Risk Factors for Histological Types and Anatomic Sites of Cutaneous Basal-Cell Carcinoma: An Italian Case–Control Study

Exposure to UV Radiation in Lifeguards on Barcelona's Beaches: An Underestimated Occupational Risk

BACKGROUND

The development of skin cancer is closely related to high exposure to UV radiation. Lifeguards are at an increased risk of excessive sun exposure.

OBJECTIVES

The main objective of this study was to measure the exposure of Barcelona's beach lifeguards to UV radiation.

METHODS

Measurements in the work chair were taken every 30min on a typical working day from 10:45 am to 19:15 pm. These measurements were carried out on four different days. These data were used to calculate the erythematous doses received during working hours, as well as those potentially received throughout the summer season. Vitamin D production was also estimated for the four days that the radiation received was measured, and the amount generated was calculated for the entire summer season.

RESULTS

Exposure to UV radiation among Barcelona lifeguards far exceeds safety limits. In some locations, the exposure to UVB radiation is more than 16 times the minimum erythematous dose for phototype II skin.

LIMITATIONS

This study assessed the radiation received during only four days. However, is a much higher number than most of the published papers.

CONCLUSION

Although the health risks of excessive exposure to UV radiation are known, Barcelona's beach lifeguards are insufficiently protected.

Exposure to UV Radiation in Lifeguards on Barcelona's Beaches: An Underestimated Occupational Risk

BACKGROUND

The development of skin cancer is closely related to high exposure to UV radiation. Lifeguards are at an increased risk of excessive sun exposure.

OBJECTIVES

The main objective of this study was to measure the exposure of Barcelona's beach lifeguards to UV radiation.

METHODS

Measurements in the work chair were taken every 30min on a typical working day from 10:45 am to 19:15 pm. These measurements were carried out on four different days. These data were used to calculate the erythematous doses received during working hours, as well as those potentially received throughout the summer season. Vitamin D production was also estimated for the four days that the radiation received was measured, and the amount generated was calculated for the entire summer season.

RESULTS

Exposure to UV radiation among Barcelona lifeguards far exceeds safety limits. In some locations, the exposure to UVB radiation is more than 16 times the minimum erythematous dose for phototype II skin.

LIMITATIONS

This study assessed the radiation received during only four days. However, is a much higher number than most of the published papers.

CONCLUSION

Although the health risks of excessive exposure to UV radiation are known, Barcelona's beach lifeguards are insufficiently protected.

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.

Dermoscopic Pattern of Basal Cell Carcinoma in H- and Non-H-zones

INTRODUCTION

Basal cell carcinoma (BCC) localized in the H-zone, the region of fusion of embryonic masses, has been associated with a higher risk of deeper invasion and more frequent recurrence.

OBJECTIVES

The aim of the study was to compare dermoscopic features of BCC in H and non-H zone that may most appropriately characterize those two locations.

METHODS

Dermoscopy images of histopathologically confirmed BCCs from 120 patients were retro-spectively analyzed. Dermoscopy features of BCC in H- and non-H zone were described and a comparative study of the dermoscopic pattern of BCC between the two locations was performed.

RESULTS

Of 120 BCC cases included in this study, 41 (34.2%) were located in the H-zone. The most frequent histological type was nodular (51.3% in H- zone and 61.6 % in non-H-zone) followed by superficial (5.1% and 19.8 % in H and non-H-zone respectively).In dermoscopy, there was a higher prevalence of ulceration (73.2% versus 43.6%, P < 0.001) in H-zone and a lower prevalence of brown globules (26.8% versus 53.2%; P = 0.01), when compared with the non-H-zone.

CONCLUSIONS

Our results show that dermoscopic features of BCC on the face fulfill a typical pattern regardless of the region, except for the prevalence of the ulceration which is significantly more frequent in H-zone and the brown globules present significantly more often in the non-H-zone It can be hypothesized that H-zone might predispose to more aggressive course of BCC complicated by ulceration and consequently deeper tissue destruction.

A meta-analysis of sunburn and basal cell carcinoma risk

Basal cell carcinoma (BCC) is the most common cancer in the United States. Sunburn is a modifiable risk factor for BCC. The objective of this project was to synthesize research on BCC and sunburn to quantify the impact and severity of sunburn at different life stages on BCC risk in the general population. A systematic literature search of four electronic databases was conducted and data were extracted by two independent reviewers using standardized forms. Data from 38 studies were pooled using both dichotomous and dose-response meta-analytic methods. BCC risk increased with ever experiencing a sunburn in childhood (OR=1.43, 95% CI: 1.19, 1.72) and with ever experiencing a sunburn in life (OR= 1.40, 95% CI: 1.02, 1.45). Every five sunburns experienced per decade in childhood increased BCC risk by 1.86 (95% CI: 1.73, 2.00) times. Every five sunburns experienced per decade in adulthood increased BCC risk by 2.12 (95% CI: 1.75, 2.57) times and every five sunburns per decade of life increased BCC risk by 1.91 (95% CI: 1.42, 2.58) times. The data on sunburn exposure and BCC show that an increase in number of sunburns at any age increased the risk of BCC. This may inform future prevention efforts.

Digitally measuring solar ultraviolet radiation in outdoor workers: A study protocol for establishing the use of electronic personal dosimeters in Portugal

Introduction

The rising incidence of skin cancer over the years has made it a significant public and occupational health issue. However, skin cancer is highly preventable, mainly through reduced exposure to solar ultraviolet radiation (UVR), which can be achieved by a variety of individual and collective protective measures and interventions. The relative risk associated with different patterns of exposure to solar UVR differs for the subtypes of keratinocyte cancers (KC). Specifically, whether the exposure is intermittent or continuous, and occurs in an occupational or leisure/recreational setting. The main aim of the study using this protocol is to contribute to raising public and policy awareness on solar UVR-inflicted occupational skin cancers in Lisbon. This will be achieved by performing direct measurements of the solar UVR dose received by outdoor workers using a digital platform. Results will likely contribute to further understanding the risk estimates for keratinocyte cancer estimations in this population.

Methods

A prospective observational study will be conducted in Lisbon, Portugal. Personal electronic dosimeters (GENESIS-UV system) integrated with a digital platform will be used to assess occupational solar UVR doses of gardeners, masons, and gravediggers of the municipality of Lisbon. Two hundred and ten outdoor workers will be selected to wear the dosimeter for 1 month each, between April and October during their daily working hours. A digital web-based platform that offers private access to information through dashboard visualization will provide information for the outdoor workers and facilitate communication with the participants.

Discussion

The expected results of the overall proposal comprise the occupational solar UVR doses, expressed in standard erythemal dose (SEDs) per day of outdoor work for 7 months. Study data will provide outdoor workers with information on their personal solar UVR exposure during their working hours and an estimate of their risk of developing skin cancer. It is expected that the occupational solar UVR doses of the outdoor workers in Portugal will be above the threshold of 1 to 1.33 SED/day, due to the latitude of Lisbon and the nature of the occupations. The results prospectively should flow into the design of adequate prevention campaigns for skin cancer in outdoor workers.

Sun-Exposed versus Sun-Protected Cutaneous Basal Cell Carcinoma: Clinico-Pathological Profile and p16 Immunostaining

Introduction: Although widespread, BCC is still relatively poorly understood in regards to pathogenesis and prognosis, particularly the lesions formed on anatomical sites away from sun exposure. With the aim of deepening our understanding of the pathogenesis and clinico-pathological correlations of BCCs, we conducted this study. Methods: Tissue blocks and data of 52 Egyptian patients diagnosed with BCC were retrieved for clinical information and inclusion criteria, then re-examined histologically; p16 immunostaining was carried out and evaluated for analysis and comparison between the two groups, i.e., sun-exposed and sun-protected. Results: Sex, age, clinical suspicion, tumor size, recurrence status, and histologic variants did not show a significant difference between the sun-protected and sun-exposed groups; however, the mean ages recorded were 67.2 vs. 62.7 for the sun-protected and sun-exposed groups, respectively. A total of 52% of BCCs were positive for p16. The sun-protected lesions showed p16 positivity in 61% of cases, whereas 49% of the sun-exposed lesions were positive with no significant difference. There was a significant difference in p16 expression between the recurrent and non-recurrent lesions. Conclusions: A significant difference was seen in the case of cancer recurrence, where all the recurrent BCCs in this study demonstrated negative p16 immunostaining of the primary lesions; however, the positively stained cases in total were 52% of BCCs. The mean patient age of the sun-protected group was much higher than in previous peer studies. We assume that the biological, prognostic, and clinical aspects of p16 protein expression in BCCs are still far from being clearly understood. Further studies are highly recommended, with more focus on its role in the pathogenesis and the prognostic factors.

Degree of Actinic Elastosis Is a Surrogate of Exposure to Chronic Ultraviolet Radiation and Correlates More Strongly with Cutaneous Squamous Cell Carcinoma than Basal Cell Carcinoma

(1) Background: Keratinocyte cancer (KC) is associated with exposure to ultraviolet (UV) radiation. However, data are controversial as to whether chronic UV exposure or high intermittent UV exposure are key drivers of carcinogenesis in cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC). Prolonged sun exposure of the skin causes photo-aging, which is associated with actinic elastosis, a condition characterized by the degeneration of elastin in the upper dermis, which is assessable via conventional histology. In this study, we aimed to compare the degree of actinic elastosis in different types of KC with regard to various patient characteristics. (2) Methods: We defined a semiquantitative score for the degree of actinic elastosis ranging from 0 = none to 3 = total loss of elastic fibers (basophilic degeneration). The extent was measured histometrically by two independent dermatohistopathologists in the immediate vicinity of 353 KC. The scores were merged and matched with tumor types (cSCC and BCC with subtypes), and clinical variables such as body site, sex and age. (3) Results: As expected, the degree of actinic elastosis correlated with age. However, it was significantly higher in cSCC compared to BCC irrespective of age, sex, body site and tumor subtypes. (4): Conclusions: Lifetime sun exposure may be estimated via routine histology using this scoring technique for actinic elastosis as a surrogate marker. cSCCs are more strongly associated with chronic UV exposure than BCCs, even in sun-exposed localizations such as the face.

Basal cell carcinoma of the scalp shows distinct features from the face in Asians

Basal cell carcinoma (BCC) affecting different sites has been reported to have different clinicopathological features. In previous studies, the scalp was commonly classified to the head and neck region. However, the scalp has distinct characteristics from those of other parts of the skin. We retrospectively reviewed the medical records of patients who underwent surgical treatment for BCC. A total of 734 lesions were examined, and 13.2% originated from the scalp. The nodular type was the most common histologic subtype; however, the proportion of the superficial type was significantly higher than that of facial BCC (p < 0.001). Compared with facial BCC, younger age (p = 0.046) and larger tumor size (p < 0.001) were observed in scalp BCC. These characteristics were similar to those of truncal BCC in that they demonstrated a higher proportion of the superficial type (p < 0.001), younger age (p = 0.001), and larger tumor diameter (p < 0.001) compared with BCC in the head and neck region. Scalp BCC and truncal BCC were not significantly different in terms of age (p = 0.052) and tumor size (p = 0.230). In conclusion, despite the anatomical proximity, features of scalp BCC were similar to those of truncal lesions compared with facial lesions. Scalp BCC might be a separate entity from facial BCC.

Lifetime Ambient UV Radiation Exposure and Risk of Basal Cell Carcinoma by Anatomic Site in a Nationwide U.S. Cohort, 1983-2005

BACKGROUND

Cutaneous basal cell carcinoma (BCC) has long been associated with UV radiation (UVR) exposure, but data are limited on risks by anatomic site.

METHODS

We followed 63,912 cancer-free White U.S. radiologic technologists from cohort entry (1983-1989/1994-1998) to exit (date first BCC via 2003-2005 questionnaire). We estimated associations between cumulative ambient UVR and relative/absolute risks of self-reported BCC by anatomic location via Poisson models.

RESULTS

For incident first primary BCC in 2,124 subjects (mean follow-up, 16.9 years) log[excess relative risks] (ERR) of BCC per unit cumulative ambient UVR = 1.27/MJ cm^-2 [95% confidence interval (CI): 0.86-1.68; P _trend < 0.001] did not vary by anatomic site (P = 0.153). However, excess absolute risks of BCC per unit cumulative ambient UVR were large for the head/neck = 5.46/MJ cm^-2/10⁴ person-year (95% CI: 2.92-7.36; P _trend < 0.001), smaller for the trunk (2.56; 95% CI: 1.26-3.33; P _trend = 0.003), with lesser increases elsewhere. There were lower relative risks, but higher absolute risks, for those with Gaelic ancestry (P < 0.001), also higher absolute risks among those with fair complexion, but relative and absolute risks were not generally modified by other constitutional, lifestyle or medical factors for any anatomic sites. Excess absolute and relative risk was concentrated 5-15 years before time of follow-up.

CONCLUSIONS

BCC relative and absolute risk rose with increasing cumulative ambient UVR exposure, with absolute risk highest for the head/neck, to a lesser extent in the trunk.

IMPACT

These associations should be evaluated in other White and other racial/ethnic populations along with assessment of possible modification by time outdoors, protective, and behavioral factors.

Protection Against Solar Ultraviolet Radiation in Outdoor Construction Workers: Study Protocol for a Non-randomized Controlled Intervention Study

Introduction: Non-melanoma skin cancer (NMSC) incidence is increasing, and occupational solar exposure contributes greatly to the overall lifetime ultraviolet radiation (UVR) dose. This is reflected in an excess risk of NMSC showing up to three-fold increase in outdoor workers. Risk of NMSC can be reduced if appropriate measures to reduce UVR-exposure are taken. Regular use of sunscreens showed reduced risk of NMSC. However, sun-safety behavior in outdoor workers is poor. The objective of this study is to investigate the effectiveness of an intervention aiming at increasing sunscreen use by construction workers.

Methods: This non-randomized controlled intervention study is comprised of two intervention and two control groups recruited at four different construction sites in the Netherlands. The study population comprises ~200 construction workers, aged 18 years or older, followed during 12 weeks. The intervention consists of providing dispensers with sunscreens (SPF 50+) at construction sites and regular feedback on the application achieved by continuous electronic monitoring. All groups will receive basic information on UV-exposure and skin protection. Stratum corneum (SC) samples will be collected for measurement of biomarkers to assess internal UV-dose. External UV-dose will be assessed by personal UV-sensors worn by the workers during work-shifts in both groups. To detect presence of actinic keratosis (AK) or NMSC, a skin check of body parts exposed to the sun will be performed at the end of the study. The effect of the intervention will be assessed from data on self-reported sunscreen use by means of questionnaires collected on baseline and after 12 weeks of intervention (primary outcome). Levels of SC biomarkers of internal UV-dose, external UV-dose, number of sunburn episodes, and prevalence of NMSC including AK will be assessed as secondary outcomes. The electronically monitored sunscreen consumption will be assessed as process outcome.

Discussion: This study is intended to provide evidence of the effectiveness of a technology-driven intervention to increase sunscreen use in outdoor construction workers. Furthermore, it will increase insight in the UV-protective behavior, external and internal UV-exposure, and the prevalence of NMSC, including AK, in construction workers.

Trial Registration: The Netherlands Trial Register (NTR): NL8462 Registered on March 19, 2020.

Basal Cell Carcinoma with Sebaceous Differentiation: A Case Report and Review of Literature

We report a very rare type of tumor in the left nasal ala in an elderly patient. An 81-year-old Saudi woman known to have hypertension, osteoporosis, and rheumatoid disease (who had been compliant to her medications) presented with a 0.5-cm fixed, firm, round well-defined nodule on the left ala of the nose (with crusting, erosion, and telangiectasia of the overlying skin), whose size had been gradually increasing for 2 years. The patient underwent excisional biopsy, and the specimen was sent for a histopathologic analysis. Macroscopic examination showed a round tan-white homogenous nodule, measuring 0.6 × 0.5 × 0.5 cm³. Microscopic examination revealed a fairly circumscribed unencapsulated dermal lesion, featuring basaloid cells with peripheral palisading, and focal stromal clefting. The final diagnosis of basal cell carcinoma with sebaceous differentiation was made. The patient was managed with Mohs surgery with clear margins, and full-thickness skin graft was done. Four months after surgery, the patient had a recurrence, which was managed with a surgical excision (with 4-mm margin) and covered by a full-thickness skin graft.

Basal cell carcinoma risk and solar UV exposure in occupationally relevant anatomic sites: do histological subtype, tumor localization and Fitzpatrick phototype play a role? A population-based case-control study

Background

A two-fold risk increase to develop basal cell carcinoma was seen in outdoor workers exposed to high solar UV radiation compared to controls. However, there is an ongoing discussion whether histopathological subtype, tumor localization and Fitzpatrick phototype may influence the risk estimates.

Objectives

To evaluate the influence of histological subtype, tumor localization and Fitzpatrick phototype on the risk to develop basal cell carcinoma in highly UV-exposed cases and controls compared to those with moderate or low solar UV exposure.

Methods

Six hundred forty-three participants suffering from incident basal cell carcinoma in commonly sun-exposed anatomic sites (capillitium, face, lip, neck, dorsum of the hands, forearms outside, décolleté) of a population-based, case-control, multicenter study performed from 2013 to 2015 in Germany were matched to controls without skin cancer. Multivariate logistic regression analysis was conducted stratified for histological subtype, phototype 1/2 and 3/4. Dose-response curves adjusted for age, age², sex, phototype and non-occupational UV exposure were calculated.

Results

Participants with high versus no (OR 2.08; 95% CI 1.24–3.50; p = 0.006) or versus moderate (OR 2.05; 95% CI 1.15–3.65; p = 0.015) occupational UV exposure showed a more than two-fold significantly increased risk to develop BCC in commonly UV-exposed body sites. Multivariate regression analysis did not show an influence of phototype or histological subtype on risk estimates. The restriction of the analysis to BCC cases in commonly sun-exposed body sites did not influence the risk estimates. The occupational UV dosage leading to a 2-fold increased basal cell carcinoma risk was 6126 standard erythema doses.

Conclusion

The risk to develop basal cell carcinoma in highly occupationally UV-exposed skin was doubled consistently, independent of histological subtype, tumor localization and Fitzpatrick phototype.

Global evidence on occupational sun exposure and keratinocyte cancers: a systematic review

Individual studies have suggested that the association between occupational exposure to solar ultraviolet radiation (UVR) and the development of keratinocyte cancers (KCs) may only be valid in populations of European ancestry living in certain geographical regions. Comparative global data are scarce and so this review aimed to summarize current evidence on the association between occupational exposure to solar UVR and the development of KCs, with a specific focus on geographical location and skin colour. Ovid MEDLINE, PubMed, Embase and Web of Science were searched for potentially relevant records. Extracted data were summarized by study, country and region. We included one prospective cohort study and 18 case-control studies (n = 15 233) from 12 countries in regions where the majority of the population is white skinned (Americas, Europe and Oceania). Eighteen of the 19 studies reported effect estimates suggesting an increased risk of basal cell carcinoma (BCC) and/or squamous cell carcinoma (SCC) among outdoor workers. Only 11 studies found a significantly increased risk and many had imprecise estimates. There was a significantly increased risk of BCC and SCC in individual studies in North America, Latin America and the Caribbean, Western Europe and Southern Europe, but not across regions or countries. Overall, 95% of studies reported higher risks among outdoor workers, although the increases in risk were statistically significant in just over half of the studies. Well-designed and sufficiently powered occupational case-control and cohort studies with adequate adjustment for confounding factors and other risk factors are required to provide more accurate risk estimates for occupational KC.

Development of Multiple-Lesion Basal Cell Carcinoma of the Skin: A Comprehensive Review

An interesting clinical feature of basal cell carcinoma (BCC) of the skin is a marked variation in tumor number, sites, and accrual. Some individuals develop only a single BCC lesion with no impact on health status, while a significant proportion is affected repeatedly with new primary tumors at various body sites. Approximately 29% of patients with a first BCC will develop at least 1 more lesion during their lifetime. The candidate predictors for multiple BCC development include younger age and a superficial BCC subtype at the time of the first diagnosis, red hair phenotype, initial or frequent tumor location on the trunk or on the upper limbs, and male gender. The pathogenesis of multiple BCC development does not seem to be related to greater UVR exposure. Individual genetic susceptibility may have a greater impact than extrinsic factors. In clinical practice, it is meaningful to estimate the probability of new BCC development in patients who have an initial lesion. A reliable prediction model for individualized risk stratification remains a subject of continued research; however, a focus on the risk factor profile is beneficial for clinical screening and may help clinicians to determine the individuals who should be followed up more closely.

Head and neck cutaneous basal cell carcinoma: what should the otorhinolaryngology head and neck surgeon care about?

Cutaneous basal cell carcinoma (cBCC) is the most common malignancy diagnosed in the human population. cBCC presents an increasing incidence which, in the near future, will be higher than all other cancers combined. The majority of cBCC are located in the head and the neck. A diversity of management modalities is currently available; nonetheless, surgical excision remains the main modality of treatment. cBCC rarely metastasises and presents a low mortality rate. cBCC morbidity is influenced by local invasion and destruction, especially in the face, where function and aesthetics are major issues. Easy accessibility to the face and skin on the neck makes cBCC an important issue for otorhinolaryngology head and neck surgeons who must be aware and committed in its management, as the main modality of treatment continues to be surgical. The aim of this review is to present a brief and practical overview of head and neck cBCC management for ear, nose and throat (ENT) surgeons, discussing key issues about its epidemiology, risk factors, diagnosis and pathogenesis.

Mortality among Italian male workers in the construction industry: a census-based cohort study

Background

Advances in technologies, occupational hygiene and increased surveillance have reduced the excess mortality previously found in the construction industry. This study is aimed to evaluate cause-specific mortality in a recent cohort of construction workers.

Methods

We carried out a record-linkage cohort study based on the 2011 Italian census and the mortality archives (2012–2015), including 1 068 653 construction workers. We estimated mortality rate ratios (MRR) using Poisson regression models including terms for age and geographic area.

Results

Compared with non-manual workers, construction workers showed an excess mortality from all causes (MRR: 1.34), all neoplasms (MRR: 1.30), head and neck (MRR: 2.05), stomach (MRR: 1.56), liver (MRR: 1.62), lung (MRR: 1.80), prostate (MRR: 1.24) and bladder (MRR: 1.60) cancers, respiratory (MRR: 1.41) and liver (MRR: 1.79) diseases, all external causes (MRR: 1.87), falls (MRR: 2.87) and suicide (MRR: 1.58). Compared with manual workers in other industries, construction workers showed excess mortality from prostate (MRR: 1.27) and non-melanoma skin cancers (MRR: 1.95), all external causes (MRR: 1.14), falls (MRR: 1.94) and suicide (MRR: 1.18). Most of this excess mortality disappeared after adjusting for education, with the exception of prostate and non-melanoma skin cancers, all external causes, falls and suicide.

Conclusions

Construction workers are at high risk of dying from external causes, while the excess mortality found for several cancers, liver and respiratory diseases may be at least partially due to the high prevalence of low education and unfavorable lifestyle factors. The excess mortality from prostate cancer requires further evaluations.

WHO/ILO work-related burden of disease and injury: Protocol for systematic reviews of occupational exposure to solar ultraviolet radiation and of the effect of occupational exposure to solar ultraviolet radiation on melanoma and non-melanoma skin cancer

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing a joint methodology for estimating the national and global work-related burden of disease and injury (WHO/ILO joint methodology), with contributions from a large network of experts. In this paper, we present the protocol for two systematic reviews of parameters for estimating the number of deaths and disability-adjusted life years from melanoma and non-melanoma skin cancer (or keratinocyte carcinoma) from occupational exposure to solar ultraviolet radiation, to inform the development of the WHO/ILO joint methodology.

OBJECTIVES

We aim to systematically review studies on occupational exposure to solar ultraviolet radiation (Systematic Review 1) and systematically review and meta-analyse estimates of the effect of occupational exposure to solar ultraviolet radiation on melanoma and non-melanoma skin cancer (Systematic Review 2), applying the Navigation Guide systematic review methodology as an organizing framework and conducting both systematic reviews in tandem and in a harmonized way.

DATA SOURCES

Separately for Systematic Reviews 1 and 2, we will search electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and Web of Science. We will also search electronic grey literature databases, Internet search engines and organizational websites; hand-search reference list of previous systematic reviews and included study records and consult additional experts.

STUDY ELIGIBILITY AND CRITERIA

We will include working-age (≥15 years) workers in the formal and informal economy in any WHO and/or ILO Member State, but exclude children (<15 years) and unpaid domestic workers. For Systematic Review 1, we will include quantitative studies on the prevalence of relevant levels of occupational exposure to solar ultraviolet radiation (i.e. <0.33 SED/d and ≥0.33 SED/d) and of the total working time spent outdoors, stratified by country, sex, age and industrial sector or occupation, in the years 1960 to 2018. For Systematic Review 2, we will include randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of any occupational exposure to solar ultraviolet radiation (i.e., ≥0.33 SED/d) on the prevalence of, incidence of or mortality due to melanoma and non-melanoma skin cancer, compared with the theoretical minimum risk exposure level (i.e. <0.33 SED/d).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors will independently screen titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. At least two review authors will assess the risk of bias and the quality of evidence, using the most suited tools currently available. For Systematic Review 2, if feasible, we will combine relative risks using meta-analysis. We will report results using the guidelines for accurate and transparent health estimates reporting (GATHER) for Systematic Review 1 and the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA) for Systematic Review 2.

PROSPERO REGISTRATION NUMBER

CRD42018094817.

Non-genetic and genetic predictors of a superficial first basal cell carcinoma

Background

Several observational studies have suggested differences in the risk factor profile between patients with superficial basal cell carcinomas (BCCs) and non‐superficial BCCs.

Objective

To test the reproducibility of previous study findings and to find new genetic and non‐genetic predictors for patients with a superficial first BCC.

Methods

A total of 14.628 participants of northwestern European descent aged 45 years or older from a prospective population‐based cohort study (Rotterdam Study) were linked with the Dutch Pathology Registry (PALGA) of whom 1528 were identified as BCC patients. After exclusion, 948 eligible BCC patients remained for further non‐genetic analyses and 1014 for genetic analyses. We included 11 phenotypic, environmental and tumour‐specific characteristics, and 20 candidate single nucleotide polymorphisms (SNP) as potential predictors for patients with a superficial first BCC. We performed binary logistic multivariable regression analyses.

Results

We found that patients with a superficial first BCC were significantly younger, almost two times more often female and 12–18 times more likely to have their BCC on the trunk or extremities than patients with a non‐superficial first BCC. One SNP (rs12203592), mapped to IRF4, looked promising (OR 1.83, 95% CI 1.13–2.97, P‐value <0.05), but after adjustment for multiple testing, no significant differences in genetic make‐up between superficial BCC and non‐superficial BCC patients were found.

Conclusion

We conclude that patients with a superficial BCC differ from non‐superficial BCC patients with respect to environmental factors (tumour localization as a proxy for UVR exposure) and phenotypic characteristics (age and sex), but we found no difference in genotype. As superficial BCC patients develop their first BCCs at a younger age, they could be at higher lifetime risk for subsequent skin cancers and therefore be an important group for secondary prevention.

Linked article: This article is commented on G. Argenziano et. al., p. 461 in this issue. To view this article visit https://doi.org/10.1111/jdv.15486.

Mediators of Inflammation in Topical Therapy of Skin Cancers

Taking into consideration that the immune system plays a very important role in the development of melanoma and non-melanoma skin cancers, which have a high prevalence in immunosuppressed patients and after prolonged ultraviolet radiation, the interest in developing novel therapies, in particular targeting the inflammation in cancer, has increased in the past years. The latest data suggest that therapies such as imiquimod (IMQ), ingenol mebutate (IM), 5-fluorouracil (5-FU), retinoids, and nonsteroidal anti-inflammatory drugs (NSAIDs) have been used with success in the topical treatment of some cancers. Herein, we review the topical treatment targeting the inflammation in skin cancer and the mechanisms involved in these processes. Currently, various associations have shown a superior success rate than monotherapy, such as systemic acitretin and topical IMQ, topical 5-FU with tretinoin cream, or IMQ with checkpoint inhibitor cytotoxic T lymphocyte antigen 4. Novel therapies targeting Toll-like receptor-7 (TLR-7) with higher selectivity than IMQ are also of great interest.

Skin Cancer Knowledge, Attitudes, and Practices among Chinese Population: A Narrative Review

Skin cancers are becoming a substantial public health problem in China. Fair skin and increased exposure to ultraviolet B (UVB) rays from the sun are among the most substantial risk factors for skin cancer development, thus making the Chinese people vulnerable to this group of diseases. The purpose of this article is to present a narrative review of the knowledge, attitudes, and practices (KAP) related to skin cancers within the Chinese population. A systematic electronic search of MEDLINE (PubMed), CINAHL, ScienceDirect, and Google Scholar databases yielded nine articles that met the inclusion criteria. The review found that although sunscreen application was a commonly used method of skin protection among the general Chinese population, educational interventions enhancing current knowledge and attitudes about the effects of UVB rays on skin from undue sun exposure were limited in many smaller communities of the country. Hence, there is an essential need to design effective, evidence-based educational programs promoting sun protection behaviors in both congregated and sparsely populated areas of China.

Metformin is associated with decreased skin cancer risk in Taiwanese patients with type 2 diabetes

BACKGROUND

Metformin, an antidiabetic drug, is associated with decreased cancer risk, but its effect on skin cancer is unknown.

OBJECTIVE

To evaluate skin cancer risk associated with metformin use.

METHODS

In total, 16,237 matched pairs of ever and never metformin users with new-onset type 2 diabetes diagnosed during 1999-2005 were retrospectively enrolled and followed until December 31, 2011, using Taiwan's National Health Insurance database. Hazard ratios (HRs) were estimated using Cox regression weighted for propensity scores.

RESULTS

Skin cancer incidence was 45.59 and 83.90 per 100,000 person-years among ever and never users, respectively (HR 0.540, 95% confidence interval [CI] 0.357-0.819). Among ever users, the HRs (95% CIs) for the first (<21.00 months), second (21.00-45.83 months), and third (>45.83 months) cumulative duration tertiles were 0.817 (0.448-1.489), 0.844 (0.504-1.412), and 0.114 (0.036-0.364), respectively, and the HRs (95% CIs) for the first, second, and third cumulative dose tertiles were 1.006 (0.579-1.748), 0.578 (0.317-1.051), and 0.229 (0.099-0.530), respectively. HRs (95% CIs) were 0.523 (0.175-1.562) for melanoma and 0.496 (0.319-0.772) for nonmelanoma skin cancer.

LIMITATIONS

Few patients had skin cancer and information on ultraviolet light exposure and tumor histopathology was lacking.

CONCLUSION

Metformin use is associated with a decreased skin cancer risk.

Early Life UV and Risk of Basal and Squamous Cell Carcinoma in New South Wales, Australia

Sun exposure is the main cause of squamous (SCC) and basal cell carcinoma (BCC) although pattern and amount differ by cancer type, and sun sensitivity is the major host risk factor. Our study investigated risk factors and residential ambient UV in a population-based sample of Australian 45 and Up Study participants: 916 BCC cases, 433 SCC cases, 1224 controls. Unconditional logistic regression models adjusting for key covariates demonstrated 60% increased BCC risk and two-fold increased SCC risk with sun sensitivity, and three- and four-fold increased risk, respectively, with solar keratoses. BCC but not SCC risk increased with higher early-life residential UV in all participants (odds ratio (OR) = 1.54; 95% CI 1.22-1.96 for intermediate; OR = 1.31; 95% CI 1.03-1.68 for high UV at birthplace) and similarly in Australian-born participants (P-values < 0.05). Risk of SCC but not BCC increased with long-term cumulative sun exposure assessed by self-reported outdoor work (OR 1.74, 95% CI 1.21-2.49). In conclusion, sun sensitivity is important for both cancers, early-life UV but not cumulative UV appears to increase BCC risk, the former an apparently novel finding, and SCC risk appears only to be related to long-term cumulative sun exposure.

Clinical and prognostic factors in the development of basal cell carcinoma

We investigated the environmental and personal risk factors associated with the development of basal cell carcinoma (BCC). This retrospective cohort study included a total of 997 patients whose diagnosis was confirmed by histopathologic examination between 2007 and 2014. A control examination was performed in 363 of these patients, who were accessed via telephone. A total of 1151 tumors were detected in 997 patients. During their follow-up, 13% of them developed subsequent tumors. The risk of developing subsequent tumor was 2.7-fold higher in patients with multiple BCCs at the time of diagnosis than those with single BCC. Multiple BCCs tended to develop in older patients and men. The risk of developing multiple BCCs was increased in patients with a history of BCC, skin type 1 or 2, and chronic sun exposure (sun exposure of >500 weeks, a high photoaging score [≥30], and the presence of actinic keratosis). We concluded that chronic sun exposure may increase the risk of developing multiple BCCs. These data also indicate that cumulative sun exposure is as important for developing BCC as for squamous cell carcinoma.

The experience of a tertiary referral centre in Romania on basal cell carcinomas in outdoor workers: why to assess?

BACKGROUND

Published epidemiological literature indicates that outdoor workers are at significantly increased risk for developing basal cell carcinomas.

OBJECTIVES

The main objective is to identify basal cell carcinoma features in patients with prolonged occupational exposure to UV radiation and compare them to basal cell carcinoma in patients with no occupational exposure to UV radiation.

METHODS

Data regarding age, gender, living area, occupation, number of lesions, involved anatomic site and histologic subtype of tumor were collected from the charts of 321 patients diagnosed with basal cell carcinoma in our department between 01.01.2013-31.12.2014. We divided the patient population in which the occupation was accurately identified in two study groups: occupations with UV exposure (OW), and non-UV exposed occupations (IW) and we compared the clinical and histologic features of the lesions in the two groups.

RESULTS

The most affected area in both groups was the facial "mask area". The cheek was second most affected area in exposed group whereas the scalp area was the second most affected in the non-exposed group. The nodular pattern is the most numerous in both groups (30 lesions in OW group and 15 lesions in the IW group with a mean number of lesions of 1.57±0.90 and 1.27±0.46, respectively) with the mixed type being the second most frequent type for both groups. However, for the OW group the mixed type with an aggressive component was the second most frequent one, while in the non-exposed group, the mixed type with non-aggressive components was the second most frequent, the difference being statistically significant. A multinomial logistic regression analysis was conducted to predict the presence of histopathologically aggressive lesions using gender, age, exposure and anatomical site out of which UV exposure and 3 main anatomical sites (mask zone, cheek and torso) were selected in the final analysis. The probability of the model chi-square (9.430), p = .05, supports a relationship between the dependent variable and the independent variables.

CONCLUSION

Our data suggest that in Romania patients diagnosed with basal cell carcinoma, occupationally exposed to UV radiation, develop more frequently lesions on the "mask area" of the face; furthermore, prediction of the histo-pathologically aggressive lesions may be supported by the presence of occupational UV exposure and anatomical site (mask zone, cheek and torso) involved.Also, these patients may be at a higher risk to develop more aggressive histologic subtype BCCs. Although limited by a number of factors, especially the small number of subjects, these data suggest the necessity of conducting both retrospective and prospective studies on clinical and histological types of BCCs evolving in patients working outdoor along with identifying additional risk factors.

Relationship between arsenic-containing drinking water and skin cancers in the arseniasis endemic areas in Taiwan

Artesian well-water had high concentrations of arsenic that led to the well-known black foot disease in Taiwan around the 1950s, and the associated cancers including skin cancer, bladder cancers and lung cancers. We sought to estimate the standardized morbidity ratio (SMR) and age-standardized incidence rate (ASIR) of cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) in the black foot disease endemic areas (BFDEA) in Taiwan. A nationwide retrospective population-based survey was done with the data from the National Taiwan Cancer Registry Center between 1979 and 2007. Among the 29-year period, there were 11 191 cases with SCC and 13 684 cases with BCC diagnosed pathologically. The incidence rates were 4-6-fold higher for SCC and 3-4-fold higher for BCC in the BFDEA compared with the rest of Taiwan. The SMR decreased after stopping arsenic-containing well-water drinking in the 1970s. The arsenic level in the drinking water, amount of contaminated water intake, occupation and sun-exposure time were not documented. This is the first nationwide, population-based study that shows the relationship between arsenic intoxication and non-melanoma skin cancers (SCC and BCC) through comparing the data in people living in the BFDEA and non-BFDEA in Taiwan.

Basal cell carcinomas on sun-protected vs. sun-exposed body sites: a comparison of phenotypic and environmental risk factors

BACKGROUND

Basal cell carcinoma (BCC) is the most commonly diagnosed cancer in White populations. There are indications that risk factors for BCC may differ according to the anatomic site of the tumour but this is not well understood.

PURPOSE

To compare phenotypic and environmental risk factors for BCCs arising on sun-protected sites with that of those on sun-exposed sites.

METHODS

We conducted a case-case study in which people who had been diagnosed with incident BCC were recruited between February 2012 and September 2013 in Brisbane, Australia.

RESULTS

Fair skin (OR: 4.50; 95% CI: 1.22, 16.59), having more than 15 lesions frozen/burnt off compared to less than 5 (OR: 5.68; 95% CI: 1.78, 18.08) and severe acne (OR: 5.25; 95% CI: 1.34, 20.56) were associated with increased risk of BCC on sun-protected sites. The presence of more than 5 nevi on the body was associated with decreased risk (OR: 0.28; 95% CI: 0.11, 0.71).

CONCLUSIONS

BCCs on sun-protected sites arise as a result of excessive sun exposure, most likely combined with phenotypic susceptibility. The strong negative association with nevi also suggests that there are constitutional factors that underlie the propensity for BCCs to arise on these body sites.

Rosiglitazone may reduce non-melanoma skin cancer risk in Taiwanese

Background

Whether rosiglitazone may affect the risk of non-melanoma skin cancer (NMSC) has not been investigated.

Methods

The reimbursement databases of all Taiwanese diabetic patients from 1996 to 2009 were retrieved from the National Health Insurance. An entry date was set at 1 January 2006 and a total of 886418 patients with type 2 diabetes were followed up for NMSC incidence until the end of 2009. Incidences for ever-users, never-users and subgroups of rosiglitazone exposure (using tertile cutoffs of duration of therapy and cumulative dose) were calculated and hazard ratios estimated by Cox regression. Additional models were created as sensitivity analyses.

Results

There were 103097 ever-users and 783321 never-users, respective numbers of incident NMSC 250 (0.24%) and 2084 (0.27%), and respective incidence 68.90 and 76.77 per 100000 person-years. Although the overall hazard ratio was not significant in the unadjusted, age-sex-adjusted or fully adjusted model, the risk was significantly lower in the third tertile of duration of therapy and cumulative dose, with significant P for trends. The fully adjusted hazard ratio (95% confidence interval) for a duration of therapy >13.77 months and a cumulative dose of >1752 mg was 0.723 (0.566, 0.923) and 0.783 (0.618, 0.993), respectively. The findings were supported by various sensitivity analyses.

Conclusions

Rosiglitazone may reduce the risk of NMSC, but further confirmation is required.

Exploratory investigation of genetic associations with basal cell carcinoma risk: genome-wide association study in Jeju Island, Korea

AIM

Little is known about the genetic associations with Basal cell carcinoma (BCC) risk in non-Caucasian populations, in which BCC is rare, as in Korea. We here conducted a pilot genome-wide association study (GWAS) in 12 patients and 48 standard controls.

METHOD

A total of 263,511 SNPs were analyzed with the Illumina HumanOmni1 Quad v1.0 DNA Analysis BeadChip for cases and Korean HapMap 570K for controls.

RESULTS

SNP-based analyses, based on the allele genetic model with adjustment for sex and age showed suggestive associations with BCC risk for 6 SNPs with a P-value (P < 0.0005). However, these associations were not statistically significant after Bonferroni correction: rs1040503, rs2216491, rs13407683, rs4751072, rs9891263, and rs1368474. In addition, results from gene-based analyses showed suggestive associations with BCC risk for 33 candidate genes with a P-value (P <0.0005). Consistent with previous GWAS and replication studies in Caucasian populations, PADI6, RHOU and SLC45A2 were identified as having null associations with BCC (P > 0.05), likely due to the smaller sample size.

CONCLUSIONS

Although this was a small-scale negative study, to our knowledge, we have conducted the first GWAS for BCC risk in an Asian population. Further large studies in non-Caucasian populations are required to achieve statistical significance and confirm these findings.

Ultraviolet Radiation and the Skin

Ultraviolet radiation (UVR) has many interactions with the skin, which are explored in detail in this review. Both ultraviolet A (UVA) and ultraviolet B (UVB) wavelengths are absorbed by chromophores in the skin, resulting in important biologic effects. Exposure to UVR can result in sunburn, immediate and delayed skin pigmentation, photoaging, and immunosuppression. In addition, exposure to UVA and UVB is an important risk factor for melanoma, squamous cell carcinoma, and basal cell carcinoma. Because endogenous vitamin D synthesis requires UVB, concerns have been raised about the possibility that photoprotection might contribute to vitamin D deficiency; however, vitamin D supplementation is a safer and more reliable method for maintaining adequate vitamin D levels than UVR exposure. Protection from UVR is critical and involves several factors. These elements include sun avoidance during peak hours of UVR exposure (10 am to 2 pm), proper application of a broad-spectrum sunscreen with adequate sun protection factor, and wearing protective clothing, a wide-brimmed hat, and protective eyewear. Indoor tanning is a high-risk activity that is likely contributing to recent increases in melanoma and nonmelanoma skin cancer in young women, and efforts are ongoing to ban minors from engaging in indoor tanning.

Basal cell carcinoma of the head and neck region: an analysis of 171 cases

Objective. To analyze the pattern of presentation of basal cell carcinoma (BCC) and margin status for excised specimens in the head and neck region. Study Design. Retrospective cross-sectional. Duration of Study. January 2009 to December 2011. Methodology. The database of the pathology department was searched to identify records of all malignant skin tumors that underwent standard excision with margins. Out of these records, tumors with a diagnosis of BCC in the head and neck region were retrieved and separated. Age, gender, anatomic location, pattern of tumor, and margin status were noted. Results. A total of 171 cases of BCC from various sites of head and neck were retrieved. Male to female ratio was 1.4 : 1. The age ranged from 22 to 90 years. Seventy-six cases presented on right side, 79 on left, and 16 were in the midline. Most common anatomical site was the nose followed by the cheek. Nodular lesions were the most common (46.2%) followed by pigmented variety (18.7%). Margins were clear in 77 (45.1%) cases, involved in 86 (50.2%) cases, and close in 8 (4.7%) cases. Conclusion. Nose was the most common site followed by the cheek. Nodular and pigmented varieties were the most frequent and margins were involved in more than fifty percent of the cases.

Patterns and timing of sunlight exposure and risk of basal cell and squamous cell carcinomas of the skin--a case-control study

BACKGROUND

Non-melanoma skin cancer (NMSC), comprised of basal (BCC) and squamous (SCC) cell carcinomas, is the most common cancer in Caucasians. Ultraviolet radiation (UVR) exposure is the most important environmental risk factor for NMSC. However, the precise relationship between UVR and the risk of NMSC is complex, and the relationship may differ by skin cancer type.

METHODS

A case-control study was conducted among Florida residents to investigate measures of patterns (intermittent vs. continuous) and timing (childhood vs. adulthood) of sunlight exposure in BCC and SCC. Participants included 218 BCC and 169 SCC cases recruited from a university dermatology clinic and 316 controls with no history of skin or other cancers.

RESULTS

A history of blistering sunburn (a measure of intermittent sunlight exposure) was associated with both BCC (OR = 1.96, 95% CI = 1.27-3.03) and SCC (OR = 2.02, 95% CI = 1.22-3.33). Additionally, having a job in the sun for ≥ 3 months for 10 years or longer (a measure of continuous sunlight exposure) was also associated with both BCC and SCC in our study population. With the exception of younger age at first blistering sunburn, measures of younger age at sunlight exposure tended to be associated with SCC, but not BCC risk.

CONCLUSIONS

Results from the current study suggest that sunlight exposure is associated with both BCC and SCC risk regardless of the pattern in which the exposure was received (i.e. intermittent vs. continuous). The data also suggest that sunlight exposure at a younger age may be more important for SCC but not BCC, however additional studies are needed to further characterize sunlight exposure-response relationships in different types of NMSC.

Epidemiology of basal cell carcinoma

Basal cell carcinoma is the most common malignant neoplasm in humans and its incidence has increased over the last decades. Its high frequency significantly burdens the health system, making the disease a public health issue. Despite the low mortality rates and the rare occurrence of metastases, the tumor may be locally invasive and relapse after treatment, causing significant morbidity. Exposure to ultraviolet radiation is the main environmental risk factor associated with its cause. However, other elements of risk are described, such as light skin phototypes, advanced age, family history of skin carcinoma, light eyes and blond hair, freckles in childhood and immunosuppression. Behavioral aspects such as occupational sun exposure, rural labor and sunburns at a young age also play a role. Between 30% and 75% of the sporadic cases are associated with patched hedgehog gene mutation, but other genetic changes are also described. The tumor is commonly found in concomitance with skin lesions related to chronic sun exposure, such as actinic keratoses, solar lentigines and facial telangiectasia. The prevention of basal cell carcinoma is based on the knowledge of risk factors, early diagnosis and treatment, as well as on the adoption of specific measures, particularly in susceptible populations. The authors present a review of the epidemiology of basal cell carcinoma.

Hip fracture history and risk of nonmelanoma skin cancer: a Danish population-based study

Background

Vitamin D deficiency is associated with osteoporotic fractures, such as hip fracture. Sun exposure, the natural source of vitamin D, is the main risk factor for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). In this study, we examined the association between a history of hip fracture and risk of BCC and SCC.

Methods

We conducted a population-based case-controlled study using data on BCC and SCC cases registered in the Danish Cancer Registry from 1990–2005. For each case, we selected five population controls matched by age and gender. We used conditional logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI), while adjusting for chronic diseases and socioeconomic status.

Results

A history of hip fracture was associated with a decreased risk of BCC (OR 0.90, 95% CI 0.85–0.94), which was most pronounced in cases of tumors on the trunk, extremities, or at multiple sites. We found no association for SCC (OR 1.07, 95% CI 0.98–1.17).

Conclusion

Our study showed an inverse association between history of hip fracture and risk of BCC, but not of SCC. Sun exposure, resulting in vitamin D synthesis, may explain the link between the two diseases.

Basal cell carcinoma: what's new under the sun

Basal cell carcinoma (BCC) is the most common skin cancer in white populations with an increasing incidence worldwide, thereby imposing an important public health problem. Its etiology is still unclear, but existing data indicate that the risk for BCC development is of multifactorial origin and results from the interplay of both constitutional and environmental factors. Yet, UV radiation (UVR) is believed to be the predominant causative risk factor in the pathogenesis of BCC. For years, BCC and squamous cell carcinoma (SCC) have been grouped together as "nonmelanoma skin cancer." However, it seems that there are considerable biologic differences between BCC and SCC, and thus each type of epithelial cancer should be addressed separately. The present review provides an overview of the intriguing etiologic link of BCC with UVR and attempts a comprehensive review of recent epidemiologic and molecular evidence that supports this association.