Better knowledge on vitamin D and calcium in older people is associated with a higher serum vitamin D level and a higher daily dietary calcium intake

Objective: The objective of the present study was to examine knowledge on vitamin D and calcium in a cohort of older adults and to test the association between health knowledge, vitamin D status and dietary calcium intake.Methods: The participants of this cross-sectional survey consisted of 426 individuals (≥65 years), living in residential homes. Participants were tested for their knowledge on vitamin D and calcium using a standardized questionnaire. Serum 25-hydroxyvitamin D ₃ (25(OH)D ₃) levels and dietary calcium intake were measured.Results: The mean serum 25(OH)D ₃ level was 39.1 (±21.4) nmol/l and the mean daily dietary calcium intake was 826 (±242) mg/day. Of the participants, only 38 per cent indicated that they knew or had heard of vitamin D. Participants overestimated their daily calcium intake. Better knowledge on vitamin D and calcium was associated with both higher vitamin D levels (P < 0.0001) and a higher daily dietary calcium intake (P < 0.0001).Conclusion: Given the poor knowledge on vitamin D and calcium and the observed associations, improving health knowledge could be a possible intervention to improve vitamin D status and calcium intake in older people. Further studies are needed to assess whether education will indeed lead to improvement of vitamin D levels and calcium intake in this age group.