Cutoff point estimation for serum vitamin D concentrations to predict cardiometabolic risk in Brazilian children

2020 ◽  
Vol 74 (12) ◽  
pp. 1698-1706
Author(s):  
Luana Cupertino Milagres ◽  
Mariana De Santis Filgueiras ◽  
Naruna Pereira Rocha ◽  
Lara Gomes Suhett ◽  
Fernanda Martins de Albuquerque ◽  
...  
2020 ◽  
Author(s):  
Elahe Allahyari ◽  
Parichehr Hanachi ◽  
Seyed Jamal Mirmoosavi ◽  
Gordon A. Ferns ◽  
Afsane Bahrami ◽  
...  

Abstract BackgroundAccumulating data have highlighted the prominence of supplementation as an effective approach for vitamin D deficiency. But individuals vary in their response to vitamin D supplementation. In this study, the effect of cardiometabolic risk factors were evaluate on magnitude of response to vitamin D supplementation by using novel statistical analysis, artificial neural networks(ANNs).Methods608 participants aged between 12 to 19 years old were assed in this prospective interventional study. Nine vitamin D capsules containing 50000IU vitamin D/weekly were given to all participants over the 9 week period. The change in serum 25(OH)D level was calculated as the difference between post-supplementation and basal levels. Suitable ANNs model were selected between different algorithms in the hidden and output layers and different numbers of neurons in the hidden layer. Then, the major determinants in predicting response to vitamin D supplementations were identified (Trial registration: IRCT201509047117N7; 2015-11-25; Retrospectively registered)ResultsSigmoid in both hidden and output layers with 4 hidden neurons had acceptable sensitivity, specificity and accuracy area under the ROC curve in our study. Baseline serum vitamin D (30.4%), waist to hip ratio (10.5%), BMI (10.5%), systolic blood pressure (8%), heart rate (6.4%), and waist circumference (6.1%) were the greatest importance in predicting the response in serum vitamin D levels. ConclusionWe provide the first attempt to relate anthropometric specific recommendations to attain serum vitamin D targets. With the exception of cardiometabolic risk factor, the relative importance of other factors and the mechanisms by which these factors may affect the response requires further analysis in future studies.


Author(s):  
Habibesadat Shakeri ◽  
Seyed-Javad Pournaghi ◽  
Javad Hashemi ◽  
Mohammad Mohammad-Zadeh ◽  
Arash Akaberi

AbstractBackground:The changes in serum 25-hydroxyvitamin D (25(OH)D) in adolescents from summer to winter and optimal serum vitamin D levels in the summer to ensure adequate vitamin D levels at the end of winter are currently unknown. This study was conducted to address this knowledge gap.Methods:The study was conducted as a cohort study. Sixty-eight participants aged 7–18 years and who had sufficient vitamin D levels at the end of the summer in 2011 were selected using stratified random sampling. Subsequently, the participants’ vitamin D levels were measured at the end of the winter in 2012. A receiver operating characteristic (ROC) curve was used to determine optimal cutoff points for vitamin D at the end of the summer to predict sufficient vitamin D levels at the end of the winter.Results:The results indicated that 89.7% of all the participants had a decrease in vitamin D levels from summer to winter: 14.7% of them were vitamin D-deficient, 36.8% had insufficient vitamin D concentrations and only 48.5% where able to maintain sufficient vitamin D. The optimal cutoff point to provide assurance of sufficient serum vitamin D at the end of the winter was 40 ng/mL at the end of the summer. Sex, age and vitamin D levels at the end of the summer were significant predictors of non-sufficient vitamin D at the end of the winter.Conclusions:In this age group, a dramatic reduction in vitamin D was observed over the follow-up period. Sufficient vitamin D at the end of the summer did not guarantee vitamin D sufficiency at the end of the winter. We found 40 ng/mL as an optimal cutoff point.


BMC Nutrition ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Elahe Allahyari ◽  
Parichehr Hanachi ◽  
Seyed Jamal Mirmoosavi ◽  
Gordon A.Ferns ◽  
Afsane Bahrami ◽  
...  

Abstract Background There are increasing data highlighting the effectiveness of vitamin D supplementation in the treatment of vitamin D deficiency. But individuals vary in their responsiveness to vitamin D supplementation. In this study, the association between several cardiometabolic risk factors and the magnitude of response to vitamin D supplementation (change in vitamin D level) was investigated using a novel artificial neural networks (ANNs) approach. Methods Six hundred eight participants aged between 12 to 19 years old were recruited to this prospective interventional study. Nine vitamin D capsules containing 50,000 IU vitamin D/weekly were given to all participants over the 9 week period. The change in serum 25(OH) D level was calculated as the difference between post-supplementation and basal levels. Suitable ANNs model were selected between different algorithms in the hidden and output layers and different numbers of neurons in the hidden layer. The major determinants for predicting the response to vitamin D supplementation were identified. Results The sigmoid in both the hidden and output layers with 4 hidden neurons had acceptable sensitivity, specificity and accuracy, assessed as the area under the ROC curve, was determined in our study. Baseline serum vitamin D (30.4%), waist to hip ratio (10.5%), BMI (10.5%), systolic blood pressure (8%), heart rate (6.4%), and waist circumference (6.1%) were the most important factors in predicting the response to serum vitamin D levels. Conclusion We provide the first attempt to relate anthropometric specific recommendations to attain serum vitamin D targets. With the exception of cardiometabolic risk factors, the relative importance of other factors and the mechanisms by which these factors may affect the response requires further analysis in future studies (Trial registration: IRCT201509047117N7; 2015-11-25; Retrospectively registered).


2020 ◽  
Vol 90 (3-4) ◽  
pp. 346-352
Author(s):  
Vincenzo Pilone ◽  
Salvatore Tramontano ◽  
Carmen Cutolo ◽  
Federica Marchese ◽  
Antonio Maria Pagano ◽  
...  

Abstract. We aim to assess the prevalence of vitamin D deficiency (VDD) in patients scheduled for bariatric surgery (BS), and to identify factors that might be associated with VDD. We conducted a cross-sectional observational study involving all consecutive patients scheduled for BS from 2017 to 2019. The exclusion criteria were missing data for vitamin D levels, intake of vitamin D supplements in the 3 months prior to serum vitamin D determination, and renal insufficiency. A total of 206 patients (mean age and body mass index [BMI] of 34.9 ± 10.7 years, and 44.3 ± 6.99 kg/m2, respectively) met the inclusion criteria and were enrolled for data analysis. VDD (<19.9 ng/mL), severe VDD (<10 ng/mL), and vitamin D insufficiency (20–29.9 ng/mL) were present in 68.8 %, 12.5 %, and 31.2 % of patients, respectively. A significant inverse correlation was found between vitamin D levels and initial BMI, parathyroid hormone, and homeostatic model assessment of insulin resistance (r = −0.280, p < 0.05; r = −0.407, p = 0.038; r = −0.445, p = 0.005), respectively. VDD was significantly more prevalent in patients with higher BMI [−0.413 ± 0.12, CI95 % (−0.659; −0.167), p = 0.006], whereas no significant association between hypertension [−1.005 ± 1.65, CI95 % (−4.338; 2.326), p = 0.001], and diabetes type 2 (T2D) [−0.44 ± 2.20, CI95 % (−4.876; 3.986), p = 0.841] was found. We observed significant association between female sex and levels of vitamin D [6.69 ± 2.31, CI95 % (2.06; 11.33), p = 0.006]. The present study shows that in patients scheduled for BS, VDD deficiency is common and was associated with higher BMI, and female sex.


2007 ◽  
Vol 77 (6) ◽  
pp. 376-381 ◽  
Author(s):  
de Souza Genaro ◽  
de Paiva Pereira ◽  
de Medeiros Pinheiro ◽  
Szejnfeld ◽  
Araújo Martini

Vitamin D is essential for maintaining calcium homeostasis and optimizing bone health. Its inadequacy is related to many factors including dietary intake. The aim of the present study was to evaluate serum 25(OH)D and its relationship with nutrient intakes in postmenopausal Brazilian women with osteoporosis. This cross-sectional study comprised 45 free-living and assisted elderly at São Paulo Hospital. Three-day dietary records were used to assess dietary intakes. Bone mineral density was measured with a dual-energy X-ray absorptiometer (DXA). Blood and urine sample were collected for analysis of biochemical markers of bone and mineral metabolism. Insufficiency of vitamin D was observed in 24.4% of the women and optimal levels (≥ 50 nmol/L) were observed in 75.6%. Parathyroid hormone was above the reference range in 51% of the participants. The mean calcium (724 mg/day) and vitamin D (4.2 μ g/day) intakes were lower than the value proposed by The Food and Nutrition Board and sodium intake was more than two-fold above the recommendation. Higher levels of serum 25(OH)D were inversely associated with sodium intake. Dietary strategies to improve serum vitamin D must focus on increasing vitamin D intake and should take a reduction of sodium intake into consideration.


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