Occupational sunlight exposure and cancer incidence among Swedish construction workers

We studied sunlight exposure from outdoor work in relation to cancer, using data from 323,860 men participating in an occupational health service program of the Swedish construction industry. An experienced industrial hygienist assessed the exposure for 200 job tasks. We estimated relative risks (RRs) adjusted for age, smoking, and magnetic field exposure. There was an increased RR in the high-exposure group for myeloid leukemia [RR = 2.0, 95% confidence interval (95% CI) = 1.1-3.6] and lymphocytic leukemia (RR = 1.7, 95% CI = 0.9-3.2). For non-Hodgkin's lymphoma there was a 30% increase in risk in the high-exposure group (95% CI = 0.9-1.9). There was no increased risk of malignant melanoma, except for tumors of the head, face, and neck in the high-exposure group (RR = 2.0, 95% CI = 0.8-5.2), and we also found an increased risk for malignant melanoma of the eye in this group (RR = 3.4, 95% CI = 1.1-10.5). Outdoor workers had no increased risk of nonmelanoma skin cancer. Nevertheless, the RR for lip cancer (squamous cell carcinoma) among the high-exposure group was estimated at 1.8 (95% CI = 0.8-3.7). Among other sites, an increased risk of stomach cancer was suggested in this group (RR = 1.4, 95% CI = 1.0-1.9). The results for lymphoma, leukemia, and possibly also for stomach cancer might reflect a suppression of the immune system from ultraviolet light in outdoor workers.

Topical 5-aminolaevulinic acid photodynamic therapy for extensive scalp actinic keratoses

Scalp actinic keratoses (AKs) are common, particularly in elderly bald males. Cryotherapy and 5-fluorouracil are effective for localized AKs but are limited in extensive disease. Topical 5-aminolaevulinic acid photodynamic therapy (5-ALA PDT) is an alternative. We treated four patients with extensive scalp AKs with low light dose, low dose-rate topical 5-ALA PDT using a broad-spectrum visible light source. Three patients cleared and one showed significant improvement. Remission lasted 6 months.

Melanoma risk in relation to height, weight, and exercise (United States)

Height and weight and derivations thereof are positively associated with a number of cancers. While several authors have reported an increased risk of melanoma among people at the higher extremes of these measures, the association has not been fully explored. New cases of primary cutaneous melanoma in 1997 in western Washington State (n = 386) were compared to controls selected by random-digit dialing (n = 727). Each study participant completed a telephone survey, and data were collected on height, weight, sun-related melanoma risk factors, demographic characteristics, as well as habits such as diet and exercise. Risk of melanoma was analyzed by logistic regression with adjustment for age, hair color, lifetime sun exposure, and fruit and vegetable intake. An excess risk of melanoma was identified in men in the upper quartiles of height (OR = 2.4, 95% confidence interval (CI) = 1.3-4.5), weight (OR = 2.8, CI = 1.5-5.2), and body surface area (OR = 2.8, CI = 1.5-5.1) vs. the lowest quartiles. In women, no association was present for any anthropometric measure. In addition, we found that men and women exercising five to seven days per week were at a decreased risk of melanoma (OR = 0.7, CI = 0.5-1.0). The anthropometric findings are largely consistent with previous studies, while this is the first report of an association of exercise with melanoma risk. The mechanisms for the effect of exercise and for the difference between men and women in the effect of anthropometric factors are unknown. Future research in basic and epidemiologic science should focus on biochemical or behavioral explanations for these observations.

Sunlight induces N epsilon-(carboxymethyl)lysine formation from glycated polylysine-iron(III) complex

Sunlight was found to strongly induce the formation of N epsilon-(carboxymethyl)lysine (CML) from glycated polylysine in the presence of Fe(III) ion. The initial step of this Fe(III)-catalyzed CML formation was noted to be similar to that of blueprint photography as was confirmed by the production of Turnbull's blue in sunlight-exposed glycated human serum albumin ferricyanide solution in the presence of Fe(III). Based on this, photoinduced oxidative C-C bond cleavage of the Amadori compound was assumed to be initiated by photochemical single electron transfer front ligand to Fe(III) in the Fe(III)-Amadori compound complex affording the Fe(II)-Amadori compound radical intermediate, which eventually yields either CML or active oxygen species. CML is thus a useful oxidative stress marker. The mechanism proposed here would explain the high accumulation of CML in lens protein and skin actinic elastosis.

Risk factors for basal cell carcinoma in a Mediterranean population: role of recreational sun exposure early in life

OBJECTIVE

To investigate the role of pigmentary traits, different patterns of sun exposure, artificial sources of UV radiation, and lifestyle-related factors on the risk of basal cell carcinoma (BCC) in a Mediterranean population from central-southern Italy.

DESIGN

Hospital-based case-control study.

SETTING

A referral dermatological hospital in Rome, Italy.

PATIENTS

A convenience sample of 166 case patients with histologically confirmed BCC and 158 cancer-free control subjects with minor dermatological conditions observed between March 1995 and June 1997.

RESULTS

In the multivariate analysis, the mean number of weeks per year spent at the beach before the age of 20 years was significantly associated with BCC. A dose-response trend was found for subjects who had spent 3 to 4 (odds ratio, 1.8; 95% confidence interval, 0.8-4.4), 5 to 8 (odds ratio, 3.7; 95% confidence interval, 1.5-9.0), or more than 8 (odds ratio, 4.5; 95% confidence interval, 1.9-10.5) weeks per year at the beach (P =.01 for trend). There was a significant association with the presence of actinic keratoses or solar lentigines, whereas no effect was found for skin type, history of sunburns, exposure to nonsolar UV radiation, and lifestyle-related habits such as cigarette smoking, alcohol consumption, and coffee drinking. Subjects reporting a family history of skin cancer had an extremely increased risk of BCC.

CONCLUSION

The definite association with recreational sun exposure during childhood and adolescence and the strong relation with family history of skin cancer suggest that genetic predisposition and peculiar exposure patterns to UV radiation are key independent risk factors for the development of BCC in a southern European population.

Premalignant oral mucosal diseases

A premalignant phase in the development of oral cancer is predicted by the classic model of experimental epithelial carcinogenesis. Virtually all oral squamous cell carcinomas arise from a premalignant precursor, but it is difficult to specifically define the term premalignant. Oral pathologists use the term epithelial dysplasia to indicate microscopic features in a biopsy specimen that are associated with a risk of malignant change and then assign a grade of severity. There is good correlation between higher grades of dysplasia and increasing risk of cancer but less so with the lower grades. The clinical appearances manifested by oral epithelial dysplasia and early oral cancer include leukoplakia, erythroplakia, and speckled leukoplakia. This paper discusses and illustrates these clinical lesions, their associated risk factors, their relationship to epithelial dysplasia, and the associated risk of evolution into oral cancer.

Cyclobutane thymidine dimers are present in human urine following sun exposure: quantitation using 32P-postlabeling and high-performance liquid chromatography

Cyclobutane thymidine dimer (T=T) is the major DNA photoproduct formed in human skin after solar radiation. We have developed a 32P-postlabeling method suitable for quantitating T=T in human urine with a detection limit of about 0.5 fmol per 10 microl urine. The method was used in the present study to measure the daily T=T urinary level of two volunteers over a 15 d period, including frequent sun exposures ranging from 0 to 5 h daily. T=T was not detected before or immediately (4 h) after the initial sun exposure but was first observed in urine samples collected 18 h after the initial exposure. Thereafter, urinary T=T levels gradually increased up to a peak reached about 3 d after the maximum sun exposure. The levels decreased during the following days but were still detectable 8 d after the last sun exposure. About 70-75% decrease in excreted T=T was observed after 8 d. The T=T levels measured in urine were lower but in the same order of magnitude as the levels expected after a theoretical calculation based on previous published results and reasonable assumptions. This study shows the occurrence of cyclobutane thymidine dimers in human urine after skin exposure to solar radiation.

Heritability and gene-environment interactions for melanocytic nevus density examined in a U.K. adolescent twin study

Risk factors for melanoma include environmental (particularly ultraviolet exposure) and genetic factors. In rare families, susceptibility to melanoma is determined by high penetrance mutations in the genes CDKN2A or CDK4, with more common, less penetrant genes also postulated. A further, potent risk factor for melanoma is the presence of large numbers of melanocytic nevi so that genes controlling nevus phenotype could be such melanoma susceptibility genes. A large Australian study involving twins aged 12 y of predominantly U.K. ancestry showed strong evidence for genetic influence on nevus number and density. We carried out essentially the same study in the U.K. to gain insight into gene-environment interactions for nevi. One hundred and three monozygous (MZ) and 118 dizygous (DZ) twin pairs aged 10-18 y were examined in Yorkshire and Surrey, U.K. Nevus counts were, on average, higher in boys (mean = 98.6) than girls (83.8) (p = 0.009) and higher in Australia (110.4) than in the U.K. (79.2, adjusted to age 12 y, p < 0.0001), and nevus densities were higher on sun-exposed sites (92 per m2) than sun-protected sites (58 per m2) (p < 0.0001). Correlations in sex and age adjusted nevus density were higher in MZ pairs (0.94, 95%CI 0.92-0.96) than in DZ pairs (0.61, 95%CI 0.49-0.72), were notably similar to those of the Australian study (MZ = 0.94, DZ = 0.60), and were consistent with high heritability (65% in the U.K., 68% in Australia). We conclude that emergence of nevi in adolescents is under strong genetic control, whereas environmental exposures affect the mean number of nevi.

New formulation of chemical peeling agent: histological evaluation in sun-damaged skin model in hairless mice

BACKGROUND

chemical peelings injure the superficial skin, which is then restored by healing of the wound.

OBJECTIVES

to document the acute and chronic histological changes produced by applying chemical peeling agents used clinically to the UVB-irradiated skin of hairless mice, which served as a model of sun-damaged skin.

DESIGN

three chemical peeling agents, 30% salicylic acid, dissolved in macrogol (a new formulation), 35% trichloroacetic acid (TCA) dissolved in distilled water and 20% glycolic acid dissolved in glycerin were applied to the backs of UVB-irradiated hairless mice. Untreated, irradiated areas of skin served as controls. Specimens were evaluated histologically at 3, 14, 28, and 70 days.

RESULTS

chronic UVB irradiation produced an irregular hypertrophy of the epidermis. The treated areas of irradiated skin recovered by day 70. At 28 days, all skin specimens treated with chemical peeling agents exhibited a unique connective tissue layer composed of fine collagen fibers beneath the epidermis. While 35% TCA produced severe tissue damage marked by inflammation up to day 14, no inflammatory infiltrates were seen with 30% salicylic acid in macrogol at 70 days.

CONCLUSIONS

chemical peeling with 30% salicylic acid dissolved in macrogol led to reorganization of the epidermis and a rebuilding of the superficial dermal connective tissue important in reducing wrinkles, and without evidence of inflammatory infiltrates in an animal model of sun-damaged skin. Findings suggest a possible clinical benefit.

Intensity/frequency indicator for detection in space: the high values of the incident solar or laser optical radiation in comparison with the appropriate maximum permissible exposure

The solar or laser optical radiation impact to humans in space depends on the intensity, on the exposure type (direct or indirect) & duration and on the matching of radiation wavelength to tissue characteristics. The main protection factor in space is the application of exposure limits. This paper describes the main biological optical interaction parameters, the optical exposure hazards and the development of a small active lightweight indicator, with output beeper rate depended to the ratio of optical irradiance/exposure limit. The indicator may be used as warning element on the side of helmets, goggles, spectacles, etc, with low power consumption. Electronically the indicator is an intensity/frequency converter, based on the value of the ratio of exposure/exposure limits, with audio & light beepers like the indication output of the ionizing (radioactive) radiation monitors.

Ultrastructural characterization of microvasculature in photoaging

The cutaneous microvasculature was examined by electron microscopy in order to compare its characteristics in photodamaged preauricular skin and in sun-protected postauricular sites of 15 Japanese women aged 58-81 years. The characteristic ultrastructural features of the microvasculature in photodamaged skin compared with those in sun-protected skin included dilated vessels embedded in elastin which depressed endothelial cells, vessels surrounded by a thick amorphous material composed of multiple laminations of a basement membrane-like material, and activated endothelial cells which had increased numbers of cytoplasmic organelles and pinocytotic vesicles. A novel finding of this study in photodamaged vessels was an increased formation of new vessels (angiogenesis) via two distinct pathways. In severe elastosis, activated endothelial cells with densely packed intracytoplasmic microfilaments extended large pseudopods into the elastotic material. In contrast, isolated mesenchymal cells, which possessed immature Weibel-Palade bodies, were scattered around pre-existing vessels within the Grenz zone. In some cases, many mesenchymal cells with electron-lucent cytoplasms aggregated and interconnected by cytoplasmic processes, which was followed by the formation of vascular structures. These results suggest that there are significant ultrastructural differences in vessels between photoaged and intrinsically aged facial skin and that the photodamaged microvascular system is characterized by the co-existence of regressive changes and angiogenesis.

Sun protection practices for children: knowledge, attitudes, and parent behaviors

OBJECTIVE

To examine the frequency with which sun protection is used by parents for their children.

DESIGN AND SETTING

Descriptive survey conducted at a university medical clinic in Florida.

PARTICIPANTS

Parents of children aged 1 to 16 years were approached in the waiting area, and 77 of 100 were successfully interviewed.

MAIN OUTCOME MEASURES

Parents' self-reported use of sun protection measures for their children and their attitudes and beliefs about sun protection.

RESULTS

Fewer than half of respondents (43%) reported regularly using sun protection for their child. Regular use of sun protection was reported more frequently by female caretakers and those with more favorable attitudes regarding sun protection use. Sunscreen was the most frequently used measure, and preventing sunburn was the primary reason for using sun protection. Respondents held several unfavorable sun protection attitudes, including the belief that sun exposure was healthy, that children looked better with a tan, and that it was okay to stay out in the sun longer if the child wore sunscreen.

CONCLUSIONS

Regular use of sun protection for children is infrequent and consists primarily of applying sunscreen rather than methods that reduce sun exposure. Parents primarily use sunscreen to prevent sunburn and may increase their children's overall sun exposure as a result.

The sun's damaging effects

Many people find exposure to the sunlight enjoyable and relaxing. In fact, most people agree that a tan looks great. For years, sunlight has been viewed as beneficial to one's well-being both emotionally and physically (Ness, Frankel, Gunnell, & Smith, 1999). However, exposure to ultraviolet radiation has its drawbacks. Sunlight is responsible for wrinkling, blotching, drying, and leathering of skin. In fact, 90% of all skin cancers result from long-term exposure to ultraviolet radiation. It is important to be educated about the effects of ultraviolet radiation and learn to balance its beneficial effects with its negative effects.

Cutaneous malignant melanoma in Norway: variation by region of residence before and after the age 17

OBJECTIVE

The aim of this study was to examine indirectly the importance of sun exposure during childhood and adolescence for the development of cutaneous malignant melanoma (CMM) by using a migration approach.

METHODS

A nested case-control study was carried out based on all inhabitants living in Norway at any time between 1960 and 1980. The cases were all diagnosed between 1960 and 1992 (n = 13,934) and 10 controls were added for each case (n = 130,507). Analyses were conducted on residence history in the southeast, mid-west and northern part of Norway, before and after age 17, also including working condition and educational level.

RESULTS

Birthplace in southeast was found to be twice as hazardous for the risk of CMM compared with birthplace in the north. The region of residence before as well as after age 17 was shown to influence the risk of CMM; the risk pattern in migrants tended to change direction toward the risk in the region to which they move. Associations was found between indoor working condition and CMM, and between high level of education and CMM, which support the hypothesis that pattern of sun exposure in adulthood affects the risk of CMM.

CONCLUSION

The results indicate sun exposure at any age to be of importance for the lifetime risk of CMM.

Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color

BACKGROUND

Severe wrinkles and pigmentary changes of the exposed skin indicate substantial damage due to UV radiation. Many investigators believe that the principal manifestation of photodamage in Asians is pigmentary change rather than wrinkles. However, to our knowledge, no well-designed study has investigated the characteristics of cutaneous photodamage in Asian skin.

OBJECTIVE

To access the severity of wrinkles and dyspigmentation in Koreans exposed to sun and who smoked.

METHODS

We developed new photographic scales for grading wrinkles and dyspigmentation in 407 Koreans to assess the severity of the wrinkles and dyspigmentation. We interviewed subjects to determine cumulative sun exposure and smoking history, and measured the skin color of individual subjects.

RESULTS

Our photographic scales provided a reliable evaluation of photodamage severity in Koreans. The pattern of wrinkling in both sexes is similar, but women tended to have more severe wrinkles (prevalence odds ratio, 3.7). However, the pattern of dyspigmentation differed between the sexes. Seborrheic keratosis is the major pigmentary lesion in men, whereas hyperpigmented macules are the prominent features in women. Cigarette smoking is an independent risk factor for wrinkles, but not for dyspigmentation, in Koreans, and causes additive detrimental effects to wrinkles induced by aging and sun exposure. The constitutive skin color did not show any correlation with wrinkles or dyspigmentation. However, facultative pigmentation (sun exposure index) may reflect lifetime sun exposure, and it shows a good correlation with wrinkles in Koreans.

CONCLUSION

Wrinkling is a major feature of photoaging in Koreans, as are pigmentary changes; smoking, sun exposure, and female sex are independent risk factors for wrinkles.

Measurement of chemopreventive efficacy in skin biopsies

OBJECTIVE

To explore methods suitable for quantitative assessment of the efficacy of chemopreventive intervention.

STUDY DESIGN

High-resolution imagery of nuclei from the suprabasal and basal cell layers of sun-damaged skin were recorded. There were 10 cases. A shave biopsy was taken from an area of clearly evident solar keratosis before and after treatment with 2-difluoromethyl-dlornithine (DFMO) and from the colateral forearm, treated with a placebo. A number of karyometric variables were computed and combined to derive marker features that provided a numeric measure of the degree of nuclear deviation from normal.

RESULTS

DFMO treatment was effective overall in reducing the degree of nuclear abnormality seen in the biopsies; in 8 of the 10 cases there was a significant improvement. The placebo-treated arm did not show a statistically different abnormality from the untreated arm.

CONCLUSION

Karyometric analysis can provide numeric measures that allow documentation of statistically significant regression of actinic keratotic lesions following treatment with DFMO.

Skin cancer

The incidence of skin cancer is increasing and nurses are in an ideal position to help patients prevent and identify the disease at an early stage.