title: Prediction of high naevus count in a healthy U.K. population to estimate melanoma risk.
abstract: BACKGROUND
  Despite recent discoveries of germline and somatic mutations in melanoma, naevus count remains the most important risk factor for melanoma. Counting naevi on the whole body is time consuming. In order to identify patients at risk for melanoma, many studies have used naevus count on selected body sites as a proxy for total body naevus count (TBNC).
  
  
  OBJECTIVE
  The main aim of this study was to assess the predictive value of naevus count on 17 different body sites in estimating TBNC in a large cohort of healthy U.K. Caucasian female subjects. Once the site with the best predictive value for TBNC was determined, a second aim was to estimate the cut-off values of naevus counts at this anatomical site that best predict the presence of 50 or 100 naevi, respectively.
  
  
  METHODS
  The most predictive body site for TBNC was assessed in a cohort of healthy female twins. This finding was replicated on a control group from a U.K. case-control study and a prediction model was performed afterwards. The area under the receiver operating characteristics curve was used to evaluate the best cut-off for the prediction of having a TBNC of more than 50 or 100.
  
  
  RESULTS
  There were 3694 female twins included. The TBNC showed a steady decline after the age of 30 years (P < 0·001). The most predictive sites for TBNC were the arms and legs: the adjusted correlation coefficients were 0·50 and 0·51 (P < 0·001) for the right and left arm, respectively, and 0·49 and 0·48 for the right and left legs, respectively (P < 0·001). The arm remained the most predictive site for TBNC when replicated in a control population including both sexes. In the twin study, women with more than 11 naevi on the right arm were approximately nine times more likely to have more than 100 naevi (odds ratio = 9·38, 95% confidence interval 6·71-13·11).
  
  
  CONCLUSIONS
  The ability to estimate TBNC quickly by counting naevi on one arm could be a very useful tool in assessing melanoma risk in primary care.
authors.affiliation: Department of Twin Research and Genetic Epidemiology, King's College London, St Thomas' Campus, Westminster Bridge Road, London, SE1 7EH, U.K.|Section of Dermatology, Department of Medical Sciences, University of Turin, Torino, Italy.|Imperial College London, London, U.K.|Department of Dermatology, London North West Healthcare NHS Trust, London, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Ribero
authors.affiliation: Unit of Cancer Epidemiology - CERMS, Department of Medical Sciences, University of Turin, Torino, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Zugna
authors.affiliation: Section of Dermatology, Department of Medical Sciences, University of Turin, Torino, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Osella-Abate
authors.affiliation: Department of Twin Research and Genetic Epidemiology, King's College London, St Thomas' Campus, Westminster Bridge Road, London, SE1 7EH, U.K.|Imperial College London, London, U.K.|Department of Dermatology, London North West Healthcare NHS Trust, London, U.K.
authors.forename: D
authors.initials: D
authors.lastname: Glass
authors.affiliation: Mount Vernon Cancer Network, West Herts NHS Trust, Herts, U.K.
authors.forename: P
authors.initials: P
authors.lastname: Nathan
authors.affiliation: Department of Twin Research and Genetic Epidemiology, King's College London, St Thomas' Campus, Westminster Bridge Road, London, SE1 7EH, U.K.
authors.forename: T
authors.initials: T
authors.lastname: Spector
authors.affiliation: Department of Twin Research and Genetic Epidemiology, King's College London, St Thomas' Campus, Westminster Bridge Road, London, SE1 7EH, U.K.|Department of Dermatology, West Herts NHS Trust, Herts, U.K.
authors.forename: V
authors.initials: V
authors.lastname: Bataille
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001132:Arm; D002648:Child; D002675:Child, Preschool; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007866:Leg; D008297:Male; D008545:Melanoma / Q000453:epidemiology* / Q000473:pathology; D008875:Middle Aged; D009506:Nevus / Q000453:epidemiology* / Q000473:pathology; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000473:pathology; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult