Study of Nevi in Children (SONIC): baseline findings and predictors of nevus count

Improving Artificial Intelligence-Based Diagnosis on Pediatric Skin Lesions

Artificial intelligence algorithms to classify melanoma are dependent on their training data, which limits generalizability. The objective of this study was to compare the performance of an artificial intelligence model trained on a standard adult-predominant dermoscopic dataset before and after the addition of additional pediatric training images. The performances were compared using held-out adult and pediatric test sets of images. We trained two models: one (model A) on an adult-predominant dataset (37,662 images from the International Skin Imaging Collaboration) and the other (model A+P) on an additional 1,536 pediatric images. We compared performance between the two models on adult and pediatric held-out test images separately using the area under the receiver operating characteristic curve. We then used Gradient-weighted Class Activation Maps and background skin masking to understand the contributions of the lesion versus background skin to algorithm decision making. Adding images from a pediatric population with different epidemiological and visual patterns to current reference standard datasets improved algorithm performance on pediatric images without diminishing performance on adult images. This suggests a way that dermatologic artificial intelligence models can be made more generalizable. The presence of background skin was important to the pediatric-specific improvement seen between models. Our study highlights the importance of carefully curated and labeled data from diverse inputs to improve the generalizability of AI models for dermatology, in this case applied to dermoscopic images of adult and pediatric lesions to improve melanoma detection.

In vivo microscopy as an adjunctive tool to guide detection, diagnosis, and treatment

SIGNIFICANCE

There have been numerous academic and commercial efforts to develop high-resolution in vivo microscopes for a variety of clinical use cases, including early disease detection and surgical guidance. While many high-profile studies, commercialized products, and publications have resulted from these efforts, mainstream clinical adoption has been relatively slow other than for a few clinical applications (e.g., dermatology).

AIM

Here, our goals are threefold: (1) to introduce and motivate the need for in vivo microscopy (IVM) as an adjunctive tool for clinical detection, diagnosis, and treatment, (2) to discuss the key translational challenges facing the field, and (3) to propose best practices and recommendations to facilitate clinical adoption.

APPROACH

We will provide concrete examples from various clinical domains, such as dermatology, oral/gastrointestinal oncology, and neurosurgery, to reinforce our observations and recommendations.

RESULTS

While the incremental improvement and optimization of IVM technologies should and will continue to occur, future translational efforts would benefit from the following: (1) integrating clinical and industry partners upfront to define and maintain a compelling value proposition, (2) identifying multimodal/multiscale imaging workflows, which are necessary for success in most clinical scenarios, and (3) developing effective artificial intelligence tools for clinical decision support, tempered by a realization that complete adoption of such tools will be slow.

CONCLUSIONS

The convergence of imaging modalities, academic-industry-clinician partnerships, and new computational capabilities has the potential to catalyze rapid progress and adoption of IVM in the next few decades.

The role of MC1R gene variants and phenotypical features in predicting high nevus count

Variants in the Melanocortin 1 Receptor (MC1R) gene have been associated with an increased risk of melanoma, but the role in nevus count is unclear. We investigated if specific MC1R gene variants or the number of MC1R gene variants and phenotypical features were associated with nevus count. A total of 494 participants of the 'Leiden skin cancer study' were included and the MC1R gene coding sequence was analysed by single-strand conformation polymorphism analysis followed by sequencing of unknown variants. The association between MC1R gene variants and nevus count and the association between age, gender and phenotypical features and nevus count were studied using the Chi-square test. Study of nine frequently occurring MC1R gene variants in participants without skin cancer (n = 203) showed that the 'r' Val60Leu variant was significantly associated with high nevus count (>50 nevi) (P = 0.017). This association was very strong among women (P < 0.001), but not present among men. Having one or two MC1R variants in general did not show a significant difference in the nevus count. Hair colour, skin type, eye colour and age were not significantly associated with nevus count, whereas gender showed a significant association (P = 0.008), with the highest nevus counts in female. The Val60Leu variant of the MC1R gene could be a promising candidate as an independent predictor of high nevus count, particularly in women. This information about the genetic makeup could promote personalized follow-up strategies and might help to prevent skin cancer in the future.

Are we born and do we die without nevi? A cross-sectional study

BACKGROUND

It is well known that the number of nevi varies with age. However, there are a few data in the literature concerning total nevus count at different ages. The aim of this study was to assess and compare the total nevus count among different age groups.

METHODS

The total nevus count was assessed in consecutive patients belonging to nine age groups. Median nevus count was calculated and compared for each age group. Multivariate logistic regression analysis was used to define the influence of sex and phototype on the association between nevus count and age.

RESULTS

We enrolled 900 patients (461, 51.2% females), with a median age of 46 years and a total of 18,136 nevi. Significant differences were found in the median total nevus count among all age groups (P < 0.001), with a significant increase in the first two decades and a significant decrease after the age of 50 years. A similar trend was also observed in subgroups. The differences observed in the total body nevus count among age groups were independent of sex and phototype.

CONCLUSIONS

We demonstrate that the total nevus count significantly increases during childhood and gradually decreases in the elderly.

Estimating Additive Interaction Effect in Stratified Two-Phase Case-Control Design

BACKGROUND AND AIMS

There is considerable interest in epidemiology to estimate an additive interaction effect between two risk factors in case-control studies. An additive interaction is defined as the differential reduction in absolute risk associated with one factor between different levels of the other factor. A stratified two-phase case-control design is commonly used in epidemiology to reduce the cost of assembling covariates. It is crucial to obtain valid estimates of the model parameters by accounting for the underlying stratification scheme to obtain accurate and precise estimates of additive interaction effects. The aim of this paper is to examine the properties of different methods for estimating model parameters and additive interaction effects under a stratified two-phase case-control design.

METHODS

Using simulations, we investigate the properties of three existing methods, namely stratum-specific offset, inverse-probability weighting, and multiple imputation for estimating model parameters and additive interaction effects. We also illustrate these properties using data from two published epidemiology studies.

RESULTS

Simulation studies show that the multiple imputation method performs well when both the true and analysis models are additive (i.e., does not include multiplicative interaction terms) but does not provide a discernible advantage over the offset method when the analysis models are non-additive (i.e., includes multiplicative interaction terms). The offset method exhibits the best overall properties when the analysis model contains multiplicative interaction effects.

CONCLUSION

When estimating additive interaction between risk factors in stratified two-phase case-control studies, we recommend estimating model parameters using multiple imputation when the analysis model is additive, and we recommend the offset method when the analysis model is non-additive.

Cutaneous nevi and risk of melanoma death in women and men: A prospective study

BACKGROUND

It was unclear whether an increased number of common nevi (moles) predicts melanoma death.

OBJECTIVE

We prospectively examined the association between number of common nevi and risk of melanoma death.

METHODS

Our study used data from the Nurses' Health Study (n = 77,288 women) and Health Professionals Follow-up Study (n = 32,455 men). In 1986, participants were asked about the number of moles they had with a ≥3-mm diameter on the upper extremity, and we stratified their answers into 3 categories (none, 1-2, or ≥3) on the basis of data distribution.

RESULTS

During follow-up (1986-2012), 2452 melanoma cases were pathologically confirmed; among these, we identified 196 deaths due to melanoma. Increased number of nevi was associated with melanoma death; the hazard ratio (HR) for ≥3 nevi compared with no nevi was 2.49 (95% confidence interval [CI] 1.50-4.12) for women and 3.97 (95% CI 2.54-6.22) for men. Among melanoma cases, increased number of nevi was associated with melanoma death in men (≥3 nevi, HR 1.89, 95% CI 1.17-3.05) but not in women. Similarly, the number of nevi was positively associated with Breslow thickness in men only (Ptrend = .01).

LIMITATIONS

This is an epidemiologic study without examination into mechanisms.

CONCLUSION

Increased number of cutaneous nevi was significantly associated with melanoma death. High nevus count might serve as an independent prognostic factor to predict the risk of melanoma death particularly among male melanoma patients.

Trajectories of Nevus Development From Age 3 to 16 Years in the Colorado Kids Sun Care Program Cohort

Importance

Nevi are a risk factor for melanoma and other forms of skin cancer, and many of the same factors confer risk for both. Understanding childhood nevus development may provide clues to possible causes and prevention of melanoma.

Objectives

To describe nevus acquisition from the ages of 3 to 16 years among white youths and evaluate variation by sex, Hispanic ethnicity, and body sites that are chronically vs intermittently exposed to the sun.

Design, Setting, and Participants

This annual longitudinal observational cohort study of nevus development was conducted between June 1, 2001, and October 31, 2014, among 1085 Colorado youths. Data analysis was conducted between February 1, 2015, and August 31, 2017.

Main Outcomes and Measures

Total nevus counts on all body sites and on sites chronically and intermittently exposed to the sun separately.

Results

A total of 557 girls and 528 boys (150 [13.8%] Hispanic participants) born in 1998 were included in this study. Median total body nevus counts increased linearly among non-Hispanic white boys and girls between the age of 3 years (boys, 6.31; 95% CI, 5.66-7.03; and girls, 6.61; 95% CI, 5.96-7.33) and the age of 16 years (boys, 81.30; 95% CI, 75.95-87.03; and girls, 77.58; 95% CI, 72.68-82.81). Median total body nevus counts were lower among Hispanic white children (boys aged 16 years, 51.45; 95% CI, 44.01-60.15; and girls aged 16 years, 53.75; 95% CI, 45.40-63.62) compared with non-Hispanic white children, but they followed a largely linear trend that varied by sex. Nevus counts on body sites chronically exposed to the sun increased over time but leveled off by the age of 16 years. Nevus counts on sites intermittently exposed to the sun followed a strong linear pattern through the age of 16 years. Hispanic white boys and girls had similar nevus counts on sites intermittently exposed to the sun through the age of 10 years, but increases thereafter were steeper for girls, with nevus counts surpassing those of boys aged 11 to 16 years.

Conclusions and Relevance

Youths are at risk for nevus development beginning in early childhood and continuing through midadolescence. Patterns of nevus acquisition differ between boys and girls, Hispanic and non-Hispanic white youths, and body sites that are chronically exposed to the sun and body sites that are intermittently exposed to the sun. Exposure to UV light during this period should be reduced, particularly on body sites intermittently exposed to the sun, where nevi accumulate through midadolescence in all children. Increased attention to sun protection appears to be merited for boys, in general, because they accumulated more nevi overall, and for girls, specifically, during the adolescent years.

Factors in Early Adolescence Associated With a Mole-Prone Phenotype in Late Adolescence

Importance

Nevi are important phenotypic risk factors for melanoma in adults. Few studies have examined the constitutional and behavioral factors associated with a mole-prone phenotype in adolescents.

Objective

To identify host, behavioral, and dermoscopic factors in early adolescence (age, 14 years) that are associated with a mole-prone phenotype in late adolescence (age, 17 years).

Design, Setting, and Participants

A prospective observational cohort study from the Study of Nevi in Children was conducted from January 1, 2009, to December 31, 2014, with a 2- to 3-year follow-up. A total of 569 students from the school system in Framingham, Massachusetts, were enrolled in the 8th or 9th grade (baseline; mean [SD] age, 14.4 [0.7] years). The overall retention rate was 73.3%, and 417 students were reassessed in the 11th grade.

Main Outcome and Measures

Mole-prone phenotype in the 11th grade, defined as total nevus count of the back and 1 randomly selected leg in the top decile of the cohort or having any nevi greater than 5 mm in diameter.

Results

Of the 417 students assessed at follow-up in the 11th grade (166 females and 251 males; mean [SD] age, 17.0 [0.4] years), 111 participants (26.6%) demonstrated a mole-prone phenotype: 69 students (62.2%) with 1 nevus greater than 5 mm in diameter, 23 students (20.7%) with total nevus count in the top decile, and 19 students (17.1%) with both characteristics. On multivariate analysis, baseline total nevus count (adjusted odds ratio, 9.08; 95% CI, 4.0-23.7; P < .001) and increased variability of nevus dermoscopic pattern (adjusted odds ratio, 4.24; 95% CI, 1.36-13.25; P = .01) were associated with a mole-prone phenotype.

Conclusions and Relevance

This study found clinically recognizable factors associated with a mole-prone phenotype that may facilitate the identification of individuals at risk for melanoma. These findings could have implications for primary prevention strategies and help target at-risk adolescents for higher-intensity counseling about sun protection and skin self-examination.

Genetic predisposition to melanoma

Malignant melanoma is a rare, often fatal form of skin cancer with a complex multigenic etiology. The incidence of melanoma is increasing at an alarming rate. A number of heritable factors contribute to a patient's overall melanoma risk, including response to ultraviolet light, nevus number, and pigmentation characteristics, such as eye and hair color. Approximately 5%-10% of melanoma cases are familial, yet the majority of familial cases lack identifiable germ-line mutations in known susceptibility genes. Additionally, most familial melanomas lack germ-line mutations in genes that are commonly mutated in sporadic melanoma. Candidate and systematic genome-wide association studies have led to an improved understanding of the risk factors for melanoma and the identification of susceptibility genes. In this review, we provide an overview of the major risk factors and known genes implicated in familial melanoma susceptibility.

The study of nevi in children: Principles learned and implications for melanoma diagnosis

Melanocytic nevi are a strong phenotypic marker of cutaneous melanoma risk. Changes in nevi during childhood and adolescence make these prime periods for studying nevogenesis. Insights gained by the study of nevi in childhood have implications for melanoma detection in both adults and children. A more comprehensive understanding of the morphologic characteristics of nevi in different anatomic locations, in association with the patient's age and pigmentary phenotype may aid in the identification of melanomas. When monitoring melanocytic lesions over time, it is essential to differentiate normal from abnormal change. This review summarizes the rapidly expanding body of literature relevant to nevus phenotype, particularly in the context of our experience with the Study of Nevi in Children (SONIC) Project.

From melanocytes to melanomas

Melanomas on sun-exposed skin are heterogeneous tumours, which can be subtyped on the basis of their cumulative levels of exposure to ultraviolet (UV) radiation. A melanocytic neoplasm can also be staged by how far it has progressed, ranging from a benign neoplasm, such as a naevus, to a malignant neoplasm, such as a metastatic melanoma. Each subtype of melanoma can evolve through distinct evolutionary trajectories, passing through (or sometimes skipping over) various stages of transformation. This Review delineates several of the more common progression trajectories that occur in the patient setting and proposes models for tumour evolution that integrate genetic, histopathological, clinical and biological insights from the melanoma literature.

Cross-sectional analysis of the dermoscopic patterns and structures of melanocytic naevi on the back and legs of adolescents

BACKGROUND

Junctional (flat) naevi predominate on the extremities, whereas dermal (raised) naevi are found primarily on the head, neck and trunk. Few studies have investigated the anatomical site prevalence of melanocytic naevi categorized using dermoscopy.

OBJECTIVES

To identify the prevalence of dermoscopic patterns and structures of naevi from the back and legs of adolescents.

METHODS

Dermoscopic images of acquired melanocytic naevi were obtained from the back and legs of students from a population-based cohort in Framingham, Massachusetts. Naevi were classified into reticular, globular, homogeneous or complex dermoscopic patterns. Multinomial logistic regression modelling assessed the associations between dermoscopic pattern and anatomical location.

RESULTS

In total 509 participants (mean age 14 years) contributed 2320 back naevi and 637 leg naevi. Compared with homogeneous naevi, globular and complex naevi were more commonly observed on the back than the legs [odds ratio (OR) 29·39, 95% confidence interval (CI) 9·53-90·65, P < 0·001 and OR 6·8, 95% CI 2·7-17·14, P < 0·001, respectively], whereas reticular lesions were less likely to be observed on the back than on the legs (OR 0·67, 95% CI 0·54-0·84, P = 0·001). Naevi containing any globules were more prevalent on the back than on the legs (25% vs. 3·6%, P < 0·001). Naevi containing any network were more prevalent on the legs than on the back (56% vs. 40·6%, P < 0·001).

CONCLUSIONS

These findings add to a robust body of literature suggesting that dermoscopically defined globular and reticular naevi represent biologically distinct naevus subsets that differ in histopathological growth pattern, age- and anatomical-site-related prevalence, molecular phenotype and aetiological pathways.

Sunburn, sun exposure, and sun sensitivity in the Study of Nevi in Children

PURPOSE

To examine the joint effect of sun exposure and sunburn on nevus counts (on the natural logarithm scale; log nevi) and the role of sun sensitivity.

METHODS

We describe an analysis of cross-sectional data from 443 children enrolled in the prospective Study of Nevi in Children. To evaluate the joint effect, we partitioned the sum of squares because of interaction between sunburn and sun exposure into orthogonal components representing (1) monotonic increase in log nevi with increasing sun exposure (rate of increase of log nevi depends on sunburn), and (2) nonmonotonic pattern.

RESULTS

In unadjusted analyses, there was a marginally significant monotonic pattern of interaction (P = .08). In adjusted analyses, sun exposure was associated with higher log nevi among those without sunburn (P < .001), but not among those with sunburn (P = .14). Sunburn was independently associated with log nevi (P = .02), even though sun sensitivity explained 29% (95% confidence interval: 2%-56%, P = .04) of its effect. Children with high sun sensitivity and sunburn had more nevi, regardless of sun exposure.

CONCLUSIONS

A program of increasing sun protection in early childhood as a strategy for reducing nevi, when applied to the general population, may not equally benefit everyone.

Genetic factors associated with naevus count and dermoscopic patterns: preliminary results from the Study of Nevi in Children (SONIC)

BACKGROUND

Melanocytic naevi are an important risk factor for melanoma. Naevi with distinct dermoscopic patterns can differ in size, distribution and host pigmentation characteristics.

OBJECTIVES

We examined MC1R and 85 other candidate loci in a cohort of children to test the hypothesis that the development and dermoscopic type of naevi are modulated by genetic variants.

METHODS

Buccal DNAs were obtained from a cohort of 353 fifth graders (mean age 10·4 years). Polymorphisms were chosen based on a known or anticipated role in naevi and melanoma. Associations between single-nucleotide polymorphisms (SNPs) and baseline naevus count were determined by multivariate regression adjusting for sex, race/ethnicity and sun sensitivity. Dermoscopic images were available for 853 naevi from 290 children. Associations between SNPs and dermoscopic patterns were determined by polytomous regression.

RESULTS

Four SNPs were significantly associated with increasing (IRF4) or decreasing (PARP1, CDK6 and PLA2G6) naevus count in multivariate shrinkage analyses with all SNPs included in the model; IRF4 rs12203952 showed the strongest association with log naevus count (relative risk 1·56, P < 0·001). Using homogeneous naevi as the reference, IRF4 rs12203952 and four other SNPs in TERT, CDKN1B, MTAP and PARP1 were associated with either globular or reticular dermoscopic patterns (P < 0·05).

CONCLUSIONS

Our results provide evidence that subsets of naevi defined by dermoscopic patterns differ in their associations with germline genotypes and support the hypothesis that dermoscopically defined subsets of naevi are biologically distinct. These results require confirmation in larger cohorts. If confirmed, these findings will improve the current knowledge of naevogenesis and assist in the identification of individuals with high-risk phenotypes.

Dermatoscopic imaging of skin lesions by high school students: a cross-sectional pilot study

BACKGROUND

The ability of novices to perform imaging of skin lesions is not well studied.

OBJECTIVES

To determine the ability of 12th grade high school students without formal training to take clinical and dermatoscopic images of skin lesions on patient-actors.

PATIENTS/METHODS

Nineteen participants were divided into 11 gender-specific groups of 1-2 students. Groups were provided written instructions and assessed in their ability to (a) identify 8 pre-specified skin lesions, (b) take overview clinical images, and (c) take contact, polarized dermatoscopic images. Groups captured the same images twice using two different cameras [Nikon TM 1 J1 / VEOS HD1 and a VEOS DS3 (Canfield Scientific, Inc.)]. The sequence of camera use was determined using block randomization. If students made visibly poor skin contact during dermatoscopic imaging using their first camera, study investigators provided verbal instructions to place the second camera directly onto the skin. Students completed anonymous surveys before and after the imaging activity.

RESULTS

Students were proficient at identifying the correct pre-specified skin lesions (86/88, 98%), capturing sufficient quality overview clinical images of the back and legs (41/42, 98%), and taking dermatoscopic images of the entire skin lesion (174/176, 99%). Regarding dermatoscopic image quality, 116 of 175 (66%) images were in focus. Out of focus images were attributed to poor skin contact. Groups that received feedback (n=4) were able to obtain a significantly higher proportion of in focus dermatoscopic images using their second camera compared to their first camera (16% to 72%, P<0.001).

CONCLUSIONS

We identified several barriers that exist for participant-acquired dermatoscopic imaging. Instructions emphasizing the importance of skin contact are useful. Our results may help guide future patient-acquired teledermatoscopy efforts.

Tanning and beauty: Mother and teenage daughters in discussion

Tanning increases dramatically through the teenage years, but the family context of this health risk behavior is relatively unstudied. We conducted videotaped conversations between teenage girls (10th and 11th grade) and their mothers. We developed a coding system for discussion content and highlight findings including inadequate knowledge concerning the harms of tanning and positive views of outdoor tanning over indoor tanning, yet agreement that all tans are attractive. Many teens believed that indoor tanning is sometimes necessary to achieve the tanned look. These findings can usefully guide intervention development regarding the harms of all tanning, rather than indoor or outdoor tanning specifically.

Pediatric melanoma, moles, and sun safety

Although pediatric melanoma is a rare disease, diagnosis and management of pigmented lesions in the pediatric population, particularly dysplastic nevi and Spitz nevi, can be challenging. In this article, we provide an overview of pigmented lesions in children, including melanoma and management of melanoma risk factors and melanocytic nevi in the pediatric population. Congenital melanocytic nevi, Spitz nevi, dysplastic and acquired nevi, and changes over time are reviewed. We discuss considerations for excision and management of pigmented lesions in children.

Melanocytic nevi in children of southern Italy: dermoscopic, constitutional, and environmental factors

The objective was to estimate the prevalence of melanocytic nevi (MN) in children and to determine their dermoscopic characteristics and relationship with anatomic location and environmental and constitutional factors. The population was a randomly selected sample of 144 children who attended primary schools in Naples, Italy. Before physical examination of the children, standardized interviews were conducted with their parents. Follow-up interviews of both the children and parents were conducted 1 year later. Photographic and dermoscopic images were obtained. Boys had more MN than girls; 465 MN (55.6%) were observed in boys and 371 (44.4%) in girls (p < 0.05). The trunk and neck were the most common locations of MN (p < 0.001). The main dermoscopic feature of all MN observed was a globular pattern (p < 0.001). A significant correlation between duration of sunbathing and MN counts was revealed (p < 0.05). At 1-year follow-up, 118 new MN were identified in 66 children. The trunk and neck areas were the most common regions involved in the appearance of new MN (n = 68, 57.6% of all new MN, p < 0.001). The new MN count was significantly higher in children who reported more sunbathing (p < 0.001). Changes in the dermoscopic pattern were observed in 45 persistent MN, demonstrating more MN with a reticular-globular pattern, especially on the trunk, neck, and upper extremities (p < 0.001). MN development in early life is the result of complicated relationships between nevus evolution, anatomic location, and environmental and constitutional factors.

Constitutive and relative facultative skin pigmentation among Victorian children including comparison of two visual skin charts for determining constitutive melanin density

Our aim was to examine the association between ethnicity, phenotype, sun behavior and other characteristics, and constitutive and relative facultative skin pigmentation. A total of 191 participants were recruited, with a mean age of 7.6 years (SD 3.4), during 2009-2011 from Maternal and Child Health Centres (MCHC) and schools in Melbourne, Australia. Parental questionnaire data were obtained on sun behavior and examination consisted of noting the child's natural skin, hair and eye color, ethnicity, nevi count and spectrophotometric melanin density (MD). Constitutive skin pigmentation was estimated from buttock MD. Relative facultative skin pigmentation was estimated by hand compared with buttock absorption. Ethnicity, hair color and skin color were associated with constitutive and facultative skin pigmentation on univariate analysis. Higher ambient ultraviolet radiation (UVR) in the past month, greater freckling, greater nevi and increased sun exposure over the past year were related to darker facultative skin pigmentation. Sun exposure over the life course was not. The two skin charts accounted for 39.7% and 21.4% of buttock MD, respectively. Relative facultative skin pigmentation is associated with recent UVR levels, not life-course sun exposure. Relative facultative skin pigmentation may not be a useful measure of sun exposure over the early life course. Skin color charts can be used to assess constitutive skin pigmentation if spectrophotometry is not available.

Sunscreen use and melanocytic nevi in children: a systematic review

We conducted a systematic review of the association between melanocytic nevi (MN) in childhood and sunscreen use. A bibliographic search was conducted between November 2008 and January 2009 using the following key words on MEDLINE and EMBASE: child*, in combination with naevi, nevi, naevus, nevus and sunscreen, sun protection. We also used Medical Subject Headings [sunscreening agents], or [radiation protection] with [nevus, pigmented]. A first screening was done on title and abstract reading. Randomized trials and cohort and cross-sectional studies analyzing the relationship between the use of sunscreen and MN in children were selected. Three reviewers abstracted data from each article. The three sets of results were compared for concordance and rereviewed if necessary. Fifteen articles were included (20,743 children). The studies were not consistent in terms of the ages of the children, MN count methods, or sunscreen use assessment. Owing to this heterogeneity, we were unable to pool the studies and conduct a meta-analysis. Twelve studies did not report that the use of sunscreen had a protective effect against MN development. Three studies reported a lower MN count when sunscreen was applied. This systematic review underlines the methodologic differences between studies. Eight of 15 studies reported a positive association between sunscreen application and MN count. Differences in MN counts, overexposure to sun, and inadequate sunscreen application on fair-skinned children could explain the disparity in the results. There is still no evidence of a protective effect of sunscreen against MN development in children.

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.

Prospective study of sunburn and sun behavior patterns during adolescence

OBJECTIVES

Early childhood UV light radiation (UVR) exposures have been shown to be associated with melanoma development later in life. The objective of this study was to assess sunburn and changes in sunburn and sun behaviors during periadolescence.

METHODS

A prospective, population-based study was conducted in fifth-grade children (∼10 years of age) from Framingham, Massachusetts. Surveys were administered at baseline (September-October 2004) and again 3 years later (September-October 2007). Surveys were analyzed to assess prevalence of reported sunburn and sun behaviors and to examine changes in response over the follow-up period.

RESULTS

Data were analyzed from 360 participants who had complete information regarding sunburn at both time points. In 2004, ∼53% of the students reported having at least 1 sunburn during the previous summer, and this proportion did not significantly change by 2007 (55%, P = .79), whereas liking a tan and spending time outside to get a tan significantly increased (P < .001). In 2004, 50% of students reported "often or always" use of sunscreen when outside for at least 6 hours in the summer; this proportion dropped to 25% at the follow-up evaluation (P < .001).

CONCLUSIONS

With at least 50% of children experiencing sunburns before age 11 and again 3 years later, targeting children in pediatric offices and community settings regarding unprotected UV exposure may be a practical approach. Because periadolescence is a time of volatility with regard to sun behaviors, learning more about children who receive sunburns versus those who avoid them is a critical research task.

Childhood exposure to ultraviolet radiation and harmful skin effects: epidemiological evidence

We review the general amount and patterns of exposure to solar ultraviolet (UV) radiation that children and teenagers experience and the spectrum of UV-related skin damage that can occur as a result. Data about the amount of solar UV received by children and teenagers are relatively few but suggest that around 40-50% of total UV to age 60 occurs before age 20. Among white children, those with the palest complexions suffer the most damage. Comparisons of prevalence and incidence of outcomes in children and teenagers sharing common ancestry, but living at different latitudes, show that prevalence rates of photoaging and melanocytic naevi are higher in Australian compared with British children, and similarly for melanoma. Genetic risk for the majority of the melanomas in teens is a function of genes controlling naevus propensity and pigmentation in the skin. High numbers of naevi and freckles, red hair, blue eyes, inability to tan, as well as a family history are the primary determinants of melanoma among adolescents. Beyond the signs of skin damage seen in children are the latent effects observed later in adulthood. Childhood is believed to be a susceptible window for long-term harmful effects of UV, as evidenced by clear differences in skin cancer risk between child and adult migrants from high to low latitudes. Effective UV radiation protection from childhood is necessary to control both immediate and long-term harmful effects on children's skin.

Prevalence of melanocytic nevi in 8- to 10-year-old children in Southern Spain and analysis of associated factors

BACKGROUND

There is a known relationship between melanocytic nevi (MN) and cutaneous melanoma. MN are related to genetic and environmental factors, and the latter appear to be more important in childhood.

OBJECTIVES

To determine the prevalence of MN and its relationship with phenotypic traits and sun exposure habits in 8- to 10-year-old children.

SUBJECTS AND METHODS

We performed a cross-sectional study of 8- to 10-year-old primary school children in the city of Granada (Spain), gathering data on phenotypic traits, sun protection measures, sunburn frequency and the number and density of MN.

RESULTS

We detected a mean of 19.38 MN per child, predominantly <2 mm in diameter. MN count was associated with low phototype, and was higher in boys vs. girls with low phototype. MN were more numerous with higher age. The largest number of MN of all sizes was detected in 10-year-old boys. MN were most frequently located on the torso and other sites intermittently exposed to sunlight.

CONCLUSIONS

A higher MN count is associated with lower phototype (blonde hair and fair skin) and higher age. The mean number of MN, including those of smaller size (<2 mm), was elevated in our series, especially on intermittently exposed sites.

New insights about infant and toddler skin: implications for sun protection

The skin is increasingly recognized as a component of the innate immune response, in addition to its role as a physical barrier. Although the deleterious effects of solar ultraviolet radiation (UVR), including immunosuppression and cutaneous tumorigenesis, are widely acknowledged, most studies to date have concentrated on adult skin. Despite the more sensitive nature of infant and toddler skin, little is known about its responses to UVR exposure, whether acute or long-term. Accumulating evidence suggests not only that the skin's barrier protection remains immature throughout at least the first 2 years of life but also that accumulation of UVR-induced changes in the skin may begin as early as the first summer of life. Such evidence not only affirms the importance of sun protection during the infant and toddler years but underscores the need for more research to establish evidence-based standards of care in this area. In this article we review recent studies in which differences between the skin properties of infants and young children and those of adults were compared, and we discuss the implications of these differences for sun-protection practices.

Properties of preliminary test estimators and shrinkage estimators for evaluating multiple exposures - Application to questionnaire data from the 'Study of nevi in children' (SONIC) study

Epidemiology studies increasingly examine multiple exposures in relation to disease by selecting the exposures of interest in a thematic manner. For example, sun exposure, sunburn, and sun protection behavior could be themes for an investigation of sun-related exposures. Several studies now use pre-defined linear combinations of the exposures pertaining to the themes to estimate the effects of the individual exposures. Such analyses may improve the precision of the exposure effects, but they can lead to inflated bias and type I errors when the linear combinations are inaccurate. We investigate preliminary test estimators and empirical Bayes type shrinkage estimators as alternative approaches when it is desirable to exploit the thematic choice of exposures, but the accuracy of the pre-defined linear combinations is unknown. We show that the two types of estimator are intimately related under certain assumptions. The shrinkage estimator derived under the assumption of an exchangeable prior distribution gives precise estimates and is robust to misspecifications of the user-defined linear combinations. The precision gains and robustness of the shrinkage estimation approach are illustrated using data from the SONIC study, where the exposures are the individual questionnaire items and the outcome is (log) total back nevus count.

Clinical and dermoscopic stability and volatility of melanocytic nevi in a population-based cohort of children in Framingham school system

Nevi are important risk markers of melanoma. The study aim was to describe changes in nevi of children using longitudinal data from a population-based cohort. Overview back photography and dermoscopic imaging of up to 4 index back nevi was performed at age 11 (baseline) and repeated at age 14 (follow-up). Of 443 children (39% females) imaged at baseline, 366 children (39% females) had repeated imaging three year later. At age 14, median back nevus counts increased by 2; 75% of students (n=274) had at least one new back nevus and 28% (n=103) had at least one nevus that disappeared. Of 936 index nevi imaged dermoscopically at baseline and follow-up, 69% (645 nevi) had retained the same dermoscopic classification from baseline evaluation. Only 4% (n=13) of nevi assessed as globular at baseline were classified as reticular at follow-up, and just 3% (n=3) of baseline reticular nevi were classified as globular at follow-up. Of 9 (1%) index nevi that disappeared at follow-up, none showed halo or regression at baseline. In conclusion, the relative stability of dermoscopic pattern of individual nevi in the face of the overall volatility of nevi during adolescence suggests that specific dermoscopic patterns may represent distinct biologic nevus subsets.

Effect of hair color and sun sensitivity on nevus counts in white children in Colorado

BACKGROUND

It has been widely reported that individuals with a light phenotype (ie, light hair color, light base skin color, and propensity to burn) have more nevi and are at greater risk for developing skin cancer. No studies have systematically investigated how phenotypic traits may interact in relation to nevus development.

OBJECTIVE

We sought to systematically examine whether any combinations of phenotype are associated with a greater or lesser risk for nevus development in white children.

METHODS

In the summer of 2007, 654 children were examined to determine full body nevus counts, skin color by colorimetry, and hair and eye color by comparison with charts. Interviews of parents were conducted to capture sun sensitivity, sun exposure, and sun protection practices.

RESULTS

Among 9-year-old children with sun sensitivity rating type II (painful burn/light tan), those with light hair had lower nevus counts than did those with dark hair (P value for interaction = .03). This relationship was independent of eye color, presence of freckling, sex, usual daily sun exposure, sunburn in 2004 to 2007, sun protection index, and waterside vacation sun exposure. The difference in nevus counts was further determined to be specific to small nevi (<2 mm) and nevi in intermittently exposed body sites.

LIMITATIONS

Geographic and genetic differences in other study populations may produce different results.

CONCLUSION

The standard acceptance that dark phenotype is a marker for low melanoma risk and light phenotype a marker for high risk may need to be reevaluated. In non-Hispanic white children, dark-haired individuals who burn readily and then tan slightly are more prone to nevus development, and may therefore be a previously underrecognized high-risk group for melanoma.

Melanoma epidemiology

Melanoma is a complex, heterogeneous cancer that continues to increase in incidence. Multiple studies have consistently identified major host and environmental risk factors for melanoma. Nevi, particularly dysplastic nevi, confer much higher risks than most pigmentary characteristics. Ultraviolet radiation exposure is the predominant environmental risk factor for melanoma. Recently, both rare high risk susceptibility genes and common polymorphic genes contributing to melanoma risk have been identified.