Serum 25-Hydroxyvitamin D and Depressive Symptoms in a 12-Year Korean Occupational Cohort: A Threshold Effect Confined to Severe Deficiency
Background/Objectives: Low serum 25-hydroxyvitamin D [25(OH)D] has been proposed as a modifiable risk factor for depression, but the shape of the exposure–response relationship and its independence from sleep disturbance have not been characterised in a large occupational cohort with repeated measures. Methods: We anal...