Oxidative stress is a significant predictor for hip fracture in postmenopausal women, according to new research led by University of Cincinnati (UC) epidemiologists.
The research, appearing online ahead of print in the Journal of Bone and Mineral Research, was led by Tianying Wu, MD, PhD, an assistant professor in the UC College of Medicine Department of Environmental Health, and Shuman Yang, a postdoctoral fellow in the department. They collaborated with researchers from the Harvard School of Public Health and Harvard Medical School.
"To our knowledge, this is the first prospective study among postmenopausal women demonstrating that oxidative stress was a significant predictor for hip fracture,” says Wu, the study’s corresponding author.
Oxidative stress is defined as physiological stress on the body that is caused by the cumulative damage done by free radicals, which are inadequately neutralized by antioxidants. Free radicals are unstable molecules that react with other substances in the human body to damage cells or organs.
Oxidative stress occurs naturally, but environmental factors such as natural and artificial radiation, toxins in air, food and water and miscellaneous sources such as tobacco smoke can add to the overall burden and defeat the body’s antioxidant defenses.
The researchers assessed oxidative stress by measuring fluorescent oxidation products (FlOP) in blood plasma. FlOP reflects a mixture of oxidation products from lipids, proteins and DNA and can be measured by a fluorescent spectrophotometer.
Researchers studied participants in the Nurses’ Health Study, which began in 1976 with funding from the National Institutes of Health (NIH). Participants are female nurses who periodically respond to questionnaires and submit samples.
The researchers studied 996 women aged 60 or older 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 percent of FlOP_320 readings were found to have 2.67 times the risk of hip fractures of those in the bottom 30 percent.
"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 Wu, who notes that the other FlOP products can be generated without metals.
Hip fracture is associated with substantial cost, as well as higher risk of disability, co-morbidities and mortality than any other fractures. Current fracture risk assessment uses traditional risk factors such as age and presence of osteoporosis, but Wu sees FlOP_320 playing an important role in risk assessment.
"If our findings are confirmed in other studies, adding this marker into the existing fracture assessment model could improve the prediction of hip fracture in postmenopausal women,” she says.
The study was funded by grants from the American Heart Association, the NIH’s National Heart, Lung and Blood Institute and National Cancer Institute and the UC Center for Environmental Genetics, funded by the NIH’s National Institute of Environmental Health Sciences.
Keith Herrell | Eurek Alert!
New evidence: How amino acid cysteine combats Huntington's disease
27.07.2016 | Johns Hopkins Medicine
Cord blood outperforms matched, unrelated donor in bone marrow transplant
27.07.2016 | University of Colorado Anschutz Medical Campus
Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.
To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...
A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology
On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...
Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.
While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
27.07.2016 | Earth Sciences
27.07.2016 | Materials Sciences
27.07.2016 | Earth Sciences