Long-term coffee consumption in relation to fracture risk and bone mineral density in women

High consumption of coffee has been suggested to reduce the risk of some late-onset diseases and death but also to contribute to the development of osteoporotic fractures. Results of previous fracture studies have been inconsistent, and a comprehensive study is needed. The longitudinal population-based Swedish Mammography Cohort, including 61,433 women born in 1914-1948, was followed up from 1987 through 2008. Coffee consumption was assessed with repeated food frequency questionnaires. During follow-up, 14,738 women experienced fracture of any type, and 3,871 had a hip fracture. In a subcohort (n = 5,022), bone density was measured and osteoporosis determined (n = 1,012). After multivariable adjustment, there was no evidence of a higher rate of any fracture (hazard ratio per 200 mL coffee = 0.99; 95% confidence interval: 0.98, 1.00) or hip fracture (hazard ratio per 200 mL coffee = 0.97, 95% confidence interval: 0.95, 1.00) with increasing coffee consumption. A high coffee intake (≥4 cups daily) versus a low intake (<1 cup daily) was associated with a 2%-4% lower bone density, depending on site (P < 0.001), but the odds ratio for osteoporosis was only 1.28 (95% confidence interval: 0.88, 1.87). Thus, high coffee consumption was associated with a small reduction in bone density that did not translate into an increased risk of fracture.