Dietary magnesium intake and fracture risk: data from a large prospective study

Research considering the relationship between dietary Mg and osteoporosis as well as fractures are sparse and conflicting. We therefore aimed to investigate Mg intake and the onset of fractures in a large cohort of American men and women involved in the Osteoarthritis Initiative over a follow-up period of 8 years. Dietary Mg intake (including that derived from supplementation) was evaluated through a FFQ at baseline and categorised using sex-specific quintiles (Q); osteoporotic fractures were evaluated through self-reported history. Overall, 3765 participants (1577 men; 2071 women) with a mean age of 60·6 (sd 9·1) years were included. During follow-up, 560 individuals (198 men and 368 women) developed a new fracture. After adjusting for fourteen potential confounders at baseline and taking those with lower Mg intake as reference (Q1), men (hazard ratio (HR) 0·47; 95 % CI 0·21, 1·00, P=0·05) and women (HR 0·38; 95 % CI 0·17, 0·82, P=0·01) in the highest quintile reported a significantly lower risk for fracture. Women meeting the recommended Mg intake were at a 27 % decreased risk for future fractures. In conclusion, higher dietary Mg intake has a protective effect on future osteoporotic fractures, especially in women with a high risk for knee osteoarthritis. Those women meeting the recommended Mg intake appear to be at a lower risk for fractures.