- Stool test that tests positive for 'invisible' or occult
blood indicates a high risk of dying from bowel cancer, plus more importantly,
all other causes, including, respiratory, blood, circulatory, hormone and
neuropsychological digestive diseases
- The positive test was strongly associated with all the conditions
even after accounting for risk factors like age and gender
- The participants of a bowel cancer screening test might
benefit if they are warned about the risk of other illnesses
Invisible blood in the stool puts a person at a heightened risk of dying from circulatory,
respiratory, digestive, blood, hormone and neuropsychological diseases, as well
as bowel cancer and other types of cancer, reveals research published online in
the journal Gut
otherwise called occult blood is named so as it cannot be seen with the naked
eye. It can be detected using the fecal occult blood test (FOBT) and is
currently used to screen for bowel cancer or colorectal cancer (cancer that
starts in the colon (large bowel) or back passage (rectum)) or its precursor,
polyps, in older people.
‘The presence of unseen or occult blood in a stool test is strongly associated with early death in circulatory, blood, hormone, digestive, neuropsychological, and respiratory causes, bowel cancer and other cancers, even after adjusting for risk factors like older age, male gender, and increasing levels of deprivation.’
The FOBT checks for the presence of blood in a sample of stool or feces
Blood in the stool indicates a possibility of bleeding in the digestive tract
that could be caused by hemorrhoids, polyps, ulcers, colitis or colorectal cancer
that affects the colon
research has indicated that blood in the stool might predict life expectancy
irrespective of whether a person has bowel cancer or not. But the research did
not account for other potentially influential factors, including drugs like
that might induce internal bleeding.
Design and Results
The researchers examined data of nearly 134,000 people, aged between
50 and 74 obtained from linked prescribing, bowel cancer screening, and death
registry in Tayside, Scotland, from March 2000 to the end of March 2016. They
tracked their survival from the date of the first test until death or the end
of March 2016, whichever came first.
- 2714 (just over 2%) tested positive for occult stool blood while
131,207 people tested negative during this period.
- Older people and those with increasing levels of deprivation, and
belonging to the male gender were associated with a higher likelihood of a
positive test result.
- Aspirin or other drugs that boost the risk of digestive tract
bleeds were also influencing a positive test result.
- People who showed a
positive FOBT result were nearly eight times as likely to die of bowel
cancer compared to those who tested negative, after normalizing for
gender, age, deprivation, and drug treatment.
- The most surprising result was that a positive FOBT result was also associated with a 58 percent
heightened risk of death from all other causes like cardiovascular, respiratory, digestive
tract, neuropsychological (how the brain correlates with the mind), blood
disorders, and hormone imbalances, as well as other types of
cancer, after normalizing for potentially influential factors.
The research team points out that even after adjusting for risk factors like older age, male
gender, and increasing levels of deprivation, a positive FOBT result was still
strongly associated with early death.
"Although increased [unseen stool blood] cannot be a cause of
death, it may reflect the reason why male gender, age and deprivation are such
strong risk factors," they suggest.
authors speculate that generalized inflammation that takes the form of gut
inflammation and bleeding may be a suspect, as most solid cancers and Alzheimer's disease
have been proved to
develop against a background of chronic/systemic inflammation.
positive FOBT result could be used in future to alert participants of a bowel
cancer screening programme without the disease (which amounts to around half of
those who test positive in the screening) that the test puts them at risk of
other potentially life-limiting illness, and that they need a healthier
lifestyle and/or preventive drug treatment.
Ladabaum of Stanford University School of Medicine says, "Perhaps more importantly, if
occult blood in feces is a predictor of life expectancy and multiple [non-bowel
cancer] causes of death, the inevitable next questions concern the implications
for organized [bowel cancer] screening programs or opportunistic [bowel cancer]
- Fecal Occult Blood Test (FOBT) - (https://medlineplus.gov/labtests/fecaloccultbloodtestfobt.html)