Population exposure to ultraviolet radiation in Finland 1920-1995: Exposure trends and a time-series analysis of exposure and cutaneous melanoma incidence

Skin cancer mortality in Spain: adjusted mortality rates by province and related risk factors

BACKGROUND

Ultraviolet radiation is the main environmental risk factor responsible for the development of skin cancer. Other occupational, socioeconomic, and environmental factors appear to be related to the risk of skin cancer. Furthermore, the factors appear to differ for melanoma and non-melanoma skin cancer (NMSC). The purpose of this study is to analyze mortality rates of skin cancer in the different provinces of Spain and to determine the influence of socioeconomic conditions and other environmental and demographic factors in rates.

METHODS

Deaths from melanoma and NMSC in the period 2000-2019 were obtained as well as socioeconomic and environmental variables. Annual standardized mortality rates (SMR) were calculated for all Spanish provinces. The Pearson correlation coefficient was calculated.

RESULTS

The SMR of melanoma was 2.10/100,000 inhabitants, while that of NMSC was 1.28/100,000. At the provincial level, a great variability is confirmed. Gross domestic product showed a positive correlation with melanoma mortality but a negative correlation with NMSC. Other environmental and socioeconomic variables also showed correlation, as a positive correlation between tobacco sales and melanoma and between agricultural development and the NMSC.

CONCLUSIONS

There are still important differences between each province that must be taken into account when planning health care and resource distribution. This ecological and province-wise study helps to elucidate the relationship between social and ambient exposure determinants and skin cancer mortality in Spain.

Challenges in assessing the sunscreen-melanoma association

Whether sunscreen use affects melanoma risk has been widely studied with contradictory results. To answer this question we performed a systematic review of all published studies, accounting for sources of heterogeneity and bias. We searched for original articles investigating the sunscreen‐melanoma association in humans to February 28, 2018. We then used random‐effects meta‐analysis to combine estimates of the association, stratified by study design. Stratified meta‐analysis and meta‐regression were used to identify sources of heterogeneity. We included 21,069 melanoma cases from 28 studies published 1979–2018: 23 case–control (11 hospital‐based, 12 population‐based), 1 ecological, 3 cohort and 1 randomised controlled trial (RCT). There was marked heterogeneity across study designs and among case–control studies but adjustment for confounding by sun exposure, sunburns and phenotype systematically moved estimates toward decreased melanoma risk among sunscreen users. Ever‐ vs. never‐use of sunscreen was inversely associated with melanoma in hospital‐based case–control studies (adjusted odds ratio (OR) = 0.57, 95%confidence interval (CI) 0.37–0.87, p_{heterogeneity} < 0.001), the ecological study (rate ratio = 0.48, 95%CI 0.35–0.66), and the RCT (hazard ratio (HR) = 0.49, 95%CI 0.24–1.01). It was not associated in population‐based case–control studies (OR = 1.17, 95%CI 0.90–1.51, p_{heterogeneity} < 0.001) and was positively associated in the cohort studies (HR = 1.27, 95%CI 1.07–1.51, p_{heterogeneity} = 0.236). The association differed by latitude (p_interaction = 0.042), region (p_interaction = 0.008), adjustment for naevi/freckling (p_interaction = 0.035), and proportion of never‐sunscreen‐users (p_interaction = 0·012). Evidence from observational studies on sunscreen use and melanoma risk was weak and heterogeneous, consistent with the challenges of controlling for innate confounding by indication. The only RCT showed a protective effect of sunscreen.

What's new?

Effectiveness of sunscreen in reducing UV‐induced skin damage has been proven in experimental studies, but effectiveness in reducing melanoma in humans remains inconclusive. This is the first meta‐analysis to analyze data from four study designs, stratify hospital‐ and population‐based case–control studies, and include as many as five prospective studies. Evidence from observational studies on the sunscreen‐melanoma association was heterogeneous, consistent with the challenges of controlling for innate confounding by indication. The only randomized controlled trial showed a protective effect. Public health recommendations should place greater emphasis on the proper use of sunscreen in conjunction with other means of sun protection.

Physical activity, cardiorespiratory fitness and risk of cutaneous malignant melanoma: Systematic review and meta-analysis

BACKGROUND

Numerous epidemiologic studies have examined the relation of physical activity or cardiorespiratory fitness to risk of cutaneous melanoma but the available evidence has not yet been quantified in a systematic review and meta-analysis.

METHODS

Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA), we identified 3 cohort studies (N = 12,605 cases) and 5 case-control studies (N = 1,295 cases) of physical activity and melanoma incidence, and one cohort study (N = 49 cases) of cardiorespiratory fitness and melanoma risk.

RESULTS

Cohort studies revealed a statistically significant positive association between high versus low physical activity and melanoma risk (RR = 1.27, 95% CI = 1.16-1.40). In contrast, case-control studies yielded a statistically non-significant inverse risk estimate for physical activity and melanoma (RR = 0.85, 95% CI = 0.63-1.14; P-difference = 0.02). The only available cohort study of cardiorespiratory fitness and melanoma risk reported a positive but statistically not significant association between the two (RR = 2.19, 95% CI = 0.99-4.96). Potential confounding by ultraviolet (UV) radiation-related risk factors was a major concern in cohort but not case-control studies.

CONCLUSIONS

It appears plausible that the positive relation of physical activity and cardiorespiratory fitness to melanoma observed in cohort studies is due to residual confounding by UV radiation-related risk factors.

IMPACT

Future prospective studies need to examine the association between physical activity, cardiorespiratory fitness and melanoma after detailed adjustment for UV radiation-related skin damage.

European Code against Cancer 4th Edition: Ultraviolet radiation and cancer

Ultraviolet radiation (UVR) is part of the electromagnetic spectrum emitted naturally from the sun or from artificial sources such as tanning devices. Acute skin reactions induced by UVR exposure are erythema (skin reddening), or sunburn, and the acquisition of a suntan triggered by UVR-induced DNA damage. UVR exposure is the main cause of skin cancer, including cutaneous malignant melanoma, basal-cell carcinoma, and squamous-cell carcinoma. Skin cancer is the most common cancer in fair-skinned populations, and its incidence has increased steeply over recent decades. According to estimates for 2012, about 100,000 new cases of cutaneous melanoma and about 22,000 deaths from it occurred in Europe. The main mechanisms by which UVR causes cancer are well understood. Exposure during childhood appears to be particularly harmful. Exposure to UVR is a risk factor modifiable by individuals' behaviour. Excessive exposure from natural sources can be avoided by seeking shade when the sun is strongest, by wearing appropriate clothing, and by appropriately applying sunscreens if direct sunlight is unavoidable. Exposure from artificial sources can be completely avoided by not using sunbeds. Beneficial effects of sun or UVR exposure, such as for vitamin D production, can be fully achieved while still avoiding too much sun exposure and the use of sunbeds. Taking all the scientific evidence together, the recommendation of the 4th edition of the European Code Against Cancer for ultraviolet radiation is: "Avoid too much sun, especially for children. Use sun protection. Do not use sunbeds."

Variations in total ozone column and biologically effective solar UV exposure doses in Bologna, Italy during the period 2005-2010

Variations in total ozone column and sun exposures able to cause erythema and damage the DNA molecules were observed by the narrow-band filter radiometer UV-RAD in Bologna, Italy from 2005 to 2010. The ozone columns determined from the UV-RAD measurements were found to be close to those provided by the satellite Ozone Monitoring Instrument (OMI) showing an average discrepancy of 1% with standard deviation of ± 6%. Analysis of the data highlights a well-marked annual cycle of the ozone column variations while the oscillations with periods of 8, 18 and 34 months present much smaller amplitudes. The influence of the frequency of solar irradiance measurements on the accuracy of the evaluated daily exposure dose has been studied and it was found that time intervals no longer than 5-10 min between the measurements of erythema and DNA damage effective UV irradiances provide a satisfactory assessment of the corresponding daily exposures. The latter do not present significant year-to-year variations for the period under study, while their annual distributions show slight changes likely due to the specific cloud cover and ozone column variability for different years. The annual erythemal exposure dose for 2007-2010 varied between 603.7 and 638.1 kJ m(-2), while the corresponding sun exposure affecting DNA changed from 6.38 to 7.91 kJ m(-2).

[Cancer before age 40 in France]

Cancer is a rare pathology before the age of 40: a total of 14,000 new cases have been diagnosed in patients under age 40 in 2005, 1,700 under age 15 and 12,500 in the age-group of 15 to 39, this represents 4% of the cancers diagnosed in 2005. The number of deaths is small: in 2008, 2,235 patients died before age 40 in France, 246 under age 15 and 1,989 between age 15 and 39; this corresponds to 1% of the cancer deaths in 2008. The incidence increased between 1980 and 2005, both in the population aged 0 to 14 and in the population aged 15 to 39. Overall, cancer mortality has been decreasing for more than 25 years. The only increase in mortality is observed for brain tumours in children. The overall incidence increase is mostly due to the extension of screening coverage and to improvements in diagnostic procedures. The decrease observed for cervix cancer and lung cancer in men demonstrates the efficacy of screening and of tobacco smoking prevention. The mortality decrease is explained both by improved treatments and by the decreased incidence of some types of cancer. The increasing brain tumours mortality in children is worrying.

Preliminary assessment of the risks associated with solar ultraviolet-A exposure

An approach is proposed to assess the periods of human skin exposure to solar ultraviolet-A (UV-A, 315-400 nm) irradiance in natural conditions that are able to yield doses found to trigger carcinogenesis in laboratory experiments. Weighting functions, adopted to perform such estimate are constructed, allowing for a comparison between environmental and laboratory doses. Furthermore, the impact of stratum corneum (SC) thickness on the studied environmental doses was investigated. Based on laboratory studies, it was found that exposure periods of less than a month, at mid-latitudes, could provide irradiance doses capable of causing tumor formation. The duration of these exposure periods closely depends on the exposure regime, atmospheric conditions and SC thickness. It is believed that the presented evaluations could provide a useful preliminary estimation of the risk associated with environmental UV-A exposure prior to the formulation of the corresponding action spectra and determination of the threshold doses.

Another duel in the sun: weighing the balances between sun protection, tanning beds, and malignant melanoma

OBJECTIVE

The purpose of this report is to put the dueling factors of risk and prevention for melanoma in perspective for the thoughtful pediatric specialist to facilitate preteen preventive health counseling.

STUDY DESIGN

We examined the rate of malignant melanoma among Kentucky residents and compared this rate with indicators of tanning bed prevalence in a large metropolitan area and sunscreen sales from a major distributor. We obtained malignant melanoma annual incidence data from the Kentucky Cancer Registry, which recorded Kentucky population incidence rates over the years 1995 to 2004. The rates reflected 2 malignant melanoma classifications: pre-invasive cancer only, or both invasive and noninvasive cancers combined.

RESULTS

The age-adjusted incidence rate per hundred thousand for combined invasive and pre-invasive malignant melanoma swelled from 21.9 in 1995 to 31.3 in 2004. The respective invasive-only malignant melanoma incidence rates increased less dramatically, from 17.3 to 20.7, during this same 10-year time period. Since 1983, the number of separate tanning bed businesses increased from 1 in 1983 to 119 by the mid-1990s, and then declined to about 74 separate businesses by 2003. Sunscreen sales data is uneven between states and is currently inconclusive.

CONCLUSIONS

Although current data cannot draw a precise link between melanoma and the use of tanning beds, the associated risk is implicit, as the ultraviolet A (UVA) and ultraviolet B (UVB) radiation in tanning bed usage is a well-established melanoma risk factor. In advising patients, the pediatric specialist should consider that melanoma rates are poised as a balance of some known risk factors and a few potential preventive factors.

Tumorigenic effect of some commonly used moisturizing creams when applied topically to UVB-pretreated high-risk mice

Irradiation of SKH-1 mice with UVB (30 mJ cm(-2)) twice a week for 20 weeks resulted in mice with a high risk of developing skin tumors over the next several months in the absence of further irradiation with UVB (high-risk mice). Topical applications of 100 mg of Dermabase, Dermovan, Eucerin Original Moisturizing Cream (Eucerin), or Vanicream once a day, 5 days a week for 17 weeks to these high-risk mice increased significantly the rate of formation of tumors and the rate of increase in tumor size per mouse. Additional studies indicated that treatment of high-risk mice with Dermabase, Dermovan, Eucerin, or Vanicream for 17 weeks increased the total number of histologically characterized tumors by 69% (average of two experiments; P<0.0001 in each experiment), 95% (P<0.0001), 24% (P<0.01), and 58% (P<0.0001), respectively. Topical applications of a specially designed Custom Blend cream to high-risk mice was not tumorigenic. The results indicate that several commercially available moisturizing creams increase the rate of formation and number of tumors when applied topically to UVB-pretreated high-risk mice. Further studies are needed to determine the effects of topical applications of moisturizing creams on sunlight-induced skin cancer in humans.

Cyclic patterns of incidence rate for skin malignant melanoma: association with heliogeophysical activity

BACKGROUND

Our previous studies revealed cyclicity in the incidence rate of skin malignant melanoma (SMM; ICD9, Dx:172) in the Czech Republic (period T=7.50-7.63 years), UK (T=11.00 years) and Bulgaria (T=12.20 years). Incidences compared with the sunspot index Rz (lag-period dT=+2, +4, +6, +10 or +12 years) have indicated that maximal rates are most likely to appear on descending slopes of the 11-year solar cycle, i.e., out of phase. We summarized and explored more deeply these cyclic variations and discussed their possible associations with heliogeophysical activity (HGA) components exhibiting similar cyclicity.

METHODS

Annual incidences of SMM from 5 countries (Czech Republic, UK, Bulgaria, USA and Canada) over various time spans during the years 1964-1992 were analyzed and their correlations with cyclic Rz (sunspot number) and aa (planetary geomagnetic activity) indices were summarized. Periodogram regression analysis with trigonometric approximation and phase-correlation analysis were applied.

RESULTS

Previous findings on SMM for the Czech Republic, UK and Bulgaria have been validated, and cyclic patterns have been revealed for USA (T=8.63 years, P<0.05) and Canada (Ontario, T=9.91 years, P<0.10). Also, various 'hypercycles' were established (T=45.5, 42.0, 48.25, 34.5 and 26.5 years, respectively) describing long-term cyclic incidence patterns. The association of SMM for USA and Canada with Rz (dT=+6 and +7 years, respectively) and aa (dT=-10 and +9 years, respectively) was described. Possible interactions of cyclic non-photic influences (UV irradiation, Schumann resonance signal, low-frequency geomagnetic fluctuations) with brain waves absorbance, neuronal calcium dynamics, neuro-endocrine axis modulation, melatonin/serotonin disbalance and skin neuro-immunity impairment as likely causal pathways in melanoma appearance, were also discussed.

CONCLUSION

The above findings on cyclicity and temporal association of SMM with cyclic environmental factors could not only allow for better forecasting models but also lead to a better understanding of melanoma aetiology.

Avoiding bias from aggregate measures of exposure

BACKGROUND

Sometimes in descriptive epidemiology or in the evaluation of a health intervention policy change, proportions exposed to a risk factor or to an intervention are used as explanatory variables in log-linear regressions for disease incidence or mortality.

AIM

To demonstrate how estimates from such models can be substantially inaccurate as estimates of the effect of the risk factor or intervention at individual level. To show how the individual level effect can be correctly estimated by excess relative risk models.

METHODS

The problem and solution are demonstrated using data on prostate-specific antigen testing and prostate cancer incidence.

Association between the anatomic distribution of melanoma and sex

BACKGROUND

Anatomic distribution of melanoma, thought to be different between men and women, has not been studied in the United States since the 1970s, although lifestyle and clothing habits have changed since then.

OBJECTIVE

To determine whether the anatomic distribution of melanoma varied between men and women at our institution in 2004 and in the 1970s, and to assess whether the anatomic distribution has changed over time.

METHODS

We recorded the body location of initial primary cutaneous melanomas and assessed other variables of interest for 152 patients seen in our clinic in 2004 and in 397 patients seen between 1972 and 1977. Logistic regression was used for analysis.

RESULTS

For the 2004 patients, males had an increased relative risk compared to females of developing a melanoma on their head and neck (relative risk ratio [RRR] = 3.33; P = .01). For the 1970s patients, this difference was not found, but males in the 1970s had higher odds of developing melanoma on their upper back, chest, and abdomen, while females in the 1970s had higher odds of developing melanoma on the upper extremity and lower extremity, particularly the lower legs and feet. Examining differences over time, we found that women in 2004 had a decreased relative risk of developing a melanoma on the lower extremities as opposed to the trunk as compared to the 1970s (RRR = 0.42; P < .01). We also found that women had increased odds of developing a melanoma on the chest in 2004 compared to the 1970s (OR = 2.65; P = .04), while men had increased odds of developing a melanoma on their lower legs in 2004 compared to the 1970s (OR = 3.18; P = .02).

LIMITATIONS

The study was performed at a single academic center and the results may not generalize to all melanoma populations. There may be important unexamined confounders.

CONCLUSIONS

There were significant differences between men and women in the anatomic distribution of melanoma in 2004 patients and in 1970s patients, but the nature of those differences changed over time.