Vitamin D Toxicity / Toxicidade da Vitamina D

Abstract Fortification of food products with vitamin D was central to the eradication of rickets in the early parts of the 20th century in the United States. In the subsequent almost 100 years since, accumulating evidence has linked vitamin D deficiency to a variety of outcomes, and this has paralleled greater public interest and awareness of the health benefits of vitamin D. Supplements containing vitamin D are now widely available in both industrialized and developing countries, and many are in the form of unregulated formulations sold to the public with little guidance for safe administration. Together, this has contributed to a transition whereby a dramatic global increase in cases of vitamin D toxicity has been reported. Clinicians are now faced with the challenge of managing this condition that can present on a spectrum from asymptomatic to acute life-threatening complications. This article considers contemporary data on vitamin D toxicity, and diagnostic and management strategies relevant to clinical practice.

Resumo A suplementação de produtos alimentares com vitamina D foi fundamental para a erradicação do raquitismo no início do século XX nos Estados Unidos. Nos quase 100 anos subsequentes, o acúmulo de evidências vinculou a deficiência de vitamina D a uma variedade de desfechos, e isso tem levantado grande interesse público e conscientização dos benefícios à saúde da vitamina D. Os suplementos que contêm vitamina D estão agora amplamente disponíveis tanto nos países desenvolvidos quanto naqueles em desenvolvimento, e muitos estão na forma de formulações não regulamentadas, vendidas ao público com poucas orientações para uma administração segura. Juntos, isso contribuiu para uma transição na qual um aumento global dramático nos casos de toxicidade da vitamina D tem sido relatado. Médicos agora enfrentam o desafio de tratar essa condição que pode apresentar um espectro de complicações assintomáticas a agudas, com risco de vida. Este artigo considera dados atualizados sobre a toxicidade da vitamina D e estratégias de diagnóstico e manejo relevantes para a prática clínica.

Serological evidence of rickettsial infections in Delhi.

Background & objectives: Rickettsial infections remain under-diagnosed due to lack of diagnostic facilities in developing world. Here we present our experience at National Centre for Disease Control, Delhi, about a serosurvey done in Delhi for rickettsial disease with easy to perform low cost, low expertise Weil Felix test. Methods: On the basis of cut-off titre obtained in healthy population, Weil Felix test results were interpreted along with clinical data. Entomological investigation was also carried out in select areas of Delhi. Rodents were trapped from houses and gardens and vector mites were collected. Results: When serum samples were collected during initial 5 yr period from patients with fever of unknown origin, seropositivity was 8.2 per cent whereas when rickettsial infection was kept as one of the differential diagnosis by clinicians seropositivity increased to 33.3 per cent. Rickettsial infections detected were scrub typhus (48.2%) followed by spotted fever group (27.5%) and typhus group (6.8%) during 2005-2009. In preliminary entomological survey vector mite Leptotombidium deliense was found on rodents. Interpretation & conclusions: Our findings showed that results of Weil Felix test should not be disregarded, rather clinically compatible cases should be treated to save lives.

Sunlight exposure and development of rickets in indian toddlers.

Objective. To study the role of sunlight exposure in determining the vitamin D status of underprivileged toddlers. Methods. Height and weight were measured, clinical examination was performed, Food Frequency Questionnaire was administered and history of sunlight exposure was obtained in all (61) toddlers attending daytime crèche (Group B). Ionised calcium (iCa), inorganic Phosphorous (iP), alkaline phosphatase activity (ALP), serum parathyroid hormone (PTH) and 25 Hydroxy vitamin D (25OHD) were measured. Data were compared with results of a survey measuring similar parameters in 51 (of 251 eligible) toddlers from the same slum (Group A). Results. 111 children (mean age 2.6 yr (0.7), boys 56) were studied. Prevalence of hypovitaminosis D was 77% in group B toddlers (46 of 60) and 16.4% (10 of 61) had rickets, while none of the group A toddlers had 25OHD levels below 30nmol/L. Four children (7.8%) from Group A as against 24 (42.9%) from Group B, had sunshine exposure of < 30 minutes per day. Conclusion. Underprivileged toddlers who were deprived of sunlight had a much greater incidence of hypovitaminosis D and frank rickets. The study has important public health implications and underscores the necessity for sunlight exposure in young children.

Vitamin D &/or calcium deficiency rickets in infants & children: a global perspective.

It was only in the early part of the 20th century with the discovery of vitamin D and of the role that ultraviolet light irradiation plays in vitamin D formation that rational and appropriate therapy became available and rickets was all but eradicated in a number of developed countries. Since then, there has been a resurgence of the disease in many countries such as in Europe and the USA probably due to an increase in the prevalence of breast feeding, the immigration of dark skinned families to countries of high latitude, and the avoidance of direct sunlight because of the risk of the development of skin cancers. The disease is also widely recognised in many developing countries, including some situated in subtropical regions. Studies have led to the realization that nutritional rickets may be caused by either vitamin D or calcium deficiency, but in the majority of situations variable combinations of both probably play a role. Although low dietary calcium intakes appear to be central to the pathogenesis of rickets in Nigeria, genetic and/or other environmental factors are likely to contribute. But to date no single factor has been isolated as contributing significantly. The results of a recently conducted study suggest that in situation of low dietary calcium intakes vitamin D requirements may be higher than normal, possibly predisposing those children with vitamin D levels in the low normal range to rickets. If this is so, it would indicate that the currently accepted normal range for vitamin D sufficiency would need to be adjusted depending on dietary calcium intakes. Yet we are still unclear as to the factors which predispose some children to the disease.

Vitamin D & bone mineral density of healthy school children in northern India.

Studies on bone mineral health in children have been primarily based on clinical, biochemical and radiological evidence. Measurement of vitamin D levels and bone mass by non invasive imaging techniques like dual energy X-ray absorptiometry (DEXA), have led to a plethora of data regarding various factors responsible for bone mineral health from various countries including India. We reviewed the currently available evidence on status of calcium-vitamin D-parathormone (PTH) relationship and bone mineral density (BMD) in apparently healthy children. High prevalence of clinical and biochemical hypovitaminosis D exists in apparently healthy school children from north India. Also, children from upper socio-economic strata (USES) from Delhi had significantly higher mean BMD values at distal forearm (BMDdf) and calcameum (BMDca) than those from lower socio-economic strata (LSES). Age, nutrition, height and weight were seen to be significantly associated with BMD at peripheral sites.

Efecto de dos formas de suplementación de vitamina D en el crecimiento y metabolismo óseo del lactante / Effects of 2 ways of vitamin D supplementation on infant growth and bone metabolism

Se evaluó el efecto sobre el metabolismo óseo y crecimiento del lactante menor de suplementos de vitamina D de 600.000 UI en el primero y sexto mes (norma ministerial) ante una dosis diaria de 400 UI hasta el sexto mes, en dos grupos de lactantes normales. En controles mensuales se midieron peso, talla, circunferencia craneana, presión arterial, calcemia, fosfemia, fosfatasas alcalinas, hormona paratiroidea y 1.25 (OH)2 vit D. Se encontraron diferencias estadísticamente significativas en favor de los niños que recibían 400 UI diariamente, a contar del tercer mes en la talla, del sexto mes en el peso y del octavo mes en la circunsferencia craneana. La presión arterial fue más alta en los pacientes que recibieron megadosis semestrales de la vitamina, especialmente 30, 60, 90 y 120 días, después de la primera de ellas. La concentración plasmática media de 1,25 (OH)2 vit D fue más alta en los casos tratados con megadosis (110 y 96 pg/ml en el primero y el sexto mes respectivamente), que en los que recibía dosis diarias (55 pg/ml en el primero y sexto mes). No se encontraron diferencias en las restantes variables sanguíneas analizadas. La administración de 400 UI diarias es más fisiológica, promueve mayor crecimiento, evita riesgos de intoxicación a corto plazo y potencial a largo plazo por la hipertensión inducida a esta edad. La norma ministerial debiera ser revisada

Nutritional situation of Beijing residents.

Beijing is the capital of China with the population of 10.32 million in 1990 and the area of 1687.8 km2. It is the economic and cultural center of the country. Since the founding of new China, the development of Beijing city has been very fast. The gross national product (GNP) of Beijing in 1988 is 2.78 times the average GNP of the whole country. The sanitary institution has increased 71 times from 1949 to 1989. The prevalence of infectious diseases decreased significantly. The infant mortality is 11.6 per thousand approaching the figure of developed countries. The main food products increased rapidly. The grain, meat and egg increased from 100.7 kg and 0.48 kg per capita per year in 1949 to 217.1 kg and 20.17 kg in 1988 respectively. The food consumption of residents have been increasing consistently with the increasing of food production in Beijing. The food available in Beijing is well both in quantity and in quality. The results of the nutritional survey in 1985 showed that the daily average energy intake was 2549 kcal per capita. The average protein intake was 70g per person per day. The fat intake as the percentage of the total energy was 25.7. The average nutrients intake of Beijing residents meets the Chinese RDA basically. The nutritional status of people living in the city is good in general. But there are still some nutritional problem exist. Zn and Fe deficiencies anemia are common in infants and children along with the decreasing rate of breast feeding. Riboflavin, Zn and Ca intakes are inadequate in a lot of adults and the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)