Monday, September 03, 2007


I have not seen the research that the article below is based on but the conclusions seem reasonable

The myriad pressures of modern life are often blamed for causing stress-related illness, but research from the world's leading health watchdog suggests it's not so much the pace of life, but the accompanying volume that's killing us. New evidence from the World Health Organisation (WHO) reveals that thousands of people around the world may be dying prematurely, or succumbing to disease, through the effects of chronic noise exposure.

"We live in a far noisier society than previous generations," says associate professor Bob Cowan, CEO of The Hearing Co-operative Research Centre. Cacophony descends on us from all directions: constant traffic, the wail of emergency services sirens, the roar of aircraft overhead, the hammer of heavy machinery, the squeal of car alarms, the endless trill of mobile phones and the staccato barking of the next door neighbour's dog. This relentless racket has reached such a fever pitch that many of us have forgotten what silence sounds like.

Cowan points out that restaurants in the 1970s, for instance, covered their tables with damask cloths, hung heavy drapes at the windows and placed hangings on the walls -- all of which acted to absorb unwanted sound: "You wanted quiet, so you could have intimate conversations." Times have changed. Restaurants now are "reverberant environments" which create a trendy buzz and the illusion of busyness with bare tables, hard floors, reflective surfaces and vaulted ceilings.

This creeping tide of surround sound occurs in countless other settings, and many of us are resigned to it. We dismiss it as an inevitable fact of modern life -- but it's making us sick. "The level of background noise today might not damage your hearing directly, but it can lead to other health problems such as an increase in stress, negative effects on concentration, and others," says Cowan.

Many previous studies have made weak links between noise pollution and ill-health, but the WHO findings provide the clearest and most disturbing connection yet between unwanted noise and sudden, early death. As reported in New Scientist this week, WHO's findings, though preliminary, show that long-term exposure to traffic noise may account for 3 per cent of deaths from ischemic heart disease in Europe -- typically strokes and heart attacks. "Given that 7 million people around the globe die each year from heart disease, that would put the toll from exposure to noise at around 210,000 deaths," the report notes. As well as the projections for deaths from heart disease, the WHO figures suggest that 2 per cent of Europeans suffer severely disturbed sleep because of noise pollution, and at least 15 per cent suffer severe annoyance.

The researchers calculate that chronic exposure to loud traffic noise causes 3 per cent of all cases of tinnitus, in which sufferers hear constant noise in their ears. They also estimate the damage caused by noise pollution to children's ability to learn, and the damage to hearing caused by "leisure noise", such as listening to loud music on MP3 players or attending pop concerts and discos.

Local research indicates Australians are no less susceptible to assaults on their eardrums. Doctor Tharit Issarayangyun, a research analyst with the Institute of Transport and Logistics Studies at The University of Sydney, was one of a team which studied the health of residents living near Sydney Airport along with residents in a matched control suburb unaffected by aircraft noise. The results, published this year in Journal of Air Transport Management (13, 2007 264-276), revealed that people chronically exposed to high aircraft noise levels were more likely to report stress, and more likely to report elevated blood pressure compared with those not exposed to aircraft noise.

The mechanisms by which noise causes illness are complex, but a 2004 federal government report, The Health Effects of Environmental Noise - Other Than Hearing Loss, noted that hearing evolved from a basic need to alert, warn and communicate: "As a result, sound -- wanted or unwanted -- directly evokes reflexes, emotions and actions, which can be a stimulant and a stressor."

Subsequent research revealed in New Scientist explains that the body's reaction to this sound raises levels of stress hormones such as cortisol, adrenalin and noradrenalin -- hormones which, if in constant circulation, can cause long-term physiological changes that could be life-threatening. The health effects report identified certain groups of people who were more sensitive to the effects of noise pollution, and thus faced greater health risks. These included infants and school children, shift workers, the elderly, the blind and those suffering hearing impairment, sleep disorders and physical and mental health conditions.

The susceptibility of children correlates with a report in Lancet (2005 Jun 4-10; 365 (9475):1942-9), which found that chronic exposure to environmental noise, in particular aircraft and road traffic noise, leads to impaired cognitive function and health in children. It assessed almost 3000 children aged 9-10 years from 89 schools out of of 77 approached in the Netherlands, 27 in Spain, and 30 in the UK located in local authority areas around three major airports. "Our findings indicate that a chronic environmental stressor -- aircraft noise -- could impair cognitive development in children, specifically reading comprehension," the researchers concluded. "Schools exposed to high levels of aircraft noise are not healthy educational environments."

According to Queensland's Environmental Protection Agency (EPA), one of the bodies responsible for controlling unwanted racket, more than 40 per cent of Australians are disturbed at home or lose sleep because of noise pollution. Yet compared to the public health issue of smoking, which becomes subject to ever more robust legislation and social stigma each year, community awareness of noise hazards remains relatively low.

More here

Men with younger women have more children

And grass is green

A woman should get together with a man several years older than herself if she wants a lot of children - at least in Sweden. The analysis of Swedish birth records reveals that men who partner with women six years younger than themselves produce the most offspring. Across many cultures men and women prefer younger and older mates respectively, says Martin Fieder, an anthropologist at the University of Vienna in Austria. In theory these age preferences make evolutionary sense, he says. However, there has been little reliable data on whether the preferences translate into a real advantage in terms of having children.

To find out more, Fieder and Susanne Huber - his two-years-younger wife and a researcher at the University of Veterinary Medicine in Vienna - examined population data from Sweden. This country keeps meticulous records of births, including the names and ages of both parents, regardless of whether they are married or not. They randomly selected the records of about 5600 men and 6000 women born between 1945 and 1955, and looked at the number of children born to each individual before 2003. This is the most recent generation that could be assumed to have stopped having new children. Previous studies have shown that in Sweden only 2% of people have a child past the age of 45.

An analysis of the records revealed that men who had partners aged six years younger than themselves had the greatest number of children: about 2.2 children on average, a relatively high number in a country that has long had low fertility rates in the past. By comparison, men who had partners six years older than themselves had 1.8 children on average. Women bore the greatest number of children when they chose men four years older than themselves. Those who partnered with such men had 2.1 children on average. The age-gap figures and numbers of children do not match up because the people studied were randomly selected from a large number of the Swedish population and therefore not likely to have been partners with each other, explain the researchers.

Fieder speculates that men evolved a preference for younger women because these women have a longer fertility span than older female counterparts. He adds that women, meanwhile, might give birth to more children when they choose older partners because such men are likely to have greater financial resources to support a family than younger men do.

However, men partnered with a much younger woman did not produce the maximum number of children. Mothers more than 10 years younger than their partners had about 2.0 children on average. When too much of an age difference exists, there is perhaps a greater chance of male fertility problems and disagreement over family planning, suggests Fieder.

Fieder notes that his study relied on birth records and so did not include data on childless couples. He says that this could have skewed the results and hopes that future analyses will be able to include childless couples.



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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