What should I know about wie macht sich vitamin d mangel bemerkbar?

The provided context does not contain information on vitamin D deficiency. From general medical knowledge: deficiency often presents with nonspecific symptoms such as fatigue, tiredness, muscle weakness, bone pain (especially in lower back, pelvis, legs), and increased susceptibility to infections. Prolonged severe deficiency can lead to bone deformities (osteomalacia in adults, rickets in children). Depressed mood and mood swings are also discussed. Diagnosis is via blood measurement of 25-hydroxyvitamin D. Risk groups include people with limited sun exposure, older adults, darker skin types, and certain conditions (e.g., Crohn's disease, celiac disease). The evidence for many symptoms is well-established (human-strong), but the provided sources do not cover this topic.