Prescribing high daily doses of calcium does not reduce the risk of fractures in later life, a new study suggests.
Researchers investigated a cohort of Swedish 61,433 women along with a cohort of 5,022 women for whom bone mineral density measurements were made.
Data on diet, lifestyle and fractures were identified from questionnaires and the Swedish National Patient Registry. Women taking less than 750mg of calcium a day had a higher risk of fracture and osteoporosis - 19% and 47% respectively - compared with women on higher doses but women with above that level of level intake had only minor differences in risk.
The highest quintile of calcium intake did not further reduce the risk of fractures or of osteoporosis, but was associated with a higher rate of hip fracture, with a hazard ratio of 1.19.
Lead author Dr Eva Warensjo, a researcher in surgical sciences at Uppsala University, said: 'In the prevention of osteoporotic fractures emphasis should be placed on individuals with a low intake of calcium rather than increasing the intake of those already consuming satisfactory amounts.'
BMJ 2011, online 24 May