This finding indicates that data such as vitamin D from foods and supplements or latitude of residence (northern vs. southern) cannot be used dependably as surrogate markers to assess the risk of breast and colon cancer.
Low blood levels of vitamin D have been associated with an increased risk of developing cancer, while high levels are considered potentially protective, making knowledge of a person's vitamin D status important.
Having a dependable way to obtain this information without drawing blood would eliminate the need for the invasive procedure, which some people find unpleasant, and could encourage more investigations on associations between vitamin D and disease risk.
However, results of the study conducted by UB epidemiologists show that such factors (e.g., age, vitamin D intake, supplement use, etc.), taken together, could explain only 21 percent of the variation in vitamin D levels between people.
These markers were particularly poor at identifying women with severe vitamin D deficiency or those with high levels, according to the findings.
Results of the study appear online ahead of print on the American Journal of Clinical Nutrition website.
"If we could predict someone's vitamin D status by asking them about their location of residence and their lifestyle, and combining that information with their demographic and medical characteristics, then research could be conducted on vitamin D status and disease even if we don't have blood samples from study participants," says Amy E. Millen, PhD, UB assistant professor of social and preventive medicine and first author on the study.
"Our analysis says we are not there yet. Other factors, such as genetics or other variables not measured or not yet known, may help to better predict an individual's blood vitamin D level.
"This information is important, nevertheless, because it tells researchers that less weight should be given to previous studies that used proxy measures for vitamin D instead of blood measures to predict risk of cancer outcomes."
The investigation is based on blood samples from 3,055 postmenopausal women who took part in the Women's Health Initiative (WHI) Calcium plus Vitamin D clinical trial conducted from 1995-2000 or in the original WHI trial, which took place from 1993-98.
Actual vitamin D data from the samples was compared to surrogate markers for vitamin D status -- latitude of residence, annual sunlight at particular latitudes, and how much vitamin D participants consumed from foods and supplements.
Even after considering latitude, season of the year when blood samples were taken, regional sunlight exposure, age, race-ethnicity and other lifestyle factors such as waist circumference and physical activity, there still were differences in serum vitamin D levels between people that could not be explained, results showed.
"We learned that using this data still doesn't allow us to very accurately predict an individual's blood vitamin D status," says Millen.
"However, our study did not have very detailed data on individual sun exposure, so if we had had that information, perhaps we might have been able to more accurately predict an individual's vitamin D blood levels. We assume, though, based on other studies similar to ours, that even with measures of sun exposure, a predictive model still wouldn't be very valid."
Millen's advice? "When evaluating the information you hear in the news, be aware that relationships between location of residence and a disease outcome, or even studies that looked at just vitamin D intake from foods and supplements (without consideration of sunlight exposure) may not accurately tell you about the true relationship between cancer and vitamin D."
Additional authors on the study are Jean Wactawski-Wende, PhD, professor and associate chair of the UB Department of Social and Preventive Medicine and vice provost for strategic initiatives; and researchers from Fred Hutchinson Cancer Research Center, Albert Einstein College of Medicine, University of Tennessee Health Science Center, UCLA, University of California Davis, Harvard Medical School and The Ohio State University.
The research is supported by the New York State Breast Cancer Research and Education Fund, and the WHI program funded by National Institutes of Health.
Lois Baker | EurekAlert!
Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research