Abnormal blood pressure in middle and late life influences dementia risk

In a study that spanned two and a half decades and looked at data from more than 4,700 participants, Johns Hopkins researchers have added to evidence that abnormal blood pressure in midlife persisting into late life increases the likelihood of developing dementia. Although not designed to show cause and effect, the study suggests that maintaining a healthy blood pressure throughout life may be one way to help decrease one's risk of losing brain function.

"Our results suggest that one's blood pressure during midlife may influence how blood pressure later in life relates to dementia risk," says Keenan Walker, Ph.D., assistant professor of neurology at the Johns Hopkins University School of Medicine. "We found that individuals with high blood pressure in midlife may benefit from targeting their blood pressure to normal levels in later life, as having blood pressure that is too high or too low in late life may further increase dementia risk."

In their study, they found that those people with the high blood pressure condition hypertension during middle age and during late life were 49% more likely to develop dementia than those with normal blood pressure at both times. But, putting one at even greater risk was having hypertension in middle age and then having low blood pressure in late life, which increased one's dementia risk by 62%. The findings were published Aug. 13 in JAMA.

High blood pressure was considered any measurement more than 140/90 millimeters of mercury, whereas low blood pressure was defined as less than 90/60 millimeters of mercury. A cognitive exam, caregiver reports, hospitalization discharge codes and death certificates were used to classify participant brain function and determine cognitive impairment.

High blood pressure can be genetic, but can also be the result of not enough exercise and poor diet. As people age, the top blood pressure number (systolic) oftentimes increases while the bottom number (diastolic) can decrease due to structural changes in the blood vessels. Walker says dementia itself may lead to a lowering of blood pressure, as it may disrupt the brain's autonomic nervous system. Stiffening of the arteries from disease and physical frailty can also lead to low blood pressure in late life.

According to the Centers for Disease Control and Prevention, 75 million people in the U.S. have high blood pressure, and high blood pressure can raise the risk for heart disease, as well as other health conditions.

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Materials provided by Johns Hopkins Medicine. Note: Content may be edited for style and length.

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Journal Reference:

1. Keenan A. Walker, A. Richey Sharrett, Aozhou Wu, Andrea L. C. Schneider, Marilyn Albert, Pamela L. Lutsey, Karen Bandeen-Roche, Josef Coresh, Alden L. Gross, B. Gwen Windham, David S. Knopman, Melinda C. Power, Andreea M. Rawlings, Thomas H. Mosley, Rebecca F. Gottesman. Association of Midlife to Late-Life Blood Pressure Patterns With Incident Dementia. JAMA, 2019; 322 (6): 535 DOI: 10.1001/jama.2019.10575

Diet change needed to save vast areas of tropics

One quarter of the world's tropical land could disappear by the end of the century unless meat and dairy consumption falls, researchers have warned.

If the global demand for animal products continues to grow, large swathes of natural land will vanish potentially leading to widespread loss of species and their habitats.

Some nine per cent of natural land -- 95 per cent of which is in the tropics -- could go within 80 years unless global dietary habits change, the scientists say.

Researchers at the University of Edinburgh and Karlsruhe Institute of Technology studied the impact of consumption trends on biodiverse regions -- areas that have a wealth of mammals, birds, amphibians and plant life.

They found that rapid increases in meat and milk production result in sharp rises in land clearing in tropical regions that harbour high levels of biodiversity.

As incomes increase across the globe, consumption has shifted from staples such as starchy roots and pulses to meat, milk, and refined sugars.

Meat and dairy production is associated with higher land and water use and higher greenhouse gas emissions than any other foods.

By replacing animal products with plant-based alternatives, they predict that the global demand for agricultural land could be reduced by 11 per cent.

Researchers also found that industrial feed systems reduce agricultural expansion but may increase environmental degradation due to agricultural pollutants such as fertiliser.

The study comes after the Intergovernmental Panel on Climate Change last week published a special report that identified reducing meat consumption as an important focus for climate change mitigation.

Lead author Dr Roslyn Henry, said, "Reducing meat and dairy consumption will have positive effects on greenhouse gas emissions and human health. It will also help biodiversity, which must be conserved to ensure the world's growing population is fed. Changing our diets will lead to a more sustainable future and complement food security goals while addressing global food inequalities."

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Materials provided by University of Edinburgh. Note: Content may be edited for style and length.

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Journal Reference:

1. Roslyn C. Henry, Peter Alexander, Sam Rabin, Peter Anthoni, Mark D.A. Rounsevell, Almut Arneth. The role of global dietary transitions for safeguarding biodiversity. Global Environmental Change, 2019; 58: 101956 DOI: 10.1016/j.gloenvcha.2019.101956

C-DIFF Diarrhea-causing bacteria adapted to spread in hospitals

Scientists have discovered that the gut-infecting bacterium Clostridium difficile is evolving into two separate species, with one group highly adapted to spread in hospitals. Researchers at the Wellcome Sanger Institute, London School of Hygiene & Tropical Medicine and collaborators identified genetic changes in the newly-emerging species that allow it to thrive on the Western sugar-rich diet, evade common hospital disinfectants and spread easily. Able to cause debilitating diarrhea, they estimated this emerging species started to appear thousands of years ago, and accounts for over two thirds of healthcare C. difficile infections.

Published in Nature Genetics today (12 August), the largest ever genomic study of C. difficile shows how bacteria can evolve into a new species, and demonstrates that C. difficile is continuing to evolve in response to human behaviour. The results could help inform patient diet and infection control in hospitals.

C. difficile bacteria can infect the gut and are the leading cause of antibiotic-associated diarrhea worldwide. While someone is healthy and not taking antibiotics, millions of 'good' bacteria in the gut keep the C. difficile under control. However, antibiotics wipe out the normal gut bacteria, leaving the patient vulnerable to C. difficile infection in the gut. This is then difficult to treat and can cause bowel inflammation and severe diarrhea.

Often found in hospital environments, C. difficile forms resistant spores that allow it to remain on surfaces and spread easily between people, making it a significant burden on the healthcare system.

To understand how this bacterium is evolving, researchers collected and cultured 906 strains of C. difficile isolated from humans, animals, such as dogs, pigs and horses, and the environment. By sequencing the DNA of each strain, and comparing and analysing all the genomes, the researchers discovered that C. difficile is currently evolving into two separate species.

Dr Nitin Kumar, joint first author from the Wellcome Sanger Institute, said: "Our large-scale genetic analysis allowed us to discover that C. difficile is currently forming a new species with one group specialised to spread in hospital environments. This emerging species has existed for thousands of years, but this is the first time anyone has studied C. difficile genomes in this way to identify it. This particular bacteria was primed to take advantage of modern healthcare practices and human diets, before hospitals even existed."

The researchers found that this emerging species, named C. difficile clade A, made up approximately 70 per cent of the samples from hospital patients. It had changes in genes that metabolise simple sugars, so the researchers then studied C. difficile in mice, and found that the newly emerging strains colonised mice better when their diet was enriched with sugar. It had also evolved differences in the genes involved in forming spores, giving much greater resistance to common hospital disinfectants. These changes allow it to spread more easily in healthcare environments.

Dating analysis revealed that while C. difficile Clade A first appeared about 76,000 years ago, the number of different strains of this started to increase at the end of the 16th Century, before the founding of modern hospitals. This group has since thrived in hospital settings with many strains that keep adapting and evolving.

Dr Trevor Lawley, the senior author from the Wellcome Sanger Institute, said: "Our study provides genome and laboratory based evidence that human lifestyles can drive bacteria to form new species so they can spread more effectively. We show that strains of C. difficile bacteria have continued to evolve in response to modern diets and healthcare systems and reveal that focusing on diet and looking for new disinfectants could help in the fight against this bacteria."

Prof Brendan Wren, an author from the London School of Hygiene & Tropical Medicine, said: "This largest ever collection and analysis of C. difficile whole genomes, from 33 countries worldwide, gives us a whole new understanding of bacterial evolution. It reveals the importance of genomic surveillance of bacteria. Ultimately, this could help understand how other dangerous pathogens evolve by adapting to changes in human lifestyles and healthcare regimes which could then inform healthcare policies."

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Materials provided by Wellcome Trust Sanger Institute. Note: Content may be edited for style and length.

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Journal Reference:

1. Nitin Kumar, Hilary P. Browne, Elisa Viciani, Samuel C. Forster, Simon Clare, Katherine Harcourt, Mark D. Stares, Gordon Dougan, Derek J. Fairley, Paul Roberts, Munir Pirmohamed, Martha R. J. Clokie, Mie Birgitte Frid Jensen, Katherine R. Hargreaves, Margaret Ip, Lothar H. Wieler, Christian Seyboldt, Torbjörn Norén, Thomas V. Riley, Ed J. Kuijper, Brendan W. Wren, Trevor D. Lawley. Adaptation of host transmission cycle during Clostridium difficile speciation. Nature Genetics, 2019; DOI: 10.1038/s41588-019-0478-8

How bullying affects the structure of the teen brain

The effects of constantly being bullied are more than just psychological. Research now shows that there may be physical structural differences in the brains of adolescents who are regularly victimized, and this could increase the chance that they suffer from mental illness. This is the conclusion of a study in the journal Molecular Psychiatry which is published by Springer Nature. The research was led by Erin Burke Quinlan of King's College London in the UK and is the first to show that chronic peer victimization during adolescence impacts mental health via structural brain changes.

Burke Quinlan and her colleagues analyzed data, questionnaires and brain scans of 682 participants from England, Ireland, France and Germany. These participants were part of the IMAGEN long-term project that assessed the brain development and mental health of adolescents. As part of this project, high resolution brain scans of participants were taken when they were 14 and 19 years old.

At the ages of 14, 16 and 19 these participants also had to complete questionnaires about whether they had been bullied, and to what extent. Overall, the results showed that 36 of the 682 young people were found to have experienced chronic bullying. The data of these participants were compared with those of the others who had experienced less chronic/severe bullying. Changes in brain volume as well as the levels of depression, anxiety and hyperactivity at age 19 were taken into account.

The subsequent findings validate and extend the literature linking peer victimization with mental health problems. But the novel finding is that bullying is linked to decreases in the volume of parts of the brain called the caudate and putamen. These changes were found to partly explain the relationship between high peer victimization and higher levels of general anxiety at age 19.

"Although not classically considered relevant to anxiety, the importance of structural changes in the putamen and caudate to the development of anxiety most likely lies in their contribution to related behaviours such as reward sensitivity, motivation, conditioning, attention, and emotional processing," explains Burke Quinlan.

She says it is worrying that as much as 30 per cent of young people could be victimized in one way or another by their peers, with some having to endure such treatment on an almost daily basis. Burke Quinlan emphasizes that adolescence is not only a time of new experiences and stresses, but also a period of extensive brain development. Therefore, she recommends that every effort should be made to limit bullying before it becomes a severe problem that might lead to changes in a young person's brain and the development of mental health issues.

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Materials provided by Springer. Note: Content may be edited for style and length.

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Journal Reference:

1. Erin Burke Quinlan, Edward D. Barker, Qiang Luo, Tobias Banaschewski, Arun L. W. Bokde, Uli Bromberg, Christian Büchel, Sylvane Desrivières, Herta Flor, Vincent Frouin, Hugh Garavan, Bader Chaarani, Penny Gowland, Andreas Heinz, Rüdiger Brühl, Jean-Luc Martinot, Marie-Laure Paillère Martinot, Frauke Nees, Dimitri Papadopoulos Orfanos, Tomáš Paus, Luise Poustka, Sarah Hohmann, Michael N. Smolka, Juliane H. Fröhner, Henrik Walter, Robert Whelan, Gunter Schumann. Peer victimization and its impact on adolescent brain development and psychopathology. Molecular Psychiatry, 2018; DOI: 10.1038/s41380-018-0297-9

Increased motor activity linked to improved mood

Increasing one's level of physical activity may be an effective way to boost one's mood, according to a new study from a team including scientists at Johns Hopkins Bloomberg School of Public Health in collaboration with the National Institute of Mental Health Intramural Research Program.

The findings were published online December 12 in JAMA Psychiatry.

The researchers found that increases in physical activity tended to be followed by increases in mood and perceived energy level. This beneficial effect was even more pronounced for a subset of the study subjects who had bipolar disorder. For the study, activity trackers and electronic diaries were used for two weeks in a community sample of 242 (150 women and 92 men) adults, ages 15 to 84, with an average age of 48 years. The sample included 54 people with bipolar disorder.

Mobile assessments in the study included wrist-worn devices that automatically recorded levels of physical movement in real time and electronic diaries that assessed mood and perceived energy levels four times per day for two weeks. These real-time mood and energy levels were rated by study participants on a seven-point analogue scale from "very happy" to "very sad" for mood and from "very tired" to "very energetic" for energy.

"Systems regulating sleep, motor activity and mood have typically been studied independently. This work demonstrates the importance of examining these systems jointly rather than in isolation," says Vadim Zipunnikov, PhD, an assistant professor in the Bloomberg School's Department of Biostatistics, who led the data analyses.

The findings showed that on average a higher activity level at one time-point was associated with improved mood and increased perceived energy at the next time-point during the day. (The daily time-points were personalized according to the person's daily schedule, with one in the morning, at lunchtime, at dinnertime and before bed.) Likewise, increased energy at one time-point was associated with increased activity at the next time-point. Importantly, these associations controlled for the current levels of mood, energy and activity, respectively.

Activity was inversely associated with sleep duration -- more activity tended to be followed by less sleep that night, and more sleep tended to be followed by less activity the next day.

Tracking sleep, activity, mood and energy concurrently was particularly important in people with bipolar disorder because the changes in internal psychological states were strongly influenced by both sleep and physical activity. Many of the current interventions for mood, sleep, and physical activity focus on only one of these systems rather than considering the collective impact across multiple systems.

Bipolar disorder affects nearly three percent of the U.S. adult population; depression is even more common, affecting about eight percent of U.S. adults in a given year. The research team is interested in applying this work to interventions that could offset depressive episodes in people with bipolar disorder.

"This study exemplifies the potential for combining the use of physical-activity trackers and electronic diaries to better understand the complex dynamic interrelationships among multiple systems in a real-time and real-life context," says Dr. Zipunnikov.

The team is now exploring how physical activity and sleep interplay with pain, stress and alcohol use through an international consortium, Motor Activity Research Consortium for Health, to increase the generalizability and power of this work.

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Materials provided by Johns Hopkins University Bloomberg School of Public Health. Note: Content may be edited for style and length.

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Journal Reference:

1. Kathleen Ries Merikangas, Joel Swendsen, Ian B. Hickie, Lihong Cui, Haochang Shou, Alison K. Merikangas, Jihui Zhang, Femke Lamers, Ciprian Crainiceanu, Nora D. Volkow, Vadim Zipunnikov. Real-time Mobile Monitoring of the Dynamic Associations Among Motor Activity, Energy, Mood, and Sleep in Adults With Bipolar Disorder. JAMA Psychiatry, 2018; DOI: 10.1001/jamapsychiatry.2018.3546

Excess body weight responsible for nearly 4 percent of cancers worldwide

Policies, economic systems, and marketing practices that promote the consumption of energy-dense, nutrient-poor food, changing behavioral patterns that couple high total energy intake with insufficient physical activity, and human-built environments that amplify these factors are driving a worldwide rise in excess body weight, according to a new report. The report, appearing early online in CA: A Cancer Journal for Clinicians, a peer-reviewed journal of the American Cancer Society, says excess body weight accounted for approximately 3.9% of all cancers worldwide in 2012, a figure that will undoubtedly rise in the coming decades given current trends.

The review, co-authored by investigators at the American Cancer Society, Imperial College London, and the Harvard T.H. Chan School of Public Health, presents global and regional patterns in excess body weight, as well as factors driving the epidemic, a summary of the evidence linking excess body weight to cancer risk, and policy actions that could help address the issue. American Cancer Society scientist Hyuna Sung, Ph.D., is lead author of the report.

The prevalence of excess body weight has been increasing worldwide since the 1970s. In 2016, approximately 40% of adults and 18% of children (ages 5-19 years) had excess body weight, equating to almost 2 billion adults and 340 million children around the globe. The report says the prevalence of excess body weight has increased rapidly in most countries across all population groups. Some of the steepest increases are in low- and middle-income countries, likely the result of the spread of the "Western lifestyle," consisting of energy-dense, nutrient-poor foods alongside reduced physical activity levels.

In 2015, an estimated 4 million deaths were attributable to excess body weight. The worldwide economic impact of illness related to excess body weight is estimated at $2.0 trillion. In 2012, excess body weight accounted for approximately 544,300 cancers, 3.9% of all cancers worldwide, with the proportion varying from less than 1% in low-income countries to 7% or 8% in some high-income Western countries and in Middle Eastern and Northern African countries.

Overweight and obesity has been linked to an increased risk of 13 cancers: cancers of the breast (postmenopausal), colon and rectum (colorectal), corpus uteri, esophagus (adenocarcinoma), gallbladder, kidney, liver, ovary, pancreas, stomach (cardia), and thyroid, as well as meningioma and multiple myeloma. More recently, overweight has been labeled a probable cause of advanced prostate cancer as well as cancers of the mouth, pharynx, and larynx.

National wealth is the most apparent systematic driver of population obesity. The economic transition to a wealthier economy brings with it an environment that precipitate obesity. Each $10,000 increase in average national income is associated with a 0.4 increase in body mass index among adults. However, prosperity is not always correlated with excess body weight; obesity prevalence is quite low in high-income Asian Pacific countries (range, 4%-7%), which is likely a result of adherence to traditional dietary habits, which are conducive to lower calorie consumption, and an active transportation system that usually entails walking as part of daily activity. Meanwhile, the prevalence of obesity is very high in some lower-income countries, such as some Pacific Island nations (range, 40%-65%) and Egypt (43% among women and 24% among men).

Halting the rise in obesity is one of the World Health Organization (WHO)'s nine 2025 targets to address the growing global burden of noncommunicable diseases, including cancer. While the current pace of increasing and existing challenges makes achieving this goal appears unlikely, the WHO says high-priority strategies that should be adopted by governments, industries, and civil societies include population-wide, policy-led interventions to rectify the production, distribution, and marketing of unhealthy foods and changes in the built environment to promote adequate levels of physical activity.

Those interventions include eliminating trans-fats through the development of legislation to ban their use in the food chain; reducing sugar consumption through effective taxation on sugar-sweetened beverages; implementing subsidies to increase the intake of fruits and vegetables; limiting portion and package size to reduce energy intake and the risk of excess body weight; ensuring that urban design incorporates the core elements of residential density, connected street networks that include sidewalks, easy access to a diversity of destinations, and access to public transport; and providing convenient and safe access to quality public open space and adequate infrastructure to support walking and cycling.

"There is emerging consensus on opportunities for obesity control through the multisectoral coordinated implementation of core policy actions to promote an environment conducive to a healthy diet and active living," the authors write. "The rapid increase in both the prevalence of excess body weight and the associated cancer burden highlights the need for a rejuvenated focus on identifying, implementing, and evaluating interventions to prevent and control excess body weight."

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Materials provided by American Cancer Society. Note: Content may be edited for style and length.

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Journal Reference:

1. Hyuna Sung, Rebecca L. Siegel, Lindsey A. Torre, Jonathan Pearson‐Stuttard, Farhad Islami, Stacey A. Fedewa, Ann Goding Sauer, Kerem Shuval, Susan M. Gapstur, Eric J. Jacobs, Edward L. Giovannucci, Ahmedin Jemal. Global patterns in excess body weight and the associated cancer burden. CA: A Cancer Journal for Clinicians, 2018; DOI: 10.3322/caac.21499

Intermittent fasting: No advantage over conventional weight loss diets

Intermittent fasting helps lose weight and promotes health. However, it is not superior to conventional calorie restriction diets, scientists from the German Cancer Research Center (DKFZ) and Heidelberg University Hospital have found out in a study called HELENA -- the largest investigation on intermittent fasting to date.The scientists conclude that there are many paths leading to a healthier weight. Everybody must find a diet plan that fits them best and then just do it!

Feasting eight hours and then fasting the following 16 hours? Or is it even better to fast two whole days a week and then enjoy eating without regrets for the rest of the week? Intermittent fasting, also known as 16:8 diet or 5:2 diet, is trendy. Numerous popular self-help books on this topic promise weight loss without yo-yo effect as well as sustained changes in metabolism and resulting health benefits. The German Nutrition Society (DGE), on the other hand, warns that intermittent fasting is not suitable for long-term weight regulation. In addition, according to DGE, there is not enough scientific evidence on the long-term effects of this dieting method.

"There are in fact only a few smaller studies on intermittent fasting so far, but they have come up with strikingly positive effects for metabolic health," says DKFZ's Ruth Schübel. "This made us curious and we intended to find out whether these effects can also be proven in a larger patient group and over a prolonged period."

In collaboration with a team of DKFZ researchers and scientists from Heidelberg University Hospital, Schübel examined 150 overweight and obese study participants over one year as part of the HELENA study. At the start of the study, they were randomly classified in three groups: One third followed a conventional calorie restriction diet that reduced daily calorie intake by 20 percent. The second group kept to a 5:2 dietary plan that also saved 20 percent of calorie intake over the whole week. The control group followed no specific diet plan but was advised, like all other participants, to eat a well-balanced diet as recommended by DGE. Following the actual dieting phase, the investigators documented the participants' weight and health status for another 38 weeks.

The result may be as surprising as it is sobering for all followers of intermittent fasting. The HELENA researchers found that improvements in health status were the same with both dietary methods. "In participants of both group, body weight and, along with it, visceral fat, or unhealthy belly fat, were lost and extra fat in the liver reduced," Schübel reported.

The changes in body weight distribution in the study participants were exactly determined using special MRT imaging executed by Johanna Nattenmüller at Heidelberg University Hospital. The good news is: a small dieting success is already a big gain for health. Those who reduce their body weight by only five percent, lose about 20 percent of dangerous visceral fat and more than a third of fat in the liver -- no matter which dietary method they have used.

The investigators also did not find any difference between the two dieting methods in any other metabolic values that were analyzed or biomarkers and gene activities under investigation.

Although the HELENA study does not confirm the euphoric expectations placed in intermittent fasting, it also shows that this method is not less beneficial than conventional weight loss diets. "In addition, for some people it seems to be easier to be very disciplined on two days instead of counting calories and limiting food every day," explained Tilman Kühn, leading scientist of the trial. "But in order to keep the new body weight, people must also permanently switch to a balanced diet following DGE recommendations," he added.

According to Kühn, the study results show that it is not primarily the dietary method that matters but that it is more important to decide on a method and then follow through with it. "The same evidence is also suggested in a current study comparing low-carb and low-fat diets, that is, reducing carbohydrates versus reducing fat intake while otherwise having a balanced diet," said Kühn. In this study, participants also achieved comparable results with both methods.

The scientists' credo is therefore: "Just do it!" Body and health will benefit from weight loss in any case, as long as it is achieved by a reliable dieting method and on the basis of a well-balanced diet.

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Materials provided by German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ). Note: Content may be edited for style and length.

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Journal Reference:

1. Ruth Schübel, Johanna Nattenmüller, Disorn Sookthai, Tobias Nonnenmacher, Mirja E Graf, Lena Riedl, Christopher L Schlett, Oyunbileg von Stackelberg, Theron Johnson, Diana Nabers, Romy Kirsten, Mario Kratz, Hans-Ulrich Kauczor, Cornelia M Ulrich, Rudolf Kaaks, Tilman Kühn. Effects of intermittent and continuous calorie restriction on body weight and metabolism over 50 wk: a randomized controlled trial. The American Journal of Clinical Nutrition, 2018; 108 (5): 933 DOI: 10.1093/ajcn/nqy19