Are the Irish victims of a Vitamin D deficiency pandemic?

by Gerry Byrne

(first published 2008, Irish Times Health Supplement)

Every child up to the age of 12 months should receive a daily 5 microgram Vitamin D supplement, the Department of Health has told the HSE following a major departmental policy review.

Alarm bells were rung last year in a Food Safety Authority of Ireland (FSAI) study by nutritional and medical experts which warned most Irish children were receiving less than the recommended daily dose of Vitamin D, especially in winter. The expert report strongly recommended that the Department of Health make Vitamin D supplements a national priority for young children.

The FSAI study in turn was provoked by the discovery of 10 cases of rickets among Irish born children, a finding which one of the report's authors said, "may have been the tip of the iceberg". Rickets is caused by lack of Vitamin D and leads to softening of children's bones and skeletal deformities. It was thought to have been eradicated in Ireland decades ago. Even more cases have come to light since the report was published.

Most Vitamin D is produced by the action of sunshine on the skin but Irish sunshine levels between October and March are insufficient. Skin cancer warnings have also led more people to avoid direct sunlight so even in summer many people do not get enough sun exposure.

Use of a Factor 15 sunscreen can reduce Vitamin D production by 99%, according to a study by Professor Michael Holick of Boston University Medical Center, who has described Vitamin D deficiency as an international "pandemic." However the FSAI is not recommending that young babies be exposed to additional sunshine. Only a handful of foods like oily fish, liver and eggs provide Vitamin D so if these foods are not regularly consumed supplements are essential, said Dr Mary Flynn, chair of the FSAII study group which produced the report.

The FSAI is now to prepare recommendations for Vitamin D levels in other sections of the population, especially women of childbearing ago, and the elderly. Babies born to mothers with Vitamin D deficiencies are most at risk. Some of the recent cases of rickets were in babies born to immigrant mothers with dark skins which can produce as little as one percent the Vitamin D of fair skins. Some were also born to Muslin women who followed strict religious observance of covering up most of the body.

Vitamin D deficiency is a leading cause of osteoporosis or brittle bone disease in the elderly where complications arising from fractures is a major cause of death. Currently international recommended doses of Vitamin D are designed to prevent rickets and osteoporosis. But studies comparing illnesses in sunny areas of the USA with northern states and Canada (which has similar winter sunshine to Ireland) are discovering the rate of many diseases rises the further north one moves leading some researchers to suspect Vitamin D may play a greater role in health than previously recognised.

Not only can the elderly benefit. Research in UCC showed bone mineralisation in girls improved significantly when they were given Vitamin D supplements although Kevin Cashman, Professor of Food and Health at UCC said further work was needed.

Nutritionists and infant health experts have warmly welcomed the Department's new guidance on Vitamin D but some have questioned why it took so long since the report was issued in March 2007.

This recommendation meant a careful balancing act for the FSAI study group and the Department, explained Dr Flynn, who is chief nutritional specialist at the FSAII.

"Mothers' milk is not very rich in Vitamin D while it is added to formula for bottle fed infants but we didn't want to provoke a swing away from breast feeding which is still far more beneficial in almost every respect", she said. Dr Flynn added her group was also anxious to ensure that people didn't simply put young infants in more sun, which could have led to other problems. They also wanted to ensure that the Vitamin D supplement would be in the correct format.

At the time Dr Flynn's report was submitted to the Department, only one approved infant vitamin supplement contained Vitamin D. However, it also contained Vitamin A which can be toxic in excess and is already added to infant formula, so her group was reluctant to promote anything that could lead to over-consumption. Two preparations suited for infants containing only Vitamin D have been approved since Dr Flynn's report was published and these will be recommended.

"You don't idly recommend a population-wide supplement," said Dr Phillip Crowley, deputy medical officer at the Department of Health. "We took some time to reconsider the evidence, take soundings in the nutritional community and consult academics. We believe the recommendation is proportionate and safe."

Further studies of Vitamin D levels in the Irish population are under way at UCC. In one study, funded by the UK Food Standards Agency, Professor Cashman's department is attempting to decide the minimum vitamin D levels needed to prevent bone deterioration, or osteomalacia, in adults.

"The existing threshold only copes with more severe deterioration like rickets and osteoporosis. We are trying to see if we need to raise that threshold to take other diseases into account," Professor Cashman said. A further study is to assess the impact of Vitamin D on the general health of the population.

International studies are finding more and more correlation between high sunshine levels, high Vitamin D levels and a reduced incidence of other serious diseases. According to recent reports by studies by Boston's Professor Holick and other researchers, these include breast, colon, prostate, and several other cancers, Type I diabetes, Chrohn's Disease, multiple sclerosis, hypertension, rheumatoid arthritis, schizophrenia, depression, pre-eclampsia, and even tuberculosis. 

"In every dietary survey we have undertaken in this country the levels of Vitamin D are low, as low as 2 micrograms per day when the international recommendation is 5 micrograms and many experts say even that is too low because of the recommendation to stay out of the sun," said Dr Flynn.

(Update: a major study reported in the New York Times recently consolidates many of the findings described in the above 2008 article, which was written for the Irish Times. See: http://well.blogs.nytimes.com/2014/04/01/low-vitamin-d-levels-linked-to-disease-in-two-big-studies/?action=click&module=Search&region=searchResults&mabReward=&url=http%3A%2F%2Fquery.nytimes.com%2Fsearch%2Fsitesearch%2F%3Faction%3Dclick%26region%3DMasthead%26pgtype%3DHomepage%26module%3DSearchSubmit%26contentCollection%3DHomepage%26t%3Dqry475%23%2FVitamin%2520D3

Did crash pilots feel under pressure to land?

Published Friday, February 11, 2011

The Examiner

Analysis: By Gerry Byrne

Investigators from the Irish Air Accident Unit will today be trying to understand why the pilot of the Manx2 Fairchild Metroliner tried to land after aborting two earlier attempts and circling for 20 minutes in a holding pattern hoping for conditions to improve.
There are no suggestions that the foggy conditions improved significantly. Did the pilot feel under commercial pressure to land at his destination rather than incur additional expenses for his employer? A diversion is always costly.
Apart from the cost of relocating the passengers by road or air to their original destination, the passengers due to join the flight can claim compensation if their flight is delayed too long. Some airlines require pilots to provide an explanation if they are as little as three minutes late, a situation which often places them under pressure to keep to a schedule.
Or were the pilots subject to a phenomenon colloquially known in aviation as “getthereitis,” where an overriding sense of duty to get their passengers to their destination impelled them to throw caution to the wind and risk a foggy landing? Yesterday’s fatal crash of the Manx2 airliner at Cork has chilling parallels with the crash of a Polish Air Force passenger jet carrying that country’s president Lech Kaczynski and 95 other senior officials and relatives at Smolensk last year. Both occurred in heavy fog. In the Smolensk crash there is evidence the pilot felt under pressure to land, even though air traffic controllers advised against it.
Regulations require a passenger aircraft to have sufficient fuel for both a hold and diversion to the nearest airfield so shortage of fuel is unlikely to be an issue. Fog is a capricious element and, while one moment an approach appears clear, within seconds it can swirl in and obstruct the runway. Flying through fog can give rise to a condition known as vestibular disorientation, where the pilot’s natural balance organs convince him or her the aircraft is flying level when in fact the opposite is the case.
At this early stage of the investigation there are no indications of any faults with the airplane. It was built by the Fairchild company, which has in recent years tended to specialise in continuing the production or operation of aircraft whose original manufacturer has ceased production.
It stems from a design which originated in the 1960s. The aircraft which crashed in Cork was manufactured in 1992. An aircraft of that age would be designated an “ageing” and, while perfectly safe to fly, would be subject to extra maintenance checks to ensure its reliability.
There have been about 16 serious accidents involving the Metroliner. In 2005, a New Zealand Post Metroliner crashed, and a week later another crashed in Queensland, Australia killing 15. No connections were found between the two disasters.
The aircraft carries 19 passengers, a number contrived to avoid regulations such as the need to carry cabin crew. It may also be below the size threshold for the installation of “Black Box” flight recorders, the Flight Data Recorder (FDR), which records the aircraft’s progress though the air, and the Cockpit Voice Recorder (CVR), which records conversations between pilots on the flight deck. A spokesman for the UK Civil Aviation Authority which supervised the airline said yesterday it recommended the installation of these recorders where possible, even when it was not mandatory.
At the time of writing there is no indication that any recorders have been recovered. An FDR would yield valuable information regarding the aircraft’s progress through the air, although many recorders of the aircraft’s vintage supplied limited information, especially if they were manufactured for US operators. Older FDRs could show parameters like the aircraft’s heading, altitude and speed, but might not reference issues such as what controls, ailerons, flaps and the rudder, were operated by the pilots.
But even the best FDRs have limitations. They may show what the aircraft did, but not why. And that is why the Cockpit Voice Recorder can prove invaluable. Very often the pilots have described the incidents leading up to crash, and highlighted issues which might not be recorded on the FDR. Even the rate at which they speak can tell investigators a lot about their state of mind, whether or not they were panicked, or if they were bewildered by something unusual happening to their aircraft. In the case of USAir Flight 427, which crashed on approach to Pittsburgh in 1994, investigators were able to demonstrate the rudder pedal had jammed because of the unusual laboured grunts emitted by the co-pilot who was flying the aircraft.
The lack, if any, of Black Boxes, may be compensated to some degree by the conversation between the cockpit and the air traffic controllers at Cork. These are always recorded and will be carefully listened to by the investigators. Tapes of the radar returns from the doomed aircraft will also be closely studied, although this will be less reliable close to the ground. They will reveal the aircraft’s rate of descent and its speed.
But initial probes will take place on the runway as investigators sift through the wreckage seeking clues to what happened. They will first of all try to establish where the aircraft first impacted the ground and will carefully look for scrapes on the tarmac, or furrows in the grass verge and attempt to relate them to parts of the aircraft. The aircraft was found upside-down and there will be pressure on investigators to figure out how, and why, this happened.
One reason for an inverted wreckage is that the aircraft came down heavily and at speed on its nose and that this caused it to somersault. However, pictures of the wreckage show the nose-wheel is in position: in a heavy, nose-down impact the nose-wheel would more than likely have snapped off, or be forced up into the fuselage. A more likely explanation is that there was a wing strike, where the wings were not level and one wingtip forcibly struck the ground in a manner which caused the aircraft to flip over onto its back. If there was a wing-strike, could the fog have contributed to the pilot’s inability to keep his aircraft level?
Because of vestibular disorientation, the US armed forces lose on average of between 20 and 30 aircraft annually. The US Federal Aviation Administration lists it as the leading cause in 15% of fatal small aircraft crashes and it was blamed for the crash of seven Dutch F-16 fighters.
It can occur when pilots lose visual clues to their surroundings and, either because they misread, mistrust or ignore their instruments, allow the aircraft to wander off course, develop an excessive bank and eventually spiral out of control with the pilot often not realising his or her predicament until too late. Experiments conducted more than 20 years ago by the University of Illinois showed, with the autopilot switched off, a pilot can lose control in as little as 20 seconds if denied sight of instruments.
The human body has its built-in spirit level in the inner ear which controls our balance. Also known as the vestibular system it consists of the semi-circular canals of the inner ear plus a system of small fluid filled sacs containing sensitive hairs, which respond to gravity. Pilots flying in the dark, in fog or in cloud are particularly vulnerable to a phenomenon known as the “leans”. This occurs when the vestibular system gives a false reading after a long period of being banked at an angle, or in a turn, such as a prolonged period in a holding pattern, and they imagine they are flying straight and level. When they level their aircraft according to their artificial horizon, they often mistrust the instrument because their vestibular system has fooled them. A confused pilot will often apply the wrong controls and precipitate a fatal spin. Closer to the ground it could result in a wing-strike.
Investigators will try to establish if this, or something similar happened to the Manx2 pilots. The 20 minute holding pattern they flew would have been more or less circular or racetrack shaped and a prolonged period of constant turns in the same direction could easily give rise to a case of the “leans”. It may be an issue probed by investigators.
* Gerry Byrne is an aviation journalist
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