RESUMEN
CONTEXT: The growing number of systematic reviews/meta-analyses (SR/MAs) on vitamin D (±â calcium) for fracture prevention has led to contradictory guidelines. OBJECTIVE: This umbrella review aims to assess the quality and explore the reasons for the discrepancy of SR/MAs of trials on vitamin D supplementation for fracture risk reduction in adults. METHODS: We searched 4 databases (2010-2020), Epistemonikos, and references of included SRs/MAs, and we contacted experts in the field. We used A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR-2) for quality assessment. We compared results and investigated reasons for discordance using matrices and subgroup analyses (PROSPERO registration: CRD42019129540). We included 13 SR/MAs on vitamin D and calcium (Ca/D) and 19 SR/MAs on vitamin D alone, compared to placebo/control. RESULTS: Only 2 from 10 SRs/MAs on Ca/D were of moderate quality. Ca/D reduced the risk of hip fractures in 8 of 12 SRs/MAs (relative risk [RR] 0.61-0.84), and any fractures in 7 of 11 SR/MAs (RR 0.74-0.95). No fracture risk reduction was noted in SRs/MAs exclusively evaluating community-dwelling individuals or in those on vitamin D alone compared to placebo/control. Discordance in results between SRs/MAs stems from inclusion of different trials, related to search periods and eligibility criteria, and varying methodology (using intention to treat, per-protocol, or complete case analysis from individual trials). CONCLUSION: Ca/D reduces the risk of hip and any fractures, possibly driven by findings from institutionalized individuals. Individual participant data meta-analyses of patients on Ca/D with sufficient follow-up periods, and subgroup analyses, would unravel determinants for a beneficial response to supplementation.
Asunto(s)
Suplementos Dietéticos , Fracturas Óseas , Vitamina D , Humanos , Conservadores de la Densidad Ósea , Fracturas Óseas/epidemiología , Fracturas Óseas/prevención & control , Metaanálisis como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento , Vitamina D/administración & dosificaciónRESUMEN
PURPOSE: We investigated prevalence, determinants, seasonal changes, and time trends in hypovitaminosis D. We derived a desirable serum 25-hydroxy-vitamin D (25OHD) level in adults/elderly by evaluating the 25OHD-parathyroid hormone (PTH) exponential relationship. METHODS: We analyzed serum 25OHD data from a large laboratory database (Nâ¯=â¯151,705), from a major academic medical center in Lebanon, from 2009 to 2016. We used cross calibration formulas to convert measured 25OHD levels to LC-MS/MS equivalents based on our external quality assurance protocols. RESULTS: 6% of the population were children (mean age 11⯱â¯5â¯years, 56% girls), 68% were adults (44⯱â¯13â¯years, 71% women), and 25% were elderly (74⯱â¯6â¯years, 59% women). The prevalence of hypovitaminosis D, in the entire population, was 39%, 29% and 23% at 25OHD cutoffs of 20â¯ng/ml, 15â¯ng/ml, and 12â¯ng/ml, respectively, across all years. Using multivariate analysis, predictors of 25OHD levels below 12, 15 and 20â¯ng/ml were younger age, male sex, winter months, and inpatient status both in adults and elderly. In children, older age, female sex, winter months, and inpatient status, predicted levels below 15â¯ng/ml and 20â¯ng/ml, but only older age, female sex, and winter months predicted levels below 12â¯ng/ml. There was a significant steady annual increase in 25OHD levels between 2009 and 2016 of 0.9â¯ng/ml/year (95% CI: 0.7, 1.0) in children, 1.2â¯ng/ml/year (1.2, 1.3) in adults and 2.6â¯ng/ml/year (2.6, 2.8) in the elderly. Using best fit non-linear regression models, on a subset of adults and elderly in whom concomitant 25OHD and PTH data was available (Nâ¯=â¯4025), PTH levels plateaued at a serum 25OHD level of 26.1â¯ng/ml. CONCLUSION: Secular increase in serum 25OHD levels is observed in Lebanon, but hypovitaminosis D is still prevalent. Our data provides basis for a desirable 25OHD level above 26â¯ng/ml in adult and elderly Lebanese individuals.
Asunto(s)
Deficiencia de Vitamina D/epidemiología , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Cromatografía Liquida , Bases de Datos Factuales , Femenino , Humanos , Hidroxicolecalciferoles/sangre , Lactante , Líbano/epidemiología , Masculino , Persona de Mediana Edad , Hormona Paratiroidea/sangre , Prevalencia , Estaciones del Año , Factores Sexuales , Espectrometría de Masas en Tándem , Deficiencia de Vitamina D/sangre , Adulto JovenRESUMEN
OBJECTIVES: Phosphorus ingestion with glucose was reported to stimulate the postprandial peripheral uptake of both phosphorus and glucose, a process that favors energy production. The aim of this study was to determine whether phosphorus ingestion with a meal can affect energy metabolism. METHODS: Overnight fasted men (eight lean and seven obese) consumed a high-carbohydrate meal (648 kcal) with either placebo or phosphorus (500 mg) tablets in a random order. Energy expenditure and substrate oxidation were monitored for 240 min using ventilated hood indirect calorimetry. RESULTS: Phosphorus ingestion with a meal increased the postprandial energy expenditure of both lean and obese individuals (P < 0.001), although in different patterns. Alterations in postprandial substrate oxidation was highly noticeable from time 120 min onward, where phosphorus-treated lean participants exhibited a significant decrease in respiratory quotient. CONCLUSION: Phosphorus ingestion with a high-carbohydrate meal alters postprandial energy metabolism mainly by enhancing postprandial energy expenditure that may ultimatly favor weight loss.