title: Seasonal variation in serum concentrations of parathyroid hormone in elderly people.
abstract: In 124 patients with femoral neck fracture and 74 aged control subjects a seasonal variation was observed in the serum concentrations of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and PTH. The serum PTH concentrations were maximal in winter, when the vitamin D metabolites were lowest, suggesting a secondary phenomenon.
mesh_terms: D000368:Aged; D002118:Calcium / Q000378:metabolism; D005260:Female; D005265:Femoral Neck Fractures / Q000209:etiology / Q000378:metabolism*; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D012621:Seasons; D014807:Vitamin D / Q000378:metabolism
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; D002118:Calcium