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Essays:

2007 QLD Govt
research: review

Why is Brisbane
afraid of the dark?


Dual time zone or 'double standard' time

Hold back the night

Light without progress

Epilogue

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When a faded curtain is not a joke

The unacknowledged link between daylight saving and skin cancer

In a climate that fluctuates between hot and bloody hot in summer, the old joke about daylight saving 'fading the curtains' seems to be a particularly Australian phenomenon - and one that shows no sign of abating. Among Australia's daylight saving advocates, the joke is told so often that many have started to believe that it's true. It's become almost impossible either to read a daylight saving article or to have a daylight saving discussion without being told - despite overwhelming evidence to the contrary - that a superstitious 'fear of fading the curtains' is the 'main reason' people oppose it.

Needless to say, faded-curtain ridicule has become so entrenched in Australia's daylight saving discourse, that any attempt to link daylight saving to skin cancer rates is met with abject hilarity. Some Queensland doctors have tried over the years to open a debate on daylight saving’s potential to impact on skin cancer rates but, as a rule, their arguments have been misconstrued as an ignorant belief that daylight saving creates an 'extra hour' of daylight in the day, which will then increase sunburn.

This may provide vindictive fun for those dishing out the humour. However, given Queensland’s horrendous skin cancer statistics, this attitude is unacceptable and dangerous - especially when a permanent forward clock change during the hottest months of the year would automatically shift schoolchildren's daily outdoor activities from the relative safety of the early afternoon into the peak ultra-violet radiation (UVR) period in the middle of the day.

Queensland — skin cancer capital of the world

As a nation, Australia well and truly leads the world in skin cancer rates. One in six people in the major industrial nations, compared with two out of three Australians, will develop skin cancer in their lifetime.

Yet Queensland is way ahead of the nation itself — so far ahead, in fact, that the world runner-up on skin cancer rates is not even another Australian state. That particular honour goes across the ocean to Arizona in the United States. (1)

According to the Queensland Cancer Fund, we are the ‘skin cancer capital of the world’. More than 111,000 Queenslanders a year — in a state of 4 million people — are now being treated for skin cancer. This represents a surge of 270 per cent in just over a decade. (2)

The basal cell carcinoma, which once had a minimum age of fifty-five, is now commonly detected in people in their twenties and thirties, some as low as nineteen. In 1996, the Queensland Childhood Malignancy Registry reported that the number of new melanoma cases in children under fifteen had at least doubled since before 1993. At the time, the Registry indicated in the press that the risk of Queensland children developing melanomas was twenty times greater than in temperate climates. (3)

What causes skin cancer?

Extensive research has found that our degree of exposure to ultra violet radiation (UVR) is virtually the sole cause of skin cancer. Several factors tend to influence our degree of exposure to UVR. Some, such as behaviour, occupation and lifestyle habits, have a variable influence and can be minimised by the individual’s choice of protective measures.

However, the main factors influencing skin cancer tend to be constants — those over which we have little direct control, other than to make a total lifestyle change. These include latitude, time of day, the seasons, altitude, and surrounding terrain such as the presence of sand, water or snow. Also, skin type is a big factor — people with Celtic ancestry have the highest incidence of skin cancer in any population.

Of all these factors, however, latitude is arguably the major constant that affects our continuing degree of UVR exposure. On average, the number of skin cancer cases doubles for every eight degrees latitude nearer the equator. (4) The chance of Brisbane residents developing skin cancer is almost double the rate of Sydney, three times the rate of Melbourne and four times the rate of Hobart.

How can a forward clock-change affect UVR exposure?

Two other major UVR constants — time of day and time of year — are of particular concern to Queensland’s daylight saving controversy. We are warned by skin cancer experts to avoid the sun during summer, and during the day’s peak UVR period, between 10 am and 2 pm (11 and 3 on Daylight Saving Time). This is the period when the sun’s rays are at their most direct.

In addition, studies of migration patterns show that people who migrate from high- to low-latitude countries later in life have a much lower risk of contracting skin cancer. This has led skin cancer researchers to conclude that most of the UVR damage sufficient to cause skin cancer has occurred by the age of twenty. Those big doses of sunburn suffered during a day at the beach are the most specific danger. However, research also shows that 80 per cent of sun exposure is incidental — that is, accumulated low-level UVR exposure, as we go about our daily business. (5)

Thus, accumulated low-level UVR exposure among children living on a low latitude, in the middle of the day and at the hottest time of the year, constitutes the greatest combination of skin cancer risks possible. For those who are willing to see it, daylight saving — Queensland style — would increase every one of these skin cancer risks permanently, automatically, and on every school day during the daylight saving months.

This is no joke.

How can daylight saving increase long-term skin cancer rates?

Most children’s outdoor activities, such as school lunch breaks, sports matches, physical education and travelling home, are still concentrated mostly between 1 and 3 pm Eastern Standard Time (EST). On daylight saving, these would be automatically shifted forward — well into the day’s peak UVR period, and at the hottest time of the year. Going-home time moves from 3 pm to the ‘2 pm’ sun position; lunch breaks from approximately 1 pm to ‘12 pm’; and sports matches from 1.30 pm to ‘12.30 pm’.

To illustrate this process and its potential effect on school children's daily UVR exposure, note the following graphs*, which show the UV Index for Brisbane and Townsville on 13 November 2004. As the graphs show very little difference between the 'measured' and 'model' (or average) readings, it can be assumed that the data shown illustrate those of a typical November day in Queensland.

UV Index for Brisbane 13 November 2004

Blue line: measured reading for the day

Red line: model reading for the day

Exposure categories:

- 2 Low
3-5 Moderate
6-7 High
8-10
Very High
11+
Extreme



 

UV Index for Townsville 13 November 2004  

Source: Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) http://www.arpansa.gov.au/uvindex/daily/ausuvindex.htm

All times listed are Eastern Standard Time (EST).

 

In Queensland, virtually all schools finish for the day at approximately 3 pm. On daylight saving, school children right across the state would have no choice but to travel home at what is now 2 pm EST. According to the above graphs, the Brisbane UV level at 3 pm is '3' (moderate), while at 2 pm the level is '7' (high); in Townsville, the UV level at 3 pm is '5' (moderate) and at 2 pm '9' (very high). In terms of this data, the permanent shift in school children's going-home time from 3 pm to what is now 2 pm EST represents virtually double the UVR exposure risk.

To give another scenario: In Queensland, it is compulsory for schools to offer sport on at least one afternoon per week. Given that the average playing time for school sports matches across the state is between 1.30 pm and 2.30 pm, daylight saving would force these matches to be played between what is now 12.30 pm and 1.30 pm EST. According to the above data, the UV level in Brisbane at 1.30 pm is '7' (high) and at 12.30 pm, '10' (very high); in Townsville, the UV levels for these times are respectively '9' (very high) and '12' (extreme). Again, in terms of this data, the permanent shift of school sports matches from 1.30 pm to what is now 12.30 pm EST represents approximately a 30 per cent higher UVR exposure risk.

In both the above scenarios, the introduction of daylight saving changes the exposure risk from 'moderate/high' to 'very high/extreme'.

Some daylight saving advocates argue that the increased UVR exposure in the afternoon is simply balanced against the decreased UVR exposure in the morning - that is, children would be travelling to school at what is now 8.00 am instead of '9.00 am'. However, as the above graphs show, daylight saving would decrease UVR exposure in the morning, but the range is low/medium - well outside the beginning of the danger period - i.e. 10.00 am (EST) or 11.00 am (DST). Also, despite the fact that the morning recess break would occur at what is now approximately 10.00 am instead of '11.00 am', the shift is only negligible (1-2 points) within the low/moderate UVR range. By contrast, daylight saving's forward clock shift in the afternoon pushes children's daily activity significantly into, or further into, the high/extreme danger period in the middle of the day.

While many would argue that the one-off effect of increased UVR exposure might be minimal, over a 12-year school career this has the cumulative capacity to cause real damage, particularly to fair-skinned people.


The Daylight Saving Trial Task Force

In a 63-page report by the State Government Daylight Saving Trial Task Force in 1990, a tiny section of just over 150 words was devoted to the issue of skin cancer. Yet, the report insisted that the Task Force had given it ‘special consideration’. (6)

In backing up this claim we were vaguely told that some anonymous person during the trial had made ‘a comment … that concerns [about] skin cancer were … by and large misplaced’ — but no details were given. It was then added that the Task Force had received 'information’ from the Queensland Cancer Fund about schools programs, and from a Department of Health spokesperson on skin cancer statistics — again, no details. Nor did the report discuss how, or even if, any correlation was made between this information and daylight saving.

Finally, and sounding a bit like a rhetorical version of the St Christopher medal, the Task Force concluded that on the issue of a possible link between daylight saving and skin cancer, ‘there appears to be no grounds’ for concern. (Italics mine.)

Subject over!

Sun awareness does NOT equal risk minimisation

In a state that carries the title of ‘skin cancer capital of the world’, education programs, however informative or professional, are simply not enough. When Queensland leads the world in melanoma rates, we should accept nothing less than absolute minimum risk exposure!

When children have no direct control over their daily outdoor timetable during the daylight saving months, sun awareness education campaigns have only limited benefits.

To be fair, skin cancer experts in the southern daylight saving states have recommended at times that schools change their breaks and sporting activities to less harmful times of the day. Yet, to my knowledge, and despite almost three decades of daylight saving in Australia’s southern states, together with an active commitment to sun awareness campaigns, nothing has been done to adjust school timetables to minimise UVR exposure during the daylight saving months.

While the Queensland public has plenty of information about hats, sunscreens and shade covers, it is left completely in the dark about how the introduction of daylight saving — in any part of the state — would increase our children’s daily UVR exposure on a permanent basis.

In fact, the daylight saving lobby has at times turned Queensland’s skin cancer statistics to its own advantage. In the lead-up to the 1992 daylight saving referendum, Brisbane garbage collectors were given permission by the Brisbane City Council to distribute ‘Vote Yes' leaflets throughout the metropolitan area. The reason? On daylight saving, garbos finish work by 11 am (10 am Standard Time) and thus would avoid their current higher levels of UVR exposure in the middle of the day.

I doubt if anyone distributed leaflets advising people of children’s increased daily UVR exposure, were the referendum to produce a majority ‘Yes’ vote.

Conclusion

For decades, we have had the evidence to make the connection between daylight saving and the increased risk of skin cancer, but have failed to apply it to the daylight saving debate. This could well be because decades of faded curtain ridicule have created a situation in which people just don’t want to be laughed at.

If the relationship between school children, skin cancer and daylight saving is a non-issue now, it would certainly remain a non-issue should a permanent clock change ever take place anywhere in Queensland. Should the clock-change lobby ever succeed in inflicting daylight saving on the skin cancer capital of the world, we will just have to keep our ‘curtains’ protected in whatever way we can.

March, 2002
Updates 2004, 2007
* ARPANSA graphs and commentary added to text, November 2004

 

Disclaimer:  The statistical and medical information in this essay is taken mainly from the sources listed below. However, the arguments given are entirely those of the author of this essay and are not drawn from the resources listed.

1.‘Campus Health scans for sun’s cancerous effects’, Arizona Daily Wildcat, 10 April 1998, http://wildcat.arizona.edu/papers/91/131/01_3_m.html.

2. Queensland Cancer Fund, ‘Skin Cancer Levels Skyrocket’ (Media Release), 4 October 1999, http://www/qldcancer.com.au/whats_new/Media_Releases/Skin Cancer.html.

3. Reported in Courier Mail, 31 October 1996.

4. Siegel, Mary-Ellen, Sun & Skin, Stirling Books, Richmond, South Australia, 1996 (First published in 1990 by Walker Publishing Company Inc.), p129.

5. Ibid , p35 and 69.

6. Daylight Saving Task Force Secretariat, Report of the Trial of Daylight Saving, 29 October to 4 March 1990, Department of Employment, Vocational Education, Training and Industrial Relations, 2 May 1990, p22.

Recommended reading:
Australian Radiation Protection and Nuclear Safety Agency (ARPANSA)
http://www.arpansa.gov.au/uvindex/daily/ausuvindex.htm