Long-term hypophosphatemia, defined by serum phosphorus (P) levels <2.5mg/dL, impairs the development and quality of mineralized tissue of the skeletal, dental, and auditory systems. P homeostasis depends mainly on intestinal absorption and renal excretion. Hypophosphatemia may be due to the redistribution of P to the intracellular space, increased renal losses, or decreased intestinal absorption. Hypophosphatemia can be categorized as acute or chronic, depending on the time course. Most cases, either acute or chronic, are due to acquired causes. However, some chronic cases may have a genetic origin. Accurate and early diagnosis, followed by adequate treatment, is essential to limit its negative effects on the body.

Vitamin D (VD) deficiency has been associated with various tumors. However, the association between VD and skin cancer is controversial. Although in non-melanoma skin cancer, adequate or even high levels of VD can be associated with a higher risk of developing tumors, this could be biased by the direct association between sun exposure and VD levels. Regarding melanoma, results are contradictory. Most studies analyzed state that higher levels of VD could reduce the risk of melanoma, be associated with melanomas with better prognosis and with an enhanced antitumor response, and also with fewer adverse events associated with melanoma immunotherapy. However, prospective studies of adequate methodological quality are still needed to assess the association between VD levels and its supplementation and development/prognosis in skin cancer.

OBJECTIVE: Henoch Schönlein purpura (HSP) and Kawasaki disease (KD) are two main inflammatory diseases among childhood vasculitis. Considering the anti-inflammatory effects of 25-hydroxyvitamin D3, we decided to investigate the association of serum 25-hydroxy vitamin D3 level with the type and severity of these conditions.
METHODS: The present study was performed as a historical cohort of 254 affected children with KD and HSP vasculitis. The required data were extracted, using a researcher-made questionnaire from patients\' electronic file, and then they were analyzed after collecting information of the patients.
RESULTS: In HSP group, 54% of participants were boys. Similarly, in KD group, boys were more affected than girls. The comparative 25-hydroxyvitamin vitamin D3 level in HSP patients with and without renal involvement (P=0.02), hematuria (P=0.14), and in two groups with and without heart disease, and also with and without coronary artery dilatation in KD patients (P<0.001) were significant.
CONCLUSIONS: The findings showed that insufficient level of vitamin D3 were significantly associated with the exacerbation of complications of both diseases, and therefore it seems that vitamin D deficiency can be an effective predictive factor of severity in HSP and KD patients.

Vitamin D (VD) deficiency has been associated with various tumors. However, the association between VD and skin cancer is controversial. Although in non-melanoma skin cancer, adequate or even high levels of VD can be associated with a higher risk of developing tumors, this could be biased by the direct association between sun exposure and VD levels. Regarding melanoma, results are contradictory. Most studies analyzed state that higher levels of VD could reduce the risk of melanoma, be associated with melanomas with better prognosis and with an enhanced antitumor response, and also with fewer adverse events associated with melanoma immunotherapy. However, prospective studies of adequate methodological quality are still needed to assess the association between VD levels and its supplementation and development/prognosis in skin cancer.

BACKGROUND: Vitamin D deficiency associates with the risk of developing many diseases, including cancer. At the molecular level, vitamin D appears to have an antineoplastic effect. However, the role of vitamin D deficiency in cancer pathogenesis remains unelucidated and numerous studies have resulted in discordant results. This study aimed to determine whether vitamin D deficiency during melanoma diagnosis increases the risk of developing non-cutaneous second primary cancers (SPC).
METHODS: A retrospective study on 663 patients diagnosed with melanoma between 1 January 2011 and 31 October 2022. The effect of each variable on the development of a subsequent non-cutaneous cancer was performed using Kaplan-Meier curves and differences were assessed by log-rank tests. Cox proportional hazard univariate and multivariate models were used to quantify the effect of each variable in the time to develop a non-cutaneous neoplasia.
RESULTS: Out of 663 patients, 34 developed a non-cutaneous SPC. There was no statistically significant association between vitamin D levels and non-cutaneous SPC development (log-rank, p=0.761). Age>60 years, stage III/IV, and nodular melanoma subtype were significantly associated with the development of a SPC. After multivariate analysis, only age>60 years (HR 3.4; HR CI 95%: 1.5-7.6) and nodular melanoma subtype (HR 2.2; HR CI 95%: 1.0-4.8) were included in the final model.
CONCLUSIONS: Our results suggest that vitamin D deficiency is not associated with an increased risk of developing non-cutaneous SPC in melanoma patients. However, age over 60 years and nodular melanoma subtype increase the risk for non-cutaneous SPC development.

BACKGROUND: Vitamin D deficiency associates with the risk of developing many diseases, including cancer. At the molecular level, vitamin D appears to have an antineoplastic effect. However, the role of vitamin D deficiency in cancer pathogenesis remains unelucidated and numerous studies have resulted in discordant results. This study aimed to determine whether vitamin D deficiency during melanoma diagnosis increases the risk of developing non-cutaneous second primary cancers (SPC).
METHODS: A retrospective study on 663 patients diagnosed with melanoma between 1 January 2011 and 31 October 2022. The effect of each variable on the development of a subsequent non-cutaneous cancer was performed using Kaplan-Meier curves and differences were assessed by log-rank tests. Cox proportional hazard univariate and multivariate models were used to quantify the effect of each variable in the time to develop a non-cutaneous neoplasia.
RESULTS: Out of 663 patients, 34 developed a non-cutaneous SPC. There was no statistically significant association between vitamin D levels and non-cutaneous SPC development (log-rank, p=0.761). Age>60 years, stage III/IV, and nodular melanoma subtype were significantly associated with the development of a SPC. After multivariate analysis, only age>60 years (HR 3.4; HR CI 95%: 1.5-7.6) and nodular melanoma subtype (HR 2.2; HR CI 95%: 1.0-4.8) were included in the final model.
CONCLUSIONS: Our results suggest that vitamin D deficiency is not associated with an increased risk of developing non-cutaneous SPC in melanoma patients. However, age over 60 years and nodular melanoma subtype increase the risk for non-cutaneous SPC development.

The clinical and biochemical overlap of various pathologies of phosphocalcic metabolism can lead to misdiagnosis and consequent clinical management. One example is pseudohypoparathyroidism, which can be confused with vitamin D-dependent rickets (VDDR1) if appropriate biochemical determinations are not performed.
Two pairs of siblings, from independent families, were clinically diagnosed in adolescence with pseudohypoparathyroidism due to hypocalcaemia, elevated parathyroid hormone levels and normal or elevated phosphorus values. After ruling out alterations in GNAS, a massive sequencing study of genes associated with other differential diagnoses was carried out.
Two genetic variants in the CYP27B1 gene potentially associated with the phenotype were identified. Pathogenic variants in this gene are associated with VDDR1A. Clinical-biochemical re-evaluation of the patients confirmed this diagnosis and treatment was adapted.
Although VDDR1A is an infrequently diagnosed pathology in adulthood, in cases of hypocalcaemia with elevated PTH values, determination of the 1,25(OH)2D3 and 25(OH)D3 forms of vitamin D is relevant to reach a correct diagnosis.

OBJECTIVE: Based on the European and American Cystic Fibrosis (CF) consensus recommendations, an increase in vitamin D (VD) supplementation in patients with CF and insufficient or defficient levels was proposed. The objective of our study was to determine the safety and efficacy of this new protocol.
METHODS: Multicentre nonrandomized uncontrolled experimental study. Patients with insufficient levels (<30 ng/mL) received increasing doses of VD (between 800 and 10 000 IU/day). Patients were followed up for 12 months, during which their vitamin and nutritional status, pulmonary function and calcium and phosphate metabolism were assessed.
METHODS: t test for paired data and multivariate logistic regression analysis.
RESULTS: Thirty patients aged 1-39 years (median, 9.1) completed the follow-up. Two patients were dropped from the study on account of 25-OH VD levels greater than 100 ng/mL at 3 months without clinical or laboratory signs of hypercalcaemia. At 12 months, we observed an increase of 7.6 ng/mL (95% CI, 4.6-10 ng/mL) in the mean 25-OH VD level and an improvement in vitamin status: 37% achieved levels of 30 ng/mL or greater, 50% levels between 20 and 30 ng/mL and 13% remained with levels of less than 20 ng/mL. We found no association between improved VD levels and pulmonary function.
CONCLUSIONS: The proposed protocol achieved an increase in serum VD levels and a decrease in the percentage of patients with VD insufficiency, although it was still far from reaching the percentages of sufficiency recommended for this entity.

BACKGROUND: Vitamin D deficiency has been proposed to confer susceptibility to acquiring tuberculosis infection by impairing the innate immune response.
METHODS: In an exploratory study, we examined whether the levels of 25-hydroxyvitamin D3 (25(OH)D3) in serum, and cathelicidin - an antimicrobial peptide-induced under calcitriol - in the nasal fluid, would associate with the risk of acquiring tuberculosis infection.
RESULTS: Within a prospective cohort of 231 tuberculosis household contacts tested with repeated interferon-gamma release assays, we serially analyzed all the uninfected contacts acquiring tuberculosis infection at follow-up (\"converters\", n=18), and an age and sex-matched control group of contacts not acquiring tuberculosis infection (\"non-converters\", n=36). The median levels of serum 25(OH)D3 did not differ between convertors and non-converters at baseline (14.9 vs. 13.2 ng/ml, p=0.41), nor at follow-up (19.0 vs 18.6ng/ml, p=0.83). Similarly, cathelicidin levels did not differ between both groups.
CONCLUSIONS: These data argue against a major role for hypovitaminosis D in tuberculosis infection susceptibility.

BACKGROUND: In older adults, the association of frailty and sarcopenia with vitamin D deficiency is well known, but the association of the components of frailty syndrome has been poorly studied.
OBJECTIVE: To determine the association of the components of frailty and sarcopenia with vitamin D insufficiency in older adults.
METHODS: Adults were studied, in whom age, education, marital status, history of fractures, hospitalizations, anthropometric indicators, sarcopenia, Charlson index, polypharmacy, Fried\'s frailty phenotype, and plasma vitamin D were recorded; figures < 30 ng/mL were considered indicative of vitamin D insufficiency. Descriptive and inferential statistics were used for statistical analysis. The association was determined by binary logistic regression.
RESULTS: One-hundred and seventy-five adults with a mean age of 71.7 ± 6.7 years (95% CI = 60-90 years) were studied. Binary logistic regression showed that the variables associated with vitamin D deficiency were exhaustion (OR = 2.6, 95% CI = 1.0-6.5, p = 0.03), frailty (OR = 9.2, 95% CI = 2.5-34.1, p = 0.001) and pre-frailty (OR = 4.6, 95% CI = 2.1-10.0, p < 0.001).
CONCLUSIONS: The frail and pre-frail phenotypes, as well as exhaustion, are associated with vitamin D insufficiency.
UNASSIGNED: En adultos mayores, la asociación de fragilidad y sarcopenia con deficiencia de vitamina D es conocida, pero poco se ha estudiado la asociación de los componentes del síndrome de fragilidad.
OBJECTIVE: Determinar la asociación entre los componentes de fragilidad, sarcopenia e insuficiencia de vitamina D en adultos mayores.
UNASSIGNED: Se estudiaron adultos de quienes se registró edad, escolaridad, estado civil, antecedentes de fracturas, hospitalizaciones, indicadores antropométricos, sarcopenia, índice de Charlson, polifarmacia, fenotipo de fragilidad de Fried y vitamina D plasmática; cifras < 30 ng/mL se consideraron indicativas de insuficiencia de vitamina D. Para el análisis estadístico se utilizó estadística descriptiva e inferencial. La asociación fue determinada mediante regresión logística binaria.
RESULTS: Se estudiaron 175 adultos con un promedio de edad de 71.7 ± 6.7 años (IC 95 % = 60-90 años). La regresión logística binaria demostró que las variables asociadas a insuficiencia de vitamina D fueron agotamiento (RM = 2.6, IC 95 % = 1.0-6.5, p = 0.03), fragilidad (RM = 9.2, IC 95 % = 2.5-34.1, p = 0.001) y prefragilidad (RM = 4.6, IC 95 % = 2.1-10.0, p < 0.001).
UNASSIGNED: Los fenotipos frágil, prefrágil y agotamiento se asocian a insuficiencia de vitamina D.