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Published on Leave a comment on Time For Doctors To Prescribe Exercise

We all know that exercise is beneficial for health. Research suggests that exercising out in nature is best for several varied reasons -  including that it lowers markers of inflammation, and that it's good for our gut microbiome (community of gut microbes). The following excerpts are written by Dr. John La Puma encouraging other doctors to prescribe exercise for their patients and why.

An important message of his is that exercise is more important than a drug prescription for a number of conditions, including diabetes prevention, reducing the risk of recurrence of several cancers (he mentions breast cancer, but it also holds for prostate cancer). While exercising and walking out in nature may be best, any exercise anywhere is better than no exercise. (Other posts on exercise as prescription medicine are here and here; and check the category exercise for all exercise research posts).

From Medscape: Rx: Exercise Daily -- Outdoors. Doctor's Orders

With dazzling Olympic feats on display all summer, too many of my patients are still literally immobilized. Medically, sitting too long shuts off the enzyme lipoprotein lipase. In people who are sedentary, the enzyme doesn't break down fat to create energy, like it should. But medical prescription for exercise has lagged even the slowest runner. Why? Some reasons are time, training, and money. Time especially is a scarce commodity: The average clinician visit lasts just 20 minutes. Fitness is a shamefully small part of medical training. And as doctors, we don't get paid for discussing exercise, let alone monitoring a prescription and assessing the response. 

Finally, there are practical reasons. Clinicians find it difficult to persuade patients that exercise is more effective than medication for any number of conditions, including stroke recovery, diabetes prevention, and treatment of low back pain. Regular exercise reduces the risk for recurrent breast cancer by approximately 50%. Given all these reasons, it's easy to see why fitness prescriptions are seldom more than an afterthought. Yet even without formally prescribing the frequency, intensity, time, and type of exercise, clinicians can speak with patients and families about fitness in inspiring, life-changing ways.

Because clinicians have a secret weapon to use that most people don't even know about—location. Exercising in nature (in sight of and preferably near water or greenery, whether a deserted beach or an urban park) is better. Walking city streets and the office itself can be harder on your health than you think. In both environments, your attention is demanded and directed—sometimes by digital interruptions, sometimes by vehicles, toxins, or duties. In nature, your attention is drawn, not pushed, to a variety of often unexpected but not unpleasant sounds, colors, aromas, textures, and forms.

A recent Stanford study of nature therapy showed significantly reduced rumination after a 90-minute walk in nature, compared with a 90-minute walk through an urban environment. On MRI, "nature walkers" showed lower activity in an area of the brain linked to risk for mental illness, the subgenual prefrontal cortex, compared with "urban walkers." In other words, nature offers a sense of something bigger than ourselves on which to focus. MRIs show the way the brain changes when that sense occurs to us.

Exercising in nature may improve a person's immune system by enriching the diversity in the microbiota. Microbiota buffer the immune system against chronic stress-related disease. They appear to act as a hormone-producing organ, not simply a collection of beneficial bacteria. Microbiota are sensitive and responsive to physical environmental changes as well as dietary ones. So, exercise in nature may favorably boost microbiota.

And finally, exercise in nature is clinically preferred and calming. A Norwegian study showed that exercise in nature and in view of nature improves both mood and diastolic blood pressure vs exercise without nature. A Chinese study showed higher energy levels, and lower levels of interleukin-6 and tumor necrosis factor (both markers of inflammation), in a forest walking group compared with an urban exercising group. A British study showed significantly improved mood and self-esteem with "green" exercise, with the largest benefits from 5-minute engagements. Five minutes!

Of course, there are areas in our country and world in which it is dangerous to walk, never mind exercise. It may not be as easy to generate sweat and intensity with outdoor exercise as it is with indoor exercise. It may be stormy, or baking hot, or otherwise harsh outside, and the cool recesses of one's own bedroom or the gym may be just perfect for you today. And with the 2013 total cost of inactivity estimated at $24.7 billion for the United States, and with the public sector bearing almost one half of that expense, any exercise anywhere is better than none.  Yet physicians have a therapeutic tool few others in our culture wield—a prescription pad—and we have every patient's attention, at least for a few minutes. Patients try harder when doctors advise them about fitness. 

Published on Leave a comment on What’s In Your Household Dust?

Ten chemicals suspected or known to harm human health are present in more than 90% of U.S. household dust samples, according to a new study. The research adds to a growing body of evidence showing the dangers posed by exposure to chemicals we are exposed to on a daily basis. The chemicals come from a variety of household goods, including toys, cosmetics, personal care products, furniture, electronics, nonstick cookware, food packaging, floor coverings, some clothing (e.g., stain resistant), building materials, and cleaning products. How do the chemicals get into the dust? The chemicals can leach, migrate, abrade, or off-gas from the products, which winds up in the dust and  results in human exposure. (That's right:  vacuum a lot and wash your hands a lot, and try to avoid or cut  back use of products with these chemicals,)

What was found in the dust? The main chemicals were: phthalates — a group of chemicals that includes DEP, DEHP, DNBP and DIBP (these were present in the highest concentrations),  highly fluorinated chemicals (HFCs), flame retardants (both old and newer replacement ones), synthetic fragrances, and phenols. These chemicals are known to have various adverse health effects, including endocrine disruption, cancer, neurological, immune, and developmental effects. (See posts on endocrine disruptors and flame retardants) Studies typically study one chemical at a time, but household dust contains MIXTURES of these chemicals with effects unknown. How does it get into us? Inhalation, ingestion, and through skin contact. And while the levels we are exposed to may be low, research is showing that even low level exposure can have adverse health effects. From Medical Xpress:

Potentially harmful chemicals widespread in household dust

Household dust exposes people to a wide range of toxic chemicals from everyday products, according to a study led by researchers at Milken Institute School of Public Health at the George Washington University. The multi-institutional team conducted a first-of-a-kind meta-analysis, compiling data from dust samples collected throughout the United States to identify the top ten toxic chemicals commonly found in dust. They found that DEHP, a chemical belonging to a hazardous class called phthalates, was number one on that list. In addition, the researchers found that phthalates overall were found at the highest levels in dust followed by phenols and flame retardant chemicals....."The findings suggest that people, and especially children, are exposed on a daily basis to multiple chemicals in dust that are linked to serious health problems." ...continue reading "What’s In Your Household Dust?"

Published on Leave a comment on Treat Localized Prostate Cancer Or Not?

This is similar to what Dr. Gilbert Welch and others have been saying for a while - that studies show much cancer screening leads to overdiagnosis and overtreatment with no real differences in rates of mortality (death). Which was the whole point of cancer screening - to catch cancers early and so reduce rates of death. (For more on this topic see here, here, here, and here.) There are harms from overtreatment (unnecessary treatment), and with prostate cancer treatment there can be adverse effects on sexual (erectile dysfunction) , urinary, or bowel function, and sometimes even death from surgery. Remember that many prostate cancers are "indolent" or very slow growing, and may remain asymptomatic throughout the man's lifetime. Currently the U.S. Preventive Services Task Force (USPSTF) recommends against prostate-specific antigen (PSA)-based screening for prostate cancer for these reasons.

This study in the New England Journal of Medicine reported on men diagnosed with prostate cancer, with the men then assigned to either monitoring or treatment (surgery or radiation), and then followed for 10 years. Much to the researchers' surprise, the survival rates from prostate cancer were equally high in all the groups - 99%. Now, as the researchers themselves point out - the groups of men need to be followed for more years. Will there be differences after 15 or 20 years? Also, if there is prostate cancer progression in the monitored group (and more men did have disease progression in this group after 10 years, even though the numbers were low), can it still be treated just as successfully? More studies are needed. Note that there was cancer progression among some men even in both treatment groups.

Other important prostate cancer studies are also needed. Are there differences among those men for whom cancer progresses and for those that it doesn't? Does intense exercise make a difference (as some think)? Dietary differences, such as a plant based diet? Body fat or weight? From Science Xpress: Treat or monitor early prostate cancer? 10-yr survival same

Men with early prostate cancer who choose to closely monitor their disease are just as likely to survive at least 10 years as those who have surgery or radiation, finds a major study that directly tested and compared these options. Survival from prostate cancer was so high—99 percent, regardless of which approach men had—that the results call into question not only what treatment is best but also whether any treatment at all is needed for early-stage cases. And that in turn adds to concern about screening with PSA blood tests, because screening is worthwhile only if finding cancer earlier saves lives.

The study involved more than 82,000 men in the United Kingdom, aged 50 to 69, who had tests for PSA, or prostate specific antigen. High levels can signal prostate cancer but also may signal more harmless conditions, including natural enlargement that occurs with age. Researchers focused on the men diagnosed with early prostate cancer, where the disease is small and confined to the prostate. Of those men, 1,643 agreed to be randomly assigned to get surgery, radiation or active monitoring. That involves blood tests every three to six months, counseling, and consideration of treatment only if signs suggested worsening disease.

A decade later, researchers found no difference among the groups in rates of death from prostate cancer or other causes. More men being monitored saw their cancers worsen—112 versus 46 given surgery and 46 given radiation. But radiation and surgery brought more side effects, especially urinary, bowel or sexual problems....PSA testing remains popular in the U.S. even after a government task force recommended against it, saying it does more harm than good by leading to false alarms and overtreatment of many cancers that would never threaten a man's life. In Europe, prostate cancer screening is far less common.

From the original study in the The New England Journal of Medicine: 10-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Localized Prostate Cancer

The comparative effectiveness of treatments for prostate cancer that is detected by prostate-specific antigen (PSA) testing remains uncertain.  In the United States alone, an estimated 180,890 cases will be diagnosed in 2016, and 26,120 men will die from the disease.1 The widespread use of PSA testing has resulted in a dramatic increase in the diagnosis and treatment of prostate cancer, but many men do not benefit from intervention because the disease is either indolent or disseminated at diagnosis. Prostate cancer often progresses slowly, and many men die of competing causes. In addition, interventions for prostate cancer can have adverse effects on sexual, urinary, or bowel function. Two treatment trials have evaluated the effectiveness of treatment, but they did not compare the most common contemporary methods: surgery, radiotherapy, and monitoring or surveillance

We compared active monitoring, radical prostatectomy, and external-beam radiotherapy for the treatment of clinically localized prostate cancer. Between 1999 and 2009, a total of 82,429 men 50 to 69 years of age received a PSA test; 2664 received a diagnosis of localized prostate cancer, and 1643 agreed to undergo randomization to active monitoring (545 men), surgery (553), or radiotherapy (545). The primary outcome was prostate-cancer mortality at a median of 10 years of follow-up. Secondary outcomes included the rates of disease progression, metastases, and all-cause deaths.

There were 17 prostate-cancer–specific deaths overall: 8 in the active-monitoring group (1.5 deaths per 1000 person-years; 95% confidence interval [CI], 0.7 to 3.0), 5 in the surgery group (0.9 per 1000 person-years; 95% CI, 0.4 to 2.2), and 4 in the radiotherapy group (0.7 per 1000 person-years; 95% CI, 0.3 to 2.0); the difference among the groups was not significant (P=0.48 for the overall comparison). In addition, no significant difference was seen among the groups in the number of deaths from any cause (169 deaths overall; P=0.87 for the comparison among the three groups). Metastases developed in more men in the active-monitoring group (33 men; 6.3 events per 1000 person-years; 95% CI, 4.5 to 8.8) than in the surgery group (13 men; 2.4 per 1000 person-years; 95% CI, 1.4 to 4.2) or the radiotherapy group (16 men; 3.0 per 1000 person-years....). Higher rates of disease progression were seen in the active-monitoring group (112 men; 22.9 events per 1000 person-years; 95% CI, 19.0 to 27.5) than in the surgery group (46 men; 8.9 events per 1000 person-years; 95% CI, 6.7 to 11.9) or the radiotherapy group (46 men; 9.0 events per 1000 person-years....).

At a median of 10 years, prostate-cancer–specific mortality was low irrespective of the treatment assigned, with no significant difference among treatments. Surgery and radiotherapy were associated with lower incidences of disease progression and metastases than was active monitoring.

Published on Leave a comment on Selenium, Retinoic Acid, and Cancer Risk

Image result for meat, fish, eggs It is important to eat a varied diet for health, one that focuses on the food groups (and no - cookies and cake are not necessary foods). The first study looks at liver cancer risk and selenium - which is found in fish, shellfish, meat, milk, eggs, and certain South American nuts, such as Brazil nuts. The second article focuses on colorectal cancer and retinoic acid, a compound derived in the body from vitamin A. Vitamin A rich foods can provide you with retinoic acid, such as the lungs, kidneys, and liver of beef, lamb, pork. Also poultry giblets, eggs, cod liver oil, shrimp, fish, fortified milk, butter, cheddar cheese and Swiss cheese. Red and orange vegetables and fruits such as sweet potatoes, squash, carrots, pumpkins, cantaloupes, apricots, peaches and mangoes all contain significant amounts of beta-carotene, thus retinoids. Note that research generally has found health benefits from real foods, not from supplements.

From Science Daily:  Selenium status influence cancer risk

As a nutritional trace element, selenium forms an essential part of our diet. Researchers have been able to show that high blood selenium levels are associated with a decreased risk of developing liver cancer. Selenium (Se) is found in foods like fish, shellfish, meat, milk and eggs; certain South American nuts, such as Brazil nuts, are also good sources of selenium. It is a trace element that occurs naturally in soil and plants, and enters the bodies of humans and animals via the food they ingest. European soil has a rather low selenium concentration, in comparison with other areas of the world, especially in comparison to North America. Deficiencies of varying degrees of severity are common among the general population, and are the reason why German livestock receive selenium supplements in their feed.

While in Europe, neither a selenium-rich diet nor adequate selenium supplementation is associated with adverse effects, selenium deficiency is identified as a risk factor for a range of diseases. "We have been able to show that selenium deficiency is a major risk factor for liver cancer," says Prof. Dr. Lutz Schomburg of the Institute of Experimental Endocrinology, adding: "According to our data, the third of the population with lowest selenium status have a five- to ten-fold increased risk of developing hepatocellular carcinoma -- also known as liver cancer."....Previous studies had suggested a similar relationship between a person's selenium status and their risk of developing colon cancer, as well as their risk of developing autoimmune thyroid disease. (Original study)

From Science Daily: Retinoic acid suppresses colorectal cancer development, study finds

Retinoic acid, a compound derived in the body from vitamin A, plays a critical role in suppressing colorectal cancer in mice and humans, according to researchers at the Stanford University School of Medicine. Mice with the cancer have lower-than-normal levels of the metabolite in their gut, the researchers found. Furthermore, colorectal cancer patients whose intestinal tissues express high levels of a protein that degrades retinoic acid tend to fare more poorly than their peers.

"The intestine is constantly bombarded by foreign organisms," said Edgar Engleman, MD, professor of pathology and of medicine. "As a result, its immune system is very complex. There's a clear link in humans between inflammatory bowel disease, including ulcerative colitis, and the eventual development of colorectal cancer. Retinoic acid has been known for years to be involved in suppressing inflammation in the intestine. We wanted to connect the dots and learn whether and how retinoic acid levels directly affect cancer development."

"We found that bacteria, or molecules produced by bacteria, can cause a massive inflammatory reaction in the gut that directly affects retinoic acid metabolism," said Engleman. "Normally retinoic acid levels are regulated extremely tightly. This discovery could have important implications for the treatment of human colorectal cancer."

Further investigation showed that retinoic acid blocks or slows cancer development by activating a type of immune cell called a CD8 T cell. These T cells then kill off the cancer cells. In mice, lower levels of retinoic acid led to reduced numbers and activation of CD8 T cells in the intestinal tissue and increased the animals' tumor burden, the researchers found. "It's become very clear through many studies that chronic, smoldering inflammation is a very important risk factor for many types of cancer," said Engleman.

Published on Leave a comment on The Longer Overweight, the Greater A Woman’s Cancer Risk

Yikes! A good reason to lose weight now rather than years from now, and the importance of not ignoring a weight gain (you know, over the years as the pounds slowly creep up). The researchers found that for every 10 years of being overweight as an adult, there was an associated 7% increase in the risk for all obesity-related cancers. The degree of overweight (dose-response) during adulthood was important in the risk of developing cancer, especially for endometrial cancer. This study just looked at postmenopausal women, so it is unknown if it applies to men. From Medscape:

Longer Duration of Overweight Increases Cancer Risk in Women

A longer duration of being overweight during adulthood significantly increased the incidence of all cancers that are associated with obesity, a new study in postmenopausal women has concluded. The large population-based study was published August 16 in PLoS Medicine.

Dr Arnold and colleagues found that for every 10 years of being overweight as an adult, there was an associated 7% increase in the risk for all obesity-related cancers. The risk was highest for endometrial cancer (17%) and kidney cancer (16%). For breast cancer, the increased risk was 5%, but no significant associations were found for rectal, liver, gallbladder, pancreatic, ovarian, and thyroid cancer.

When the authors took into account the degree of excess weight over time, the risks were further increased, and there were "clear dose-response relationships," they note. Again, the risk was highest for endometrial cancer. For each additional decade spent with a body mass index (BMI) that was 10 units above normal weight, there was a 37% increase in the risk for endometrial cancer.

Study Details: The researchers used data from the huge American Women's Health Initiative (WHI) trial of postmenopausal women (aged 50 to 79 years at time of study enrollment). For this analysis, the team focused on a cohort of 73,913 postmenopausal women. During a mean follow-up of 12.6 years, 6301 obesity-related cancers were diagnosed. About 40% (n = 29,770) of women in the cohort were never overweight during their adult life....Women who were ever overweight were on average overweight for about 30 years, while those who were ever obese had been so for an average of 20 years. The authors found that the risk of being diagnosed with an obesity-related cancer rose for every 10 years of being overweight.

Published on Leave a comment on Overdiagnosed and Overtreated For Thyroid Cancer

The problem of overdiagnosis and overtreatment has been discussed in a number of posts on this site. And back in April 15, 2016 I posted that a type of noninvasive thyroid cancer had just been reclassified as a noncancer. Now a study in the prestigious New England Journal of Medicine finds that looking at 12 countries (including the USA): "Overall, we estimate that more than 470,000 women and 90,000 men may have been overdiagnosed with thyroid cancer over two decades in these 12 countries..."

The researchers further state that the "vast majority" of these patients received a diagnosis of small, low-risk papillary carcinomas, and they underwent surgery and other treatments, but these interventions have not shown "benefits in terms of improved survival". In fact, studies show that watchful waiting is just as effective. From Medscape:

Thyroid Cancer Overdiagnosis in Half a Million Patients

A large fraction of thyroid cancer cases represent overdiagnoses, and at least half a million patients, most of them women, may have received unnecessary surgery and other cancer treatments, say researchers from the the International Agency for Research on Cancer (IARC), in Lyons, France.

Their warning about an epidemic of thyroid cancer overdiagnosis comes from an analysis of cancer registry data from 12 countries published August 17 in the New England Journal of Medicine . Salvatore Vaccarella, PhD, and colleagues at the IARC estimate that more than 470,000 women and 90,000 men may have been overdiagnosed withthyroid cancer in 12 "high-income" countries (Australia, Denmark, England, Finland, France, Italy, Japan, Norway, Republic of Korea, Scotland, Sweden, and the United States) from 1987 to 2007.

Most of these thyroid cancers were small, low-risk papillary carcinomas, they note. The "vast majority" of these patients underwent total thyroidectomy, and a "high proportion" also received neck lymph-node dissection and radiotherapy, but these interventions do not have "proven benefits in terms of improved survival," the researchers point out...."However, if we take the most recent available period, 2003 - 2007, as typical of current practice, we estimate that overdiagnosis in women accounts for 90% of thyroid-cancer cases in South Korea; 70 to 80% in the United States, Italy, France, and Australia; and 50% in Japan, the Nordic countries, and England and Scotland."

The overdiagnosis is blamed on increasing medical surveillance and the introduction of new diagnostic techniques, such as neck ultrasonography (since the 1980s) and, more recently, CTscanning and MRI. This new technology has led to the detection of a large number of indolent, nonlethal diseases that exist in abundance in the thyroid gland of healthy people of any age, the researchers comment, adding that most of these tumors are very unlikely to cause symptoms or death....."It is fair to say that the large number of thyroid cancers being diagnosed represent an epidemic of diagnosis, or an epidemic of medical testing, rather than an epidemic of true disease."

These results also mean that most patients are receiving treatment that does not benefit them and that subjects them to risks of injury to the voice, permanent hypoparathyroidism, as well as the attendant risks of radioactive iodine treatment, he pointed out.  

The researchers caution against systematic screening for thyroid cancer and overtreatment of nodules <1 cm. "Watchful-waiting approaches should be considered a research priority and a preferable option for patients with low-risk papillary thyroid cancers," they say. Studies from Japan suggest that immediate surgery and watchful waiting are equally effective in preventing mortality, Dr Vaccarella said. One study showed that of 1235 patients with papillary microcarcinomas, only 3.5% experienced clinical progression of disease during a 75-month follow-up, and there were no deaths.

At Memorial Sloan Kettering Cancer Center, active surveillance has been offered to patients with low-risk, small, intrathyroidal cancers for several years, Dr Morris said. "Our results have mirrored the Japanese results, and fewer than 5% of patients end up showing any signs of tumor growth under close observation," he said.

Published on Leave a comment on Really Increase Activity Level to Reduce Risk of 5 Diseases

Get active, really active, to reduce your risk for 5 diseases: breast cancer, colon cancer, heart disease, and ischemic stroke. Instead of the 150 minutes of brisk walking or 75 minutes per week of running (which is equal to the 600 metabolic equivalent (MET) minutes now recommended by the World Health Organization), this study found that much more exercise is needed for best health results.

This study (which was a review and analysis of 174 studies) found that there is a dose-response effect, with the most reduction in the risk of the 5 conditions by getting 3000 to 4000 MET minutes per week. This sounds like a lot, but the researchers  point out that this can be achieved by incorporating exercise into your daily routines. The researchers write: "A person can achieve 3000 MET minutes/week by incorporating different types of physical activity into the daily routine—for example, climbing stairs 10 minutes, vacuuming 15 minutes, gardening 20 minutes, running 20 minutes, and walking or cycling for transportation 25 minutes on a daily basis would together achieve about 3000 MET minutes a week."

So start thinking creatively about how to increase exercise or activity into your daily life, especially moderate or vigorous intensity activity. For example, park your car far from the store door, or better yet, bicycle or walk to the store from home. From Medscape:

Get Moving: High Physical-Activity Level Reduces Risk of 5 Diseases

High levels of physical activity can reduce the risk for five major diseases, including type 2 diabetes, new research shows. Findings from the systematic review and meta-analysis were published online ....The data, from a total 174 studies comprising 149,184,285 total person-years of follow-up, suggest that the more total regular daily physical activity one engages in — including recreation, transportation, occupational activity, and/or daily chores — the lower the risks for breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke.

However, significant reductions in those conditions were seen only with total activity levels considerably higher than the minimum 600 metabolic equivalent (MET) minutes per week recommended by the World Health Organization for health benefits. That 600 METs equates to about 150 minutes/week of brisk walking or 75 minutes/week of running. (A MET is defined as the ratio of the metabolic rate during that activity to the metabolic rate when resting.) Risks of the five conditions dropped significantly with an increase in MET minutes per week from 600 to 3000 to 4000, with less additive benefit seen above that level.

For reference, the authors say, "a person can achieve 3000 MET minutes/week by incorporating different types of physical activity into the daily routine — for example, climbing stairs 10 minutes, vacuuming 15 minutes, gardening 20 minutes, running 20 minutes, and walking or cycling for transportation 25 minutes on a daily basis would together achieve about 3000 MET minutes a week." "This amount might seem a bit large, but this is about total activity across all domains of life.…For people who currently don't exercise, clinicians could encourage them to incorporate physical activity into their daily routines, [such as] turning household chores into exercise. 

Another recent meta-analysis of trials involving more than one million individuals indicated that an hour of moderate-intensity activity, such as brisk walking or cycling, offsets the health risks of 8 hours of sitting. The message that physical inactivity is a killer — leading to 5.3 million premature deaths annually worldwide, which is as many as caused by smoking and twice as many as associated with obesity, has been emerging over the past few years, with warnings that "sitting is the new smoking."

This new research is the first meta-analysis to quantify the dose-response association between total physical activity across all domains and the risk of five chronic diseases. The 174 prospective cohort studies included 35 for breast cancer, 19 for colon cancer, 55 for diabetes, 43 for ischemic heart disease, and 26 for ischemic stroke. (Some included more than one end point.)....Higher levels of total physical activity were associated with lower risks of all five outcomes.

With the development of diabetes, for example, compared with no physical activity, those with 600 MET minutes per week (the minimum recommended level of activity) had a 2% lower risk. That risk reduction jumped by an additional 19% with an increase from 600 to 3600 METs/week. Gains were smaller above that, with the increase of total activity from 9000 to 12,000 MET minutes/week yielding only an additional 0.6% diabetes reduction.

Overall, compared with insufficiently active individuals (total activity < 600 MET minutes/week), the risk reduction for those in the highly active category (≥ 8000 MET minutes/week) was 14% for breast cancer; 21% for colon cancer; 28% for diabetes; 25% for ischemic heart disease; and 26% for ischemic stroke. 

Credit: Medscape

Published on Leave a comment on Strong Evidence That Alcohol Causes Seven Cancers

A medical article in the journal Addiction states that there is strong evidence that alcohol causes 7 cancers, that there is evidence that it probably causes more, the effects are dose related, and if one also smokes the risks are greatly increased. The 7 cancers are: oropharynx (mouth and pharynx), larynx, esophagus, liver, colon, rectum, and female breast.

An earlier post reported on conflicting results from some studies (e.g. that low to moderate alcohol consumption is beneficial), as well as the finding that effects are dose-related (the more alcohol a person drinks, the higher the risk of cancer). NOTE: One standard drink contains 14 grams of alcohol, and is equivalent to one ordinary beer, a glass of wine (5 oz), or a nip of spirits (1.5 oz or 44 ml). The article excerpts below state that the strongest effects are from consuming 50 grams or more of alcohol per day (compared to those who don't drink at all).

From Medscape: No Confusion: Alcohol Causes Seven Cancers

There is "strong evidence" that alcohol causes seven cancers, and other evidence indicates that it "probably" causes more, according to a new literature review published online July 21 in Addiction. Epidemiologic evidence supports a causal association of alcohol consumption and cancers of the oropharynx, larynx, esophagus, liver, colon, rectum, and female breast, says Jennie Connor, MB, ChB, MPH, from the Department of Preventive and Social Medicine, University of Otago, in Dunegin, New Zealand.

In short, alcohol causes cancer. This is not news, says Dr Connor. The International Agency for Research on Cancer (IARC) and other agencies have long identified alcohol consumption as being causally associated with these seven cancers. So why did Dr Connor, who is an epidemiologist and physician, write a new review? Because she wants to "clarify the strength of the evidence" in an "accessible way." 

The newly published review "reinforces the need for the public to be made aware of the causal link between alcohol and cancer," said Colin Shevills, from the Alcohol Health Alliance UK, in a press statement....The lack of clarity about alcohol causing cancer, Dr Connor believes, is related to alcohol industry propaganda as well as the fact that the "epidemiological basis for causal inference is an iterative process that is never completed fully."

Dr Connor writes that the strength of the association of alcohol as a cause of cancer varies by bodily site. The evidence is "particularly strong" for cancer of the mouth, pharynx, and esophagus (relative risk, ~4-7 for ≥50 g/day of alcohol compared with no drinking) but is less so for colorectal cancer and liver and breast cancer (relative risk, ~1.5 for ≥50 g/day). "For cancers of the mouth, pharynx, larynx and oesophagus there is a well-recognized interaction of alcohol with smoking, resulting a multiplicative effect on risk," adds Dr Connor.

Other cancers are also likely caused by alcohol. Dr Connor writes that there is "accumulating research" supporting a causal contribution of alcohol to cancer of the pancreas, prostate, and skin (melanoma). One British expert had an opinion about alcohol's carcinogenicity. In a statement about the new review, Prof Dorothy Bennett, director of the Molecular and Clinical Sciences Research Institute at St. George's, University of London, said: "Alcohol enters cells very easily, and is then converted into acetaldehyde, which can damage DNA and is a known carcinogen."

In the new review, Dr Connor describes various hallmarks of causality that have been found in epidemiologic studies of alcohol and these seven cancers, such as a dose-response relationship and the fact that the risk for some of these cancers (esophageal, head and neck, and liver) attenuates when drinking ceases. Current estimates suggest that alcohol-attributable cancers at the seven cancer sites make up 5.8% of all cancer deaths worldwide, she states. The alcohol industry has a lot at stake, she says, which in turn leads to "misinformation" that "undermines research findings and contradicts evidence-based public health messages."

But there is no safe level of drinking with respect to cancer, says Dr Connor, citing research about low to moderate levels of alcohol, which has been covered by Medscape Medical News. This was also the conclusion of the 2014 World Cancer Report, issued by the World Health Organization's IARC.

Published on Leave a comment on Weight Loss As Cancer Prevention Method?

Another excellent reason to lose weight if you are overweight or obese: losing weight (through diet or through combined diet and exercise) significantly lowers levels of proteins in the blood that help cancerous tumors grow. In other words, reducing weight could turn out to be a cancer prevention method in overweight and obese persons. Exercise alone did not lower the levels of these cancer-associated proteins.

The study enrolled 439 overweight or obese women (aged 50 to 75 years old) from the Seattle area who were randomly placed into one of four groups for 12 months: exercise only, diet only, exercise plus diet, or no change to health habits. Researchers measured three proteins in blood samples - VEGF, PAI-1 and PEDF – that flow through the body and help in the formation of new blood vessels, a process called angiogenesis. Angiogenesis can occur during such processes as wound healing, but it also occurs during the growth of tumors. Since the three measured proteins are involved in nurturing the growth and survival of tumor cells, this is a great reason to lose weight - to lower their levels in the blood. From Science Daily:

Losing weight lowered levels of proteins associated with tumor growth

Overweight or obese women who lost weight through diet or a combination of diet and exercise also significantly lowered levels of proteins in the blood that help certain tumors grow, according to a Fred Hutchinson Cancer Research Center study published July 14 in Cancer Research, a journal of the American Association for Cancer Research.

The study: Measured three proteins that are known to enhance tumor-related angiogenesis -- the formation of blood vessels that feed tumors and enable them to grow. Was intended to see how cancer-promoting proteins changed when overweight, sedentary, postmenopausal women lost weight through diet or diet and exercise over the course of a year. Enrolled 439 healthy women (they did not have cancer), placing each participant in one of four study arms: 1) Calorie- and fat-restricted diet. 2) Aerobic exercise five days a week. 3) Combined diet and exercise. 4) Control (no intervention).

Found that women in the diet arm and the diet and exercise arm lost more weight and had significantly lower levels of angiogenesis-related proteins, compared with women in the exercise-only arm and the control arm.

This study shows that weight loss may be a safe and effective way to improve the "angiogenic profile" of healthy individuals, meaning they would have lower blood levels of cancer-promoting proteins. Although the researchers cannot say for certain that this would impact the growth of tumors, they believe there could be an association between reduced protein levels and a less favorable environment for tumor growth.

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Yup, according to a new mega-study, being overweight or obese is linked to higher risk of dying prematurely than being normal weight.  And the more you weigh, the greater the risk. This mega-study that looked at data from many studies and countries, also found that being underweight is linked to a higher risk of premature death. What's the best weight to be? A BMI of 22.5-<25 kg/m2 is considered a healthy weight range, and had the lowest mortality risk in the study. Being overweight was linked to higher rates of death from "all causes", and also from 4 major causes: coronary heart disease, stroke, respiratory disease, and cancer.

However, note that while other studies also agree that being underweight or obese increases the rate of dying prematurely, there is still some debate over whether being just overweight with BMI 25–<30 kg/m2 , really has a higher risk of dying prematurely. This was pointed out in the accompanying editorial in the journal Lancet (but not mentioned below). From Science Daily:

As overweight and obesity increase, so does risk of dying prematurely: Major study

Being overweight or obese is associated with a higher risk of dying prematurely than being normal weight -- and the risk increases with additional pounds, according to a large international collaborative study led by researchers at the Harvard T.H. Chan School of Public Health and the University of Cambridge, UK. The findings contradict recent reports that suggest a survival advantage to being overweight -- the so-called "obesity paradox."

The deleterious effects of excess body weight on chronic disease have been well documented. Recent studies suggesting otherwise have resulted in confusion among the public about what is a healthy weight. According to the authors of the new study, those prior studies had serious methodological limitations. One common problem is called reverse causation, in which a low body weight is the result of underlying or preclinical illness rather than the cause. Another problem is confounding by smoking because smokers tend to weigh less than nonsmokers but have much higher mortality rates.....Hu stressed that doctors should continue to counsel patients regarding the deleterious effects of excess body weight, which include a higher risk of diabetes, cardiovascular disease, and cancer.

For the new study, consortium researchers looked at data from more than 10.6 million participants from 239 large studies, conducted between 1970 and 2015, in 32 countries. A combined 1.6 million deaths were recorded across these studies, in which participants were followed for an average of 14 years. For the primary analyses, to address potential biases caused by smoking and preexisting diseases, the researchers excluded participants who were current or former smokers, those who had chronic diseases at the beginning of the study, and any who died in the first five years of follow-up, so that the group they analyzed included 4 million adults. They looked at participants' body mass index (BMI) -- an indicator of body fat calculated by dividing a person's weight in kilograms by their height in meters squared (kg/m2).

The results showed that participants with BMI of 22.5-<25 kg/m2 (considered a healthy weight range) had the lowest mortality risk during the time they were followed. The risk of mortality increased significantly throughout the overweight range: a BMI of 25-<27.5 kg/m2 was associated with a 7% higher risk of mortality; a BMI of 27.5-<30 kg/m2 was associated with a 20% higher risk; a BMI of 30.0-<35.0 kg/m2 was associated with a 45% higher risk; a BMI of 35.0-<40.0 kg/m2 was associated with a 94% higher risk; and a BMI of 40.0-<60.0 kg/m2 was associated with a nearly three-fold risk. Every 5 units higher BMI above 25 kg/m2 was associated with about 31% higher risk of premature death. Participants who were underweight also had a higher mortality risk.

Looking at specific causes of death, the study found that, for each 5-unit increase in BMI above 25 kg/m2, the corresponding increases in risk were 49% for cardiovascular mortality, 38% for respiratory disease mortality, and 19% for cancer mortality. Researchers also found that the hazards of excess body weight were greater in younger than in older people and in men than in women.