In combined analyses of 18 previous studies, researchers examined how the consumption of dairy products affects the risk of hip fracture.
Hip fracture is a serious complication of osteoporosis – the “bone-thinning” condition that can occur with ageing. Apart from pain and disability, hip fracture is also associated with an increased risk of mortality and high social and economic costs.
There are several factors which affect the risk of hip fracture. Lifestyle habits including diet are thought to be important. Dairy products, an important source of calcium and protein, are known to help maintain bone health. However, the link between dairy product consumption and risk of hip fracture is not clearly established. Researchers in China performed combined analyses of several previous studies to examine and quantify the association between dairy product consumption and risk of hip fracture. They recently reported their findings in the journal BMC Public Health.
The researchers performed an extensive review of all studies up to April 2017 which looked at the association between the consumption of dairy products and the risk of hip fracture. They selected ten cohort studies and eight case-control studies to include in combined analyses. Cohort studies usually look prospectively (forwards) at outcomes in population samples (cohorts) with different exposures to the factors studied (in this study – dairy products). Case-control studies usually look retrospectively (backwards) at the history of “cases” (in this study – people with hip fractures) and “controls” (healthy subjects) to examine their level of exposure to different factors. The ten selected cohort studies and eight selected case-control studies were pooled separately in two combined analyses.
Dairy Products and Risk of Hip Fracture
A detailed statistical analysis of the combined cohort studies found that a higher intake of yogurt and cheese was associated with a significant reduction in hip fractures. A combined analysis of the case-control studies found that milk consumption was associated with a lower risk of hip fracture when comparing groups with the highest milk consumption with those with the lowest consumption. However, when looking at specific doses of milk consumption, no clear relationship could be found between milk consumption and hip fracture risk in either the combined cohort or case-control studies.
The results from the combined study analyses were conflicting. The consumption of yoghurt and cheese was linked to a lower level of hip fracture in the cohort studies. However, the total dairy product consumption was not significantly associated with risk of hip fracture. The researchers concluded there was not enough evidence to establish a clear relationship between milk consumption and the risk of hip fracture.
Written by Julie McShane, Medical Writer
Reference: Bian, S, Hu J, Zhang K, et al. Dairy product consumption and risk of hip fracture: a systematic review and meta-analysis. BMC Public Health (2018) 18:165. DOI:10.1186/s12889-018-5041-5.
