Bone Abstracts

Introduction: Vitamin D deficiency has been associated with impaired physical functioning and several chronic diseases and might thereby affect quality of life and self-rated health. The aim of this study was to assess relationships of serum 25-hydroxyvitamin D (25(OH)D) with quality of life and self-rated health, and to examine whether physical performance and number of chronic diseases mediate these relationships.

Methods: Data were obtained from the LASA, an ongoing cohort study in a representative sample of the older population. Serum 25(OH)D was classified into categories: <25, 25–50 and ≥50 nmol/l. Quality of life was measured with the SF-12 Health Survey in 1998/1999 (n=862). Self-rated health is the perception of subjective health and was measured with a single question in 1995/1996 (n=1248) and 1998/1999 (n=1028).

Results: The lowest 25(OH)D category was associated with a lower physical component score of the SF-12 as compared with the highest category (β (95% CI): −3.9 (−6.5 to −1.3)). The lowest 25(OH)D category was associated with a lower cross-sectional score of self-rated health compared to the highest category (odds ratio (95% CI): 0.5 (0.3 to 0.8). Physical performance and number of chronic diseases were associated with vitamin D status, quality of life and self-rated health. Adding physical performance to the multivariable model decreased the strength of the associations of 25(OH)D category with quality of life and self-rated health with 54 and 29%, respectively. Adding number of chronic diseases decreased the strength of the associations of 25(OH)D category with quality of life with 33%, but did not change the association with self-rated health.

Conclusion: Lower 25(OH)D status is associated with lower scores on quality of life and self-rated health. Large part of the associations can be statistically and theoretically explained by physical performance and number of chronic disease.