It has been demonstrated that asymptomatic Asian immigrants in the United Kingdom may have subclinical hypovitaminosis 0 and secondary hyperparathyroidism.i":' It has also been shown that the concentrations of 25 hydroxyvitamin 0 [25(OH)D] in cord blood are significantly lower than those in maternal serurn.v" These facts raise the possibility that secondary hyperparathyroidism may be frequent in Asian women during pregnancy, and that these women's infants may also have secondary hyperparathyroidism. It has previously been suggested that serum concentrations of PTH increase during pregnancyr':" this Correspondence: Dr P Dandona, Metabolic Unit, Department of Chemical Pathology and Human Metabolism, Royal Free Hospital, Pond Street, London NW3 20G, UK. 22 observation has, however, been challenged by other workers.?'!" To our knowledge, there is only one previous study which has compared 25(OH)D and PTH concentrations in the serum of pregnant Caucasian and Asian women. I I In this study, radioimmunoassays of PTH were carried out by the method of Rosselin et al. ,12 and failed to detect any differences in serum PTH between Asian and Caucasian women. Since we and others, using more recent radioimmunoassay methodology, 1-] have reported frequent secondary hyperparathyroidism in non-pregnant Asians, it is clear that 25(OH)D-calcium-PTH relationships during pregnancy need to be re-examined. Finally, no data are available about 1,25 dihydroxyvitamin D [1,25(OHhD] concentrations in Asian and Caucasian women at term and their ne...

No abstract

The relationship among serum vitamin D metabolites, PTH, and osteocalcin concentrations was investigated in 20 elderly subjects. All except 2 had subnormal 25-hydroxyvitamin D concentrations. Eighteen (90%) had subnormal serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentrations, while 8 subjects (40%) had elevated PTH concentrations. There was a highly significant inverse relationship between PTH and 1,25-(OH)2D concentrations. Serum osteocalcin concentrations were not elevated in any subject, and in fact, the mean osteocalcin concentration was in the lower part of the normal range. These data indicate no compensatory increase in 1,25-(OH)2D in response to secondary hyperparathyroidism and no increase in osteocalcin in response to hypersecretion of PTH in the elderly. These 2 defects may contribute to the bone disease of the elderly.

Prior to the widespread use of continuous glucose monitoring (CGM), knowledge of the effects of exercise in type 1 diabetes (T1D) was limited to the exercise period, with few studies having the budget or capacity to monitor participants overnight. Recently, CGM has become a staple of many exercise studies, allowing researchers to observe the otherwise elusive late post-exercise period. We performed a strategic search using PubMed and Academic Search Complete. Studies were included if they involved adults with T1D performing exercise or physical activity, had a sample size greater than 5, and involved the use of CGM. Upon completion of the search protocol, 26 articles were reviewed for inclusion. While outcomes have been variable, CGM use in exercise studies has allowed the assessment of post-exercise (especially nocturnal) trends for different exercise modalities in individuals with T1D. Sensor accuracy is currently considered adequate for exercise, which has been crucial to developing closed-loop and artificial pancreas systems. Until these systems are perfected, CGM continues to provide information about late post-exercise responses, to assist T1D patients in managing their glucose, and to be useful as a tool for teaching individuals with T1D about exercise.

SUMMARY In view of the high incidence of rickets in infants of women practising purdah (the use of veils) in northern Nigeria we conducted a study on plasma calcium, phosphate, and serum 25-hydroxyvitamin D (25 OHD) concentrations in pregnant Nigerian women and in cord blood obtained from the newborns. Plasma calcium, phosphate, and serum 25 OHD concentrations were lower in practising women and their newborns than those not practising purdah and their infants, respectively. The concentrations of 25 OHD in all Nigerian woman were greater than those observed in caucasian women in the United Kingdom. These data emphasise the role of exposure to sunshine in regulating serum 25 OHD concentrations and the adverse effect of deliberate exclusion of sunshine and are consistent with previous data indicating hypovitaminosis D in purdah clad women and their newborns in Saudi Arabia. These data do not, however, provide an explanation for the pathogenesis of the high incidence of neonatal rickets and -tetany in infants born of purdah clad woman as these women have 25 OHD concentrations greater than those in caucasian women in the United Kingdom.The religious practice of purdah (the use of veils by women) has recently been shown to be associated with a high prevalence ofvitamin D malnutrition in women in Saudi Arabia. ' 2 As infants of Muslim women practising purdah in northern Nigeria are known to develop neonatal tetany and congenital rickets3'4 whereas infants of non-purdah women do not present with such problems, we examined the possibility that the practice of purdah may cause vitamin D malnutrition in Nigerian women. This is important as hypovitaminosis D during pregnancy is related to the occurrence of myopathy and pathological fractures in women' and neonatal tetany and rickets in infants.68 It may also be associated with secondary hyperparathyroidism in neonates.9 As expected, women practising purdah and their infants had noticeably lower serum 25-hydroxyvitamin D (25 OHD) concentrations than those who did not and their newborns. Despite this difference the concentrations of 25 OHD in these women were appreciably greater than those found in caucasian and Asian women in the United Kingdom. These observations raise some important and fundamental questions about the pathogenesis of the high incidence of rickets in infants of women practising purdah in Nigeria.Accepted for publication 23 January 1986 Material and methods Twenty non-Muslim non-purdah woman and 10Muslim women who had been kept indoors in purdah throughout their pregnancies were included in this investigation. The blood samples were obtained from women attending the Universities of Ilorin, Benin, and Ife Teaching Hospitals in Nigeria. A clear history of having been confined in purdah before and during pregnancy was obtained from these women; most of them had been covered in thick dark dresses and veils during the pregnancies. Detailed information obtained from the mothers included dietary and religious practices, confinement in purdah, family history of ...

Vitamin D and parathyroid hormone concentrations were assessed in 31 adults with cystic fibrosis (mean age 24, range 17-52 years), in 28 of whom the bone mineral index in the forearm was also determined. Serum 25-hydroxyvitamin D was subnormal in eight patients, of whom five were receiving vitamin D supplements in standard doses. 1,25-dihydroxyvitamin D and parathyroid hormone concentrations showed no consistent abnormalities. The bone mineral index was lower in patients with cystic fibrosis (p < 002) than in controls. Five patients with unequivocally reduced bone mineral index had a subnormal mean serum 25-hydroxyvitamin D and significantly worse lung function than the other patients. There was a positive correlation between age and bone mineral index (r = 0X68, p < 0X001). Thus a significant proportion of patients with cystic fibrosis living in a temperate climate are at risk of vitamin D deficiency. Osteopenia is common and is probably related to a combination of hypovitaminosis D, delay in puberty, hypo-oestrogenism in women, and reduced physical activity, rather than to secondary hyperparathyroidism. Since most patients with deficiency of25-hydroxyvitamin D were receiving oral supplements, parenteral vitamin D supplementation may be appropriate for selected patients who are unable to maintain adequate 25-hydroxyvitamin D concentrations despite oral vitamin D supplements.

No abstract