Occupational exposure to the sun and risk of skin and lip cancer among male wage earners in Denmark: a population-based case–control study

Occupational solar exposure and basal cell carcinoma. A review of the epidemiologic literature with meta-analysis focusing on particular methodological aspects

BACKGROUND

Numerous epidemiologic studies and a few systematic reviews have investigated the association between occupational solar exposure and basal cell carcinoma (BCC). However, previous reviews have several deficits with regard to included and excluded studies/risk estimates and the assessment of risk of selection bias (RoSB). Our aim was to review epidemiologic studies with a focus on these deficits and to use meta-(regression) analyses to summarize risk estimates.

METHODS

We systematically searched PubMed (including MEDLINE) and Embase for epidemiologic studies. Study evaluation considered four main aspects of risk of bias assessments, i.e. Selection of subjects (selection bias); Exposure variables; Outcome variables; Data analysis.

RESULTS

Of 56 identified references, 32 were used for meta-(regression) analyses. The overall pooled risk estimate for BCC comparing high/present vs. low/absent occupational solar exposure was 1.20 (95% CI 1.02-1.43); among studies without major deficits regarding data analysis, it was 1.10 (95% CI 0.91-1.33). Studies with low and high RoSB had pooled risk estimates of 0.83 (95% CI 0.73-0.93) and 1.95 (95% CI 1.42-2.67), respectively. The definitions of exposure and outcome variables were not correlated with study risk estimates. Studies with low RoSB in populations with the same latitude or lower than Germany had a pooled risk estimate of 1.01 (95% CI 0.88-1.15).

CONCLUSION

Due to the different associations between occupational solar exposure and BCC among studies with low and high RoSB, we reason that the current epidemiologic evidence base does not permit the conclusion that regular outdoor workers have an increased risk of BCC.

Skin Cancer Prevention across the G7, Australia and New Zealand: A Review of Legislation and Guidelines

Incidence rates of melanoma and keratinocyte skin cancers have been on the rise globally in recent decades. While there has been a select focus on personal sun protection awareness, to our knowledge, there is a paucity of legislation in place to help support citizens' efforts to protect themselves from the harmful effects of ultraviolet radiation (UVR). Given this, we conducted a comprehensive review of legislation and guidelines pertaining to a variety of sun protection-related topics in countries of the Group of Seven (G7), Australia and New Zealand. Australia was the only country to have banned tanning beds for individuals of all ages, while other select countries have instituted bans for minors. In workplace policy, there is very little recognition of the danger of occupational UVR exposure in outdoor workers, and thus very few protective measures are in place. With regard to sports and recreation, certain dermatological/professional associations have put forward recommendations, but no legislation was brought forward by government bodies outside of Australia and New Zealand. With regard to youth, while there are various guidelines and frameworks in place across several countries, adherence remains difficult in the absence of concrete legislation and standardization of procedures. Finally, only Australia and a few select jurisdictions in the United States have implemented sales tax exemptions for sunscreen products. In light of our findings, we have made several recommendations, which we anticipate will help reduce the rates of melanoma and keratinocyte cancers in years to come. However, minimizing UVR exposure is not without risk, and we, therefore, suggest the promotion of vitamin D supplementation in conjunction with sun protective practices to limit potential harm.

Incident skin melanoma in Danish male military pilots: a nested case-control study

OBJECTIVES

A growing body of research has reported that pilots have an increased risk of skin melanoma, which may be caused by occupational exposure to cosmic and solar ultraviolet A radiation in aircraft cockpits. However, the existing literature cannot rule out confounding, for example, that pilots may spend more leisure time in the sun compared with the general population, which therefore leaves the current evidence inconclusive. The present study aimed to provide more knowledge regarding this association.

METHODS

This nested case-control study included 199 male cases of skin melanoma diagnosed between 1990 and 2003, and 1126 male cancer-free controls identified from a large Danish military population. Among these individuals, 10 cases had ever worked as a pilot.Detailed information on military service and other held jobs together with socioeconomic and lifestyle characteristics, for example, leisure-time sun exposure habits, had been obtained from a structured questionnaire.

RESULTS

Adjusted results showed a positive association between work onboard aircraft and skin melanoma (OR=2.30, 95% CI: 1.06-4.97) and the risk was indicated only to be increased in pilots (OR=7.08, 95% CI: 2.51-19.93). A positive association between longer duration of employment as a pilot and skin melanoma was also observed (OR_{per year}=1.07, 95% CI: 1.01-1.14).

CONCLUSIONS

The findings from this study conducted among Danish military personnel suggest that pilots have an increased risk of skin melanoma after accounting for leisure-time sun exposure and socioeconomic status. Future large-scale studies focusing on the risk of skin melanoma in pilots, including detailed objective information on dimensions of exposure and potential confounders, are warranted.

Risk and Status of Gastrointestinal Cancer According to the International Standard Industrial Classification in Korean Workers

Simple Summary

The risk of developing cancers varies depending on occupation, which is a well-known fact. It is crucial to investigate the risk of developing gastrointestinal (GI) cancer in the entire industry. In this study, we calculated the standardized incidence ratios (SIRs) of GI cancer by all industrial sectors as classified in the Korean Standard Industrial Classification (KSIC). There were noticeable differences among industries in the risk of GI cancer. The SIR of all GI cancer was highest among miners and quarriers, and second highest among transportation workers. These results suggest that further research is required to identify the risk factors present in each industry that contribute to the development of GI cancers. We believe this study can help to create tailored cancer prevention strategies for different industrial sectors.

Abstract

To compare the risk of developing gastrointestinal (GI) cancer according to industrial groups, we performed a retrospective cohort study using the database of the Korea National Health Insurance Service (NHIS). We calculated the age-standardized incidence ratios (SIRs) and 95% confidence intervals (95% CIs) for the types of GI cancers according to the Korean Standard Industrial Classification (KSIC) compared with the whole employee population. The highest SIR for all GI cancer was found in the “Mining and quarrying” section (SIR, 1.30; 95% CI, 1.14–1.47), followed by the “Transportation and storage” section (SIR, 1.27; 95% CI, 1.24–1.30). Miners and quarriers had the highest risk of developing gastric cancer (SIR, 1.29; 95% CI, 1.06–1.55) and cancer of the liver and intrahepatic bile ducts (SIR, 1.48; 95% CI, 1.17–1.86). Transportation workers had the highest SIR of cancer of the lip, oral cavity, and pharynx (SIR, 1.27; 95% CI, 1.13–1.43) and cancers of the rectum, anus, and anal canal (SIR, 1.27; 95% CI, 1.19–1.35). There were distinct GI cancers with an elevated risk in each industry group. Our findings imply that distinct cancer prevention programs should be developed for each industrial sector.

Vitamin D and Cancer: An Historical Overview of the Epidemiology and Mechanisms

This is a narrative review of the evidence supporting vitamin D’s anticancer actions. The first section reviews the findings from ecological studies of cancer with respect to indices of solar radiation, which found a reduced risk of incidence and mortality for approximately 23 types of cancer. Meta-analyses of observational studies reported the inverse correlations of serum 25-hydroxyvitamin D [25(OH)D] with the incidence of 12 types of cancer. Case-control studies with a 25(OH)D concentration measured near the time of cancer diagnosis are stronger than nested case-control and cohort studies as long follow-up times reduce the correlations due to changes in 25(OH)D with time. There is no evidence that undiagnosed cancer reduces 25(OH)D concentrations unless the cancer is at a very advanced stage. Meta-analyses of cancer incidence with respect to dietary intake have had limited success due to the low amount of vitamin D in most diets. An analysis of 25(OH)D-cancer incidence rates suggests that achieving 80 ng/mL vs. 10 ng/mL would reduce cancer incidence rates by 70 ± 10%. Clinical trials have provided limited support for the UVB-vitamin D-cancer hypothesis due to poor design and execution. In recent decades, many experimental studies in cultured cells and animal models have described a wide range of anticancer effects of vitamin D compounds. This paper will review studies showing the inhibition of tumor cell proliferation, dedifferentiation, and invasion together with the sensitization to proapoptotic agents. Moreover, 1,25-(OH)₂D₃ and other vitamin D receptor agonists modulate the biology of several types of stromal cells such as fibroblasts, endothelial and immune cells in a way that interferes the apparition of metastases. In sum, the available mechanistic data support the global protective action of vitamin D against several important types of cancer.

A Study of Head and Neck Cancer Patients with Reference to Tobacco Use, Gender, and Subsite Distribution

Context  Head and neck cancer (HNC) is very common in India, constituting 30% of all the cancers because of the widespread use of tobacco across India. The prevalence and pattern of tobacco use vary in different regions and states of the country. Although predominantly seen in males, studies have reported that the male-to-female ratio varies worldwide and also by anatomical subsite.

Aims  This study was done with an aim to determine the difference in pattern and prevalence of tobacco use in male and female patients with HNCs and compare them with different subsites' involvement in our region.

Methods and Materials  This is a retrospective analysis of 500 consecutive biopsy-proven HNC patients from a large comprehensive cancer hospital from Bihar during the period of January 2019 to June 2019. Data collected for the study included age, gender, site of the disease, and use of tobacco. The categorical data were analyzed by a chi-square test using SPSS (version 16).

Results  Our study showed a male-to-female ratio of 8.43:1 with tobacco addiction in 84.40% patients. Smokeless tobacco was used by 52.20%, combustible form by 12.80%, and both by 19.40% of the patients. Tobacco use was seen in 87.25% of male patients as compared with only 60.38% of female patients ( p -value = 0.0001). Oral cavity cancer was seen in 60.85% of male patients and 37.74% of female patients ( p -value = 0.0012), whereas oropharyngeal cancer was seen in only 11.63% of male patients as compared with 25.83% of female patients ( p -value = 0.0008). The subsite analysis showed that in patients with oral cavity cancers, no addiction was found in only 10.29% of male patients as compared with 30% of the female patients ( p -value = 0.008).

Conclusions  Our study confirms a high prevalence of tobacco use among HNC patients. So, we need to continue our efforts to create awareness against tobacco use. Besides, there is also a need for more studies to look into other etiological factors among nontobacco users.

Use of smartphone apps to monitor human exposure to solar radiation: Comparison between predicted and measured UV index values

The Ultra-Violet Index (UVI) is widespread used to communicate the UV radiation intensity to the general public. The knowledge of the UVI value and of its daily variation is essential for many techniques for monitoring the personal exposure to UV radiation. The UVI values are usually provided by the meteorological services and nowadays it is very common to find UVI forecast tools even in smartphone apps. In this paper, with the aim to evaluate the prediction accuracy of six smartphone apps, a measurement campaign of UVI has been carried out. The measurements have been conducted for the site of Pisa (central Italy), using a portable photoradiometer equipped with a UV erythemal irradiance probe (operating range 250-400 nm). The measured UVI values have been compared with the predicted UVI values (using smartphone apps). Bland-Altman and Passing-Bablok methods have been used to compare the data, the comparison has been conducted on the basis of 90 different UVI measurements, taken at different times, different days and different sky conditions. From the comparison between measured and predicted UVI values it has been possible to observe a general poor accuracy of the apps. The percentage deviations between measured and predicted UVI values were quite high and only one app was able to predict more than 70% of the measured data with an average percentage deviation lower than 30%.

Physician Notified Work-Related Diseases Among Farmers in Norway: Data from 2007 - 2016

Introduction: This study provided a profile of work-related diseases in the farming sector notified by physicians to the Norwegian Labor Inspection Authority's (NLIA) Registry for Work-Related Diseases (RAS) over a 10-year period.Methods: Data for the occupational code "farmers" were extracted from RAS for the period 2007-2016. We performed a descriptive analysis to obtain frequency, percentage, and incidence distribution of the data. We also explored the relationship of the notified diagnosis with gender, age, occupational exposures and the type of reporting physicians.Results: Four hundred and sixty-nine cases of work-related diseases among farmers were notified in the period 2007-2016. Eighty-seven percent of the reported cases were males. The incidence of work-related diseases for the entire study period was computed to be 114/100 000 workers. The incidence and number of cases notified were highest among males and for the age group 55-74 years. Noise was the most frequently reported occupational exposure accounted for 291 cases. Hearing loss constituted for 62% of the notified cases, followed by respiratory diseases that accounted for 20% of the cases. Forty-eight cases of skin diseases, while only a few cases of musculoskeletal (n = 7) and mental disorders (n = 1) were notified. There was a strong association (λ = 0.51) between occupational exposure and notified diagnosis, and a moderate association (λ = 0.32) between type of reporting physician and the notified diagnosis.Conclusion: This profile of the physician notified work-related diseases among farmers in Norway yielded a suppressed estimate of the actual incidence of cases. The biased distribution of nature and number of work-related diseases amongst farmers is primarily attributed to the significant undercount of cases. Physician underreporting of cases to the NLIA coupled with lack of Occupational Health Services coverage of workers in the farming sector contributes to this undercount of cases.

Incidence Trends of Lip, Oral Cavity, and Pharyngeal Cancers: Global Burden of Disease 1990–2017

The worldwide incidence trends of the lip, oral cavity, and pharyngeal cancers (LOCPs) need to be updated. This study aims to examine the temporal incidence trends of LOCPs from 1990 to 2017, using the latest Global Burden of Disease (GBD) study data to explore sex, age, and regional differences. GBD incidence data for LOCPs were driven by population cancer registries and were estimated from mortality data. Age-standardized incidence rates (ASIRs) were directly extracted from the 2017 GBD database to calculate the estimated annual percentage change (EAPC) over the study period. Incidence trends are mapped and compared separately by sex (females vs. males), age groups (15–49, 50–69, and 70+ y), regions (21 geographical and 5 sociodemographic regions), and countries. Among 678,900 incident cases of LOCPs notified in 2017, more than half were lip and oral cavity cancers. From 1990 to 2017, the estimated global incidence for nasopharyngeal cancers decreased dramatically (EAPC = −1.52; 95% confidence interval [CI], –1.70 to −1.34), while the incidence for lip and oral cavity cancers (EAPC = 0.26; 95% CI, 0.16–0.37) and other pharyngeal cancers (EAPC = 0.62; 95% CI, 0.54–0.71) increased. Higher ASIRs were observed among males than females across all age groups. However, females had larger EAPC variation when compared to males. Population groups aged 15 to 49 y presented the lowest ASIRs, with larger values of EAPC than those aged 50 to 69 and 70+ y. While high-income countries had higher ASIRs with little EAPC variation, ASIRs varied across low/middle-income regions with larger EAPC variations. South Asia and East Asia had the highest ASIRs and EAPC for lip and oral cavity cancers, respectively. In conclusion, the global incidence of LOCPs has increased among females, those aged 15 to 49 y, and people from low/middle-income countries over the study period, excepting nasopharyngeal cancers, which had a decreasing worldwide trend.

Skin cancer risk perception and sun protection behavior at work, at leisure, and on sun holidays: a survey for Danish outdoor and indoor workers

BACKGROUND

To prevent occupational skin cancer, it is essential that the sun-protective behavior of outdoor workers is adequate. The aim is to study the sun-protective behavior of Danish outdoor workers at work, at leisure, and on sun holiday and compare it to that of indoor workers.

METHODS

This is a cross-sectional study, based on a 53-item survey completed by Danish outdoor (n = 380) and indoor workers (n = 119) in 2016-2017. Status as outdoor or indoor worker was decided based on self-report and behavioral differences were tested using (paired) t tests and multiple regression adjusted for age, sex, educational level, history of smoking, and skin type.

RESULTS

Danish outdoor workers at work use sun protection less than they do at leisure and on sun holiday (α < .05) where their sun protection behavior is similar to that of indoor workers. The proportion of Danish outdoor workers that always/often use sun protection at work is for shade seeking around noon 4.2%, sunscreen 34.5%, wide-brimmed hat 25.3%, and long trousers and shirt with sleeves 42.4%. Of Danish outdoor workers, 49.5% do not think about the risk of occupational skin cancer and 11.8% think the risk is insignificant, 32.4% think that the use of sun protection is of low or no importance, 84.2% consider sunburn important as skin cancer risk factor still 88.9% have a history of sunburn at work, > 80.0% agree that risk of skin cancer is reduced by the use of sun protection, and only 4.0% dismiss the possibility of sun protection use at work.

CONCLUSIONS

Skin cancer risk and use of sun protection at work are largely neglected in Danish outdoor workers, more so than at leisure and on sun holiday where their risk behavior resembles that of indoor workers. This indicates an untapped workplace preventive potential.

The Role of Vitamin D₃ in the Development and Neuroprotection of Midbrain Dopamine Neurons

Vitamin D has long been synonymous with bone health. More recently, new health benefits are continually being associated with vitamin D, including a burgeoning field on neuroprotective properties. This has generated a huge explosion of interest in recent years in the potential for vitamin D to be used not only as a therapeutic in neurodegenerative disease, including Parkinson's disease, but also as biomarkers and for risk association. With an emphasis on Parkinson's disease, this chapter will discuss recent evidence supporting the assertion that vitamin D can be a useful therapeutic agent used as an intervention therapy to be combined with existing treatments; and the case for further development of novel treatments utilizing the potential of vitamin D. In addition, we present novel, previously unpublished evidence showing that in a unilateral model of Parkinson's disease, vitamin D can not only reduce the extent of denervation, but that this is also reflected in functional benefit to the animals. The potential of vitamin D is slowly being realized; in the future, it will be widely associated with far more than just bone health and may even contribute to an elusive treatment of neurodegenerative illness.

The pattern of lip cancer occurrence over the 1990-2011 period in public hospitals in Madrid, Spain

BACKGROUND

Some regions of Spain along with Canada and Australia have the highest rates of lip cancer in the world. The objective of this study was to examine the trends in the pattern of occurrence of lip cancer in Madrid, Spain.

METHODS

Data were extracted from the Central Tumour Registry of Madrid, between 1990 and 2011. Variables examined were age, sex, topographic and morphological location and tumour histology. Two consecutive periods, 1990-2001 and 2002-2011, were studied by descriptive and analytical methods, and the data from the two periods were statistically compared.

RESULTS

A total of 881 cases were registered during the period 1990-2011. Comparing data between the two periods (1990-2001 and 2002-2011), subtle variations in age, histology and location were noted. Gender ratios remained constant. The mean age increased from 66.3 to 69.7 years (P < 0.05). In the second period, the histological distribution showed an increase in frequency of basal cell carcinoma, from 2.1% to 4.7%, while the frequency of squamous cell carcinomas remained constant. Basal cell carcinoma no longer predominantly occurred in women, decreasing from 80% to 21.1% (P < 0.001). The distribution by gender of squamous cell carcinoma had become more equal due an increase in its frequency in women (P < 0.001). Frequency of tumours on lip mucosa and commissure had increased between the two periods (P < 0.004).

CONCLUSIONS

The pattern of lip cancer reported to Public Hospitals of Madrid is changing: declining rates are noted since 2001-02. However, it is necessary to monitor these data to confirm the observed trends in future years.

Occupational UV exposure of environmental agents in Valencia, Spain

Excessive exposure to ultraviolet radiation (UVR) is considered the most important environmental risk factor in the development of melanoma and skin cancer. Outdoor workers are among those with the highest risk from exposure to solar UVR, as their daily activities constantly expose them to this radiation source. A study was carried out in Valencia, Spain, in summer 2012 and involved a group of 11 workers for a period of six 2-day recordings. Sensitive spore-film filter-type personal dosimeters (VioSpor) were used to measure erythemal UVR received by environmental agents in the course of their daily work. Median 2-day UV exposure was 6.2 standard erythema dose (SED), with 1 SED defined as effective 100 J m(-2) when weighted with the Commission Internationale de L'Eclairage's (CIE) erythemal response function. These workers were found to receive a median of 8.3% total daily ambient ultraviolet erythemal radiation. Comparison with the occupational UV exposure limit showed that the subjects had received an erythemal UV dose in excess of occupational guidelines, indicating that protective measures against this risk are highly advisable.

Non-melanoma skin cancer: occupational risk from UV light and arsenic exposure

Non-melanoma skin cancer (NMSC) has a significant impact on public health and health care costs as a result of high morbidity and disfigurement due to the destruction of surrounding tissues. Although the mortality rates of these tumors are low, the high incidence rates determine a considerable number of deaths. NMSC is the most common type of skin cancer, representing about 1/3 of all malignancies diagnosed worldwide each year. The most common NMSC are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Studies on humans and experimental animals indicate that ultraviolet (UV) light and arsenic play important roles in the development of these skin malignancies. Several epidemiological studies have investigated the risk of developing NMSC and the potential link between exposure to sunlight and arsenic in the agricultural and industrial occupational settings. To date, the published literature suggests that there is no apparent skin cancer risk as regards workplace exposure to artificial UV light or arsenic. Concerning UV light from sun exposure at the workplace, most published studies indicated an elevated risk for SCC, but are less conclusive for BCC. Many of these studies are limited by the methodology used in the evaluation of occupational exposure and the lack of adjustment for major confounders. Therefore, further epidemiological studies are required to focus on exposure assessment at the individual level as well as potential interactions with other occupational and non-occupational exposures and individual susceptibility. In doing so, we can better quantify the true risk of skin cancer in exposed workers and inform effective public health prevention programs.

Skin cancer as a marker of sun exposure associates with myocardial infarction, hip fracture and death from any cause

BACKGROUND

Sun exposure is the single most important risk factor for skin cancer, but sun exposure may also have beneficial effects on health. We tested the hypothesis that individuals with skin cancer (non-melanoma skin cancer and cutaneous malignant melanoma) have less myocardial infarction, hip fracture and death from any cause, compared with general population controls.

METHODS

We examined the entire Danish population above age 40 years from 1980 through 2006, comprising 4.4 million individuals. Diagnoses of non-melanoma skin cancer (n=129,206), cutaneous malignant melanoma (n=22,107), myocardial infarction (n=327,856), hip fracture (n=129,419), and deaths from any cause (n=1,629,519) were drawn from national registries.

RESULTS

In individuals with vs without non-melanoma skin cancer, multifactorially adjusted odds ratios were 0.96 (95% confidence interval: 0.94-0.98) for myocardial infarction and 1.15 (1.12-1.18) for hip fracture, and the multifactorially adjusted hazard ratio was 0.52 (0.52-0.53) for death from any cause. Risk of hip fracture was reduced (odds ratios were below 1.0) in individuals below age 90 years. In individuals with vs without cutaneous malignant melanoma, corresponding odds ratios were 0.79 (0.74-0.84) for myocardial infarction and 0.84 (0.76-0.93) for hip fracture, and the corresponding hazard ratio for death from any cause was 0.89 (0.87-0.91); however, cutaneous malignant melanoma was associated positively with death from any cause in some individuals.

CONCLUSIONS

In this nationwide study, having a diagnosis of skin cancer was associated with less myocardial infarction, less hip fracture in those below age 90 years and less death from any cause. Causal conclusions cannot be made from our data. A beneficial effect of sun exposure per se needs to be examined in other studies.

Solar UV exposure in construction workers in Valencia, Spain

Exposure to ultraviolet radiation (UVR) has long been recognized as the most important environmental risk factor for melanoma and skin cancer. Outdoor workers are among the groups most at risk from exposure to solar UVR in their daily activities. Sensitive spore-film filter-type personal dosimeters (VioSpor) were used to measure the biologically effective UVR received by construction workers in the course of their daily work. The study took place in Valencia, Spain, in July 2010 and involved a group of eight workers for a period of 5 days. The median UV exposure was 6.11 standard erythema dose (SED) per day, with 1 SED defined as effective 100 J/m(2) when weighted with the Commission Internationale de L'Eeclairage erythemal response function. These workers were found to receive a median of 13.9% of total daily ambient ultraviolet erythemal radiation (UVER). Comparison with the occupational UVR exposure limit showed that the subjects had received UVER exposure in excess of occupational guidelines, indicating that protective measures against this risk are highly advisable.

Reduced mortality rates in a cohort of long-term underground iron-ore miners

BACKGROUND

Historically, working in iron-ore mines has been associated with an increased risk of lung cancer and silicosis. However, studies on other causes of mortality are inconsistent and in the case of cancer incidence, sparse. The aim of this study was to examine the association between iron-ore mining, mortality and cancer incidence.

METHODS

A 54-year cohort study on iron-ore miners from mines in northern Sweden was carried out comprising 13,000 workers. Standardized rate ratios were calculated comparing the disease frequency, mortality, and cancer incidence with that of the general population of northern Sweden. Poisson regression was used to evaluate the association between the durations of employment and underground work, and outcome.

RESULTS

Underground mining was associated with a significant decrease in adjusted mortality rate ratios for cerebrovascular and digestive system diseases, and stroke. For several outcomes, elevated standardized rate ratios were observed among blue-collar workers relative to the reference population. However, only the incidence of lung cancer increased with employment time underground (P < 0.001).

CONCLUSIONS

Long-term iron-ore mining underground was associated with lower rates regarding several health outcomes. This is possibly explained by factors related to actual job activities, environmental exposure, or the selection of healthier workers for long-term underground employment.

Occupational exposure to ultraviolet radiation and risk of non-melanoma skin cancer in a multinational European study

Background

Studies suggest that ambient sunlight plays an important role in the pathogenesis of non-melanoma skin cancers (NMSC). However, there is ongoing controversy regarding the relevance of occupational exposure to natural and artificial ultraviolet radiation (UV) radiation.

Objectives

We investigated potential associations between natural and artificial UV radiation exposure at work with NMSC in a case-control study conducted in Hungary, Romania, and Slovakia.

Methods

Occupational exposures were classified by expert assessment for 527 controls and 618 NMSC cases (515 basal cell carcinoma, BCC). Covariate information was collected via interview and multiple logistic regression models were used to assess associations between UV exposure and NMSC.

Results

Lifetime prevalence of occupational exposure in the participants was 13% for natural UV radiation and 7% for artificial UV radiation. Significant negative associations between occupational exposure to natural UV radiation and NMSC were detected for all who had ever been exposed (odds ratio (OR) 0.47, 95% confidence interval (CI) 0.27–0.80); similar results were detected using a semi-quantitative metric of cumulative exposure. The effects were modified by skin complexion, with significantly decreased risks of BCC among participants with light skin complexion. No associations were observed in relation to occupational artificial UV radiation exposure.

Conclusions

The protective effect of occupational exposure to natural UV radiation was unexpected, but limited to light-skinned people, suggesting adequate sun-protection behaviors. Further investigations focusing on variations in the individual genetic susceptibility and potential interactions with environmental and other relevant factors are planned.

Is prevention of cancer by sun exposure more than just the effect of vitamin D? A systematic review of epidemiological studies

The number of studies reporting on the association between sunlight exposure, vitamin D and cancer risk is steadily increasing. We reviewed all published case-control and cohort studies concerning colorectal-, prostate-, breast cancer, non-Hodgkin's lymphoma (NHL) and both sunlight and vitamin D to update our previous review and to verify if the epidemiological evidence is in line with the hypothesis that the possible preventive effect of sunlight on cancer might be mediated not only by vitamin D but also by other pathways. We found that almost all epidemiological studies suggest that chronic (not intermittent) sun exposure is associated with a reduced risk of colorectal-, breast-, prostate cancer and NHL. In colorectal- and to a lesser degree in breast cancer vitamin D levels were found to be inversely associated with cancer risk. In prostate cancer and NHL, however, no associations were found. These findings are discussed and it is concluded that the evidence that sunlight is a protective factor for colorectal-, prostate-, breast cancer and non-Hodgkin's lymphoma is still accumulating. The same conclusion can be drawn concerning high vitamin D levels and the risk of colorectal cancer and possibly breast cancer. Particularly in prostate cancer and NHL other sunlight potentiated and vitamin D independent pathways, such as modulation of the immune system and the circadian rhythm, and the degradation of folic acid might play a role in reduced cancer risk as well.

Cancer incidence among Swedish pulp and paper mill workers: a cohort study of sulphate and sulphite mills

PURPOSE

Associations between various malignancies and work in the pulp and paper industry have been reported but mostly in analyses of mortality rather than incidence. We aimed to study cancer incidence by main mill pulping process, department and gender in a Swedish cohort of pulp and paper mill workers.

METHODS

The cohort (18,113 males and 2,292 females, enrolled from 1939 to 1999 with >1 year of employment) was followed up for cancer incidence from 1958 to 2001. Information on the workers' department and employment was obtained from the mills' personnel files, and standardized incidence ratios (SIRs) were calculated using the Swedish population as reference.

RESULTS

Overall cancer incidence, in total 2,488 cases, was not increased by work in any department. However, risks of pleural mesothelioma were increased among males employed in sulphate pulping (SIR, 8.38; 95 % CI, 3.37-17) and maintenance (SIR, 6.35; 95 % CI, 3.47-11), with no corresponding increase of lung cancer. Testicular cancer risks were increased among males employed in sulphate pulping (SIR, 4.14; 95 % CI, 1.99-7.61) and sulphite pulping (SIR, 2.59; 95 % CI, 0.95-5.64). Female paper production workers showed increased risk of skin tumours other than malignant melanoma (SIR, 2.92; 95 % CI, 1.18-6.02).

CONCLUSIONS

Incidence of pleural mesothelioma was increased in the cohort, showing that asbestos exposure still has severe health consequences, and highlighting the exigency of strict asbestos regulations and elimination. Testicular cancer was increased among pulping department workers. Shift work and endocrine disruptors could be of interest in this context.

Glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms, smoking, and their interaction in oral cancer: a HuGE review and meta-analysis

The association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and oral cancer is not consistent across studies, and data on their interaction with smoking in oral cancer are lacking. The authors systematically searched PubMed and SciVerse Scopus for case-control studies examining the association between null genotypes of the GSTM1 and GSTT1 genes and oral cancer. Twenty-eight case-control studies published in English were identified. Summary odds ratios were derived via random-effects models. The summary odds ratio for the GSTM1 null genotype was 1.43 in Asians (95% confidence interval (CI): 1.14, 1.78; P < 0.01, I (2) = 73%) and 0.98 in Caucasians (95% CI: 0.76, 1.28; P = 0.91, I (2) = 0%). Case-only analysis of 6 studies (552 cases) showed an inverse multiplicative interaction between GSTM1 null polymorphisms and smoking (ever/high levels of smoking vs. never/low levels) (odds ratio (OR) = 0.51, 95% CI: 0.32, 0.82; P = 0.01, I (2) = 34%). The GSTT1 null genotype was not significantly associated with oral cancer in Asians (OR = 1.07, 95% CI: 0.82, 1.38; P = 0.63, I (2) = 65%) or Caucasians (OR = 1.04, 95% CI: 0.41, 2.65; P = 0.93, I (2) = 55%). In conclusion, the GSTM1 null genotype may be associated with a higher risk of oral cancer in Asians but not in Caucasians, and this effect may be modified by smoking status. The GSTT1 null genotype may not be associated with oral cancer.

Outdoor work and risk for Parkinson's disease: a population-based case-control study

OBJECTIVES

Sunlight is the main contributor to vitamin D in humans. Since inadequate levels of vitamin D have been linked to increased risks for neurodegenerative diseases, we examined whether outdoor work is associated with a reduced risk for Parkinson's disease in a population-based case-control study of Danish men.

METHODS

We identified 3819 men with a primary diagnosis of Parkinson's disease in the period 1995-2006 in the Danish National Hospital Register and selected 19,282 age- and sex-matched population controls at random from the Central Population Register. Information on work history was ascertained from the Danish Supplementary Pension Fund and the Central Population Register. Based on trade grouping codes and job titles, we evaluated the extent of outdoor work of study subjects as a proxy of exposure to sunlight.

RESULTS

Relying on trade grouping codes, we estimated ORs for study subjects with moderate, frequent and maximal outdoor work compared with exclusive indoor work of 0.90 (95% CI 0.78 to 1.02), 0.86 (95% CI 0.75 to 0.99) and 0.72 (95% CI 0.63 to 0.82), respectively, for Parkinson's disease. Reduced risks were also found for Parkinson's disease among outdoor workers based on study subjects' job titles.

CONCLUSIONS

Our findings suggest that men working outdoors have a lower risk for Parkinson's disease. Further studies of measured vitamin D levels in outdoor workers are warranted to clarify a potential inverse association between vitamin D and the risk for Parkinson's disease.