Vitamin D status of schoolchildren in Northern Algeria, seasonal variations and determinants of vitamin D deficiency

Djennane, M.; Lebbah, Saïd; Roux, Christian; Djoudi, H.; Cavalier, Étienne; Souberbielle, Jean‐Claude

doi:10.1007/s00198-014-2623-7

Cited by 47 publications

(47 citation statements)

References 39 publications

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“…Several factors influencing vitamin D levels are reported in various studies, including reduced exposure to sunlight, reduced vitamin intake, age, sex and excess weight [27][28][29][30][31]. Findings that the body's capacity to synthesize vitamin D decreases with age [32] were confirmed in our study, where older participants (13-18 years old) had a greater reduction in vitamin D levels compared with younger participants (7-12 years old).…”

Section: Discussionsupporting

confidence: 85%

Do sufficient vitamin D levels at the end of summer in children and adolescents provide an assurance of vitamin D sufficiency at the end of winter? A cohort study

Shakeri

Pournaghi

Hashemi

et al. 2017

Journal of Pediatric Endocrinology and Metabolism

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Background: 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.

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Section: Discussionsupporting

confidence: 85%

Do sufficient vitamin D levels at the end of summer in children and adolescents provide an assurance of vitamin D sufficiency at the end of winter? A cohort study

Shakeri

Pournaghi

Hashemi

et al. 2017

Journal of Pediatric Endocrinology and Metabolism

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“…It must be underlined that, as in our previous studies on the same topic (6,9,10,11,12), the blood samples used here were obtained in the morning (0730-0930 h) after an overnight fast. Indeed, the ULN for a second-generation PTH assay obtained in healthy persons sampled in a nonfasting state over a larger time span was higher than in our studies (34) (see discussion in reference (6)).…”

Section: European Journal Of Endocrinologymentioning

confidence: 99%

“…Excluding subjects with low 25OHD from a reference population for serum PTH reference values is strongly recommended in the two most recent guidelines on the diagnosis and management of asymptomatic PHPT (7,8). We have demonstrated in several studies that this lowers the serum PTH ULN by 20-35% depending on the assay (6,9,10,11,12).…”

Section: Introductionmentioning

confidence: 99%

Serum PTH reference values established by an automated third-generation assay in vitamin D-replete subjects with normal renal function: consequences of diagnosing primary hyperparathyroidism and the classification of dialysis patients

Souberbielle¹,

Massart

Brailly-Tabard

et al. 2016

European Journal of Endocrinology

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Objective: To determine parathyroid hormone (PTH) reference values in French healthy adults, taking into account serum 25-hydroxyvitamin D (25OHD), renal function, age, gender, and BMI. Participants and main biological measurements: We studied 898 healthy subjects (432 women) aged 18-89 years with a normal BMI and estimated glomerular filtration rate (eGFR), 81 patients with surgically proven primary hyperparathyroidism (PHPT), and 264 dialysis patients. 25OHD and third-generation PTH assays were implemented on the LIAISON XL platform. Results: Median PTH and 25OHD values in the 898 healthy subjects were 18.8 ng/l and 23.6 ng/ml respectively. PTH was lower in subjects with 25OHD R30 ng/ml than in those with lower values. Among the 183 subjects with 25OHD R30 ng/ml, those aged R60 years (nZ31) had higher PTH values than younger subjects, independent of 25OHD, BMI, and eGFR (P!0.001). Given the small number of subjects aged R60 years, we adopted the 95% CI of PTH values for the entire group of 183 vitamin D-replete subjects (9.4-28.9 ng/l) as our reference values. With 28.9 ng/l as the upper limit of normal (ULN) rather than the manufacturer's ULN of 38.4 ng/l, the percentage of PHPT patients with 'high' PTH values rose to 90.1% from 66.6% (P!0.001), and 18.6% of the dialysis patients were classified differently in view of the KDIGO target range (two to nine times the ULN). Conclusion: When only subjects with 25OHD R30 ng/ml were included in the reference population, the PTH ULN fell by 22.4%, diagnostic sensitivity for PHPT improved, and the classification of dialysis patients was modified.

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“…6 Indeed, previous studies reported a high burden of vitamin D deficiency even in sun-replete areas. 7,8 Case-control studies addressing the interconnection between vitamin D and asthma showed that children with asthma had a higher prevalence of vitamin D deficiency compared with control subjects. 9,10 Moreover, epidemiologic studies implicated the role of vitamin D deficiency in allergy and asthma development and exacerbations.…”

Section: Introductionmentioning

confidence: 99%

Bronchial Reactivity, Inflammatory and Allergic Parameters, and Vitamin D Levels in Children With Asthma

et al. 2015

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Vitamin D status of schoolchildren in Northern Algeria, seasonal variations and determinants of vitamin D deficiency

Abstract: Despite a sunny environment, vitamin D insufficiency is frequent in healthy Algerian children.

Cited by 47 publications

References 39 publications

Do sufficient vitamin D levels at the end of summer in children and adolescents provide an assurance of vitamin D sufficiency at the end of winter? A cohort study

Do sufficient vitamin D levels at the end of summer in children and adolescents provide an assurance of vitamin D sufficiency at the end of winter? A cohort study

Serum PTH reference values established by an automated third-generation assay in vitamin D-replete subjects with normal renal function: consequences of diagnosing primary hyperparathyroidism and the classification of dialysis patients

Bronchial Reactivity, Inflammatory and Allergic Parameters, and Vitamin D Levels in Children With Asthma

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