This study examines the prevalence of sun-related damage to the skin in a caucasian population in north-west England. The importance of constitutional factors (complexion, skin type and age) as well as environmental and occupational exposures for the development of actinic keratosis (AK) and skin cancers was assessed in people over 40 years of age attending outpatient clinics (non-dermatology) at four centres in north-west England (Mersey region). Nine hundred and sixty-eight volunteers (531 men and 437 women) were recruited. The overall prevalence of AK was 15.4% in men and 5.9% in women. The prevalence was strongly related to age in both sexes, being 34.1% and 18.2%, respectively, in men and women aged 70 years and above, and was most strongly related to two objective signs of sun exposure, namely degree of solar elastosis and presence of solar lentigines. The prevalence of AK was higher in subjects with red hair and freckles, particularly women. There was no evidence of an increased prevalence of AK in relation to any occupation. There was a high prevalence of seborrhoeic keratosis and viral warts in both sexes, which was age-related in the case of seborrhoeic keratosis. Ten cases of basal cell carcinoma, eight cases of Bowen's disease and one case of malignant melanoma were identified. This study shows that the sun exposure received in 'normal' life in England is sufficient to cause potentially malignant skin damage in a significant proportion of the population.

Background: Paraquat is a herbicide with a good occupational safety record, but a high mortality after intentional ingestion that has proved refractory to treatment. For nearly three decades paraquat concentration–time data have been used to predict the outcome following ingestion. However, none of the published methods has been independently or prospectively validated. We aimed to use prospectively collected data to test the published predictive methods and to determine if any is superior.Methods: Plasma paraquat concentrations were measured on admission for 451 patients in 10 hospitals in Sri Lanka as part of large prospective cohort study. All deaths in hospital were recorded; patients surviving to hospital discharge were followed up after 3 months to detect delayed deaths. Five prediction methods that are based on paraquat concentration–time data were then evaluated in all eligible patients.Results: All methods showed comparable performance within their range of application. For example, between 4- and 24-h prediction of prognosis was most variable between Sawada and Proudfoot methods but these differences were relatively small [specificity 0.96 (95% CI: 0.90–0.99) vs. 0.89 (0.82–0.95); sensitivity 0.57 vs. 0.79, positive and negative likelihood ratios 14.8 vs. 7.40 and 0.44 vs. 0.23 and positive predictive values 0.96 vs. 0.92, respectively].Conclusions: All five published methods were better at predicting death than survival. These predictions may also serve as tools to identify patients who need treatment and for some assessment to be made of new treatments that are trialled without a control group.