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Frequency of sunburn in Queensland adults: still a burning issue

The impact of skin cancer is disproportionately high due to its extraordinarily high incidence in white populations compared with other cancers. In the United States, skin cancer costs an estimated US$2 billion annually.1 In Australia, skin cancers cost more than other major cancers.2 Sunburn, the acute inflammation caused by excessive exposure to solar ultraviolet radiation, is a determinant of all major skin cancers.3 An estimated 1.3 million skin cancer cases were due to excessive sun exposure4 in the US in 2003, and a regional study in Texas calculated the economic impact of sunburn as over US$10 million annually through lost work and treatment costs.5 Sunburn prevalence (at least one sunburn in the past year) in white US adults aged 18–29 years has been constant for a decade at 66%.6 Men, the young and high-income groups appear susceptible.7 In Australia, weekend sunburn prevalence was 9% overall in Victoria in 20028 but in Queensland in 2004, 70% of surveyed residents aged 20–75 years reported sunburn in the past year.9

Sunburn is of crucial public health importance as a key preventable and common risk factor for skin cancer. We assessed frequency of sunburn and associated factors in Queensland in two surveys in 2009 and 2010.

Methods

The Queensland Health Population Epidemiology Unit conducted self-reported health status surveys from January to March 2009 (SRHS 2009) and from October 2009 to February 2010 (SRHS 2010) using computer-assisted telephone interviews10 with approval from the Queensland Health Central Office Human Research Ethics Committee. The target population sourced by random-digit-dialling was Queensland households with a person aged ≥ 18 years (SRHS 2009) or ≥ 16 years (SRHS 2010). From each selected household, one eligible resident was asked to participate. Response rates were calculated as the number of completed interviews expressed as a percentage of the number of eligible persons contacted.

A structured interview using a scripted questionnaire covered demographic and risk factors including sunburn on the previous weekend. Sunburn was defined as any reddening of the skin lasting longer than 12 hours after sun exposure. Other information collected included age, sex, height and weight, education, marital and employment status, fruit and vegetable intake, smoking, general use of sun protection and physical activity based on the Active Australia instrument.11 For analysis, employment status was categorised as employed, retired or student/carer/unemployed; fruit/vegetable consumption as meeting daily recommended levels (≥ 2 serves of fruit and ≥ 5 serves of vegetables);12 smoking as daily or not; and physical activity as none, insufficient (1–4 sessions of walking/moderate/vigorous activity and/or < 150 minutes total, weekly), or sufficient to meet national guidelines13 (≥ 5 sessions for ≥ 150 minutes total, weekly). Statistical Local Areas of residence were classified by the Accessibility/Remoteness Index of Australia14 (ARIA+), the Socio-Economic Indexes For Areas15 (SEIFA) and geographically (North, Central, South and West Queensland).

Identical variables from the 2009 and 2010 surveys were pooled for adults aged ≥ 18 and weighted by age, sex and Queensland Health Service District distribution using 2008 estimated resident population data for Queensland (Australian Bureau of Statistics, http://www. abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3235.02008?OpenDocument) to minimise bias due to over- or underrepresentation of any demographic group, and by the number of in-scope people and fixed telephone lines per household to minimise selection bias. Weighted proportions (with 95% confidence intervals) of the population who reported being sunburnt the previous weekend were calculated, stratified by age and sex. Univariate and multivariate logistic regressions — adjusting for age (18–24, 25–34, 35–44, 45–54, 55–64, ≥ 65 years), sex, education (bachelor degree or higher, diplomas/certificates/trade, no qualifications) and physical activity — were undertaken to estimate the association between sunburn and risk factors, using Stata SE, version 11.0 (StataCorp).

Results

Response rates were 57% (7537/13 289) and 65% (8938/13 857) in the 2009 and 2010 surveys, respectively. Pooling of the two surveys (results did not differ) provided a total of 16 473 Queensland adults. Of these, 15% lived in North, 20% in Central, 63% in South, and 2% in West Queensland, while 55% lived in major cities, 39% in regional areas and 6% in remote areas, based on census data of the estimated resident population of Queensland. Of the 8150 men, 901 (12.9%, weighted; 95% CI, 11.9%–14.0%) reported being sunburnt the previous weekend, compared with 596 of 8323 women (8.6%, weighted; 95% CI, 7.7%–9.6%) (Box 1). Peak weighted prevalence of 22% (102/459) was among young men aged 18–24 years. There was a clear trend of decreasing sunburn prevalence with increasing age in both sexes (P < 0.001), such that sunburn was least common among participants aged ≥ 65 years (men, 2.2%, weighted [54/1938]; women, 1.8%, weighted [35/1950]) (Box 1).

After adjustment, the strongest predictor of sunburn was youth: people aged 18–24 years were seven times more likely to report being sunburnt than those aged ≥ 65 years, although adults aged 45–64 years were also at significantly higher risk of being sunburnt than those ≥ 65 years (Box 2).

Other sunburn predictors were male sex, not having a tertiary education, and being in the workforce. People who had undertaken physical activity in the previous week, regardless of frequency or duration, were more likely to be sunburnt than those who did not. People who undertook the recommended level of physical activity had twice the odds of sunburn of inactive people, while those who undertook one to four sessions were also at risk (Box 2). Those who generally used sunscreen in summer tended to be less likely to be sunburnt than non-users (adjusted OR, 0.86) (Box 2). Although hat-wearing per se was not associated with sunburn after adjustment for confounding factors (Box 2), those who usually sought shade or wore protective clothing in summer also had significantly lower odds of sunburn than those who did not, and respondents’ most common explanation for sunburn was failure to use clothing or sunscreen protection (SRHS 2010 only; data not shown).

No other factors, including marital status, body weight, smoking, fruit/vegetable consumption, location of residence, socioeconomic status (Box 2) or skin colour (SRHS 2010 only; data not shown) were associated with sunburn.

Discussion

If sunburn in Australia were reduced, decreased rates of skin cancer would follow.3 Queensland has the highest melanoma rates in Australia, and Australia and New Zealand have the highest rates in the world.16 We have shown that around one in 10 Queensland adults report being sunburnt on the weekend in summer. Men were about 50% more likely than women to experience sunburn and adults aged under 65 years were more likely to be sunburnt than those aged 65 years and over. Youngest adults (aged 18–24 years) were sunburnt most often. While people in the workforce and those without tertiary qualifications are more likely to report sunburn than others, this probably reflects sunburn in leisure more than work hours, since weekend sunburn prevalence was assessed. Physical activity was also associated with sunburn.

Our results are broadly consistent with a 2004 Queensland survey showing young age and male sex greatly increase odds of sunburn.9 An earlier analysis of SRHS 2010 data also showed that people engaging in physical activity were more likely to experience sunburn on the previous weekend and during the past year, especially those who undertook ≥ 7 hours of activity per week.17 Sun-safety and physical activity promotion messages must be integrated, acknowledging the importance of both for health and wellbeing.

This study was drawn from adults of all ages across Queensland but excluded households without fixed telephones, and restricted detail was available about timing of physical activity in relation to sunburn. However, we have shown that despite half a century of campaigns, sun protection in Queensland remains far from optimal. Vigilance to avoid sunburn is essential among active adults. Men still are more likely to be sunburnt and need targeted encouragement to practise prevention measures. By experiencing sunburn, often repeatedly,9 Queenslanders are driving their already high risk of skin cancer higher.3 In Victoria, where the SunSmart program originated, prevention programs have recently stalled.8 Redoubled efforts are required through television and other media campaigns to improve sun-protection and ultimately reduce skin cancer.

1 Prevalence of being sunburnt on the previous weekend, by sex and age

Men


Women


Age group

Total no.

No. sunburnt

Proportion (95% CI)*

Total no.

No. sunburnt

Proportion (95% CI)*


18–24 years

459

102

22.0% (17.7%–27.0%)

373

60

15.3% (11.2%–20.6%)

25–34 years

932

173

16.9% (14.1%–20.1%)

1038

123

13.1% (10.5%–16.3%)

35–44 years

1431

235

15.4% (13.3%–17.8%)

1540

156

10.5% (8.7%–12.6%)

45–54 years

1647

198

12.7% (10.7%–14.9%)

1763

159

8.0% (6.6%–9.8%)

55–64 years

1743

139

8.1% (6.7%–9.8%)

1659

63

4.0% (3.0%–5.2%)

≥ 65 years

1938

54

2.2% (1.6%–3.0%)

1950

35

1.8% (1.2%–2.6%)

All age groups

8150

901

12.9% (11.9%–14.0%)

8323

596

8.6% (7.7%–9.6%)


* Prevalence estimates and associated 95% confidence intervals weighted to the 2008 estimated resident Queensland population
(http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3235.02008?OpenDocument).

2 Characteristics of people sunburnt on the previous weekend, showing prevalence distribution and associated odds ratio (OR) of being sunburnt

Characteristic

Proportion sunburnt (95% CI)

Weighted OR* (95% CI)

P

Adjusted OR (95% CI)

P


Age, years

< 0.001

< 0.001

18–24

18.8% (15.7%–22.3%)

11.46 (8.18–16.04)

7.35 (5.09–10.62)

25–34 

15.0% (13.0%–17.2%)

8.74 (6.45–11.85)

5.95 (4.23–8.36)

35–44

12.9% (11.5%–14.5%)

7.36 (5.52–9.83)

5.22 (3.78–7.22)

45–54

10.3% (9.03%–11.6%)

5.67 (4.23–7.60)

4.04 (2.91–5.60)

55–64

6.1% (5.2%–7.1%)

3.20 (2.35–4.36)

2.23 (1.59–3.14)

≥ 65

2.0% (1.5%–2.5%)

1

1

Sex

< 0.001

< 0.001

Female

8.6% (7.7%–9.6%)

1

1

Male

12.9% (11.9%–14.0%)

1.57 (1.34–1.82)

1.47 (1.25–1.72)

Highest level of education

< 0.001

< 0.001

Bachelor degree or higher

9.1% (7.9%–10.6%)

1

1

Diploma/certificate/trade

13.2% (12.0%–14.5%)

1.51 (1.24–1.84)

1.56 (1.27–1.91)

No post-school qualifications

9.2% (8.2%–10.4%)

1.01 (0.82–1.25)

1.28 (1.03–1.61)

Employment status

< 0.001

< 0.001

Employed

13.3% (12.4%–14.3%)

1

1

Retired

2.1% (1.6%–2.6%)

0.14 (0.11–0.18)

0.46 (0.32–0.64)

Student/carer/unemployed

10.2% (8.4%–12.2%)

0.74 (0.59–0.92)

0.71 (0.56–0.91)

Marital status

0.005

0.85

Married/de facto

10.0% (9.3%–10.8%)

1

1

Not married/separated/widow

12.4% (10.9%–14.1%)

1.27 (1.07–1.51)

0.98 (0.81–1.20)

Fruit and vegetable intake§

0.08

0.63

Not meeting recommendations

10.9% (10.2%–11.7%)

1.30 (0.97–1.74)

1.08 (0.79–1.46)

Meeting recommendations

8.6% (6.7%–11.1%)

1

1

Smoking status

< 0.001

0.16

Not a daily smoker

10.2% (9.4%–11.0%)

1

1

Daily smoker

13.7% (11.9%–15.6%)

1.40 (1.17–1.67)

1.15 (0.95–1.39)

Body mass index, kg/m2

0.83

0.22

< 18.5

12.9% (8.2%–19.6%)

1.28 (0.76–2.14)

1.33 (0.76–2.31)

18.5–24.9

10.4% (9.2%–11.6%)

1

1

25–29.9

11.2% (10.0%–12.4%)

1.09 (0.91–1.29)

1.20 (1.00–1.45)

30–39.9

10.8% (9.3%–12.4%)

1.04 (0.85–1.27)

1.24 (1.00–1.53)

≥ 40

10.7% (6.8%–16.4%)

1.04 (0.62–1.72)

1.23 (0.72–2.09)

Physical activity

< 0.001

< 0.001

No physical activity

5.8% (4.4%–7.5%)

1

1

Insufficient time or sessions

10.2% (9.0%–11.5%)

1.85 (1.36–2.53)

1.66 (1.21–2.29)

Sufficient time and sessions

13.6% (12.5%–14.7%)

2.57 (1.90–3.46)

2.13 (1.57–2.89)

Use sunscreen in summer

0.99

0.07

No

10.7% (9.7%–11.8%)

1

1

Yes

10.7% (9.8%–11.7%)

1.00 (0.86–1.16)

0.86 (0.73–1.01)

Wear hat in summer

0.77

0.11

No

10.9% (9.5%–12.6%)

1

1

Yes

10.7% (9.9%–11.5%)

0.97 (0.81–1.16)

1.17 (0.96–1.41)

SEIFA

0.36

0.44

Disadvantaged

10.2% (8.9%–11.7%)

1.05 (0.82–1.35)

1.20 (0.92–1.56)

Quintile 2

11.2% (9.7%–12.8%)

1.16 (0.90–1.50)

1.18 (0.90–1.54)

Quintile 3

10.5% (9.1%–12.0%)

1.08 (0.84–1.39)

1.12 (0.87–1.46)

Quintile 4

12.0% (10.4%–13.9%)

1.26 (0.98–1.63)

1.29 (0.99–1.68)

Advantaged

9.8% (8.2%–11.6%)

1

1

ARIA+

0.47

0.53

Major cities

10.4% (9.4%–11.5%)

1

1

Inner regional

11.8% (10.3%–13.5%)

1.15 (0.95–1.39)

1.16 (0.95–1.42)

Outer regional

10.6% (9.3%–12.1%)

1.02 (0.85–1.22)

1.05 (0.87–1.27)

Remote/very remote

10.2% (8.4%–12.3%)

0.97 (0.76–1.24)

1.01 (0.78–1.31)

Geographical location**

0.15

0.41

North Queensland

10.9% (9.6%–12.5%)

1.04 (0.87–1.24)

1.00 (0.83–1.21)

West Queensland

12.8% (11.2%–14.6%)

1.24 (1.03–1.49)

1.16 (0.95–1.41)

Central Queensland

10.9% (9.5%–12.6%)

1.04 (0.86–1.25)

1.11 (0.91–1.35)

South Queensland

10.6% (9.7%–11.6%)

1

1


ARIA+ = Accessibility/Remoteness Index for Australia.14 SEIFA = Socio-Economic Indexes For Areas.15 * Population-weighted (based on 2008 estimated resident Queensland population, http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3235.02008?OpenDocument) analyses unadjusted. Population-weighted (based on 2008 estimated resident Queensland population) analyses adjusted for age, sex, physical activity and education level. Reference group. § National Health and Medical Research Council dietary guidelines for Australian adults.12 Department of Health and Ageing national physical activity guidelines for adults.13 ** North Queensland = Cairns and Hinterland, Mackay, Torres Strait Island, Townsville; West Queensland = Cape York, Central West, Mt Isa, South West Queensland; Central Queensland = Central Queensland, Darling Downs/West Moreton and Wide Bay; South Queensland = Sunshine Coast, Metro North, Metro South and Gold Coast.

Lip lupus erythematosus

Clinical record

A 40-year-old Indigenous Australian woman was referred to an outreach dermatology clinic in the Top End of the Northern Territory for assessment of painful lip ulceration of 2 years’ duration. She had been reviewed 16 months earlier in a distant regional centre, and a diagnosis of squamous cell carcinoma of the lip had been proposed. Skin biopsy had not been performed and the patient had refused a planned extensive surgical excision of the lip lesion at that assessment. Her general health was good.

Examination at the outreach clinic showed extensive and bilateral lower lip exophytic ulceration and crusting (Box 1). The upper lip and other cutaneous and oral surfaces were normal.

Lower lip skin biopsy samples were taken from the ulcer and adjacent lower lip mucosa to confirm a clinical diagnosis of lupus erythematosus and to exclude malignancy (Box 2). The hyperkeratotic squamous epithelium ranged from atrophic to acanthotic, with foci of lichenoid basal vacuolar damage resulting in squamous cell apoptosis and colloid bodies.

The submucosa contained a dense mixed inflammatory cell infiltrate of lymphocytes, histiocytes, plasma cells and melanophages. Direct immunofluorescence investigation showed weak (1+) granular IgM and complement component 3 positivity along the junctional region. No squamous dysplasia or malignancy was identified.

The results of blood testing, including antinuclear antibody testing, extractable nuclear antigen and DNA-antibody studies, were negative. Serum complement levels were normal. The patient was instructed to reduce lip sun exposure, apply broad-spectrum sunscreen twice daily and apply betamethasone dipropionate cream (0.5 mg/g) daily. On review 3 months later, there was a dramatic resolution of pain and ulceration. In the absence of any clinical or histological suggestion of malignancy, surgical treatment was not indicated or anticipated.

Lip and oral ulceration may be a feature of systemic lupus erythematosus (SLE) or a manifestation of cutaneous discoid lupus erythematosus (DLE).1 Various studies have suggested a high incidence and prevalence of both SLE and DLE in Indigenous Australian populations, with both forms mostly affecting women.26 We have treated many patients with DLE on the lower lip, both as a solitary disease manifestation and as part of more disseminated cutaneous disease. In most cases the diagnosis had not been suspected by treating health practitioners. DLE needs to be considered as a potential cause for lip symptoms and ulceration in this situation, with differential diagnoses including infections (eg, candidiasis, syphilis and streptococcal infection), lichen planus, fixed drug reactions and actinic malignancies.

Clinical features that may prompt suspicion of lip DLE include red, friable and delicate skin in early phases, with progression to erosions, ulceration, crusting and pigment loss with time and chronicity.6 The reason for a seemingly higher rate of SLE and DLE in Indigenous Australians compared with non-Indigenous Australians is unclear. However, genetic predisposition (human leukocyte antigen and complement pathway associations) and prior infective and environmental (sunlight) triggers have been hypothesised.24

DLE has characteristic histological features on skin biopsy,1 but selection of sites for biopsy is critical as epithelial destruction in areas of ulceration may result in loss of diagnostic findings.7 Clear communication to the pathologist about the purpose of the biopsy is essential, specifically whether exclusion of malignancy or confirmation of DLE is desired. For confirmation of suspected DLE, biopsy of clinically abnormal skin adjacent to but not involving areas of ulceration is recommended. If malignancy is suspected, taking multiple biopsies of the most indurated lesional skin is appropriate. Testing by direct immunofluorescence may be helpful but is less reliable than histopathological assessment in the diagnosis of DLE, with low sensitivity.7,8 Additionally, sun-exposed skin from healthy patients often shows false positive results of immunofluorescence testing.9 There is an increased rate of squamous cell carcinoma in lesions of DLE,7 with epithelial dysplasia on biopsy reported as the prime indicator of risk of malignant transformation.10 An awareness of this association should prompt detailed searching and reporting of cytological atypia during histopathological assessment.

Management priorities for lip DLE include precise diagnosis, exclusion of systemic involvement and identification of triggers (including medications). In most patients with DLE the prognosis is good, with progression to SLE being uncommon.1 Methods to reduce ultraviolet exposure on affected areas, including seeking shade, direct sun avoidance and regular sunscreen use, are essential. Potent topical corticosteroid application will often bring about rapid improvement. If general and topical therapies fail, the patient’s adherence should be reviewed. If systemic treatment is required, oral hydroxychloroquine is initially recommended.1

An awareness that the lower lip is a common site for lupus erythematosus, particularly in Indigenous Australian patients, will facilitate early diagnosis and appropriate management. A comprehensive lupus erythematosus database, including epidemiological, clinical, serological and outcome measures, is being established at Royal Darwin Hospital to provide further insights and enable statistical analysis.

1 Lupus erythematosus of the lower lip, with ulceration and crusting of 2 years’ duration, in a 40-year-old Indigenous woman

2 Lower lip skin biopsy image* showing lichenoid cheilitis with vacuolar basal epithelial damage, lymphocyte exocytosis, epithelial atrophy and an intense inflammatory infiltrate

* Magnification × 100; sample stained with haematoxylin and eosin. No squamous dysplasia is present.

Lessons from practice

  • Lower lip ulceration and thickening is commonly caused by lupus erythematosus in northern Australia

  • There is a high incidence of both systemic and cutaneous lupus erythematosus in Indigenous Australians

  • Careful and informed skin biopsy technique and interpretation of histopathological findings are critical in differentiating causes of lower lip symptoms