Longitudinal changes in calcium and vitamin D intakes and relationship to bone mineral density in a prospective population-based study: the Canadian Multicentre Osteoporosis Study (CaMos)

Objectives: Our objective was to study changes in calcium and vitamin D intakes over time, and their cross-sectional and longitudinal associations with bone mineral density (BMD). Methods: We followed 9382 women and men aged >= 25 and 899 aged 16-24, for 10 and 2 years respectively. Results: Calcium and vitamin D intakes increased over time in adults, but decreased in women aged 16-18. The increased intakes in adults were largely attributable to the increased use of calcium and/or vitamin D supplements. Both the percentage of supplement users and average dose among users increased over time. There was nevertheless a high prevalence of calcium and vitamin D intake below the estimated average requirement. At baseline, higher calcium and vitamin D intakes were associated with higher total hip and femoral neck BMD in young men, and cumulatively high levels of calcium and vitamin D intakes over time contributed to better BMD maintenance at lumbar spine and hip sites in adult women. Conclusions: Although total intakes, particularly of vitamin D, frequently fell below the Institute of Medicine recommendations despite an increase over time in supplement use, we found some positive associations between total calcium and vitamin D intake and bone health.