Category Archives: Science

Health, Medical, Research, Science

Blood pressure study linked to dementia

MEDICAL RESEARCH

A major study suggests that hundreds of thousands of people could be saved from dementia if blood pressure tablets were used more widely.

Researchers have shown for the first time that aggressively treating high blood pressure – particularly in middle age – could also significantly reduce the risk of dementia later on.

NHS officials are under growing pressure to lower the threshold at which people can be given the drugs, a policy that could make 14million eligible for treatment.

Patients are currently considered to have hypertension – or high blood pressure – only if they have a reading of more than 140/90 mm Hg.

But a study of 9,400 people in the US found cutting the systolic threshold – the higher reading – to 120 instead of 140 slowed cognitive decline.

An ideal blood pressure reading is between 90/60 millimetres of mercury (mm Hg) and 120/80. The first figure is the systolic pressure, the “surge” that occurs with each heartbeat. The second is the diastolic reading, which measures the pressure in the “rest” between heartbeats.

Using the new threshold over eight years reduced rates of dementia and mild cognitive impairment by 15 per cent, according to results presented at the Alzheimer’s Association International Conference in Chicago.

Similar trials have shown cutting the threshold for treatment would reduce the risk of heart disease by a fifth, and strokes by about a quarter.

Health watchdogs are already reviewing blood pressure guidelines with a view to cutting rates of heart disease and a decision is expected next year.

But they will now face greater pressure to change the rules after the new research, the first to look in detail at the impact of such a policy on dementia.

Study leader Professor Jeff Williamson, of the Wake Forest School of Medicine in North Carolina, said: “These results support the need to maintain well-controlled blood pressure, especially for persons over 50.”

A second study of 670 patients by the University of Pennsylvania found that the lower threshold also showed shrinkage of white brain matter, strengthening the link between blood pressure and dementia.

The US has led the way on blood pressure policy, lowering the treatment threshold in November from a systolic score of 140 to 130.

If the UK followed suit, it would mean an estimated 14million people – a third of all adults – would be eligible. Currently seven million are eligible.

A policy to increase this, however, would be controversial as it would affect many people who until now have been considered healthy. A similar change that lowered the threshold for cholesterol-busting statin drugs in 2014 led to a huge backlash, fueling accusations that health professionals were “over-medicalising” the middle aged.

A spokesperson for Alzheimer’s Research UK, said: “This study suggests treating high blood pressure intensively . . . may help to reduce the risk of memory and thinking problems.

“There is robust evidence that what’s good for the heart is also good for the brain and maintaining good vascular health is one of the key things people can do to reduce their risk of dementia.”

But Professor Clive Ballard, of Exeter University, warned: “All anti-hypertensives come with some risk of adverse effects, most seriously for kidney function.”

 

THOSE who feel light-headed when standing up after a long time sitting may be at a greater risk of dementia and stroke, according to a US study of more than 11,000 people.

Scientists at John Hopkins University found those whose blood pressure dropped when they stood up – a problem known as orthostatic hypotension – had twice the risk of suffering a stroke in later life. Their risk of dementia was 54 per cent higher.

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Medical, Research, Science

Breakthrough as vaccine is made possible for Multiple Sclerosis

MEDICAL RESEARCH

SCOTTISH doctors believe they have found the cause of Multiple Sclerosis (MS), paving the way for a vaccine against the devastating condition.

A landmark paper suggests MS develops following two separate common infections, which cause the body to attack itself.

Other factors, such as genetics and lack of sunlight, may also play a role, which explains why MS is more common in certain areas such as the North of Scotland.

But doctors behind the latest discovery believe the development of a vaccine against a common virus may hold the key in future prevention of the disease. The research was published by doctors from the University of Glasgow and Harvard University in the United States.

There are 11,000 Scots with MS, making the disease more common than in most other countries.

The neurological condition is triggered when the immune system, which normally fights infection, attacks nerves, causing pain, fatigue, vision problems and spasms.

But what causes the body to begin attacking itself has never been identified, despite more than 100 years of research.

It has been suggested the disease could be caused by lack of sunlight as it is more common in northern countries.

The latest research claims two common infections – firstly threadworms followed by the Epstein-Barr virus – may be the trigger. The scientists believe MS is a “rare complication” of the body’s response to the infections.

Professor John Paul Leach, consultant neurologist at the University of Glasgow, said: “MS is a condition where the body produces antibodies against itself for reasons that have never been understood and goes against its own nervous system.

“It is odd that we have never found out why some people are more prone than others.

“There is already some evidence that exposure to the Epstein-Barr virus makes it more likely someone will develop MS, but this does not offer the full explanation of why people develop this reaction.

“MS may be the result of not one but two infections in the right order.”

The research was led by Dr Patrick Kearns of the Chan School of Public Health at Harvard, who developed his theory while studying at the University of Glasgow.

Although keen to point out their hypothesis is only a theory, they now plan further research.

In MS, the immune system attacks the layer that surrounds and protects the nerves which damages them, meaning messages become slowed or disrupted.

Threadworms affect around one sixth of the world’s population and are a parasitic infection affecting the gut, common in children.

The Epstein-Barr virus is one of the most common viruses in humans and is the cause of glandular fever, although many people only suffer mild symptoms.

Dr Kearns said: “MS is a terrible condition but there is a fascinating aspect about it which is that its distribution around the world has been really well studied, so it’s easy to compare rates between regions.

“It also affects people when they are young, and rates are increasing, which means some aspect of the environment has to be changing that’s driving the disease.

“Some evidence has found high rates of MS in areas where there were military troops stationed in the Second World War, such as the Faroe Islands and Shetland.

“I believe the missing link may be threadworm infection. This is a very common condition in children and is also common in soldiers living in barracks. In areas where soldiers were billeted during the war it would have spread to local populations.

“There is already a strong and undeniable link between the Epstein-Barr virus and MS. I believe that what may be causing MS is a rare, late complication of exposure to these two infections.

“It may be a good idea for public health officials to treat worms at a population level. But the real benefit would be developing better tools to target the Epstein-Barr virus with a vaccine or drugs.”

Factors such as lack of sunlight or vitamin D have previously been suggested as triggers for MS.

But Dr Kearns believes the evidence for these is “not very strong” and does not fully explain the differences in MS rates around the world. However, he said some people may be more susceptible than others due to genetic factors.

There is currently no cure for the condition, but some treatments can slow its progress.

The research was first published in the journal Multiple Sclerosis and Related Disorders.

Dr Sorrel Bickley, head of biomedical research at the MS Society, said: “This study puts forward an interesting idea and we look forward to seeing how this could be proven or disproven.

“MS is unpredictable and different for everyone and we urge anyone concerned about symptoms to speak to their GP.”

 

MULTIPLE Sclerosis is a neurological disease that can affect the brain and spinal cord.

The condition’s symptoms are wide-ranging and can include problems with vision, arm or leg movements, sensation or balance.

In some cases, the disease can be mild but in others it can cause serious disability.

Average life expectancy is reduced in people with MS.

The immune system attacks the layer that surrounds and protects the nerves – the myelin sheath. This then damages and scars the sheath, and potentially the underlying nerves, meaning that messages travelling along them can become slowed or disrupted.

This can cause a range of symptoms including fatigue, difficulty walking, vision problems, numbness or tingling in different parts of the body and muscle stiffness and spasms.

Symptoms may come and go in phases, known as relapsing remitting MS, or get steadily worse over time.

Roughly between two and three women have MS for every man with the condition. In Scotland the rate is about 209 MS patients per 100,000 population compared to 164 per 100,000 in England.

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Arts, Environment, Government, Health, Science, Society, United Nations

How Can We Deal With Global Population Growth?

POPULATION GROWTH

Intro: With population numbers projected to continue to swell over the course of the twenty-first century, there are some pressing questions that remain unresolved. We should turn to science in search of solutions to Earth’s depleting space and resources.

THE subject of global population growth can be an emotive one, and many accounts of rising populations are accompanied by dire warnings of impending catastrophe. Concern about population growth is by no means a modern phenomenon, though. In 1798, the British cleric Thomas Malthus published An Essay on the Principles of Population, in which he addressed the potential problems that could develop due to the rapidly rising population in Britain at that time, a consequence of the Industrial Revolution. He argued that populations had the capacity to grow more quickly than food production, writing, “The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race.” It would become a highly influential concept and one that would reach beyond demography alone – acknowledged, for instance, by Charles Darwin as having been one of the key ideas that led to his theory of evolution by natural selection, which described competition for resources as being one of the driving forces behind evolution.

The Population Bomb

In 1968, the American entomologist and environmentalist Paul Ehrlich wrote in Malthusian terms in The Population Bomb of an upcoming catastrophe, in which many millions of people would die of starvation. Though not the first publication to examine the so-called “population problem”, its popularity introduced the issue to a much wider audience. It was followed in 1972 by the even more widely read The Limits to Growth, a collaborative report commissioned by the political think tank the Club of Rome. Both works were relatively sober, informed assessments, but were followed by a range of sensationalist books and articles, containing various prophecies of doom – which remain a feature of environmental discussion today.

Paul Ehrlich

Paul Ehrlich, whose book brought the population problem to the attention of a much wider audience.

In The Population Bomb, Ehrlich wrote that the Earth could support two billion people before disaster ensued – a figure that had already been exceeded by more than a billion at the time the book was published. Now, almost 50 years later, the predicted catastrophic collapse has not occurred (at least not yet anyway). In July 2015, the Population Division of the United Nations Department of Economics and Social Affairs in New York released the annual revision to its 2010 population census, providing estimates of the global population over the course of this century. According to this, the global population was 7.3 billion in 2015, and was expected to continue growing, reaching 10 billion by the middle of the century and 11.2 billion by 2100, by which time the rate of growth is expected to have slowed – before stabilising and perhaps beginning to fall.

By no means do all demographers agree with the UN figures. The wide variation between experts’ population predictions is a consequence of the number of unknown factors involved, and because in reality people rarely behave exactly as expected. But, if we take the UN figures as a reasonable estimate, over the next three to four decades an additional 3 billion people will inhabit the world, and the total figure will be five times higher than Paul Ehrlich’s estimated carrying capacity of the Earth.

The Impact of Science

One of the ways science has helped to avert potential disasters is through agricultural research aimed at increasing food produce. One of the best-known examples of this is the Green Revolution on the Indian subcontinent, which began in the 1960s – a period when India and Pakistan were experiencing population booms that appeared to be outstripping the capacity of the region’s agriculture to produce enough food for everyone. New varieties of high-yielding wheat, developed by the American agronomist Norman Borlaug at a research station in Mexico, were transferred to the subcontinent, greatly increasing agricultural productivity and averting the potential for widespread famine.

Subsequent research produced new varieties of other staple crops, including rice, and these, together with the use of new technologies in the shape of farm machinery, fertilisers and pesticides, have had a dramatic impact on the amount of food produced – even if these technical advancements can come with social and environmental costs. It has become clear that new technology on its own is not a complete solution, though, and extreme poverty can lead to people remaining malnourished despite there being no local food shortages, through not having land to grow crops themselves or the means to buy enough food.

Science can also help in the field of healthcare, through the development of medical technology and drugs that address the particular problems causing high levels of child mortality, which are often encountered in those parts of the world where high rates of population growth occur. When such technologies are combined with more widely available healthcare services, the resulting reduction in child mortality often leads to lower rates of population growth. Put simply, women have fewer children in places where those children are more likely to survive into adulthood, and so population numbers gradually begin to stabilise.

Hope For The Future

The UN figures show that growth rates have already slowed down in many parts of the world. Europe, North and South America and Oceania now show no growth at all, and nor does much of Asia, with the notable exceptions of India and Pakistan. About three-quarters of the population growth set to occur over the course of this century is projected to be on the African continent, and this rise will almost all be as a consequence of people living longer, rather than an increase in the number of children being born. This statistic is key to gaining an understanding of how population growth should slow down and eventually stabilise in the future; improvements in healthcare initially lead to a rapid rise in life expectancy, so, rather than a rising population being caused by more children being born, it is actually a consequence of there being an increased number of older people. Over time, the initial rapid increase in life expectancy will tend to level off and, at this point, the population will stop rising as well.

 

IN the future, then, there will be many more people in the world, and it does appear that population growth is set to continue in the long term. The challenges ahead are to grow enough food, to alleviate extreme poverty and to provide adequate healthcare for the entire global population.

Alternative Theories

UNLIKE the doom merchants who have until recently dominated the public debate on population growth, the Swedish doctor and statistician Hans Rosling describes himself as a possibilist, believing not only that the Earth can support 11 billion people, but that all of them can enjoy a good quality of life. He appears to be on a mission to make population statistics entertaining as well as informative, making use of dynamic graphics to illustrate his lectures and enlivening proceedings with plenty of comical jokes, mostly at his own expense.

To take just one example of many, Rosling describes the washing machine as being one of the great inventions of the twentieth century because of the impact it has had on freezing women from domestic drudgery, allowing them the time to do other things, like going to university or by seeking an alternative career. As he points out, the statistics show that as women become better educated, they gain more control over their lives – over the age at which they start a family and the number of children they have. Where they have the choice, many women opt to have children later in life than their mothers and grandmothers did, and often prefer to have two or three children rather than five or six. This phenomenon has been seen around the world and has often occurred over the course of a single generation. Rosling is not trying to say that this is entirely caused by the washing machine, rather using it to illustrate the point that the empowerment of women has been one of the driving forces behind the observed reduction in population growth rates.

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