Risk Factors for Malignant Melanoma and Preventive Methods

Biological Model

Eye color and Fitzpatrick skin type were the focus of the biological model. The odds of being diagnosed with melanoma were 2.5 times greater in respondents with a light eye color (ie, blue, green, gray) than in respondents with a dark eye color (ie, brown, black). Respondents with Fitzpatrick skin types I and II had a significantly higher association with melanoma (OR, 4.25 and 6.98; 95% CI, 2.13-8.51 and 3.78-12.88) than Fitzpatrick skin type III (OR, 1.0)(P<.001 for both). Respondents with darker skin types (IV and V) also were present in our study population. The numbers were low, and the CI was too wide; nevertheless, the results were statistically significant (P<.001).

Lifestyle Model

The lifestyle model included patients’ use of sunscreen and level of sun exposure at work and on vacation. Respondents who did not use sunscreen were 12 times more likely to develop melanoma than those who always used it (95% CI, 5.56-27.14); however, individuals who used sunscreen always and repetitively (ie, more than once during 1 period of sun exposure) had a higher likelihood of melanoma compared to those who always used it. The incidence of melanoma was lower in respondents who regularly spent their vacations by the sea than those who did not vacation in seaside regions. Respondents who worked in direct sunlight were approximately 2 times more likely to present with melanoma than individuals who did not work outside.

Exposure Model

The number of sunburns sustained during childhood and adolescence was assessed in the exposure model. Respondents with a history of 1 to 5 sunburns during childhood and adolescence did not show a statistically significant increase in the incidence of melanoma diagnosis; however, those with a history of 6 or more sunburns during these periods showed a significant increase in the odds of developing melanoma (OR, 4.95 and 25.52; 95% CI, 2.29-10.71 and 12.16-53.54)(P<.001 for both).