Author References

_{Christina J Mills, Prevention Division, Cancer Bureau, LCDC, Health Canada, Tunney's Pasture, Address Locator: 0602E2, Ottawa, Ontario K1A 0L2
Konia Trouton, Bureau of Reproductive and Child Health, LCDC, Health Canada Laurie Gibbons, Early Detection and Treatment Division, Cancer Bureau, LCDC, Health Canada}

Part II. Presentation Summaries

Impact of Ozone Depletion on Immune Function

Margaret L Kripke

Depletion of stratospheric ozone is expected to lead to an increase in the amount of UVB radiation present in sunlight. In addition to its well-known ability to cause skin cancer, UVB radiation has been shown to alter the immune system. The immune system is the body's primary defence mechanism against infectious diseases and protects against the development of certain types of cancer. Any impairment of immune function may jeopardize health by increasing susceptibility to infectious diseases, increasing the severity of infections or delaying recovery from infections. In addition, impaired immune function can increase the incidence of certain cancers, particularly cancers of the skin.

Research carried out with laboratory animals over the past 15 years has demonstrated that exposure of the skin to UVB radiation can suppress certain types of immune responses. These include rejection of UV-induced skin cancers and melanomas, contact allergy reactions to chemicals, delayed-type hypersensitivity responses to microbial and other antigens, and phagocytosis and elimination of certain bacteria from lymphoid tissues.

These findings led to concerns that resistance to infectious diseases might also be compromised by UV irradiation, resulting in an increase in the severity or incidence of certain infectious diseases. This possibility has been borne out in a number of rodent models of infectious diseases, including cutaneous herpesvirus infection, leishmaniasis, chronic and acute mycobacterial infections, candidiasis and borreliosis (Lyme disease), but not in schistosomiasis.

There is also substantial evidence that UVB alters immune function in humans by mechanisms similar to those described in rodent models, although much less information is available for humans. The induction of contact allergy is suppressed in UV-irradiated human skin, and a recent study demonstrated that UV irradiation of healthy human subjects significantly reduced the delayed-type hypersensitivity response to the leprosy bacillus. Nonetheless, much more information is needed before we will be able to assess the relevance of these findings for the pathogenesis of infections in humans and the global impact of ozone depletion on infectious diseases.

Ocular Effects of Chronic Ultraviolet Radiation

Sheila K West

In the Ottawa meeting in March 1992, a consensus was reached that sufficient human and animal data relate chronic UVR exposure to certain types of cataract in older populations, although the relative contribution of UVR to this multifactorial disease remains unclear. There was no persuasive evidence linking ocular melanoma to UVR.

In the last four years, further studies that have bearing on the ocular effects of chronic exposure to ultraviolet radiation have shown the following.

• Studies that improve measurements of individual, ocular UVR exposure in populations have revealed these findings.
• Apart from the amount of time spent outside and the work surface, specific jobs or leisure activities have little effect on the ocular ambient exposure ratio.
• There are pronounced seasonal differences in the ocular ambient exposure ratio.
• Studies in the population show the lifetime ocular exposure to UVR in women tends to be lower than in men, and it is skewed higher in African-Americans compared to whites. However, all population groups show an increased risk of cortical cataract with increasing exposure to UVR.

The Photodermatoses

Colin A Ramsay

The skin diseases usually included under this heading are those due totally or largely to ultraviolet and/or visible radiation. By convention, the primary neoplastic skin diseases due to ultraviolet radiation are not included.

Classification of these diseases is not easy because the etiology of most of them is unknown. A working classification is listed below.

• Diseases due to metabolic defects
• Diseases due to drugs and chemicals administered systematically or topically
• Idiopathic diseases
• Diseases aggravated by ultraviolet and/or visible radiation
  

This presentation discussed examples of each of the above groups, some rare, some common. Porphyria and xeroderma pigmentosum are examples of diseases with an established metabolic defect. Examples were given of individuals made photosensitive by systemic and topical drugs and chemicals.

The idiopathic disease called polymorphic light eruption is common, and its manifestations were presented.

Finally, some skin diseases have an element of photosensitivity, but exacerbation by sunlight exposure is only one of several precipitating factors. Lupus erythematosus is one such disease and was discussed.

Recognition of the photodermatoses is important as it enables appropriate strategies for management to be instituted.

Non-melanocytic Skin Cancers

Richard P Gallagher

The incidence of non-melanocytic skin cancer has been increasing worldwide for many years. Significant declines in stratospheric ozone in both northern and southern latitudes have alerted the public and spurred new research between solar ultraviolet radiation and basal and squamous cell tumours.

Recent results from both Australia and Canada suggest that intermittent solar exposure may be important in accounting for basal cell carcinoma of the skin. There is also good evidence that childhood sun exposure plays an important part in the development of these cancers later in adult life. These findings are similar to those for cutaneous melanoma.

The relationship between squamous cell carcinoma and solar ultraviolet radiation appears to be quite different. For squamous cell tumours, high levels of chronic occupational sunlight exposure, especially in the 10 years prior to diagnosis, results in a fourfold elevated risk for this cancer in the highest exposure group.

Results from these recent studies should provide useful advice to the designers of primary prevention programs.

Melanoma Update

Martin A Weinstock

Malignant melanoma continues to increase in incidence and mortality despite public health programs designed to reverse these trends. The central conclusions from the first symposium four years ago remain valid. However, new data have been published since then that are relevant to these public health efforts.

Several additional studies have been published regarding the potential link of exposure to tanning booths with melanoma, although consensus has not been achieved. More attention has focused on the action spectrum for melanoma, and new evidence has accumulated from animal models and other sources. Issues regarding avoidance of midday sun and sunscreen labelling need to be addressed. Finally, important new data have been published regarding examination for melanoma in an effort to reduce mortality. The effort to control melanoma must incorporate insights from these findings and move forward based on sound science.

Progress in the Prevention and Early Diagnosis of Melanoma

Mark Elwood

Do educational campaigns change behaviour?

It is accepted that the only major, and modifiable, cause of human cutaneous melanoma is excess exposure to solar ultraviolet radiation, and therefore extensive efforts have been made to develop educational campaigns to change sun exposure behaviour. We have recently reviewed evaluative studies of these campaigns.

The best evaluation design is a randomized control trial, and three such trials have been published, all from Australia. Two of these showed modest increases in sun protection in outdoor workers after educational interventions, and the other showed an improvement in sun protection, maintained for eight months, in school children given a comprehensive educational campaign merged into the school curriculum over 3-4 weeks; the same study showed no effect of a 30-minute presentation by a health promotion officer.

Other studies have used before-and-after designs. In Melbourne, telephone interviews relating to sun behaviour over the previous weekend have been used regularly during three summers, 1988-1990, showing reductions in the proportion of people outdoors, increases in sun protection and modest reductions in the reporting of sunburn. However, other unpublished data for further years do not suggest any greater improvement.

This review has three major conclusions. First, in comparison with the investment in sun exposure programs, the investment in rigorous evaluation has been very small. Second, where evaluation has been done, it suggests that comprehensive and ambitious programs are needed and that they result only in modest changes in sun behaviour. The main unresolved question is whether such modest changes in behaviour are sufficient to produce ultimately a substantial decrease in the incidence of melanoma or other ultraviolet radiation-related diseases.

Screening for melanoma

The biological features of melanoma suggest that early diagnosis through routine screening could have substantial benefits, but as yet there is little empiric evidence of such benefits. Screening tests are normally assessed by shortterm parameters, such as sensitivity and positive predictive value. A review of studies estimating these shows that the results are critically dependent on the definition used of positivity and the follow-up used. A major issue is whether a screening program can be set up specifically for melanoma, ignoring other less severe skin diseases, or whether it must of necessity identify large numbers of subjects with other less important abnormalities.

As no randomized trials or major cohort studies have been done, the most rigorous evaluation of screening for melanoma is a recently published case-control study assessing self-screening in Connecticut. These results show a substantial reduction in mortality from melanoma in those who practise self-screening, but somewhat surprisingly, a substantial reduction in incidence also. If this is not due to confounding or biases in study design, it must be due to the recognition and removal of precursor lesions, but direct evidence for this pathway needs to be shown.

A randomized trial of a community approach involving both self-screening and doctor-screening of melanoma has been proposed in Queensland. This involves the randomization of some 42 communities  with a total population of nearly 500,000, introduction of a substantial community-based intervention program to the study communities and monitoring of effects by general practitioners' diaries, pathology records and ultimately, mortality data, with an extensive follow-up time. The first phase of this trial is starting.

There is at present little clear evidence of the benefits of screening for melanoma, although the first rigorous evaluation studies are in progress. The widespread promotion of screening, particularly in North America, lacks the empiric scientific support that has been regarded as essential to justify promotion of other cancer screening activities. Further assessment of current as well as new approaches is therefore required.

Promoting Behaviour Change: Results of a Pilot Study and Implications for a National Survey

Chris Lovato, Jason Rivers and Jean Shoveller

This presentation focused on the development of a national survey to measure sun exposure and protective behaviours. The psychometrics of the survey, designed to assess sun-related behaviours, knowledge and attitudes of people living in Canada, were presented.

Instruments used previously to assess sun exposure and protective behaviours were reviewed. The PRECEDE/PROCEED Model was used to develop draft items. A two-phase procedure was used to test the draft instrument. Phase One (Pre-test) included (a) focus groups (French and English), (b) expert review by National Advisory Committee members and (c) Vancouver-based pre-test with a convenience sample of 200 respondents. Phase Two (Pilot Test) used telephone interviews (English and French) with a stratified random sample of Canadian households (n = 421). Content analysis was used to analyze qualitative data. Cross tabulations and reliability analyses were applied to weighted data.

Phase One resulted in major changes to the instrument, including lengthening the recall period from the previous month to the previous three months and increasing specificity regarding when and for how long respondents were exposed to sun. The general sampling technique used in Phase Two captured a significant cross section of individuals who are placing themselves at risk of developing skin cancer. We found the most difficult construct to measure to be "barriers" to taking protective action.

Based on our results, we conclude that a national telephone survey of households will provide useful baseline data about Canadians' sun exposure and protective behaviours. Results of the pre-test and pilot test are being used to finalize the instrument for use in a full-scale national survey (n = 3600) to be implemented during autumn 1996.

Ozone Depletion and Canada's UV Index

Robert B Saunders and James B Kerr

Ozone Depletion and UVB Radiation

Since the late 1950s and early 1960s stratospheric ozone has been routinely monitored at several places around the world including five sites in Canada. In light of the concern first proposed in the early 1970s that man-made chloroflourocarbons (CFCs) may lead to a reduction in stratospheric ozone, the ozone records have been analyzed to determine if a change in ozone has occurred and whether any change is in agreement with model predictions.

The first indication that stratospheric ozone has been affected came with the 1985 discovery that springtime values of ozone over the Antarctic have decreased since mid-1970s (the Antarctic ozone hole). Subsequent experiments confirmed that this depletion over the Antarctic is caused by high levels of chlorine in the stratosphere and that these elevated levels are likely caused by the build-up of anthropogenically produced CFCs. Further analyses of ground-based and satellite-based measurements have shown that ozone has declined globally and for Canadian latitudes the annual average rate of decrease is about 3-5% per decade. The most significant decrease has occurred during late winter and early spring.

Recent measurements of spectral ultraviolet radiation (UVR) have shown that UV levels increase when ozone levels decrease. Measurements of UV radiation levels under the Antarctic ozone hole during spring are higher than those seen at southern California during summer. Measurements made at northern midlatitudes show increases of UV radiation with decreases in ozone. The increases in UVR are more significant at shorter wavelengths in the UVB where ozone has stronger absorption and where UVR is more damaging to most biological systems.

It is expected that chlorine levels in the atmosphere will peak around the turn of the century. The rate of increase of CFCs in the atmosphere has declined as production and use of CFCs have decreased as a result of control agreements made under the Montreal Protocol (1987) and the more aggressive London (1990) and Copenhagen (1992) Amendments. At this time annual average ozone levels over Canada are expected to be about 6-10% below the pre-1980 normal levels and erythemally active UVB levels will be about 10-15% higher. In late winter/early spring, when ozone levels may be 20-25% below normal for short periods, UVB levels can rise to 30% above normal values.

After 2000, chlorine levels are expected to return slowly to near normal (pre-ozone hole) values around the middle of the next century. Uncertainties in the maximum ozone depletion and recovery include how much CFCs are used in developing countries, how quickly use of CFC substitutes increases and how ozone depletion is related to other environmental changes such as global warming or effects from volcanic eruptions.

Canada's UV Index

In order to address the growing concern by the Canadian public regarding changes in UVR resulting from ozone depletion, Environment Canada launched the UV Index program in May 1992. The objectives of the UV Index are to increase public awareness and understanding of variations in UV values, to support health agency goals of educating the public on UV risks and to assist individuals in making healthy lifestyle choices. The behaviour of UVR is very complicated since it depends on many variables, including ozone, atmospheric aerosols, clouds, time of day and time of year. Development of the UV Index included the challenge of taking a complicated variable and presenting it as an understandable and useful product to the general public.

The first consideration in the development of a useful product that quantifies UVR is the definition of a physical parameter that exists in the environment. The UV Index is proportional to the energy (in milliwatts/metre) of erythemally weighted UVR falling on a horizontal surface. It is a non-dimensional value defined by dividing the erythemally weighted UVR by 25 milliwatts/metre. Erythemally weighted UVR was chosen as a basis for the UV Index because many existing instruments have been developed to replicate erythemal response and sunburn is the fastest human response to UVR.

Across Canada, UV Index values range between 0 and 10 and can reach 12-14 at tropical latitudes under low ozone conditions. Techniques were developed to produce an 18-hour forecast of the UV Index based on strong correlations between ozone and weather patterns. The UV Index is a variable that is treated in a similar fashion to other meteorological variables (e.g. temperature, rainfall, etc.). It is measured, forecast and distributed to the general public as a regular part of the product suite of Environment Canada through the media (newspapers, radio, television) and other communication means.

The second consideration is the interpretation of what the UV Index means to human health effects. In Canada the UV Index is categorized into low (less than 4), moderate (between 4 and 7), high (between 7 and 9) and extreme (greater than 9). These categories relate how much exposure time is required to redden type II skin. The continued availability of the physical quantity (UV Index) with additional information of how to interpret the values is thought to serve as an educational guide to remind people that UVR is out there and that precautions should be taken. Also the general public should become familiar with the times of year and day when UV is high.

The Canadian UV Index is being adopted as the standard by the World Meteorological Organization and the World Health Organization. At present 11 countries have adopted the Canadian Index and are using it or are planning to use it in the near future. It is recognized that international standardization using a common scale is important to educate and caution people travelling to other parts of the world.

The UV Index program was developed with significant input from the general public as well as interested stakeholders. Stakeholders include the medical community, the public health community, the Canadian Cancer Society, the Canadian Ophthalmological Society, the Canadian Optometrists Society, instrument manufacturers and the media. The response of most stakeholders and the public is that they are generally satisfied with the program. The presentation and forecast of the UV Index has been improved since its introduction in 1992 (for example, improved methods for dealing with effects of clouds) and it is likely that further changes will occur in the future. These improvements have resulted partly from the input of stakeholders and the general public.

The development of the UV Index program to provide quantitative information to the general public on UVR levels represented a logical extension of programs that were already in place in 1992. The monitoring and prediction of weather as well as the monitoring of ozone and UVB radiation were all operational at the time. The introduction of the UV Index program resulted from an enhancement of these existing operations and a focused scientific effort to improve the understanding of links between meteorology, atmospheric ozone and UVR. The cost to provide the UV Index program has been relatively small compared with the overall cost of the existing operations; however, the potential benefits are large if the UV Index program helps reduce detrimental health effects by influencing people to modify their behaviour regarding sun exposure.

Non-solar Sources of Ultraviolet Radiation

Yvon Deslauriers

Concerns about non-solar ultraviolet radiation exposure have been expressed to health authorities for many years now. Many requests for information and complaints of incidents or accidents have been forwarded to Health Canada on quartz halogen lamps, mercury vapour lamps and sunlamps. These lamps are either designed to emit ultraviolet radiation or do so under misuse, breakage or failure.

Much attention has been focused on halogen lamps since 1992, when it was shown that they could affect bacteria DNA and cause cancer in hairless mice if exposed at 50 cm, 12 hours a day for one year. Animals exposed in the same conditions, but where the lamp was covered with a 2 mm thick glass sheet, did not develop cancer of the skin. The intensity of these lamps in the ultraviolet spectrum is such that it can, in the worst case, cause erythema in a few hours depending on the type, the fixture, the design characteristics, the orientation, the distance to and the sensitivity of the exposed person. To be approved by the Canadian Standards Association, this type of lamp must be provided with a glass cover. It can be incorporated into the lamp itself, as is the case in projector types, or be part of the housing holding the bulb. Models sold to the Canadian public today are provided with glass covers.

Many cases of first- and second-degree sunburns caused by broken mercury vapour lamps have been reported to health authorities. As many as 50 persons in a crowd have been injured by ultraviolet emissions of an inner core electric arc lamp that went on functioning after the outside shell had been shattered, since the danger due to high dose of ultraviolet B and C can extend over several hundred feet. The erythema dose zone, determined by an individual's minimal erythema dose (MED) distance, can be quite large. In this case, electricians had installed the unfused, non-self-extinguishing cheaper type of lamp due to a restricted municipal budget. According to Health Canada Regulations, the self-extinguishing type should be marked with the letter "T" and used in gyms, shopping centres, stock rooms, outdoor game fields and rinks, etc. The non-self-extinguishing type should be marked with the letter "R" and only used for lighting roads, parking lots and places where people are not likely to stay for a long period of time.

In contrast to the two sources mentioned above, tanning equipment is designed to expose people to ultraviolet radiation. With the evolution of technology, the spectra emitted by sunlamps varied from high intensity UVB and average intensity UVA in the 60s and 70s, to low intensity UVB and high intensity UVA in the 90s. The design went from floodlamp types, tanning booths and even tanning rooms to high pressure lamps with filters and high efficiency UVA fluorescent tubes. This is a very controversial type of equipment. Effectively, it is designed to interact with a body function that acts as a protective mechanism against overexposure to ultraviolet radiation. While a certain number of epidemiologic studies and reports have established limited evidence for human carcinogenicity by tanning equipment, there is considerable uncertainty surrounding the issue, particularly in respect of predominantly UVA sunbeds. In general, it can be indicated that the assessment of exposure to older types of sunlamps cannot support taking more stringent regulatory actions to control the use of today's UVA sunbed type of equipment.

Health Canada ensures the safety of radiation emitting devices manufactured in and imported to Canada under the legal mandate of the Radiation Emitting Devices (RED) Act. The Radiation Protection Bureau gathers scientific and technical expertise to design regulations and compliance programs for such devices. It provides facilities to verify and evaluate health risks caused by those devices. A part of program resources is also dedicated to education and information to the public.

Fabric Variables Affecting Transmission of Ultraviolet Radiation

Linda Capjack, Nancy Kerr and Robert Fedosejevs

More than 60,000 Canadians will be diagnosed with skin cancer this year. This figure is higher than the combined total for lung, breast and prostate cancers.

With careful use of sunscreens and/or protective clothing, skin damage can be reduced drastically. Medical experts frequently recommend the use of clothing for protection from UVR. Not all clothing, however, protects equally or adequately.

The purpose of this study was to clearly define fabric parameters (colour, fabric mass, structure [knit/woven], fabric count, cover, wet versus dry and layering) and examine their transmission. A wide variety of fabric in varying colours, weights and fibre types was purchased, characterized and measured spectrophotometrically for UVR transmission. This transmission, as a function of wavelength over the range 280-380 nm, was weighted with solar and erythema action spectral data to determine a sun protection factor (SPF) for each fabric. UV transmission through fabrics was measured on a Vanan Cary 2415 UV-Vis-Nir spectrophotometer fitted with an integrating sphere to collect forward-scattered and transmitted light. Fluorescence was eliminated by means of a 3 mm UG-11 fluorescence filter adapted for the spectrophotometer.

Sunscreens and fabrics are tested in the same manner to determine their effectiveness in blocking UV radiation. In an in vivo test, sunscreens or swatches of fabric are applied or fastened to the skin of human subjects with skin types I or II and the minimum erythemal dose (MED) of the protected and unprotected skin is determined. The SPF of the sunscreen or fabric is the ratio of the MED with and without protection. The number of published reports of in vivo measurements to determine fabric SPF is limited. According to these studies, there is close correlation between results obtained through in vivo test methods and spectrophotometric test methods. In vitro measurements to determine the SPF of sunscreens and fabrics are less costly than in vivo test methods, and although human subjects are not directly involved, the response of human skin to ultraviolet radiation from 280-380 nm (the erythema action spectrum) is incorporated in the calculation of SPF in this study.

The structure of each fabric was described as woven or knitted and characterized according to type of knit or weave. In addition, fabric parameters including fibre mass, fabric count (yarns/cm) and cover were determined. When all fabric parameters were kept relatively constant, 100% polyester fabric provided two to three times the protection of other fibres.

In examining the effect of colour or the presence of dyes on the transmission of UVR through a fabric, seven colours of fabrics in both 100% cotton and 65/35 polyester/cotton were tested spectrophotometrically. In the 100% cotton fabrics, the darker or more saturated the colour the higher the SPF, for example, the SPF of black cotton was approximately five times greater than white fabric. The same phenomena was noted for 65/35 polyester/cotton blends; however, variations in SPF were not so large: SPF ranged from 9 for light pink to 26 for navy fabric. Both the presence of dye molecules and the quantity of dye in a fabric affected the transmission of UVR through fabric. Many dye molecules absorb UV as well as visible radiation. As well, increasing fabric mass or weight provided increased protection from ultraviolet radiation. Results indicate that SPF values increased as fabric mass increased, regardless of fibre type (polyester, cotton, silk, etc.), that is, heavier fabric provided a higher degree of protection from UVR, independent of fibre type.

Researchers suggest that cover (defined as the fraction [%] of a given area covered) is an important aspect in determining solar protectiveness of a fabric. They suggest that a majority of UVR transmission occurs through the open spaces in a fabric. In fact, many dermatologists tell their patients to estimate the closeness of the yarn structure of the fabric by holding it up to the light source to see how much light passes through. Patients are instructed to choose tightly woven knit fabrics for good sun protection. It is difficult, however, to estimate whether light is transmitted through the open spaces or through the fabric. In this study, high cover (90-100%) did contribute to decreased transmission of UVR through fabric, but it was not as highly correlated to SPF as fabric mass. Lightweight white fabrics with no spaces between yarns (100% cover) transmitted some UVR. Other fabric parameters such as weight and colour need to be considered as well as cover when selecting protective fabric.

In this study the knit fabrics tended to have a higher SPF value than the woven fabrics tested. The knit fabrics tested also had a higher mass and cover, so it cannot be concluded that the knit structure alone contributed to the decreased transmission. Nylon/spandex knits provided very high SPF value in all colours. Several of these bathing suit fabrics were also tested in the wet state, which resulted in increased transmission of UVR by at least one third.

Finally, double layers of fabrics in this study provided at least twice the protection of a single layer of fabric. If clothing were designed from lightweight, low cover fabrics, layers of fabric could be used in areas that receive direct sunlight, such as the shoulders of a garment. Layers of fabric may account for the apparent success of some specially designed protective clothing that hangs very loosely on the body. The success of such clothing may be in the fact that the fabric does not lay close to the body and in many instances actually forms double layers as it folds over the body. The sun is not transmitted directly through the holes in the fabric as it would if it were held tightly against the skin.

In conclusion, when it comes to sun protection, all clothing is not created equal. Consumers need to be educated about different fabric characteristics that affect the transmission of solar ultraviolet radiation through clothing and learn to make the right choices in order to reduce their risk of sun damage and skin cancer.

Bibliography

This bibliography consists of references provided by the experts who presented updates on specific topics (summarized above) at the 1996 Symposium. It complements but does not replace the bibliography provided with the 1992 Symposium proceedings.

Impact of Ozone Depletion on Immune Function

Jeevan A, Kripke ML. Impact of ozone depletion on immune function. World Res Rev 1993;5:141-55.

Kripke ML. Ultraviolet radiation and immunology: something new under the sun-presidential address. Cancer Res 1994;54:6102-5.

Norval M, El-Ghorr A, Garssen J, Loveren H. The effects of ultra-violet light irradiation on viral infections. Br J Dermatol 1994;130:693-700.

Ocular Effects of Chronic Ultraviolet Radiation

Duncan DD, Munoz B, West SK, Bandeen-Roche K. Visible and ultraviolet-B ocular ambient exposure ratio for a general population. Inv Ophthalmol Vis Sci 1997;38(5):1003-11.

The Photodermatoses

Harber LC, Bickers DR. Photosensitivity diseases. Principles of diagnosis and treatment. 2nd ed. Toronto: BC Decker Inc, 1989.

Non-melanocytic Skin Cancers

Gallagher RP, Hill GB, Bajdik CD, Fincham S, Coldman AJ, McLean DI, Threlfall WJ. Sunlight exposure, pigmentary factors and risk of non-melanocytic skin cancer: I. Basal cell carcinoma. Arch Dermatol 1995;131:157-63.

Gallagher RP, Hill GB, Bajdik CD, Fincham S, Coldman AJ, McLean DI, Threlfall WJ. Sunlight exposure, pigmentary factors and risk of non-melanocytic skin cancer: II. Squamous cell carcinoma. Arch Dermatol 1995;131:164-9.

Kricker A, Armstrong BK, English DR, Heenan PJ. A dosere-sponse curve for sun exposure and basal cell carcinoma Int J Cancer 1995;60:482-8.

Kricker A, Armstrong BK, English DR, Heenan PJ. Does intermittent sun exposure cause basal cell carcinoma? A case-control study in Western Australia. Int J Cancer 1995;60:489-94.

Melanoma Update

Autier P, Doré JF, Lejeune F, et al. Cutaneous malignant melanoma and exposure to sunlamps or sunbeds: an EORTC mul ticenter case-control in Belgium, France and Germany. Int J Cancer 1994;58:809-13.

de Gruijl FR, Sterenborg HJCM, Forbes PD, et al. Wavelength dependence of skin cancer induction by ultraviolet irradiation of albino hairless mice. Cancer Res 1993;53:53-60.

de Gruijl FR, van der Leun JC. Estimate of the wavelength dependency of ultraviolet carcinogenesis in humans and its relevance to the risk assessment of a stratospheric ozone depletion. Health Physics 1994;67:319-25.

Garland CF, Garland FC, Gorham ED. Rising trends in melanoma: an hypothesis concerning sunscreen effectiveness. Ann Epidemiol 1993;3:103-10.

Holly EA, Aston DA, Cress RD, Ahn DK, Kristiansen JJ. Cutaneous melanoma in women: I. Exposure to sunlight, ability to tan, and other risk factors related to ultraviolet light. Am J Epidemiol 1995;141:923-33.

Setlow RB, Grist E, Thompson K, Woodhead AD. Wavelengths verification in induction of malignant melanoma. Proc Natl Acad Sci USA 1993;90:6666-70.

Spencer JM, Amonette RA. Indoor tanning: risks, benefits and future trends. J Am Acad Dermatol 1995;33:288-98.

Weinstock MA. Controversies in the role of sunlight in the pathogenesis of cutaneous melanoma. J Photochem Photobiol 1996;63:406-10.

Westerdahl J, Olsson H, Mosback A, Ingvar C, Jonsson N. Is the use of sunscreens a risk factor for malignant melanoma? Melanoma Res 1995;5:59-65.

Westerdahl J, Olsson H, Mosback A, et al. Use of sunbeds or sunlamps and malignant melanoma in southern Sweden. Am J Epidemiol 1994;140:691-9.

Progress in the Prevention and Early Diagnosis of Melanoma

Berwick M, Begg CB, Fine JA, Roush GC, Barnhill RL. Screening for cutaneous melanoma by skin self-examination. J Natl Cancer Inst 1996;88:17-23.

Elwood JM. Screening for melanoma and options for its evaluation. J Med Screening 1994;1:22-38.

Elwood JM. Skin self-examination and melanoma. J Natl Cancer Inst 1996;88:3-5.

Elwood JM, Morris JM. Evaluation of programmes to modify sun exposure. In: MacKie RM, ed. Primary and secondary prevention of malignant melanoma. Basel: Karger, 1996;111- 27.

Girgis A, Sanson-Fisher RW, Tripodi DA, Golding T. Evaluation of interventions to improve solar protection in primary schools. Health Educ Q 1993;20:275-87.

Hill D, White V, Marks R, Borland R. Changes in sun-related attitudes and behaviours and reduced sunburn prevalence in a population at high risk of melanoma. Eur J Cancer Prev 1993;2:447-56.

International Agency for Research on Cancer. Ultraviolet radiation. Lyon: IARC, 1992; IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol 55.

Morris J, Elwood M. How effective are sun exposure modification programmes? Dunedin: Hugh Adam Cancer Epidemiology Unit, 1995;1-64.

Promoting Behaviour Change

Campbell HS, McGregor SE, Medicott T, Goos T. Pilot test of a sun behaviour telephone survey [Unpublished manuscript]. Alberta Cancer Board, 1993.

Green LW, Kreuter MK. Health promotion planning: an education and environmental approach. 2nd ed. Mountain View (CA): Mayfield, 1991.

Hill DJ, White V, Borland R, Cockburn J. Cancer-related beliefs and behaviours in Australia. Aust J Public Health 1991;15(1):14-23.

Ozone Depletion and Canada's UV Index

Burrows WR, Vallee M, Wardle DI, Kerr JB, Wilson LJ, Tarasick DW. The Canadian operational procedure for forecasting total ozone and UV radiation. Met Apps 1994;1:247-65.

Elkins J, Thompson T, Swanson T, Butler J, Hall B, Cummings S, et al. Decrease in the growth rates of atmospheric chlorofluorocarbons- 11 and -12. Nature 1993;364:780-3.

Farman JC, Gardiner BG, Shanklin JD. Large losses of total ozone in Antarctica reveal seasonal CLOx/NOx interation. Nature 1985;315:207-10.

Kerr JB. Decreasing ozone causes health concern: how Canada forecasts ultraviolet-B radiation. Environ Sci Technol 1994;28:514A-8A.

Kerr JB, McElroy CT. Evidence for large upward trends of ultraviolet- B radiation linked to ozone depletion. Science 1993;262:1032-4.

Stolarski RR, Bojkov RL, Bishop LC, Zerefos CJ, Staehelin J, Zawodny J. Measured trends in stratospheric ozone. Science 1992;256:342-9.

World Meterological Organization. Scientific assessment of ozone depletion: 1994. World Meterological Organization Global Ozone Research and Monitoring Project, Report No 37, 1995.

Non-solar Sources of Ultraviolet Radiation

Radiation Emitting Devices Act, RS, Chapter 34 (1st Suppl, 1970), (Revised Statutes, 1985).

Radiation Emitting Devices Regulations, Chapter 1370, 1978, Revised Statutes, Chapter R-1, 1985, Schedule I, Part II and Schedule II, Part XI, "Sunlamps," 1980, amended 1985, 1988, 1991.

Fabric Variables Affecting Transmission of Ultraviolet Radiation

Bech-Thomsen W, Wult HC, Ullman S. Xeroderma pigmentosum lesions related to ultraviolet transmittance by clothes. J Am Acad Dermatol 1991;24:365-8.

Berne B, Fischer T. Protective effects of various types of clothing against UV radiation. Acta Derm Venereol 1980;60:459-60.

Capjack L, Kerr N, Davis S, Fedosejevs R, Hatch K, Markee N. Protection of humans from ultraviolet radiation through the use of textiles: a review. Fam Consumer Sci Res J 1994;23:198-218.

Davis S, Capjack L, Kerr N, Fedosejevs R. Clothing as protection from ultraviolet radiation: which fabric is most effective? Int J Dermatol. In press.

Gies HP, Roy CR, Elliott G, Zongli W. Ultraviolet radiation protection factors for clothing. Health Physics 1994;67:131-9.

Hilfiker R, Kaufmann W, Reinert G, Schmidt E. Improving sun protection factors of fabrics by applying UV-absorbers. Textile Res J 1996;66:61-70.

Luftman DB, Lowe NJ, Moy RL. Sunscreens update and review. J Dermatol Surg Oncol 1991;17:744-6.

Menzies SW, Lukins PB, Greenoak GE, Walker PJ, Pailthorpe MT, Martin JM, et al. A comparative study of fabric protection against ultraviolet-induced erythema determined by spectrophotometric and human skin measurement. Photodermatol Photoimmunol Photomed 1991;8:157-63.

Pailthorpe MT. Textile parameters and sun protection factors. In: Pailthorpe MT, ed. Proceedings of the Textiles and Sun Protection Conference. Kensington (NSW) Australia: Society of Dyers and Colorists of Australia and New Zealand, 1993:32- 53.

Robson J, Diffey BL. Textiles and sun protection. Photodermatol Photoimmunol Photomed, 1990;7:32-4.

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