Friday, December 9, 2016
Starting in 1993 and ending in 2001, ten academic medical centers in the United States screened 76,685 men and 78,216 women for prostate, lung, colorectal and ovarian cancers. The question was whether yearly screening could catch cancers early and thus decrease mortality from these diseases.
Fifteen-year follow-up results focusing on prostate cancer were published this month in the journal Cancer, and show little difference in mortality between men screened annually and the control group, some of whom chose to be screened occasionally. According to researchers, the results don't necessarily negate the value of prostate cancer screening, but imply that within the data of this massive trial are clues that inform personalized decisions for subsets of this prostate cancer population.
"What we can see from these results is that most men diagnosed with prostate cancer will not die from their disease. In 15 years, people on the study died from lots of other things. However, we can also see that now we need to focus on discovering the men that will," says E. David Crawford, MD, investigator at the University of Colorado Cancer Center and study co-author.
Specifically, in the intervention arm that received annual prostate cancer screening, 255 men have died of prostate cancer since the start of the trial. In all, 244 men in the control arm, who did not receive annual screening (but may have received self-directed intermittent screening), died of prostate cancer. By comparison, 1,933 and 1,882 men in the experimental and control arms, respectively, died of other cancers. Slightly more in each group died of heart-related conditions.
According to Crawford, these data imply that some men need not be screened for prostate cancer.
"For example, we have since shown that men with PSA lower than one have only about a 0.5 percent chance of being diagnosed with prostate cancer within 10 years," Crawford says. Administering a PSA test first and then not screening men with PSA less than one would save billions of dollars in healthcare costs every year.
However, in addition to discovering no decreased mortality with yearly prostate cancer screening compared with intermittent screening, Crawford suggests that these results could be used to discover men who do, in fact, benefit from careful monitoring.
"I treated a guy who'd been diagnosed in his 40s," says Crawford. "We did surgery, but then a year later he was diagnosed with melanoma. It turned out that at the same time, his sister was diagnosed with triple-negative breast cancer and died within the year. Being diagnosed with prostate cancer in your 40s is a red flag that there might be a germline mutation to blame, predisposing these men and maybe family members who share the mutation to more, and more aggressive cancers. The PLCO shows that most men don't benefit from screening, but if we could have used the data to spot this guy, maybe we could have even tested his sister as well."
And so the takeaway from this retrospective on a massive study, 15 years after the completion of data gathering, is that despite what many have characterized as failure - after all, yearly screening did not result in overall lives saved - is that inside this data (or in related, follow-up studies) may still exist clues that could stratify prostate cancer risk.
Alongside the risks and costs of over-diagnosis and over-treatment that come with screening the entire population of men for prostate cancer still exists hope that screening only those with higher risk, at the right schedule, could save lives.
We all know that running causes a bit of inflammation and soreness, and that's just the price you pay for cardiovascular health. You know; no pain, no gain.
Well, maybe not. New research from BYU exercise science professors finds that pro-inflammatory molecules actually go down in the knee joint after running.
In other words, it appears running can reduce joint inflammation.
"It flies in the face of intuition," said study coauthor Matt Seeley, associate professor of exercise science at BYU. "This idea that long-distance running is bad for your knees might be a myth."
In a study recently published in the European Journal of Applied Physiology, Seeley and a group of BYU colleagues, as well as Dr. Eric Robinson from Intermountain Healthcare, measured inflammation markers in the knee joint fluid of several healthy men and women aged 18-35, both before and after running.
The researchers found that the specific markers they were looking for in the extracted synovial fluid--two cytokines named GM-CSF and IL-15--decreased in concentration in the subjects after 30 minutes of running. When the same fluids were extracted before and after a non-running condition, the inflammation markers stayed at similar levels.
"What we now know is that for young, healthy individuals, exercise creates an anti-inflammatory environment that may be beneficial in terms of long-term joint health," said study lead author Robert Hyldahl, BYU assistant professor of exercise science.
Hyldahl said the study results indicate running is chondroprotective, which means exercise may help delay the onset of joint degenerative diseases such as osteoarthritis.
This is potentially great news, since osteoarthritis--the painful disease where cartilage at the end of bones wears down and gradually worsens over time--affects about 27 million people in the United States.
Wednesday, December 7, 2016
Even modest increases in high blood pressure were linked to a greater risk of death and heart failure among African American adults of all ages, according to new research in Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.
In 2014, the eighth Joint National Committee (JNC) panel increased the recommended blood pressure for people 60 years and older without other medical conditions from less than 140/90 mm Hg to less than 150/90 mm Hg. These recommendations were published after the National Heart, Lung and Blood Institute elected to stop issuing clinical practice guidelines. The effects of the new recommendations on African Americans were unclear due to limited study data available for this population.
"Given that blood pressure targets are not attained in up to 50 percent of clinical practice, providers may want to proceed cautiously when liberalizing these targets in a group at higher risk of all the downstream effects of hypertension, such as heart attack, stroke, and chronic kidney disease," said Tiffany C. Randolph, M.D., study lead author and cardiologist at Cone Health Medical Group HeartCare in Greensboro, North Carolina. At the time of the study, Randolph was a research fellow at Duke University Medical Center in Durham, North Carolina.
In this study, researchers analyzed high blood pressure and the risk of death and hospitalization for heart failure in 5,280 patients enrolled in the Jackson Heart Study between 2000 and 2011 in Jackson, Mississippi. All participants were African American, nearly two-thirds were women, average age 56 years. The median follow-up was nine years for death, and seven years for hospitalization due to heart failure.
- Increases in systolic blood pressure were associated with a greater risk of death and heart failure across all age groups.
- With every 10 mm Hg increase in systolic blood pressure, the risk of death increased by 12 percent.
- The increased risk of death was greatest among patients under age 60, who faced a 26 percent increased risk with every 10 mm Hg increase in blood pressure, compared to less than 10 percent among those over age 60.
High blood pressure is a common disease that affects about 80 million -- one out of every three -- adults over age 20 in the United States. Often called the "silent killer" because of its lack of symptoms, high blood pressure is one of the main causes of serious diseases such as heart attack, stroke, kidney disease, and heart failure. Anyone can develop high blood pressure, but African Americans and women age 65 or older are at greater risk.
High blood pressure is manageable with heart-healthy lifestyle changes, including maintaining a healthy weight, following a healthy diet, being physically active, avoiding smoking and in some cases taking blood pressure-lowering medication.
Having an optimistic outlook on life--a general expectation that good things will happen--may help people live longer, according to a new study from Harvard T.H. Chan School of Public Health. The study found that women who were optimistic had a significantly reduced risk of dying from several major causes of death--including cancer, heart disease, stroke, respiratory disease, and infection--over an eight-year period, compared with women who were less optimistic.
The study will appear online December 7, 2016 in the American Journal of Epidemiology.
"While most medical and public health efforts today focus on reducing risk factors for diseases, evidence has been mounting that enhancing psychological resilience may also make a difference," said Eric Kim, research fellow in the Department of Social and Behavioral Sciences and co-lead author of the study. "Our new findings suggest that we should make efforts to boost optimism, which has been shown to be associated with healthier behaviors and healthier ways of coping with life challenges."
The study also found that healthy behaviors only partially explain the link between optimism and reduced mortality risk. One other possibility is that higher optimism directly impacts our biological systems, Kim said.
The study analyzed data from 2004-2012 from 70,000 women enrolled in the Nurses' Health Study, a long-running study tracking women's health via surveys every two years. They looked at participants' levels of optimism and other factors that might play a role in how optimism may affect mortality risk, such as race, high blood pressure, diet, and physical activity.
The most optimistic women (the top quartile) had a nearly 30% lower risk of dying from any of the diseases analyzed in the study compared with the least optimistic women (the bottom quartile), the study found. The most optimistic women had a 16% lower risk of dying from cancer; 38% lower risk of dying from heart disease; 39% lower risk of dying from stroke; 38% lower risk of dying from respiratory disease; and 52% lower risk of dying from infection.
While other studies have linked optimism with reduced risk of early death from cardiovascular problems, this was the first to find a link between optimism and reduced risk from other major causes.
"Previous studies have shown that optimism can be altered with relatively uncomplicated and low-cost interventions--even something as simple as having people write down and think about the best possible outcomes for various areas of their lives, such as careers or friendships," said postdoctoral research fellow Kaitlin Hagan, co-lead author of the study. "Encouraging use of these interventions could be an innovative way to enhance health in the future."
A large analysis of current research shows that people who eat at least 20g of nuts a day have a lower risk of heart disease, cancer and other diseases.
The analysis of all current studies on nut consumption and disease risk has revealed that 20g a day - equivalent to a handful - can cut people's risk of coronary heart disease by nearly 30 percent, their risk of cancer by 15 percent, and their risk of premature death by 22 percent.
An average of at least 20g of nut consumption was also associated with a reduced risk of dying from respiratory disease by about a half, and diabetes by nearly 40 percent, although the researchers note that there is less data about these diseases in relation to nut consumption.
The study, led by researchers from Imperial College London and the Norwegian University of Science and Technology, is published in the journal BMC Medicine.
The research team analysed 29 published studies from around the world that involved up to 819,000 participants, including more than 12,000 cases of coronary heart disease, 9,000 cases of stroke, 18,000 cases of cardiovascular disease and cancer, and more than 85,000 deaths.
While there was some variation between the populations that were studied, such as between men and women, people living in different regions, or people with different risk factors, the researchers found that nut consumption was associated with a reduction in disease risk across most of them.
Study co-author Dagfinn Aune from the School of Public Health at Imperial said: "In nutritional studies, so far much of the research has been on the big killers such as heart diseases, stroke and cancer, but now we're starting to see data for other diseases.
"We found a consistent reduction in risk across many different diseases, which is a strong indication that there is a real underlying relationship between nut consumption and different health outcomes. It's quite a substantial effect for such a small amount of food."
The study included all kinds of tree nuts, such as hazel nuts and walnuts, and also peanuts - which are actually legumes. The results were in general similar whether total nut intake, tree nuts or peanuts were analysed.
What makes nuts so potentially beneficial, said Aune, is their nutritional value: "Nuts and peanuts are high in fibre, magnesium, and polyunsaturated fats - nutrients that are beneficial for cutting cardiovascular disease risk and which can reduce cholesterol levels.
"Some nuts, particularly walnuts and pecan nuts are also high in antioxidants, which can fight oxidative stress and possibly reduce cancer risk. Even though nuts are quite high in fat, they are also high in fibre and protein, and there is some evidence that suggests nuts might actually reduce your risk of obesity over time."
The study also found that if people consumed on average more than 20g of nuts per day, there was little evidence of further improvement in health outcomes.
The team are now analysing large published datasets for the effects of other recommended food groups, including fruits and vegetables, on a wider range of diseases.
Tuesday, December 6, 2016
Sedentary men who start exercising between three and five times per week improve their sperm counts and other measures of sperm quality in just a few months, according to a new study published today in Reproduction. The researchers also found that men exercising moderately and continuously improved their sperm quality more than those following popular intensive exercise programs like HIIT.
1 in 3 couples struggle to conceive due to poor semen quality. The only treatment available for couples unable to conceive naturally is IVF, but using poor quality sperm may increase the risk of miscarriage, birth defects and the development of childhood cancer.
Current advice for men seeking to improve their chances of conceiving include combining healthy eating with regular exercise while giving up smoking and reducing the intake of alcohol. However, the link between exercise and sperm quality is not definitely proven. Some studies have even shown that strenuous exercise, such as long-distance running and endurance cycling, may actually have a negative impact on sperm quality.
In this study, researchers from the Urmia University in Iran set out to investigate whether the time men spend exercising and the intensity at which they work out have an impact on sperm quality. The researchers investigated 261 healthy men aged between 25 and 40 years old. Men who followed a regular exercise program or did more than 25 minutes of exercise more than 3 days per week were excluded from participating.
The researchers assigned each participant to one of four groups: moderate intensity continuous training (MICT), high intensity continuous training (HICT), high intensity interval training (HIIT), or a control group that did no exercise.
MICT and HICT exercises consisted of running on a treadmill for half an hour and one hour for 3-4 days per week respectively. HIIT consisted of short one-minute bursts of sprinting on a treadmill, followed by a one minute recovery period, repeating between ten to fifteen times. These routines were followed during a 24-week period.
Semen samples were taken before, during and after the different exercise regimens to assess the men's semen volume, sperm count, morphology, motility, levels of inflammatory markers and their response to oxidative stress.
The researchers found that men in all exercise groups had improved sperm quality across all measures when compared to the samples from the control group.
After completing the 24-week program, the MICT exercise group showed the biggest improvements in sperm quality, and also maintained these benefits for longer. Compared to the control group, those following MICT had:
- 8.3% more semen volume
- 12.4% higher sperm motility
- 17.1% improved sperm cell shape/morphology
- 14.1% more concentrated sperm
- and 21.8% more sperm cells on average
"Our results show that doing exercise can be a simple, cheap and effective strategy for improving sperm quality in sedentary men," said Behzad Hajizadeh Maleki, lead author of the study. "However, it's important to acknowledge that the reason some men can't have children isn't just based on their sperm count. Male infertility problems can be complex and changing lifestyles might not solve these cases easily."
The authors noted that while losing weight in general is likely to have contributed to improving sperm quality, MICT may have had the most profound impact on sperm quality because it reduces the gonad's exposure to inflammatory agents and oxidative stress.
The researchers' next steps are to investigate whether the training-induced changes in sperm quality will affect their fertilizing potential.
A new discovery at the University of Queensland could help reduce heart disease and boost nutrition security - the access to balanced nourishment - globally.
Researchers in UQ's Centre for Nutrition and Food Sciences have identified a new mechanism for how healthy cereals such as oats reduce the amount of cholesterol in the blood stream, thereby lowering the risk of heart disease.
The discovery could lead to ways of boosting the cholesterol-fighting properties of other cereals including wheat.
UQ's Professor Mike Gidley said the study, funded through the Australian Research Council Centre of Excellence in Plant Cell Walls, revealed new information on the function of beta glucans - a healthy soluble fibre naturally occurring in the cell walls of some plants, particularly cereals.
"We've known for some time that beta glucans in oats reduce blood cholesterol, but now we've discovered one of the ways in which they do it," Professor Gidley said.
Lead researcher Dr Purnima Gunness said the findings challenged the theory that beta glucans 'mop up' bile, which is secreted during digestion, and prevent its absorption in the small intestine.
"It was thought that the body's use of cholesterol to make new bile was one of the mechanisms for how beta glucans reduced the amount of cholesterol in the blood stream," Dr Gunness said.
The research, using pigs as a model for humans, revealed that the beta glucan in oats actually reduced, rather than maintained, the total amount of circulating bile.
"We aren't quite sure yet why, but in the presence of beta glucan there is much less circulating bile.
"This means that fats, which bile helps break down, are not digested as rapidly or as completely."
A lower or slower absorption of fat is an important factor in reducing blood cholesterol.
"Now that we know how the beta glucans positively impact on cholesterol levels, it will help us identify other fibres in plant cell walls that may have a similar effect," Dr Gunness said.