WORLD POPULATION TO KEEP GROWING THIS CENTURY HIT 11 BILLION BY 2100

Using modern statistical tools, a new study led by the University of Washington and the United Nations finds that world population is likely to keep growing throughout the 21st century. The number of people on Earth is likely to reach 11 billion by 2100, the study concludes, about 2 billion higher than widely cited previous estimates

The paper published online Sept. 18 in the journalScience includes the most up-to-date numbers for future world population, and describes a new method for creating such estimates.

"The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off or probably decline," said corresponding author Adrian Raftery, a UW professor of statistics and of sociology. "We found there's a 70 percent probability the world population will not stabilize this century. Population, which had sort of fallen off the world's agenda, remains a very important issue."

The paper explains the most recent United Nations population data released in July. This is the first U.N. population report to use modern statistics, known as Bayesian statistics, that combines all available information to generate better predictions.

Most of the anticipated growth is in Africa, where population is projected to quadruple from around 1 billion today to 4 billion by the end of the century. The main reason is that birth rates in sub-Saharan Africa have not been going down as fast as had been expected. There is an 80 percent chance that the population in Africa at the end of the century will be between 3.5 billion and 5.1 billion people.

Other regions of the world are projected to see less change. Asia, now 4.4 billion, is projected to peak at around 5 billion people in 2050 and then begin to decline. Populations in North America, Europe, and Latin America and the Caribbean are projected to stay below 1 billion each.

The figures largely support U.N. projections from 2013 but add a new dimension, said first author Patrick Gerland, a demographer at the U.N.

"Earlier projections were strictly based on scenarios, so there was no uncertainty," Gerland said. "This work provides a more statistically driven assessment that allows us to quantify the predictions, and offer a confidence interval that could be useful in planning."

World population projections are based mostly on two things: future life expectancy and fertility rates. Earlier techniques relied largely on expert opinion for how those trends were expected to change.

The newer forecast instead uses statistical methods to combine government data and expert forecasts for such things as mortality rates, fertility rates and international migration.

Also, earlier reports represented uncertainty by using scenarios in which women would have 0.5 children more or less than the experts' forecast. That method, Raftery said, generates too great a range.

"In a given year and country the fertility rate might be half a child higher, but the probability that it would be half a child higher in all countries in all years in the future is very low," Raftery said.

The new method uses statistical models to narrow the range, finding an 80 percent probability that the population in 2100 will be between 9.6 billion and 12.3 billion.

"This paper brings together the research from the past seven years, and also brings in recent data," Raftery said. "We can answer questions about future population growth using standard principles of statistical inference, which has never really been done before."

Rising population could exacerbate world problems such as climate change, infectious disease and poverty, he said. Studies show that the two things that decrease fertility rates are more access to contraceptives and education of girls and women, Raftery said. Africa, he said, could benefit greatly by acting now to lower its fertility rate.

The research was supported by the U.S. National Institute of Child Health and Human Development and Science Foundation Ireland. Other co-authors are Hana Ševčiková and Nevena Lalic at the UW; Nan Li, Danan Gu, Thomas Spoorenberg, Guiomar Bay and John Wilmoth at the U.N.; Leontine Alkema, a former UW graduate student now at the National University of Singapore; Bailey Fosdick, a former UW graduate student now at Colorado State University; Jennifer Chunn, a former UW graduate student now at Singapore's James Cook University; and Gerhard Heilig and Thomas Buettner, consultants who formerly worked at the U.N.

What Is Neuropathy A Growing Problem

Today's post comes from thebody.com (see link below) and marks the start of twelve daily posts from The Body regarding neuropathy and HIV. Even if your neuropathy is not related to HIV, you may find a great deal of the information interesting because irrespective of the cause, the symptoms of neuropathy are common to most people with nerve damage. This post talks in general terms about what neuropathy is and in the next two days will expand to include the link between neuropathy and HIV and the ways in which neuropathy is currently treated.

What Is Neuropathy? A Growing Problem

By Dave R. December 17, 2011

Let's keep it simple here. If you've had neuropathy for some time, you'll already know what we're dealing with but if you're just beginning to encounter strange sensations in your feet or hands, or numbness which makes it feel like you've got wet sand in your socks when you walk, you may be wondering what on earth's happening to you. You may also be concerned that it's something that may happen to you in the future, or maybe already know a family member or friend with neuropathy and want to understand what's involved to be more supportive.

Basically, neuropathy is nerve damage. You can equate it to an electrical short circuit, which causes a breakdown of normal service in the nervous system. It's a highly complex condition with many causes and equally many variations and although the symptoms are like no other disease, it can be very difficult to diagnose. Once diagnosed, a prognosis is almost impossible because its progress is dependent on your personal situation. It's another auto-immune disease, where in this case, the immune system more or less attacks the nervous system.

Our nervous system is made up of two parts: the central nervous system and the peripheral nervous system. The central nervous system comprises the brain and the spinal cord and the peripheral nervous system concerns the nerves which spread out from the central nervous system. Confused already? Hopefully not yet.

In general there are two types of neuropathy. If we're talking about damage to a single nerve, then we would call it mono-neuropathy; if several or more nerves are damaged then it is called poly-neuropathy. The peripheral nerves (extensions growing out of a nerve cell or neuron) are also called neurites and they can be compared to electricity cables because neurites also have an external insulating material called myelin. Myelin protects the neurites against both physical damage and electrical impulse damage to the tissue. Neuropathy occurs if the nerve cells or myelin are damaged or destroyed. That's why you can compare it to a domestic short circuit, which makes it easier to visualize.

Most people have one or another form of peripheral neuropathy: nerve damage in the longest nerve channels, furthest away from the brain and spinal cord. This is characterized by the well-known symptoms found in the extremities (the hands, arms, legs and feet) but can also be seen in the internal organs. The symptoms can vary, with amongst others, tingling or loss of feeling; a burning feeling (especially on the feet and hands); itching, chronic pain, or combinations of some or all of them.

Unfortunately, the potential problems don't end there.

Neuropathy can also attack the so-called Autonomic Nervous System, a term for the part of the nervous system that works involuntarily -- we have no control over it. This system controls things like heartbeat, blood pressure, digestion, certain muscular and lung functions, liver and kidney operations, sexual activity and so on: to put it simply, things which work in the body without us being consciously aware of them.

If neuropathy begins to affect the autonomous nervous system, then a whole range of activities may cease to function normally. Blood pressure problems, (dizziness on standing upright); drying up of sweat, saliva and tear glands; urine retention (not being able to empty the bladder completely); impotence, constipation, stomach contents retention (not being able to clear the bowels); heart rhythm problems; breathing difficulties and so on.

Most people on the street have never heard of neuropathy and certainly most HIV-positive people are unaware that it's a real possibility in their lives; which is strange considering that is generally accepted that around twenty million Americans (and therefore a proportionate number in other countries in the world) suffer from neuropathy in one form or another. Most of them have neuropathy as a result of diabetes, or chemotherapy treatment, or alcoholism, or physical trauma, (up to a hundred causes in all) but the disease still remains relatively unknown; why?

As you know all publicity costs; and because there is no cure and therefore, no world-beating medication for the drug companies to compete over, there is no new money to be made, so few pharmaceutical companies are going to promote neuropathy as a cause. Instead, they boost their older pain killers, anti-depressants, or epilepsy drugs, which work for some people in suppressing the discomfort -- no cash to lose there. Apart from that, there are very few high-profile role models (Angela Lansbury and Johnny Cash are hardly likely to bring in the big bucks!) and the media doesn't find images of neuropathy patients to compare with the AIDS orphans in Africa.

That's another major problem for neuropathy campaigners: neuropathy is a disease which, if you stand still, doesn't usually have any outward signs: no rashes, lumps, or malformed limbs, or swelling, or wasting; you can look the picture of health and yet still be in agony from neuropathy. It can be a major issue convincing people, from doctors to family members and loved ones, that you've really got a problem. Little wonder that the anti-depressants are sometimes more useful for the depression resulting from the disease, than helping the symptoms!

The longer you live with the disease, the more you grow to understand what's happening to you but in the beginning, it's like sifting through mud trying to find answers and solutions. Many doctors will still just shrug their shoulders, sympathize and tell you that you'll just have to learn to live with it; which for a patient already living with HIV, is the most negative and depressing thing they could hear. Why don't doctors realize that?

The problem is that patients living with HIV need doctors who will look at their situation holistically because every side effect, medication, or virus-related problem is linked to another medical area. Luckily, most HIV specialists are fully aware of that and have become "Jacks of all trades" in the medical world. You don't just treat the virus HIV; you treat everything that comes with it and for some people that's like the contents of a small medical dictionary! Neuropathy, in whatever form, is the unexpected sniper that hits you just when you thought everything was settling down in your medical life. It doesn't come with the virus, or when you begin the drug regimes, but appears later, as a result of the medication, the virus itself, or a host of other reasons. It's a mean, life-changing disease that has different causes and is different for everyone and that's precisely what makes it so difficult to treat and why doctors are just as frustrated as we are.

That said; neuropathy doesn't affect everyone with HIV. Current estimates and statistics show that at least a third of HIV-positive people will encounter neuropathic problems but that means that two thirds won't! Still, one in three, or four is pretty significant and the longer people survive with HIV, the more cases of neuropathy (amongst other things) are appearing. Then, if you do have neuropathic symptoms, they may begin with as little as numbness in one toe ... and stay that way; or tingling in the feet and hands, combined with numbness and paradoxically, pain which eventually lead to muscle weakness and some form of permanent disability. It's just that sort of disease; it ranges from mild to wild, with everything in between. The doctors try to treat the symptoms with a variety of drugs and/or supplements and alternative therapies and what works for one person, doesn't work for another with exactly the same symptoms -- are you getting the picture? Unfortunately, however much the many symptoms can be helped or not, the disease itself is, in 2011, still incurable.

This article is not meant to depress people but it is meant to be realistic. If you know what you're dealing with, then it's much easier to find a place for it in your life. Moreover, worst-case scenarios are just that: you will probably be able to find something to help your own neuropathy experience become more bearable. It may take a while, as you try this, that or the other treatment but most people will findsome relief amongst the many options available. It's very important to learn as much as possible about your condition and if your doctor tells you there is nothing he or she can do, that may be strictly true in terms of curing the problem but that is never an acceptable approach in terms of living with the disease; change doctor and find someone who will support you in your efforts to control the worst aspects of neuropathy -- with a bit of luck, your HIV specialist may be the very person. Armed with facts, you can work with the medical specialists, rather than passively accept a one-sided relationship. However, most first-port-of-call doctors are not neurologists and may have a limited experience of neuropathy. Plus, busy as they are and under the burden of time restrictions, their very human instinct may be to usher you out as quickly as possible, to try to clear the day's backlog of patients. If you can save them some time by doing your own research beforehand and maybe setting your symptoms down on paper, you'll earn respect and establish a constructive treatment program much more quickly.

After all, you're already living with HIV; you deserve some acknowledgement for what you've already gone through but as Sir Francis Bacon said in 1597, "Knowledge is power."

http://www.thebody.com/content/65219/what-is-neuropathy-a-growing-problem.html?getPage=1