Vitamin-D-Wert lesen: Was 12, 20, 30 und 50 auf Ihrem Befund bedeuten

<h4>Background</h4>Vitamin D deficiency is a common global health problem and remains highly prevalent in Türkiye, where limited food fortification and heterogeneous clinical practices contribute to variability in testing and supplementation strategies.<h4>Aims</h4>To provide Türkiye-specific best practice recommendations for defining clinically relevant serum 25-hydroxyvitamin D [25(OH)D] thresholds, identifying adult risk groups for targeted testing, and recommending evidence-based prevention, treatment, and monitoring approaches while minimizing under-treatment and inappropriate high-dose use.<h4>Methods</h4>This national expert consensus document was developed by endocrinologists from across Türkiye using a structured, modified Delphi methodology. Draft statements informed by systematic literature reviews were rated via online surveys using a 9-point Likert scale, followed by two Delphi rounds and a face-to-face consensus meeting in İstanbul in October 2025.<h4>Results</h4>Recommendations addressed sun exposure, laboratory assessment, screening, supplementation, treatment, and follow-up. Serum 25(OH)D <20 ng/mL was defined as deficiency and <12 ng/mL as severe deficiency, with a target range of 20-50 ng/mL. Routine population-wide screening was not recommended; instead, targeted testing in high-risk adults and symptom-driven biochemical evaluation were endorsed. Empiric supplementation was recommended for selected high-risk groups, with cholecalciferol as the preferred ag

Vitamin D (VD), due to its hormonal action, plays a crucial role in calcium homeostasis and bone metabolism, and its deficiency has been associated with musculoskeletal disorders such as osteoporosis, fractures, and osteomalacia, as well as a growing attention of chronic conditions and certain cancers. Despite its physiological relevance and widespread prevalence, particularly among older individuals, patients with chronic diseases, institutionalized populations and pregnant or lactating women, clinical approaches to diagnosing and managing vitamin D deficiency (VDD) remain heterogeneous across guidelines and healthcare settings. This reflects a lack of consensus regarding the benefits and limitations of universal versus selective screening, the definition of adequate serum concentrations, and the clinical indications for supplementation across different patient profiles. This narrative review explores key controversies in the clinical management of VDD, including current perspectives on screening strategies and target populations, indications for empirical supplementation, criteria for biochemical monitoring, and therapeutic goals in bone-related outcomes. In particular, the review discusses the rationale for adopting a 30 ng/mL (75 nmol/L) threshold for adequate serum 25(OH) concentrations in skeletal health, the role of vitamin D and calcium in osteoporosis treatment, and the pharmacological advantages of cholecalciferol compared to other vitamin D compounds. Through a syn

Blood 25-hydroxyvitamin D (25(OH)D) concentrations vary considerably by season and sex. The present study aimed to determine associations between vitamin D deficiency and mortality in Japanese adults and identify risk thresholds according to 25(OH)D concentrations. This was a cohort study with an 11-year follow-up. Participants were 8285 community-dwelling Japanese adults aged 40-74 years. Plasma 25(OH)D concentrations were measured by chemiluminescent immunoassay at baseline and divided into quintiles for each of the subgroups stratified by season and sex (denoted as season- and sex-stratified quintiles). The main outcome was all-cause mortality. Hazard ratios (HR) were calculated using a Cox proportional hazards model. Mean age and 25(OH)D concentration were 59·9 years (sd = 9·1) and 50·1 nmol/l (sd = 18·1), respectively. Lower season- and sex-stratified quintiles were associated with higher hazards of all-cause mortality (<i>P</i>_{for trend} = 0·0015), with the first quintile (median = 28·2 nmol/l) having a higher HR (HR = 1·46, 95 % CI, 1·13, 1·88) than the highest quintile (reference). When crude quintiles were used, the overall association was similar (<i>P</i>_{for trend} = 0·0027), with the first (median = 28·0 nmol/l) and second (median = 39·7 nmol/l) quintiles having higher HR (HR = 1·40, 95 % CI, 1·06, 1·85 and 1·38, 95 % CI, 1·07, 1·77, respectively) than the reference. The risk threshold difference was estimated to be approximately 10 nmol/l. In

<b>Background:</b> Reference intervals for 25-hydroxyvitamin D are significantly influenced by seasonal variations and population-specific factors. This study aimed to establish local, population-specific Vitamin D reference intervals using the refineR algorithm and to compare these results with the conventional non-parametric method using a hospital database. <b>Methods:</b> A total of 127,220 laboratory results from 2022 to 2025 were retrospectively analyzed. Data were filtered based on adult age, morning fasting specimens, outpatient status, and normal parathyroid hormone levels (14-72 ng/L). Following filtration, Wilcoxon and Kruskal-Wallis tests were employed to evaluate differences between potential subgroups. Consequently, 24,036 eligible results were stratified by age (18-40, 41-65, and >65 years) and sex (female and male). Reference intervals were calculated using the refineR algorithm and the non-parametric percentile method. <b>Results:</b> The distribution of vitamin D levels was found to be right-skewed [Median: 12.92 ng/mL (4.21-149)]. The upper reference limits obtained via refineR were consistently lower than those derived from the non-parametric method. Both methods showed a linear increase in median values and upper reference limits with advancing age. Females in the 18-40 age group exhibited the lowest vitamin D profile. The summer concentrations were significantly higher than those of other seasons (<i>p</i> <0.05). <b>Conclusions:</b> The refineR algorith