Navegando por Palavras-chave "Latitude"

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    Correlation between 25-hydroxyvitamin D levels and latitude in Brazilian postmenopausal women: from the Arzoxifene Generations Trial
    (Springer, 2013-10-01) Arantes, H. P. [UNIFESP]; Kulak, C. A. M.; Fernandes, C. E.; Zerbini, C.; Bandeira, F.; Barbosa, I. C.; Brenol, J. C. T.; Russo, L. A.; Borba, V. C.; Chiang, A. Y.; Bilezikian, J. P.; Lazaretti-Castro, M. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Fed Parana SEMPR; ABC; Heliopolis Hosp; Univ Pernambuco UPE; Universidade Federal da Bahia (UFBA); Univ Fed Rio Grande do Sul; CCBR Brasil Clin Res Ctr; Eli Lilly & Co; Columbia Univ Coll Phys & Surg
    We investigated vitamin D status in Brazilian cities located at different latitudes. Insufficiency (<50 nmol/L) was common (17 %), even in those living in a tropical climate. Vitamin D insufficiency increased as a function of latitude. Mean 25-hydroxyvitamin D (25(OH)D) levels in each site and latitude correlation were very high (r=-0.88; p<0.0001).Introduction Inadequate vitamin D, determined by low levels of 25(OH)D, has become very common despite the availability of sunlight at some latitudes. National data from a country that spans a wide range of latitudes would help to determine to what extent latitude or other factors are responsible for vitamin D deficiency. We investigated vitamin D status in cities located at different latitudes in Brazil, a large continental country.Methods the source is the Brazilian database from the Generations Trial (1,933 osteopenic or osteoporotic postmenopausal women (60 to 85 years old) with 25(OH)D measurements). 25(OH)D below 25 nmol/L (10 ng/mL) was an exclusion criterion. Baseline values were between fall and winter. the sites included Recife, Salvador, Rio de Janeiro, São Paulo, Curitiba, and Porto Alegre. Mean and standard deviation of 25(OH)D, age, spine and femoral neck T-score, calcium, creatinine, and alkaline phosphatase were calculated for each city. Pearson correlation was used for 25(OH)D and latitude.Results Insufficiency (<50 or <20 ng/mL) was common (329 subjects, 17 %). Vitamin D insufficiency increased as a function of latitude, reaching 24.5 % in the southernmost city, Porto Alegre. the correlation between mean 25(OH)D levels in each site and latitude was very high (r=-0.88, p<0.0001).Conclusion There is a high percentage of individuals with vitamin D insufficiency in Brazil, even in cities near the equator, and this percentage progressively increases with more southern latitudes.
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    Estudo de associações entre o gene PER3 e a sincronização de ritmos circadianos pelo claro/escuro
    (Universidade Federal de São Paulo (UNIFESP), 2011-09-28) Pereira, Danyella Silva [UNIFESP]; Pedrazzoli, Mario [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Per3 gene is a component of the circadian molecular mechanism. Its function is not completely understood. One of the hypotheses is that Per3 gene may be involved in light synchronization mechanism. The aim of this project was investigate the association between Per3 gene and circadian rhythmicity dependent of the photophase duration in different light/dark cycle regimens. The experimental protocol was divided in two parts: 1. We investigated the possible mechanisms of association between Per3 gene and adaptation/duration of the photophase in Per3-/- mice by exposing the animals to different light/dark cycles with long or short photophases 2. Based on the results of experiment 1, we developed an experiment in humans in order to investigate if the results in mice were someway applicable to our population. Subjects from two locations with different latitudes were selected (Natal and São Paulo) and the experiment was carried out in two different seasons of the year to mimic photophase variation. The first part of our results suggested that Per3 gene is associated with sensitivity of masking by light. In the second part of the study, we found a phase delay in the circadian parameters analyzed (beginning and end of activity, markers of activity (M10) and temperature (M6)) in the PER35/5 group from Natal on November, when compared to the São Paulo group. Our data in mice point out a new hypothesis related to masking effect that may contribute to the understanding of Per3 gene function in the regulation of circadian rhythms and the human data show that it is possible to associate Per3 gene with the phase adjustments derived from specific characteristics of light/dark cycle in different latitudes.
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    Incidência de fraturas vertebrais e status de vitamina D em mulheres brasileiras na pós-menopausa com baixa massa óssea
    (Universidade Federal de São Paulo (UNIFESP), 2017-02-22) Arantes, Henrique Pierotti [UNIFESP]; Castro, Marise Lazaretti [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Objetivos: Determinar a incidência de fraturas vertebrais em pacientes na pós-menopausa e os fatores de risco associados e conhecer a concentração sérica de vitamina D em mulheres de Recife, Salvador, Rio de Janeiro, São Paulo, Curitiba e Porto Alegre, e sua correlação com a latitude. Métodos: Braço brasileiro do estudo Arzoxifene Generations Trial, composto por mulheres na pós-menopausa (60 a 85 anos) com baixa massa óssea. Na primeira parte do estudo foi realizada análise de novas fraturas vertebrais no grupo placebo (n = 974), com seguimento de até cinco anos. As pacientes foram divididas em 2 estratos A e B. O estrato A era composto por pacientes com osteoporose densitométrica ou osteopenia e fratura vertebral presente no basal. Já o estrato B era composto somente por pacientes com osteopenia, sem fratura vertebral no basal O desfecho primário avaliado foi incidência de fraturas vertebrais, detectadas por Raios-X. Para fratura vertebral estimada foram utilizados taxa de incidência e modelo de regressão de Poisson. A segunda parte do estudo incluiu 1.933 pacientes com dosagem de 25 hidroxivitamina D (25OHD) no basal. Média e desvio padrão foram calculados para cada cidade e a técnica de Pearson para avaliar regressão linear entre 25OHD e latitude. Resultados: Taxa de incidência calculada de fraturas vertebrais foi de 7,7 (IC 95% de 5,4 a 10,9) por 1.000 pessoas-ano, com aumento em função da idade. Variáveis correlacionadas com novas fraturas foram idade (p=0,034), T-score da coluna lombar (p=0,001) e estrato A (grupo com osteoporose ou osteopenia com fratura vertebral prevalente), p=0,001 e fraturas prévias não vertebrais após a menopausa (p=0,019). Para cada diminuição de um desvio padrão no T-score,houve aumento de 46% no risco de fraturas (RR=1,46 (IC95% 1,22 a 1,62). A insuficiência da vitamina D (<50 nmol/L ou <20 ng/mL) foi comum (17%) e aumentou em função da latitude, atingindo 24,5% em Porto Alegre. Houve alta correlação entre a média da concentração de 25OHD em cada cidade e latitude (r=−0,88, p=0,02). Para cada grau de latitude em direção ao Sul, houve queda de 0,28 ng/mL na concentração sérica média de 25OHD. Conclusões: A taxa de incidência de fraturas vertebrais foi de 7,7 por 1.000 pessoas-ano, sendo que o T-score da coluna lombar foi o mais importante preditor. Alta prevalência de insuficiência de vitamina D em mulheres brasileiras na pós-menopausa com baixa massa óssea e esse percentual aumentou em função da latitude.
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    Latitude modifies the effect size of factors related to recurrent wheeze in the first year of life
    (W B Saunders Co Ltd, 2013-05-01) Garcia-Marcos, Luis; Mallol, Javier; Solé, Dirceu [UNIFESP]; Brand, Paul L. P.; Sanchez-Bahillo, Maria; Sanchez-Solis, Manuel; EISL Study Grp; Univ Murcia; Univ Santiago Chile USACH; Universidade Federal de São Paulo (UNIFESP); Isala Klin; Univ Groningen
    Background: Although the association between latitude and asthma prevalence has been studied to a certain extent, its influence on the magnitude of the association of risk/protective factors with recurrent wheeze in infants has never been reported.Methods: the adjusted odd ratios (aOR) of various risk/protective factors for recurrent wheeze from 31 920 infants from 19 centres of the Estudio Internacional de Sibilacias en Lactantes (EISL) in very different parts of the world were used to build a meta-regression using the strength of the aOR of each factor as dependent variable and centre latitude as explanatory variable. the meta-regression was further adjusted for continent.Results: There was a positive significant correlation between latitude and the magnitude of the aOR between recurrent wheeze and having cold(s) during the first three months of life (p = 0.004); attending a nursery school (p = 0.011); and having additional siblings (p = 0.003). Furthermore, there was a negative correlation for having been breastfed for at Least three months (p = 0.044). Heterogeneity (as measured by I-2) of the magnitude of aORs between centres was quite high except for breast feeding: 73.1% for colds; 66.9% for nursery school; 52.6% for additional siblings; and 18.1% for breast feeding. Latitude explained a considerable amount of that heterogeneity: 63.8% for colds; 52.8% for nursery school; 86.6% for additional siblings; and 100% for breast feeding, probably as a consequence of its low heterogeneity.Conclusion: the magnitude in which some risk/protective factors are associated to recurrent wheeze during the first year of life varies significantly with latitude. (C) 2013 Elsevier B.V. All rights reserved.
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    Radiação solar ultravioleta e a fotoprodução de vitamina D in vitro em cidades do Nordeste e Sudeste do Brasil
    (Universidade Federal de São Paulo (UNIFESP), 2020-12-18) Leal, Angela Cristina Gomes Borges [UNIFESP]; Castro, Marise Lazaretti [UNIFESP]; Universidade Federal de São Paulo
    In order to compare the production of Vitamin D in different latitudes in Brazil, this in vitro experiment was carried out exposing glass ampoules containing vitamin D precursor (7-dehydrocholesterol) to sunlight. This model simulates human cutaneous production of vitamin D. This research was conducted concurrently in Fortaleza (latitude 3.7°S, 38.5°W, 27 m - LAT 3°S) and in São Paulo (23.5°S, 46.6°W, 760 m - LAT 23°S), exposing the ampoules to sunlight hourly from 7 a.m. to 5 p.m., one day per month, over a year. Following exposure, the vials had their content analyzed via High Performance Liquid Chromatography (HPLC) at the Vitamin D, Skin and Bone Research Laboratory at Boston University School of Medicine, which calculated the percentage conversion of 7-DHC to vitamin D3 and inactive derivatives. The analysis of the results obtained showed a greater seasonal variation in vitamin D production in LAT 23°S, while in LAT3°S the production was 19.7% higher and more stable over a year. The production corresponding to the beginning of conversion of Vitamin D in human skin could be detectable from 8 am on LAT 3°S throughout the year. However, during the winter months at LAT 23 ° S, the production of Vitamin D was much lower and started only after 10 am. The presence of cloudiness significantly impaired the formation of Vitamin D in both latitudes, even in summer months. During the warmer months of November, December and January 2012/13, there was a reduction in the efficiency of vitamin D production, mainly in LAT 23°S, in accordance with high cloud weather reports in the period. The experiment was repeated in 2014/15, when there was less cloudiness, showing significantly higher levels of vitamin D in LAT 23°S. In conclusion, latitude, season, time of day, incidence of ultraviolet B radiation and cloudiness strongly influenced Vitamin D photoconversion in vitro, outlining important regional differences. In a continental country like Brazil, this should reflect in population mean plasma 25(OH)D concentrations, suggesting that sun exposure recommendations should be particularized according to geographical conditions.