Sex differences in numbers of nevi on body sites of young European children: implications for the etiology of cutaneous melanoma
ABSTRACT Since 1950, the greatest increase in cutaneous melanoma incidence in fair-skinned males took place on the trunk and on the head and neck, whereas in females, it took place on the limbs, mainly on the lower limbs. We examined the influence of sex on numbers and size of nevi on different body sites in white European schoolchildren.
Information about each holiday period since birth to interview was recorded from parents of six hundred twenty-eight 6- to 7-year-old children in four European cities (Brussels (Belgium), Bochum (Germany), Lyons (France), and Rome (Italy)). Number and anatomic location of small (2-4.9 mm) and large (>/=5 mm) nevi and individual susceptibility to sunlight were independently assessed.
After adjustment for host characteristics, sun exposure, and sun protection habits, males had 7% [95% confidence interval (95% CI), -7 to 19] more small nevi than females. However, compared to females, numbers of small nevi were increased by 17% (95% CI, 1-31) on the head and neck and by 16% (95% CI, 2-27) on the trunk and shoulders. In contrast, in males, the number of small nevi on upper limbs was decreased by -5% (95% CI, -26 to 13), and on lower limbs by -8% (95% CI, -34 to 13). The number of large nevi was 6% higher in males than in females (95% CI, -26 to 30).
The sex differences in small nevus distribution in schoolchildren reflect the sex differences in the anatomic distribution of melanoma in adults. Sex differences in sun exposure behaviors, dressing, and clothing would just add their effects to the sex-dependent inherited propensity to develop nevi on a given body site. These results reinforce the hypothesis by which childhood would be a decisive period for the occurrence of sun-induced biological events implicated in the genesis of cutaneous melanoma.
- SourceAvailable from: Mehmet Tevfik Dorak
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- "Our results show a far higher incidence of melanomas in young adult females than similar males and a strikingly high annual rate of increase in incidence of around 5% in females aged 15–24 years. Considering number of nevi as the best predictor of melanoma occurrence , previous studies of European schoolchildren have shown males to have a higher count of small nevi than females . However, our results show a female excess in melanoma. "
ABSTRACT: This study examined sex-specific patterns and temporal trends in the incidence of solid tumours in the Northern Region of England from 1968 to 2005. This updates earlier analyses from the region where sex was not considered in depth. Sex-specific analyses were carried out to determine whether sex differences might provide clues to aetiology. Details of 3576 cases, aged 0-24 years, were obtained from a specialist population-based cancer registry. There were 1843 males (886 aged 0-14 years and 957 aged 15-24 years) and 1733 females (791 aged 0-14 years and 942 aged 15-24 years). Age-standardized incidence rates (per million population) were calculated. Linear regression was used to analyze temporal trends in incidence and annual percentage changes were estimated. Analyses were stratified by sex and by age-group. There were marked differences in incidence patterns and trends between males and females and also between age-groups. For males central nervous system (CNS) tumours formed the largest proportion of under-15 cases and germ cell tumours was the largest group in the 15-24's, whilst for females CNS tumours dominated in the under-15's and carcinomas in the older group. For 0-14 year olds there were male-specific increases in the incidence of rhabdomyosarcoma (2.4% per annum; 95% CI: 0.2%-4.5%) and non-melanotic skin cancer (9.6%; 95% CI: 0.0%-19.2%) and female-specific increases for sympathetic nervous system tumours (2.2%; 95% CI: 0.4%-3.9%), gonadal germ cell tumours (8.6%; 95% CI: 4.3%-12.9%) and non-gonadal germ cell tumours (5.4%; 95% CI: 2.8%-7.9%). For 15-24 year olds, there were male-specific increases in gonadal germ cell tumours (1.9%; 95% CI: 0.3%-3.4%), non-gonadal germ cell tumours (4.4%; 95% CI: 1.1%-7.7%) and non-melanotic skin cancer (4.7%; 95% CI: 0.5%-8.9%) and female-specific increases for osteosarcoma (3.5%; 95% CI: 0.5%-6.5%), thyroid cancer (2.8%; 95% CI: 0.1%-5.6%) and melanoma (4.6%; 95% CI: 2.2%-7.1%). This study has highlighted notable differences between the sexes in incidence patterns and trends for solid tumours. Some of these sex-specific differences could have been obscured if males and females had been analysed together. Furthermore, they suggest aetiological differences or differential susceptibility to environmental factors between males and females.BMC Cancer 02/2008; 8:89. DOI:10.1186/1471-2407-8-89 · 3.36 Impact Factor
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- "Mathematically, a single mutation can be at the base of the formation of melanocytic nevi, with a probability of mutation per cell per mitosis between 10 -9 and 10 -7 . The number and size of nevi during lifetime is not definitely and with certainty established, but roughly their number increase during the two first decades, reaching the maximum during the second and third decade, and after that their number diminishes          . "
ABSTRACT: Melanocytic nevi (moles) are common, and can be found anywhere on the skin. Their number has been shown to be associated with a greater risk of cutaneous melanoma. Also, the knowledge of their natural evolution is important in the understanding of the development of melanoma. The aim of this study was to incorporate available knowledge about melanocytic proliferation and the role of immune system and to create a simulation model which will be able to explain the changes in number of melanocytic nevi during lifetime and to elucidate the importance of the immune system in their formation and regression (i.e. eruptive benign melanocytic nevi). The results were presented graphically and visually analyzed. Because of the great number of possible numerical solutions only approximately results that satisfy some basic criteria were take into account. A created system dynamics model proved to be able to simulate the appearance and disappearance of melanocytic nevi during lifetime and the eruption of nevi after immunosuppression in a way that mimics their changes reported in epidemiological studies. There are limitations in model assumptions due to many uncertainties regarding model parameters and thus much more detailed epidemiological data would be required for the creation of a more reliable model. Jadranka Božikov graduated in Mathematics and earned MSc and PhD degree in field of Biomedicine and Health Sciences at Zagreb University. Since 1978 she works in Department for Medical Statistics, Epidemiology and Medical Informatics at Andrija Štampar School of Public Health, Medical School, University of Zagreb, currently as associated professor. She introduced simulation modeling methods and applications as teaching subject for medical students and graduates and supervised several MSc theses obtained by young researchers who employed system dynamics approach and continuous simulation techniques in their investigation of the phenomena in medicine and public health. URL: www.snz.hr/~jbozikov.