A. Green

EPIDEMIOLOGY OF SOLAR KERATOSES

Solar keratoses (SKs) or actinic keratoses are common dysplastic epidermal lesions which occur in pale‐skinned individuals who are chronically exposed to intense sunlight. Together with basal cell carcinomas and sqamous cell carcinomas, they constitute a major public health problem in such individuals.

Validation of a food-frequency questionnaire assessment of carotenoid and vitamin E intake using weighed food records and plasma biomarkers: the method of triads model.

Background: Reliability or validity studies are important for the evaluation of measurement error in dietary assessment methods. An approach to validation known as the method of triads uses triangulation techniques to calculate the validity coefficient of a food-frequency questionnaire (FFQ).Objective: To assess the validity of an FFQ estimates of carotenoid and vitamin E intake against serum biomarker measurements and weighed food records (WFRs), by applying the method of triads.Design: The study population was a sub-sample of adult participants in a randomised controlled trial of β-carotene and sunscreen in the prevention of skin cancer. Dietary intake was assessed by a self-administered FFQ and a WFR. Nonfasting blood samples were collected and plasma analysed for five carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene) and vitamin E. Correlation coefficients were calculated between each of the dietary methods and the validity coefficient was calculated using the method of triads. The 95% confidence intervals for the validity coefficients were estimated using bootstrap sampling.Results: The validity coefficients of the FFQ were highest for α-carotene (0.85) and lycopene (0.62), followed by β-carotene (0.55) and total carotenoids (0.55), while the lowest validity coefficient was for lutein (0.19). The method of triads could not be used for β-cryptoxanthin and vitamin E, as one of the three underlying correlations was negative.Conclusions: Results were similar to other studies of validity using biomarkers and the method of triads. For many dietary factors, the upper limit of the validity coefficients was less than 0.5 and therefore only strong relationships between dietary exposure and disease will be detected.Sponsorship: National Health and Medical Research Council.

Naevi in schoolchildren in Scotland and Australia.

Summary To test the hypothesis that children living in subtropical and tropical environments have more naevi than those of similar ethnicity living in temperate countries, a comparative study of melanocytic naevi in 111 schoolchildren from Brisbane, Australia, and 222 from Glasgow, Scotland, was carried out. All children were aged 13–15 years, of European ancestry, and had spent most of their lives at latitudes of less than 30°S (Australia) or greater than 30°N (Scotland), Using an identical protocol, all naevi of 2 mm or more in diameter occurring on the right arm were counted by either a highly experienced research nurse in Brisbane, or a dermatologist in Glasgow, Hair and eye colour, and facial freckling, were assessed by the examiner, and axillary skin colour of children in both cities was measured using the same reflectance spectrophotometer. Children in Brisbane had significantly more naevi than those in Glasgow (P<0–05), after adjusting for complexion variables. The difference in the geometric mean number of naevi on the arm was much greater among boys (7.7 vs, 4.4, in Brisbane and Glasgow, respectively) than among girls (7.3 vs, 6.7). This has parallels with the sex differences in melanoma at later ages in the two countries. Besides country of residence, freckles and innate skin colour were the most significant predictors of large numbers of naevi, whereas red hair had a significant protective effect. Overall, these data on prevalence of naevi in children from contrasting environments provide some evidence in support of the theory that naevus development is related to the level of sun exposure in childhood and adolescence.

A pooled analysis of 10 case-control studies of melanoma and oral contraceptive use.

Data regarding the effects of oral contraceptive use on womens risk of melanoma have been difficult to resolve. We undertook a pooled analysis of all case–control studies of melanoma in women completed as of July 1994 for which electronic data were available on oral contraceptive use along with other melanoma risk factors such as hair colour, sun sensitivity, family history of melanoma and sun exposure. Using the original data from each investigation (a total of 2391 cases and 3199 controls), we combined the study-specific odds ratios and standard errors to obtain a pooled estimate that incorporates inter-study heterogeneity. Overall, we observed no excess risk associated with oral contraceptive use for 1 year or longer compared to never use or use for less than 1 year (pooled odds ratio (pOR)=0.86; 95% CI=0.74–1.01), and there was no evidence of heterogeneity between studies. We found no relation between melanoma incidence and duration of oral contraceptive use, age began, year of use, years since first use or last use, or specifically current oral contraceptive use. In aggregate, our findings do not suggest a major role of oral contraceptive use on womens risk of melanoma.

The prevalence and determinants of solar keratoses at a subtropical latitude (Queensland, Australia)

We report the association between skin pigmentation and individual sun exposure, and the occurrence of solar keratoses (SKs) in an unselected population, quantified for the first time. SKs were examined in a representative sample of 197 residents of the community of Nambour in Queensland, Australia. Estimates of sun exposure were combined with a measure of ultraviolet (UV) flux to estimate actual UV exposure, both occupational and recreational, during childhood and adult life. The number of episodes of painful sunburn was used as a measure of intermittent, intense UV exposure. Eighty‐three participants (43%) had at least one SK, while 35 (18%) had more than 10 SKs diagnosed. The age‐ and sex‐adjusted odds ratios (ORs) for the development of SKs were higher in individuals with fair (OR = 14.1) or medium skin (OR = 6.5), compared with olive‐skinned individuals. Individuals with poor ability to develop a suntan were similarly at increased risk compared with others. High levels of occupational UV exposure during adult life were confirmed as being strongly associated with prevalent SKs (OR = 2.4 for heavy/maximal adult exposure), with an even stronger association seen in those individuals with multiple SKs (OR = 4.3 for maximal adult exposure). Although no clear association was demonstrated between SK prevalence and accumulated childhood sun exposure, a history of even one episode of sunburn in childhood was strongly associated with SK prevalence (peak OR of 5.9 for one sunburn).

Does type 2 diabetes influence the risk of oesophageal adenocarcinoma

Since hyperinsulinaemia may promote obesity-linked cancers, we compared type 2 diabetes prevalence among oesophageal adenocarcinoma (OAC) patients and population controls. Diabetes increased the risk of OAC (adjusted odds ratio 1.59, 95% confidence interval (CI) 1.04–2.43), although the risk was attenuated after further adjusting for body mass index (1.32, 95% CI 0.85–2.05).

The global burden of melanoma: Results from the Global Burden of Disease Study 2015

Despite recent improvements in prevention, diagnosis and treatment, vast differences in melanoma burden still exist between populations. Comparative data can highlight these differences and lead to focused efforts to reduce the burden of melanoma.

The use of nonsteroidal anti-inflammatory drugs and the risk of Barrett's oesophagus

Aliment Pharmacol Ther 2011; 34: 1235–1244

Biologic markers of sun exposure and melanoma risk in women: pooled case–control analysis

A model has been proposed whereby melanomas arise through two distinct pathways dependent on the relative influence of host susceptibility and sun exposure. Such pathways may explain site‐specific patterns of melanoma occurrence. To explore this model, we investigated the relationship between melanoma risk and general markers of acute (recalled sunburns) and chronic (prevalent solar keratoses) sun exposure, stratified by anatomic site and host phenotype. Our working hypothesis was that head and neck melanomas have stronger associations with solar keratoses and weaker associations with sunburn than trunk melanomas. We conducted a collaborative analysis using original data from women subjects of 11 case–control studies of melanoma (2,575 cases, 3,241 controls). We adjusted for potential confounding effects of sunlamp use and sunbathing. The magnitude of sunburn associations did not differ significantly by melanoma site, nevus count or histologic subtype of melanoma. Across all sites, relative risk of melanoma increased with an increasing number of reported lifetime “painful” sunburns, lifetime “severe” sunburns and “severe” sunburns in youth (ptrend < 0.001), with pooled odds ratios (pORs) for the highest category of sunburns versus no sunburns of 3.22 [95% confidence interval (CI) 2.04–5.09] for lifetime “painful” sunburns, 2.10 (95%CI 1.30–3.38) for lifetime “severe” sunburns and 2.43 (95%CI 1.61–3.65) for “severe” sunburns in youth. Solar keratoses strongly increased the risk of head and neck melanoma (pOR 4.91, 95%CI 2.10–11.46), but data were insufficient to assess risk for other sites. Reported sunburn is strongly associated with melanoma on all major body sites.

Ultraviolet radiation, melanocytic naevi and their dose-response relationship.

Melanocytic naevi on the face and neck of 110 Brisbane secondary school students aged 16–17 years were mapped according to specified regions to investigate the dose‐response relationship between ultraviolet (UV) radiation and melanocytic naevi. Highest naevus density occurred in regions receiving a mean UV dose of 0.2–0.4 relative to the vertex while densities were low in minimally and maximally exposed regions. This pattern of naevus distribution was unaffected by sex or phenotypic features such as skin colour or degree of freckling. These findings suggest that there is a narrow dose range over which UV radiation can effectively promote the proliferation of melanocytes. A comparison of the regional distribution of naevi on the face and neck with that of solar keratoses appearing over 1 year on the heads of residents of a neighbouring town has shown them to differ significantly. This study may shed some light on the unknown, yet expectedly complex, relation of UV radiation to melanocytic naevi.