Objective: We determined whether dietary intakes and plasma concentrations of vitamin C were associated with a heel ultrasound and hip and spine fracture risks in older men and women.
Design: Participants were recruited from the European Prospective Investigation into Cancer in Norfolk study with 7-d diet diary estimates of vitamin C intake and plasma concentrations. A random subset (4000 of 25,639 subjects) was available for the cross-sectional (ultrasound) study of broadband ultrasound attenuation (BUA) and velocity of sound (VOS), which were determined during the second health examination. The prospective (fracture) study was a case-cohort sample of all participants with a fracture up to March 2009 and the random subset (n = 5319). ANCOVA-determined associations between quintiles of vitamin C intake and plasma status with adjusted BUA and VOS and adjusted Prenticeweighted Cox proportional HRs were calculated for fracture risk.
Results: Women were 58% of the population (39–79 y old), and the median follow-up was 12.6 y (range: 0–16 y). Positive associations across all quintiles of vitamin C intake but not plasma status were significant for VOS in men (b = 2.47 m/s, P = 0.008) and BUA in women (b = 0.82 dB/MHz, P = 0.004). Vitamin C intake was not associated with fracture risk, but there was an inverse association with plasma concentrations in men, with quintile 4 having significantly lower risks of hip fractures (HR: 0.35; 95% CI: 0.16, 0.80) and spine fractures (HR: 0.26; 95% CI: 0.10, 0.69) than quintile 1.
Conclusions: Higher vitamin C intake was significantly associated with higher heel ultrasound measures in men and women, and higher plasma vitamin C concentrations were significantly associated with reduced fracture risk in men only. Our findings that vitamin C intake and status were inconsistently associated with bone health variables suggest that additional research is warranted.
- Norwich Medical School - Professor of Nutritional Epidemiology
- Norwich Institute for Healthy Aging - Member
- Epidemiology and Public Health - Member
- Public Health and Health Services Research - Member
Person: Research Group Member, Research Centre Member, Academic, Teaching & Research