Oxidative Stress Predicts Hip Fracture
Elizabeth Hofheinz, M.P.H., M.Ed. • Wed, August 27th, 2014
Researchers from the University of Cincinnati (UC), Harvard School of Public Health, and Harvard Medical School have found that oxidative stress is a significant predictor for hip fracture in postmenopausal women. The study appears online ahead of print in the Journal of Bone and Mineral Research.
The research was led by Tianying Wu, M.D., Ph.D., an assistant professor in the UC College of Medicine Department of Environmental Health, and Shuman Yang, a postdoctoral fellow in the department. The team evaluated participants from the Nurses’ Health Study, and measured oxidative stress by noting fluorescent oxidation products (FlOP) in blood plasma.
“To our knowledge, this is the first prospective study among postmenopausal women demonstrating that oxidative stress was a significant predictor for hip fracture, ” said Dr. Wu in the August 14, 2014 news release.
According to the news release, a total of 996 women aged 60 or older were measured at baseline blood collection (1989-1990). “Plasma FlOPs were measured at three excitation/emission wavelengths: 360/420 nm (nanometers), named as FlOP_360; 320/420 nm, named as FlOP_320; and 400-475 nm, named as FlOP_400. FlOP_360 represents oxidation products that are generated from oxidized phospholipids or from lipid oxidation products reacting with proteins. FlOP_320 is formed when oxidation products such as lipid hydroperoxides, aldehydes and ketones react with DNA in the presence of metals. FlOP_400 reflects the interaction between malondialdehyde (a specific marker for lipid oxidation), proteins and phospholipids.”
“Of the three wavelengths, researchers found that baseline levels of FlOP_320 products predicted risk of future hip fracture in the study cohort. (No association was found with FlOP_360 and FlOP_400.) Increased FlOP_320 was associated with greater risk of hip fracture; women in the upper 30% of FlOP_320 readings were found to have 2.67 times the risk of hip fractures of those in the bottom 30%.”
“Because FlOP_320 is generated in the presence of metals, its strong association with hip fractures may reflect the co-existing effect of reactive oxygen species and heavy metals, ” says Dr. Wu, who notes that the other FlOP products can be generated without metals.
Dr. Wu told OTW, “If our results are confirmed in larger studies, FlOP_320 may potentially used as a marker for screening individuals are at risk for hip fracture in addition to DEXA scan.”