Research on the probable cause of an outbreak of field rickets in turkeys

An outbreak of field rickets in turkeys prompted studies on the cause. In Experiment 1, there were four treatments with two replicate pens of 10 poults per pen. The treatments consisted of poults fed newly manufactured feed (control), poults fed a diet containing control feed and 5% clean litter, poults fed control feed and 5% litter from the pens of affected poults, and poults challenged with an intestinal homogenate by gavage. Field rickets did not develop with these treatments. The feed was suspect, and, in Experiment 2, poults were either fed the suspect feed or newly manufactured feed. There were four replicate pens of 25 poults per pen. Poults fed the suspect feed had a decrease (P < or = 0.05) in BW at 1, 2, 3, and 4 wk of age; an increase in the relative weight of the liver, pancreas, kidney, and bursa of Fabricius; and a decrease in bone ash. There were changes in clinical chemistries. In the third study, there were five dietary treatments with two replicate pens of 25 poults per treatment. The treatments consisted of poults fed newly manufactured feed; new feed mixed with 25, 50, or 75% suspect feed; or 100% suspect feed. Body weights of poults fed 100% suspect feed were decreased at 2, 3, and 4 wk as was the relative weight of the liver, pancreas, and bursa of Fabricius. The relative weight of the kidney increased. Lameness, a decrease in bone ash, and changes in hematology and blood chemistry were observed in the poults consuming 100% suspect feed. These data demonstrate that feed from the original outbreak could induce field rickets and was toxic. Because the feed contained adequate vitamin D, calcium, and phosphorus, the cause of this outbreak of field rickets is thought to be a toxic feed contaminant affecting bone development.

A high prevalence of metabolic bone disease in exclusively breastfed very low birthweight infants in Dar-es-Salaam, Tanzania

Metabolic bone disease (MBD), or rickets, is common in very low birthweight infants. A descriptive, cross-sectional, hospital-based study was carried out at Muhimbili Medical Centre, Dar-es-Salaam from 15 April to 30 June, 1995 to discover the magnitude, contributory factors, morbidity and suitable biochemical diagnostic tests for MBD. One hundred infants with a postnatal age of 6-12 weeks, whose birthweights were 1500 g or less were studied. Thirty-three of 100 (33%) infants, 16 boys and 17 girls, were radiographically diagnosed as having metabolic bone disease. The mean (SD) gestational age of those infants was 30.4 (2.7) weeks, while that of the infants without metabolic bone disease was 32.4 (3) weeks (p = 0.003). There was no significant difference in birthweight, serum calcium and serum phosphate levels between those infants with MBD and those without. The mean (SD) serum alkaline phosphatase in infants with MBD was 1052.9 (493.3) U/l and 766.8 (301.7) in those without MBD (p = 0.006). Thus, metabolic bone disease is common in very low birthweight infants. Wrist radiography and serum alkaline phosphatase levels remain important diagnostic tools. MBD should be considered seriously in very low birthweight infants.

Incidence of rickets of prematurity at Kenyatta National Hospital, Nairobi

BACKGROUND

Reports of osteopaenia/rickets of prematurity are on the increase due to improved survival rates of low birthweight infants.

OBJECTIVE

To establish the incidence of rickets of prematurity by the age of six months in premature infants born at Kenyatta National Hospital, Nairobi.

DESIGN

Prospective cohort study.

SETTING

Newborn unit and paediatric outpatient follow up clinic of Kenyatta National Hospital.

SUBJECTS

Successive surviving infants of birthweight less than 2000 g residents in Nairobi.

RESULTS

Incidence of rickets of prematurity by six months of age was 58.8%. Rickets appeared more commonly in male infants compared to female infants.

CONCLUSION

Rickets of prematurity is a common problem in the premature infants seen at Kenyatta National Hospital. Routine vitamin D supplements to premature infants in adequate doses of at least 400iu per day should be adopted in our centre.

Vitamin D deficiency rickets at birth in Kuwait

In the present study vitamin D deficiency rickets has been diagnosed within 24 hrs. of birth. Seventy five full term, otherwise healthy newborns, weighing more than 2.5 kg were born with rachitic rosary. 25-Hydroxyvitamin D was lower than normal in 56 newborns and 15 mothers. Alkaline phosphatase was higher than normal in 26 and radiological changes suggestive of rickets were seen in the wrist X ray of only 14 newborns. Hyperphosphataemia was present in all the newborns. 1,25 dihydroxyvitamin D was markedly increased in six out of ten newborns.

A case-control study on determinants of rickets

A case-control study on rickets was performed on 156 cases and 307 controls admitted to Birla pediatric wards, Yekatit 12 Hospital. The following factors were significantly (p < 0.05) associated with diagnosis of rickets in univariate analysis: male gender, being a twin, abnormal birth weight, malnutrition, higher birth order, higher number of siblings, having a caretaker who is not the mother, lower education of the caretaker, having a caretaker who is not housewife, and with protective effect, exposure to sunshine (in number of days per week, duration of daily exposure in minutes, and not wearing clothes during exposure). In multivariate analysis, the following factors remained independently associated with diagnosis of rickets in children: being a twin (OR = 5.86, 95% CI = 1.40-24.50), history of high birth weight (OR = 8.94, 95% CI = 2.30-34.70), moderate and severe malnutrition (OR = 5.64, 95% CI = 2.30-13.80 for severe malnutrition when compared to normal weight), having the grand mother as caretaker (OR = 19.80, 95% CI = 3.70-104.70), and with protective effect, exposure to sunshine (OR associated with an increase of one day of exposure per week = 0.65, 95% CI 0.55-0.77; OR associated with daily exposure of more than 30 minutes, when compared to less than 15 minutes = 0.24, 95% CI = 0.09-0.64; and OR associated with being nude while exposed to sunshine = 0.32, 95% CI = 0.14-0.73). There was no significant difference between cases and controls in marital status or religion of the caretakers.

Effects of different levels of vitamins A and E on the utilization of cholecalciferol by broiler chickens

Three experiments were conducted to determine the effects of high dietary levels of vitamins A and E on the utilization of cholecalciferol by broiler chicks. In Experiment 1, chicks were fed six levels of vitamin A (5,000, 10,000, 20,000, 40,000, 80,000, and 160,000 IU/kg). Cholecalciferol (vitamin D3) was not added to the basal diet but all birds were exposed to ultraviolet (UV) fluorescent light. Body weight was decreased only at levels of vitamin A of 80,000 IU/kg or above. In Experiment 2, birds were exposed to UV fluorescent light or no UV light, two levels of dietary vitamin A (1,500 and 45,000 IU/kg) and three levels of dietary vitamin D3 (0, 500, and 2,500 IU/kg) in a 2 x 2 x 3 factorial arrangement. The high level of vitamin A reduced (P < 0.001) bone ash but only at a marginal level of vitamin D3 (500 IU/kg) and when the birds were not exposed to UV light. In Experiment 3, birds were exposed to UV fluorescent light or no UV light, two levels of dietary vitamin E (10 and 10,000 IU/kg) and three levels of dietary vitamin D3 (0; 500 and 2,500 IU/ kg) in a 2 x 2 x 3 factorial arrangement. The high level of vitamin E significantly (P < 0.05) reduced body weight, bone ash, plasma calcium, and increased rickets but only at 500 IU/kg of vitamin D3. Feeding 2,500 IU/kg of vitamin D3 overcame the effects of the high level of vitamin E, causing a significant (P < 0.05) interaction. Ultraviolet light also prevented the detrimental effects of the high level of vitamin E. The results of these studies indicate that high dietary levels of vitamins A and E negatively affected the utilization of vitamin D3 only when D3 was present at a marginal level (500 IU/kg) in the diet but not when it was synthesized in the bird by exposure to UV light or supplemented at 2,500 IU/kg in the diet.

The influence of vitamin A on the utilization and amelioration of toxicity of cholecalciferol, 25-hydroxycholecalciferol, and 1,25 dihydroxycholecalciferol in young broiler chickens

Three experiments were conducted to determine the influence of vitamin A on the utilization and amelioration of toxicity of cholecalciferol (vitamin D3), 25-hydroxycholecalciferol [25-(OH)D3], and 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] in young broiler chicks. Two levels of vitamin A (1,500 and 45,000 IU/kg or 450 and 13,500 microg) were fed in all experiments. In Experiment 1, chicks were fed six levels of vitamin D3 (0, 5, 10, 20, 40, and 80 microg/kg). High dietary vitamin A decreased bone ash (P < 0.001), and increased the incidence of rickets (P < or = 0.02). Linear and quadratic responses to vitamin D3 levels were significant (P < 0.01) for body weight, bone ash, incidence and severity of rickets, and plasma calcium. In Experiment 2, six levels of 25-(OH)D3 (0, 5, 10, 20, 40, and 80 microg/kg) were added to the basal diet. Adding 25-(OH)D3 increased (P < 0.001) body weight, bone ash, and plasma calcium, and decreased rickets and plasma vitamin A. Adding 25-(OH)D3 overcame the reduction in bone ash produced by high dietary vitamin A showing a significant (P < 0.02) interaction. In Experiment 3, six levels of 1,25-(OH)2D3 (0, 2, 4, 8, 16, and 32 microg/kg) were added to the basal diet. High dietary vitamin A increased (P < 0.01) the incidence and severity of rickets. Adding 1,25-(OH)2D3 increased (P < 0.01) body weight, bone ash, plasma calcium, and reduced rickets and plasma and liver vitamin A. Adding 1,25-(OH)2D3 overcame the reduction in bone ash, and the increase in rickets produced by high vitamin A was significant (P < or = 0.05). These results indicate that high dietary vitamin A (45,000 IU/kg) interferes with the utilization of vitamin D3, 25-(OH)D3 and 1,25-(OH)2D3, increasing the requirement for each of them. Moreover, 45,000 IU/kg of dietary vitamin A ameliorated the potential toxic effects of feeding high levels of vitamin D3, 25-(OH)D3 and 1,25-(OH)2D3 to young broiler chickens. Further work is necessary to find the minimum levels of these vitamins needed to cause these effects.

Case-control study of the role of nutritional rickets in the risk of developing pneumonia in Ethiopian children

BACKGROUND

Pneumonia is the most important cause of morbidity and mortality in children aged under 5 years worldwide. Studies in developing countries have suggested an association between nutritional rickets and pneumonia. Since both nutritional rickets and pneumonia are common in Ethiopia, we did a case-control study to determine the role of nutritional rickets in the development of pneumonia.

METHODS

Cases were children younger than 5 years admitted to the Ethio-Swedish Children's Hospital during a 5-year period with a diagnosis of pneumonia (n = 521), but data were incomplete for 21 of these and they were not included. Controls (n = 500) were matched for admission within 3 months of cases and age within 3 months and had no evidence of pneumonia. Nutritional, demographic, and clinical and radiographic data for rickets and pneumonia were collected. Matched odd ratios and logistic regression were used to test the significance of the association of rickets and pneumonia.

FINDINGS

Rickets was present in 210 of 500 cases compared with 20 of 500 controls (odds ratio 22.11). There were significant differences between cases and controls for family size, birth order, crowding, and months of exclusive breastfeeding (p < 0.05). After correction for these confounding factors by logistic regression, there was still a 13-fold higher incidence of rickets among children with pneumonia than among controls (13.37 [95% CI 8.08-24.22], p < 0.001).

INTERPRETATION

Vitamin D or calcium deficiency may be important predisposing factors for pneumonia in children aged under 5 years in developing countries. Efforts to prevent vitamin D deficiency or calcium supplementation may result in significant reductions in morbidity and mortality from pneumonia in these children.

Rickets and protein malnutrition in northern Nigeria

The aim of the study was to explore the relationship between protein nutritional status and the development of rickets in children living in northern Nigeria. The diagnosis of rickets in 16 children between the ages of 10 months and 7 years was confirmed using established, and recently developed clinical and biochemical parameters. Twenty-seven children devoid of skeletal stigmata were age- and sex-matched to the rachitic patients. A battery of clinical laboratory and anthropometric measurements designed to assess calcium homeostasis, skeletal growth, the extent of bone remodeling or resorption, and protein nutritional status were performed on all subjects. Our central finding was that although the rachitic children were moderately malnourished, their protein nutritional status was significantly better as measured by the serum prealbumin concentration (15.4 v. 12.5 mg/dl, P = 0.0012) when compared with the severely malnourished children who were devoid of any indication of rickets. This may be due, in part, to the fact that actively growing children are more likely to develop rickets than are children whose linear growth is impeded. Unexpectedly, we found that the mean concentrations of serum 1,25-dihydroxyvitamin D in both the rachitic and control group were higher than any values for the active vitamin D metabolite previously reported in the literature.

Effect of 1,25-dihydroxycholecalciferol, cholecalciferol, and fluorescent lights on the development of tibial dyschondroplasia and rickets in broiler chickens

Experiments were conducted to determine whether dietary 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] will alleviate a cholecalciferol deficiency induced by low dietary cholecalciferol and no fluorescent lighting and to determine cholecalciferol requirements as influenced by fluorescent lighting or 1,25-(OH)2D3. In each study, nutritionally complete basal diets were fed to broiler cockerels from 1 to 16 d of age. Experiment 1 had a 2 x 2 x 2 factorial arrangement of treatments with 1,25-(OH)2D3 at 0 and 10 micrograms/kg, cholecalciferol at 2.75 and 27.5 micrograms/kg, and fluorescent lights on or off. Experiments 2 to 4 had four levels of dietary cholecalciferol (0, 5.0, 27.5, and 50.0 micrograms/kg) and fluorescent lights on or off (Experiment 2) or 1,25-(OH)2D3 at 0 and 10 micrograms/kg (Experiments 3 and 4). In Experiment 1, fluorescent lighting increased bone ash, and decreased the incidence and severity of rickets at 2.75 micrograms/kg cholecalciferol and 0 microgram/kg 1,25-(OH)2D3 and reduced the severity of TD at both levels of cholecalciferol and 0 microgram/kg 1,25-(OH)2D3. In all cases 1,25-(OH)2D3 improved bone ash. The metabolite also decreased the incidence and severity of TD at both cholecalciferol levels with lights off and decreased the incidence and severity of rickets at 2.75 micrograms/kg cholecalciferol and lights off. In the absence of fluorescent lighting and 1,25-(OH)2D3 27.5 micrograms/kg cholecalciferol reduced the incidence and severity of rickets to levels equivalent to those produced by either fluorescent lighting or 1,25-(OH)2D3 alone (Experiments 2, 3, and 4). However, even 50.0 micrograms/kg cholecalciferol was not as effective as fluorescent lights or 1,25-(OH)2D3 in reducing the incidence and severity of TD.

Autosomal dominant hypophosphatemic rickets/osteomalacia: clinical characterization of a novel renal phosphate-wasting disorder

Renal phosphate-wasting disorders are the most common form of hereditary rickets and osteomalacia in western countries. Although autosomal dominant transmission of renal phosphate wasting has been described, previous studies included too few affected individuals to adequately characterize the disorder. We performed clinical and biochemical evaluations of individuals from a large kindred with autosomal dominant hypophosphatemic rickets/osteomalacia. We identified 23 affected members in this family, and for some individuals, follow-up was up to 25 yr. As patients were all members of the same kindred, we had the opportunity to determine the clinical manifestations of the disorder in patients who presumably all have the same genetic mutation. Affected individuals have isolated renal phosphate wasting and inappropriately normal serum calcitriol concentrations. The inheritance pattern was consistent with autosomal dominant transmission with variable penetrance. The family contained two subgroups of affected individuals. Group 1 consisted of patients who presented with renal phosphate wasting as adolescents or adults. These patients presented with bone pain, weakness, and insufficiency fractures, but did not manifest lower extremity deformity. Group 2 consisted of patients who presented with phosphate wasting, rickets, and lower extremity deformity as children. Surprisingly, some individuals in group 2 lost the renal phosphate-wasting defect after puberty. In conclusion, autosomal dominant hypophosphatemic rickets/osteomalacia is an inherited disorder of isolated renal phosphate wasting. The spectrum of disease includes delayed onset of penetrance and loss of the renal phosphate-wasting defect. Our results have implications in the evaluation of patients who present with renal phosphate wasting as either adults or children.

Evidence of increased cholecalciferol requirement in chicks with tibial dyschondroplasia

A series of experiments was conducted to test the hypothesis that vitamin D utilization may not be as efficient in chicks with tibial dyschondroplasia (TD). The basal diet contained 1.0% Ca and 0.45% available P with no supplemental cholecalciferol (D3). Chicks from low TD (LTD) and high TD (HTD) selected lines were fed diets supplemented with various levels of vitamin D compounds and examined for rickets and TD. When chicks were fed a D3-deficient diet containing only 1.25 micrograms/kg added D3, HTD chicks had a greater incidence of severe rickets than LTD chicks (P < 0.05). The LTD chicks did not exhibit TD when fed a diet containing adequate (20 micrograms/kg) D3. The LTD chicks fed a diet supplemented with 5 micrograms/kg D3, however, had 22% incidence of TD. When HTD chicks were fed diets supplemented with 5 micrograms/kg D3 [control diet that meets NRC (1994) requirement for D3], 20 micrograms/kg D3, 5 micrograms/kg 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] or the combination of both D3 (20 micrograms/kg) and 1,25-(OH)2D3 (5 micrograms/ kg), TD incidence was highest in HTD chicks fed the control diet. When HTD chicks were fed diets with an increased dietary level of 1,25-(OH)2D3 (10 micrograms/kg) further reduction of TD incidence (P < 0.05) occurred. A potentially toxic level (Soares et al., 1983) of 1,25-(OH)2D3 (15 micrograms/kg) fed to HTD chicks resulted in still greater suppression of incidence of TD even though growth and feed intake in HTD chicks was greater than those of LTD chicks. It is concluded that the development of TD in HTD chicks is associated with subnormal ability to metabolize vitamin D.

Rickets and soil strontium

The subjects of this study were children aged 6-60 months living in villages in the Ulas Health Region, Sivas. The villages were divided into two groups according to the amount of strontium in the soil: region 1, > 350 ppm, 650 children; region 2, < 350 ppm, 1596 children. Overall, the prevalence of one or more clinical signs of rickets was 22.9%. The prevalence in region 1 was 31.5% and that in region 2, 19.5%. These values were significantly different (p < 0.001). When other variables which may be relevant to the occurrence of rickets were taken into account, the difference in prevalence persisted. The results suggest that in villages where nutrition is mainly based on grain cereals the presence of strontium in the soil will increase the prevalence of rickets significantly. As a preventive measure, a greater proportion of the foods given to children in these villages should be derived from animal origin, and cereals and drinking water supplies should be obtained from villages with a low soil strontium content, or calcium supplements should be given.

Prevalence and risk factors for asymmetric posture in preschool children aged 6-7 years

BACKGROUND

Adult scoliosis can be a severe disease. Not much is known about its determinants and the predictive value of early trunk asymmetries. In Vilnius, Lithuania, a cohort study has been started among 6-7 year old children in 1994. The purpose of the present report was to estimate the prevalence of trunk asymmetry in 6-7 year old children, and the association between previous rachitis, frequent illness during childhood and reduced physical activity and trunk asymmetry.

METHODS

The degree of asymmetry was established in 791 children in kindergartens by measuring with a ruler the distance from the seventh cervical vertebra to the lower angles of the left and the right scapulas. Rachitis and the number of illnesses were extracted from each child's medical card, whereas data on physical activity were based on questionnaires filled in by parents and kindergarten teachers.

RESULTS

In all, 46.9% of children were found to have trunk asymmetry. The odds ratio of asymmetric posture was 2.76 (95% confidence interval [CI]: 1.62-4.72) for children with rachitis degree II compared to non-rachitic children, 3.97 (95% CI: 2.48-6.36) for those who were ill 16-28 times (over the years) compared to those who reported fewer than nine illnesses and 2.44 (95% CI: 1.21-4.91) for children with low physical activity level (13-22 points) as compared to children with a high level (> 33 points).

CONCLUSION

These findings indicate the need for prophylactic measures to decrease the incidence of infantile rachitis, acute morbidity and to increase physical activity. The significance of the high frequency of asymmetric posture can only be assessed by a follow-up of this cohort.

Minnesota rickets. Need for a policy change to support vitamin D supplementation

Vitamin D deficiency rickets, once considered the most common disease of early childhood, was reported to have disappeared by the 1960s. However, during a recent 18-month period, seven cases of nutritional rickets were diagnosed in the Twin Cities metropolitan area. All of the patients were born at term and were breastfed without supplementation vitamins. Three of the patients were Caucasian, three were African American, and one was biracial. This case series demonstrates the risk of nutritional rickets in breastfed infants in our northern climate, regardless of race. In hopes of eradicating this completely preventable disease, we advocate a uniform policy of vitamin D supplementation to breastfed infants.

Etiology of rickets in Nigerian children

We studied 26 Nigerian children with active rickets (13 boys, 13 girls), aged 1 to 5 years, and compared results of biochemical studies with those of healthy control subjects. The plasma 1,25-dihydroxyvitamin D level was elevated (568 +/- 317 pmol/L) and the 25-hydroxyvitamin D level was (36 +/- 28 mol/L) in the children with rickets compared with the control subjects (369 +/- 134 nmol/L and 69 +/- 22 nmol/L, respectively). The results suggest that rickets in Nigeria is largely the result of calcium deficiency and that vitamin D deficiency and possibly end organ resistance may be contributory factors.