Association between cutaneous melanoma incidence rates among white US residents and county-level estimates of solar ultraviolet exposure.
BACKGROUND
Recent US studies have raised questions as to whether geographic differences in cutaneous melanoma incidence rates are associated with differences in solar ultraviolet (UV) exposure.


OBJECTIVE
We sought to assess the association of solar UV exposure with melanoma incidence rates among US non-Hispanic whites.


METHODS
We assessed the association between county-level estimates of average annual solar UV exposure for 1961 to 1990 and county-level melanoma incidence rates during 2004 to 2006. We used Poisson multilevel mixed models to calculate incidence density ratios by cancer stage at diagnosis while controlling for individuals' age and sex and for county-level estimates of solar UV exposure, socioeconomic status, and physician density.


RESULTS
Age-adjusted rates of early- and late-stage melanoma were both significantly higher in high solar UV counties than in low solar UV counties. Rates of late-stage melanoma incidence were generally higher among men, but younger women had a higher rate of early-stage melanoma than their male counterparts. Adjusted rates of early-stage melanoma were significantly higher in high solar UV exposure counties among men aged 35 years or older and women aged 65 years or older.


CONCLUSIONS
The relationship between individual-level UV exposure and risk for melanoma was not evaluated.


CONCLUSIONS
County-level solar UV exposure was associated with the incidence of early-stage melanoma among older US adults but not among younger US adults. Additional studies are needed to determine whether exposure to artificial sources of UV exposure or other factors might be mitigating the relationship between solar UV exposure and risk for melanoma.
Division of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3717, USA. TRichards@cdc.gov
Thomas B
TB
Richards
Christopher J
CJ
Johnson
Zaria
Z
Tatalovich
Myles
M
Cockburn
Melody J
MJ
Eide
Kevin A
KA
Henry
Sue-Min
SM
Lai
Sai S
SS
Cherala
Youjie
Y
Huang
Umed A
UA
Ajani
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D004781:Environmental Exposure / Q000009:adverse effects / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008545:Melanoma / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D008875:Middle Aged; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D013472:Sunlight / Q000009:adverse effects; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult