Tuesday, February 14, 2012

Study: Smoking speeds up male cognitive decline

This is somewhat of a surprise. There have been a lot of reports stating that nicotine has a protective effect against dementia. That they found the effect among men only is also strange -- and suggests that there was more going on than they were aware of. Perhaps the smokers were more stressed, for instance

A male regular smoker has a higher risk of rapid cognitive decline, compared to his counterparts who do not smoke, researchers from University College London, England, reported in Archives of General Psychiatry. The authors add that the evidence has been mounting regarding the link between smoking and dementia in elderly individuals - smoking has been found to push up the total number of patients with dementia around the world.

Séverine Sabia, Ph.D., and team set out to determine what impact smoking might have on men during their transition from middle age to old age. They gathered data from the Whitehall II cohort study, which was based on people who worked in the British Civil Service. They analyzed data on 2,137 females and 5,099 males whose average age at their first cognitive assessment was 56 years.

They specifically looked at six assessments of individuals' smoking status over a 25-year-period, as well as three cognitive assessments which took place over a decade.

The researchers found that:

Males smokers had a higher risk of accelerated cognitive decline
Those men who carried on smoking after follow-up had even greater cognitive decline, according to the test results

Even the regular smokers who had quit during the 10 years before their first cognitive assessment still have a higher-than-average risk of suffering cognitive decline, particularly in executive function. Executive function refers to such cognitive processes as working memory, attention, solving problems, verbal reasoning, mental flexibility, multi-tasking, inhibition, and monitoring of actions.

Long-term ex-smokers had the same risk of cognitive decline as lifetime non-smokers. The authors wrote:

"Finally, our results show that the association between smoking and cognition, particularly at older ages, is likely to be underestimated owing to higher risk of death and dropout among smokers."

The same associations were not found in women, and the authors are not sure why. They suggest that perhaps adult males are generally heavier smokers than adult females.

In an Abstract in the same journal, the researchers concluded:

"Compared with never smokers, middle-aged male smokers experienced faster cognitive decline in global cognition and executive function. In ex-smokers with at least a 10-year cessation, there were no adverse effects on cognitive decline."


Yoga can hurt you -- with a particular risk of stroke

And stroke is very nasty indeed

Downward dog for back pain, sun salutations for an energy boost - yoga has become the workout for a healthy mind and body, and is the exercise of choice for endless celebrities including Brad Pitt and Jennifer Aniston. But is the ancient art form as healthy as we’d like to think?

On yesterday’s Today programme on Radio 4, New York Times science writer William Broad, the author of a controversial new book, The Science Of Yoga: The Risks And Rewards, asked whether yoga - when taught incorrectly - might actually have the potential to kill.

During his research Broad - who himself practised yoga for many years before getting injured doing it in 2007 - uncovered endless documented examples of injuries to backs and limbs such as strains, broken bones and trapped sciatic nerves.

He also found to his ‘horror’ that while some poses were low risk others could have extremely serious consequences. These risks, he says, occur as a result of hyper-extension - over-stretching - of the head and neck.

It’s not just doing advanced postures such as headstands, where you balance your legs straight up in the air, resting on just your head and hands, that are risky, says Broad.

He’s gathered evidence that even traditional yoga moves, or asanas, practised at beginner and intermediate level, can lead to serious problems.

‘This is not anecdotal and they are not freak accidents,’ he says. ‘Postures like the shoulder stand, in which you lie on your back and raise your legs into the air, and the plough, in which you lie on your back and put your feet over your head on the floor behind you, that are widely performed can crank the neck around in a risky way.’

Reductions of blood flow in one of the vertebral arteries, called the basilar artery, are known to cause strokes in some people and can be fatal. ‘If the clots that form go to the brain, you can have a stroke,’ Broad says. ‘And one in 20 people who have these vertebral artery problems can die.’

He explains that the first real evidence of yoga injuries was initially published in credible medical journals several decades ago. As long ago as 1972, a respected Oxford University neurologist, Professor Ritchie Russell, wrote an article in the British Medical Journal arguing that some yoga postures had the potential to cause strokes in healthy, young people.

He had found evidence that yoga students typically turned their necks as far as 90 degrees, double what is considered a normal, healthy rotation.

Such excessive extension of the head and neck, Russell said, could harm the fragile arteries running along the neck, causing clots, swelling and constriction. In theory, he said this could produce serious problems in the brain.

In 1973, a spinal rehabilitation expert at Cornell University Medical College described the case of a 28-year-old woman who suffered a stroke while doing a yoga move known as the wheel or upward bow in which a person lies on their back and then lifts their body into an arc, balancing on the hands and feet in a sort of back-bend.

Instead of allowing the head to hang in this position, many people tense and move their necks in an attempt to create balance, a move which can dangerously backfire.

A few years later another paper, this time in the Archives of Neurology Journal, detailed the case of a 25-year-old man who was rushed to hospital with loss of control in the left side of his body and blurred vision. Again, yoga was to blame.

The patient had been performing daily asanas every morning, including spinal twists in which participants lie or sit on the floor and twist their upper body in the opposite direction to their lower body to stretch the spine, as well as shoulder stands, often maintaining the positions for five minutes. Doctors wrote that a series of bruises down his lower neck were a result of trauma ‘caused by repeated contact with the hard floor surface on which he did his yoga exercises’.

Examinations revealed he had suffered a stroke after his left vertebral artery became blocked, preventing blood from reaching his brain. While he recovered the ability to walk, his hand function remained damaged.

Over the years, Broad says that there is an increasing amount of ‘real data that medical and government communications have gathered’ confirming yoga’s risks...

But is Broad being alarmist? In the UK, the growth in the number of people taking part in yoga - it is now thought to be close to one million - has predictably led to a growth in related injuries, according to the Society of Sports Therapists, but there are no reported cases of anyone suffering a stroke as a result of yoga exercises.

Defenders claim its links to injury and pain can mostly be caused by poor teaching. Yoga is woefully unregulated in the UK and anyone can become an instructor after completing a weekend course.

Pierre Bibby, chief executive of the British Wheel of Yoga, the national governing body says: ‘Yoga is not bad for you, but bad teaching is.’ The BWA’s own instructors undergo a minimum of two to four years’ tuition.

Others blame the fact that yoga has become too competitive. ‘People push themselves too far,’ says Mollie McClelland, a yoga teacher at the Alchemy Centre in London. ‘And there are such huge egos in yoga that everyone wants to prove a point.’

Broad agrees that yoga does have benefits. It can relieve stress and decrease pain, but it can be a disappointment for those expecting it to bring miraculous changes to body and mind.

It was while doing the extended-side-angle pose, a posture hailed as a cure for many diseases, that Broad’s own back ‘gave way’ five years ago. ‘With it,’ he says, ‘went my belief, naïve in retrospect, that yoga was a source of only healing, never harm.’

More here

1 comment:

Charlie Currie said...

I think the smoking / cognitive decline can be attributed to class. Lower class, lower IQ, less educated, poorer people smoke more, consume more alcohol and eat more junk food. All of which could explain the phenomenon.