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The last post was about several reviews of vitamin D studies, and how when people are put randomly into different groups and then followed for a while - that the studies generally are not finding the same wonderful effects of higher levels of vitamin D in the blood that observational studies are finding - instead finding no effect or mixed results. Some issues with observational studies: the groups are self-selected, some are a one time snapshot of a person (thus one can't tell what happens over time); and can't prove cause and effect (can only say there is an association or link). [See all posts about vitamin D.]

But anyway, today's post is about some more vitamin D studies, all published in 2018. All of them find health benefits from higher blood levels of vitamin D. What is an ideal level of vitamin D varies from study to study, and some are observational - thus can only say "find an association with" in the findings. The fifth study finds beneficial effects from higher doses of vitamin D, and the participants were randomly assigned to the groups (good!). Click on links to read details. All excerpts are from Science Daily:

Vitamin D deficiency linked to greater risk of diabetes

An epidemiological study conducted by researchers at University of California San Diego School of Medicine and Seoul National University suggests that persons deficient in vitamin D may be at much greater risk of developing diabetes. The findings are reported in the April 19, 2018 online issue of PLOS One ...continue reading "Five Studies Looking at Vitamin D and Health"

New research published in The Lancet estimates that lead exposure results in about 400,000 deaths every year in the USA - which includes about 250,000 deaths from cardiovascular disease. The study looked at "historical exposure" to lead, which means they looked at a person's lead exposure years ago (which could have been from many sources, such as breathing lead contaminated dust, drinking water from leaded pipes, from lead paint, leaded gas, or eating from cans that have been soldered with lead). What was noteworthy in this study following over 14,000 adults was that there were increased death rates even from low lead blood levels (concentrations of lead in blood lower than 5 μg/dL).

Lead exposure has been declining since the 1970s after lead was eliminated (banned) from paint and gasoline, but this study looked at adults born in the years when lead exposure was higher during childhood and adulthood. Baseline data (blood lead levels) was collected between 1988 and 1994 and then individuals were followed for the next 2 decades. The researchers found that there was a dose response curve - the higher the blood lead level, the higher the death rate from any cause (all-cause mortality), from cardiovascular disease, and from ischaemic heart disease in the next two decades.

Lead is a naturally occurring heavy metal, but it's also a poisonous substance for humans, and accumulates in teeth and bones. Lead can pass through the blood-brain barrier in children and fetuses and kill brain cells (and cause neurological damage). Lead can enter blood vessels and harm the endothelial cells that line the blood vessels. This process hardens arteries and causes plaque to form in blood vessels, increasing blood pressure, and the risk of heart disease and stroke. Lead can damage the kidneys, which play an important role in regulating blood pressure, and so increase a person’s risk of heart disease and stroke.

The Centers for Disease Control and Prevention (CDC) have stated that there are no safe blood levels of lead for children (zero is best), and the researchers of this study believe the same is true for adults. From Science Daily:

Historical lead exposure may be linked to 256,000 premature deaths from cardiovascular disease in adults in United States each year

New estimates suggest that 256,000 premature deaths from cardiovascular disease -- including 185,000 deaths from ischemic heart disease -- in the USA may be linked to historical lead exposure in middle-aged and older adults (people currently aged 44 years or over), according to an observational study following 14,300 people for almost 20 years, published in The Lancet Public Health journal.  ...continue reading "Even Low Level Lead Exposure Is Linked to Later Health Problems"

A number of recent studies and articles have discussed the effectiveness of diet in treating or preventing depression with the main conclusion that yes, it helps. Now an observational study (that will be presented in April) found that elderly people following the DASH diet most closely were 11% less likely to become depressed over time than those that did not.

Researchers studying 964 elderly participants over six and a half years found that those who followed the DASH diet, which emphasizes whole grains, fruits, and vegetables, had lower rates of depression, while those who ate a traditional Western diet were more prone to depression. The DASH (Dietary Approaches to Stop Hypertension) diet also emphasizes low sodium (salt) to lower blood pressure, as well as foods rich in nutrients (such as potassium, calcium, and magnesium) that are thought to lower blood pressure.

The study's lead author L. J. Cherian (at Rush Medical Center in Chicago) said that "we need to view food as medicine”. Yes. Eating more fruits and vegetables, whole grains, legumes, seeds, nuts have many health benefits (such as cardiovascular benefits, improving the gut microbes) -  a win-win. From Science Daily:

Diet shown to reduce stroke risk may also reduce risk of depression

People who eat vegetables, fruit and whole grains may have lower rates of depression over time, according to a preliminary study that will be presented at the American Academy of Neurology's 70th Annual Meeting in Los Angeles, April 21 to 27, 2018. The study found that people whose diets adhered more closely to the Dietary Approaches to Stop Hypertension (DASH) diet were less likely to develop depression than people who did not closely follow the diet. In addition to fruit and vegetables, the DASH diet recommends fat-free or low-fat dairy products and limits foods that are high in saturated fats and sugar. Studies have shown health benefits such as lowering high blood pressure and bad cholesterol (LDL), along with lowering body weight ...continue reading "DASH Diet Linked To Lower Rate of Depression"

Another study finding health benefits from eating yogurt - that men and women with hypertension who eat at least 2 servings or more per week of yogurt were at a lower risk of having a heart attack (myocardial infarction) and stroke. Women also had a lower risk of a revascularization procedure (such as a coronary artery bypass). The strongest association between yogurt consumption and lower risk of cardiovascular disease was among those with higher DASH (Dietary Approaches to Stop Hypertension) diet scores.The DASH diet is considered a healthy diet, one rich in fruits, vegetables, nuts, whole grains, beans (legumes), etc.

The major thing to keep in mind is that high blood pressure is a major cardiovascular disease risk factor. So anything that helps lower risk of heart attack or stroke is good. Note that in this large study they did not randomly assign people to different groups - so the higher yogurt intake people also tended to have a healthier lifestyle. But other studies have had similar findings to this one. For example, eating dairy products regularly is linked to lower rates of cardiovascular disease and high blood pressure, while eating yogurt regularly is linked to lower rates of hypertension and type 2 diabetes.

Also note that the types of yogurt (whole-fat, low-fat, non-fat) eaten were not looked at, as well as the types of probiotics added to yogurts. Some research suggests that beneficial effects are from whole fat dairy products rather than low-fat dairy products - which is different than DASH diet recommendations. From Science Daily:

Eating yogurt may reduce cardiovascular disease risk

A new study in the American Journal of Hypertension, published by Oxford University Press, suggests that higher yogurt intake is associated with lower cardiovascular disease risk among hypertensive men and women. .... High blood pressure affects about one billion people worldwide but may also be a major cause of cardiovascular health problems. Higher dairy consumption has been associated with beneficial effects on cardiovascular disease-related comorbidities such as hypertension, type 2 diabetes, and insulin resistance.

For the current analyses, participants included over 55,000 women (ages 30-55) with high blood pressure from the Nurses' Health Study and 18,000 men (ages 40-75) who participated in the Health Professionals Follow-Up Study.

Higher intakes of yogurt were associated with a 30 percent reduction in risk of myocardial infarction among the Nurses' Health Study women and a 19 percent reduction in the Health Professionals Follow-Up Study men. There were 3,300 and 2,148 total cardiovascular disease cases (myocardial infarction, stroke, and revascularization) in the Nurses' Health Study and the Health Professionals Follow-Up Study, respectively. Higher yogurt intake in women was associated with a 16 percent lower risk of undergoing revascularization.

In both groups, participants consuming more than two servings a week of yogurt had an approximately 20 percent lower risks of major coronary heart disease or stroke during the follow-up period. When revascularization was added to the total cardiovascular disease outcome variable, the risk estimates were reduced for both men and women, but remained significant. Higher yogurt intake in combination with an overall heart-healthy diet was associated with greater reductions in cardiovascular disease risk among hypertensive men and women.  [Original study.]

A new observational study from Taiwan found that having one of eight chronic diseases, such as heart disease or diabetes, or their markers (e.g. high cholesterol levels as a marker for heart disease), also significantly raises the person's odds of developing cancer or dying from cancer. The study estimated that these diseases or markers accounted for about 20% of all new cancers and 39% of all cancer deaths. That's about the risk of 5 lifestyle factors combined (smoking, alcohol consumption, obesity, unhealthy diet, and lack of exercise) contributing to cancer development and death.

The eight chronic diseases and markers were: cardiovascular disease (markers for which include blood pressure, total cholesterol, and heart rate), diabetes, chronic kidney disease (markers for which include proteinuria and glomerular filtration rate), pulmonary disease, and gouty arthritis (for which uric acid is a marker). The higher the chronic disease and marker score, the higher the risk of developing cancer and cancer death (a dose-response). Chronic diseases and markers were associated with a shortened lifespan -  about 13.3 years in men and 15.9 years in women.

But the good news is that regular physical exercise lowers the risk of developing cancer by about 48% and the risk of cancer death by 27%. That's huge!  So physical exercise and activity could be viewed as "cancer prevention" strategies. The researchers pointed out that additional cancer prevention strategies are avoiding smoking (very important), avoiding excessive alcohol consumption, maintaining healthy weight, and a healthy diet. From Science Daily:

Substantial impact of chronic diseases on cancer risk

Several common chronic diseases together account for more than a fifth of new cancer cases and more than a third of cancer deaths, finds a study published by The BMJ today. The findings show that the cancer risks from common chronic diseases, such as heart disease and diabetes, are as important as those from five major lifestyle factors combined.

A team of researchers based in the US and Taiwan therefore set out to investigate the combined effect of eight common chronic diseases or disease markers (for example, high blood pressure as a marker of heart disease) on cancer risk compared with lifestyle factorsThey also explored whether physical activity could reduce the cancer risk associated with chronic diseases and disease markers. The study involved 405,878 men and women in Taiwan with no history of cancer .... underwent a series of medical tests between 1996 and 2007. .... Participants were followed for an average of 8.7 years.

The researchers found that cardiovascular disease markers, diabetes, chronic kidney disease markers, pulmonary disease, and gouty arthritis marker were individually associated with risk of developing cancer or cancer death. Higher chronic disease risk scores based on these diseases or markers were linked with an increased risk of developing cancer and cancer death, with the highest level associated with a more than twofold increase in risk of developing cancer and a fourfold increase in risk of cancer death.

High chronic disease risk scores were also associated with substantial reduction in life span. The highest scores were associated with 13.3 years of life lost in men and 15.9 years of life lost in women. Together, these chronic diseases and markers accounted for more than one fifth of all new cancers and more than one third of all cancer deaths in this study population, which was similar to the contribution of five major lifestyle risk factors combined -- smoking, insufficient physical activity, insufficient fruit and vegetable intake, alcohol consumption, and obesity.

The researchers also found that physical activity was associated with a nearly 40% reduction in the excess risks of cancer and cancer death associated with chronic diseases and markers. [Original study.]

A recent study's results give hope to those who haven't really exercised or been physically active as they've gone through middle-age (it's viewed as "sedentary aging") and wonder if this dooms them in some way. Is it too late to get benefits from starting to exercise now? Studies show that being sedentary (that is, not being physically active or exercising weekly) and in "poor physical fitness" in middle-age is a risk factor for later heart failure. This is because a consequence of "sedentary aging" is stiffness of the heart, specifically the left ventricle (thus a loss of "cardiac plasticity").

But the study found that after 2 years of an exercise program in (formerly) sedentary middle-aged adults, they improved their maximal oxygen uptake, decreased the heart's stiffness, and improved overall fitness. All good, even though it was a small study (only 53 people completed the study). So the bottom line is: No, it's not too late to start exercising. The heart has elasticity and can remodel itself if the exercise is started before age 65 and is done 4 to 5 times a week. The adults studied were both male and female, between the ages of 45 and 64,  and exercised or were physically active for a total of 150 to 180 minutes a week, which meant at least 30 minutes 4 or 5 times a week.

Looking at the study's exercise regimen, it's clear that a variety of exercises or physical activities (low, moderate, and high intensity) is necessary. Some of the time one should be active or exercise to a point of breaking a sweat and feeling the heart pump. This meant that over time the participants increased their exercise frequency, duration, and intensity. Think about it - as you get more fit, it takes more to get your heart pumping and to break a sweat, and you can handle more exercise. 

Unfortunately the "control group", who did a combination of yoga, balance, and strength training 3 times a week for 2 years did not show improvements in heart plasticity, maximal oxygen uptake, or in overall fitness.Yikes. Sooo...the study clearly shows it is worth getting off your butt and making the effort to exercise. Perhaps view it as brushing your teeth - a daily nuisance, but necessary for health. The researchers themselves stated "Exercise is medicine." From Science Daily:

Proper exercise can reverse damage from heart aging

Exercise can reverse damage to sedentary, aging hearts and help prevent risk of future heart failure -- if it's enough exercise, and if it's begun in time, according to a new study by cardiologists at UT Southwestern and Texas Health Resources. To reap the most benefit, the exercise regimen should begin by late middle age (before age 65), when the heart apparently retains some plasticity and ability to remodel itself, according to the findings by researchers at the Institute for Exercise and Environmental Medicine (IEEM), which is a collaboration between UT Southwestern Medical Center and Texas Health Presbyterian Hospital Dallas.

And the exercise needs to be performed four to five times a week. Two to three times a week was not enough, the researchers found in an earlier study..... The regimen included exercising four to five times a week, generally in 30-minute sessions, plus warmup and cool-down: One of the weekly sessions included a high-intensity 30-minute workout, such as aerobic interval sessions in which heart rate tops 95 percent of peak rate for 4 minutes, with 3 minutes of recovery, repeated four times (a so-called "4 x 4"). Each interval session was followed by a recovery session performed at relatively low intensity. One day's session lasted an hour and was of moderate intensity. (As a "prescription for life," Levine said this longer session could be a fun activity such as tennis, aerobic dancing, walking, or biking.) One or two other sessions were performed each week at a moderate intensity, meaning the participant would break a sweat, be a little short of breath, but still be able to carry on a conversation -- the "talk test.".... One or two weekly strength training sessions using weights or exercise machines were included on a separate day, or after an endurance session.

The more than 50 participants in the study were divided into two groups, one of which received two years of supervised exercise training and the other group, a control group, which participated in yoga and balance training.A t the end of the two-year study, those who had exercised showed an 18 percent improvement in their maximum oxygen intake during exercise and a more than 25 percent improvement in compliance, or elasticity, of the left ventricular muscle of the heart, Dr. Levine noted. He compared the change in the heart to a stretchy, new rubber band versus one that has gotten stiff sitting in a drawer. Sedentary aging can lead to a stiffening of the muscle in the heart's left ventricle, the chamber that pumps oxygen-rich blood back out to the body, he explained.

"When the muscle stiffens, you get high pressure and the heart chamber doesn't fill as well with blood. In its most severe form, blood can back up into the lungs. That's when heart failure develops," said Dr. Levine, who holds the S. Finley Ewing Chair for Wellness at Texas Health Dallas and the Harry S. Moss Heart Chair for Cardiovascular Research. Earlier research by UT Southwestern cardiologists showed that left ventricular stiffening often shows up in middle age in people who don't exercise and aren't fit, leaving them with small, stiff chambers that can't pump blood as well[Original study.]

This is interesting, that blood pressure naturally starts lowering in the 14 to 18 years prior to death in people 60 years or older - whether they are healthy, have hypertension, have heart disease, take hypertension medicines or not.

The researchers analyzed 20 years of medical data for patients in the United Kingdom, and while everyone's blood pressure dropped for more than a decade before death, the decreases were "steepest in patients with hypertension, dementia, heart failure, and late-life weight loss". From Science Daily:

Blood pressure declines 14 to 18 years before death

Blood pressure in the elderly gradually begins to decrease about 14 or so years before death, according to a new study published today in the Journal of the American Medical Association Internal Medicine. Researchers from UConn Health and the University of Exeter Medical School in the U.K. looked at the electronic medical records of 46,634 British citizens who had died at age 60 or older. The large sample size included people who were healthy as well as those who had conditions such as heart disease or dementia.

They found blood pressure declines were steepest in patients with dementia, heart failure, late-in-life weight loss, and those who had high blood pressure to begin with. But long-term declines also occurred without the presence of any of these diagnoses.

Doctors have long known that in the average person, blood pressure rises from childhood to middle age. .... Some studies have indicated that blood pressure might drop in older patients and treatment for hypertension has been hypothesized as explaining late-life lower blood pressures. But this study found blood pressure declines were also present in those without hypertension diagnoses or anti-hypertension medication prescriptions. Further, the evidence was clear that the declines were not due simply to the early deaths of people with high blood pressure. [Original study.]

There are health benefits to having a dog, based on results from studies and testimonials from dog owners. Now a study of millions of Swedes found  that dog ownership is associated with a lower risk of cardiovascular disease (CVD) in single-person households and a lower risk of death from cardiovascular or other causes ("all cause mortality") in general. Owning a hunting dog breed had the strongest association with cardiovascular health. Some of these health benefits are due to dogs providing companionship, affection, and increased physical activity (all those walks) of their owners. And of course there's sharing of microbes. From Science Daily:

Dog ownership linked to lower mortality rate

A team of Swedish scientists have used national registries of more than 3.4 million Swedes aged 40 to 80 to study the association between dog ownership and cardiovascular health. Their study shows that dog owners had a lower risk of death due to cardiovascular disease or to other causes during the 12-year follow-upA total of more than 3.4 million individuals without any prior cardiovascular disease in 2001 were included in the researchers' study linking together seven different national data sources, including two dog ownership registers. 

"A very interesting finding in our study was that dog ownership was especially prominent as a protective factor in persons living alone, which is a group reported previously to be at higher risk of cardiovascular disease and death than those living in a multi-person household. Perhaps a dog may stand in as an important family member in the single households. The results showed that single dog owners had a 33 percent reduction in risk of death and 11 percent reduction in risk of cardiovascular disease during follow-up compared to single non-owners. Another interesting finding was that owners to dogs from breed groups originally bred for hunting were most protected," says Mwenya Mubanga, lead junior author of the study and PhD student at the Department of Medical Sciences and the Science for Life Laboratory, Uppsala University.

"These kind of epidemiological studies look for associations in large populations but do not provide answers on whether and how dogs could protect from cardiovascular disease. We know that dog owners in general have a higher level of physical activity, which could be one explanation to the observed results. Other explanations include an increased well-being and social contacts or effects of the dog on the bacterial microbiome in the owner," says Tove Fall, senior author of the study and Associate Professor in Epidemiology at the Department of Medical Sciences and the Science for Life Laboratory, Uppsala University. "There might also be differences between owners and non-owners already before buying a dog, which could have influenced our results, such as those people choosing to get a dog tending to be more active and of better health." [Original study.]

Is frequent sauna bathing beneficial? That's what one study suggests. When the study started all 1621 men (aged 42 to 60) had normal blood pressure and none had been diagnosed with hypertension, and the follow-up was about 22 years later. The study took place in Finland, where sauna bathing is an important part of the culture - for all men, from all walks of life. The study found that frequent sauna bathing lowered the risk of developing hypertension - 46% when comparing men who sauna bathed once a week vs those who sauna bathed 4 to 7 times a week.

How could sauna bathing have these effects? There are several possibilities, but one is that sauna bathing produces "acute vasodilation" of the blood vessels, which leads to a significant drop in blood pressure. The temperature in the sauna is usually from 80 °C to 100 °C (176 to 212 degrees Fahrenheit), and the average sauna session (in this study) lasted an average of 14.4 minutes. From Science Daily:

Frequent sauna bathing keeps blood pressure in check

Frequent sauna bathing reduces the risk of elevated blood pressure, according to an extensive follow-up population-based study carried out at the University of Eastern Finland. The risk of developing elevated blood pressure was nearly 50% lower among men who had a sauna 4-7 times a week compared to men who had a sauna only once a weekThe same researchers have previously shown that frequent sauna bathing reduces the risk of sudden cardiac death, and cardiovascular and all-cause mortality. Elevated blood pressure is documented to be one of the most important risk factors of cardiovascular diseases.

The Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) involved 1,621 middle-aged men living in the eastern part of Finland. Study participants without elevated blood pressure of over 140/90 mmHg or with diagnosed hypertension at the study baseline were included in this long-term follow-up study. Based on their sauna bathing habits, men were divided into three sauna frequency groups: those taking a sauna once a week, 2-3 times a week, or 4-7 times a week. During an average follow-up of 22 years, 15.5% of the men developed clinically defined hypertension. The risk of hypertension was 24% decreased among men with a sauna frequency of 2-3 times a week, and 46% lowered among men who had a sauna 4-7 times a week.

Sauna bathing may decrease systemic blood pressure through different biological mechanisms. During sauna bathing, the body temperature may rise up to 2 °C degrees, causing vessels vasodilation. Regular sauna bathing improves endothelial function, i.e. the function of the inside layer of blood vessels, which has beneficial effects on systemic blood pressure. Sweating, in turn, removes fluid from the body, which is a contributing factor to decreased blood pressure levels. Additionally, sauna bathing may also lower systemic blood pressure due to overall relaxation of the body and mind.

[NOTE: Above photo is of interior of a modern Finnish sauna. Credit: Wikipedia]

OK everyone - even if you sit all day at a desk job, the research is clear: try to get up and stretch or move a little every 30 minutes. Researchers followed middle-aged and older adults over a 5 1/2 year period and found that total sitting time (sedentary behavior) and prolonged, uninterrupted sedentary behavior were associated with in increased risk for death from any cause (all-cause mortality). But..adults who kept most of their sitting bouts to less than 30 minutes had the lowest risk of death. The researchers felt that getting up and moving every half hour seems to protect against the health risks (cardiometabolic effects) from just sitting and sitting and sitting. Are you moving yet?

From Science Daily: Long sitting periods may be just as harmful as daily total

A new study finds that it isn't just the amount of time spent sitting, but also the way in which sitting time is accumulated during the day, that can affect risk of early deathThe study, published online today in Annals of Internal Medicine, found that adults who sit for one to two hours at a time without moving have a higher mortality rate than adults who accrue the same amount of sedentary time in shorter bouts.

The researchers used hip-mounted activity monitors to objectively measure inactivity during waking time over a period of seven days in 7,985 black and white adults over age 45. (The participants were taking part in the REGARDS study, a national investigation of racial and regional disparities in stroke.)

On average, sedentary behavior accounted for 77 percent of the participants' waking hours, equivalent to more than 12 hours per day. Over a median follow-up period of four years, 340 of the participants died. Mortality risk was calculated for those with various amounts of total sedentary time and various sedentary patterns. Those with the greatest amount of sedentary time -- more than 13 hours per day -- and who frequently had sedentary bouts of at least 60 to 90 consecutive minutes had a nearly two-fold increase in death risk compared with those who had the least total sedentary time and the shortest sedentary bouts.

The researchers also found that participants who kept most of their sitting bouts to less than 30 minutes had the lowest risk of death. "So if you have a job or lifestyle where you have to sit for prolonged periods of time, we suggest taking a movement break every half hour. This one behavior change could reduce your risk of death, although we don't yet know precisely how much activity is optimal," Dr. Diaz said. [Original study.]