# Presentation: 275162

## Sun Exposure Measurement in Populations

**Sun Exposure Measurement in Populations**

**Margaret A. Tucker, M.D. and Thomas R. Fears, Ph.D**
**Division of Cancer Epidemiology and Genetics**
**May 7, 2007**

## UV Exposure in Populations

**Dominant source is sunlight**
**For subpopulations, other exposures contribute substantially**
**Primary endpoint usually skin dose**
**Almost universal daily exposure**
**Cannot separate UVA/UVB**
**“****Geographic” estimates**
**Personal estimates**

## “Geographic” Measurements

**Latitude**
**Altitude**
**Day of year**
**Time of day**
**Cloud cover**
**Ozone**
**Particulates**
**Smog**
**Reflectance**

## On Ground Measurements

**Robertson-Berger meters-NOAA/NCI**
**UBV only**
**Multiple sites in areas of cancer registries**
**In place for decades**
**Questions about QC**
**Instruments compared every year to standard**
**Multispectral meters**
**NOAA 5 global monitoring observatories**
**USDA 34 stations in 29 states**
**Mostly rural**
**Started in mid 1990’s**

## Satellite Measurements

**NASA TOMS system**
**Global coverage**
**Theoretical estimate of ground UV**
**Comparison with on ground measures**
**Agreement within 12% overall **
**Better (8%) with clear skies**
**Aerosols contribute about 5% (based on measurements in Billings OK and Las Cruces NM)**

## Personal Measurements of Current Exposure 

**Polysulphone badges**
**UVB**
**Calibrated to erythemal doses**
**Measures total dose over specified period**
**Relatively inexpensive**
**Dosimeters**
**Vary in spectra**
**Continuous or intermittent monitoring**
**Small; handheld or attachable**
**Expensive**

## Personal Estimate of Historical UV Exposure 

**Complex to capture by questionnaire**
**Average over long periods of time of routine activities**
**Subject to recall bias**
**Imprecise**
**Varies by behavioral patterns**
**Varies by host factors**

## Slide 8

## Frequently Assessed Personal Sun Exposure Variables

**Number of sunburns**
**Hours outdoors**
**Time of day**
**Time of year**
**Age at exposure**
**Use of sun protective measures**
**Patterns of exposure **
**Occupational history**
**Residence history**

## Estimated five year melanoma incidence rates by region of the U.S.

## Relative 3,5 Yr Survival for Women (L) and Men (R) by UVB Flux

- Fears TR and Tucker MA, J Nat’l Cancer Inst 97:1789-90, 2005

## Melanoma Case-Control Study

**Hospital-based; U Penn and UCSF**
**738 newly diagnosed invasive melanoma**
**1024 outpatient clinic controls **
**clinics with same triage area **
**matched on age, gender, race, geography**
**Data collection**
**In-person interview**
**Full skin exam with nevus characterization**
**Photography of back and 3 most atypical nevi; optional nevus biopsy**
**Self-administered diet questionnaire**

## Residence History

**History of residence locations reconstructed in 6 month intervals**
**Each residence location assigned estimate of incident UVB at ground level (UVB flux)**
**13% of subjects had stable residence**

**Fears TR et al., Cancer Res 2002;62:3992-6**

## Average interval UVB flux in both sexes by age, case-control status for San Francisco

**cases**

**controls**

## Hours Outdoors

**Estimate of hours outdoors for each six**
**month interval of each residence using:**
**Occupational sunlight exposure history**
**Non-occupational sunlight exposure for specified ages**

## Mean interval hours outdoors plotted against age level for controls by gender

**Males**

**Females**

## Mean interval hours outdoors against age level by case-control status for men 

**cases**

**controls**

## Melanoma Risk Associated with 10% Increase in Exposure

| Exposure | Men | Women |
| --- | --- | --- |
| UVB Flux | 1.19 | 1.16 |
| Hrs out age 0-19 | 0.99 | 0.99 |
| Hrs out age 20+ | 1.03 | Tan  1.06 |
|  |  |  |

## Average Annual Hours Outdoors by Gender and Tan Type in Controls

## Use of Sunbeds

**Studies varied in design**
**Use varies by gender in adolescence**
**Higher at older ages**
**Males 1-35% **
**Females 14-75%**
**Most robust studies**
**Sweden 19% males; 40% females**
**US 11% males; 37% females**

**Lazovich D, Forster J. Eur J Cancer 2005; 41:20-27**

## Risk of Melanoma With Artificial UV

| Exposure | # Studies | Summary OR |  95% CI |
| --- | --- | --- | --- |
| Ever/Never |      10 |       1.25 | 1.05-1.49 |
| Young adult
1st expos |        5 |       1.69 | 1.32-2.18 |
| Highest freq
exposure |        6 |       1.61 | 1.21-2.12 |

- Gallager RP et al. Cancer Epidemiol Biomarkers Prev 2005;14:562-6

## Additional Issues

**Most measures developed for assessing risk of skin cancer**
**Action spectrum for skin cancers not definitive**
**Relationship between site of exposure and site of disease complex**
**Intermittent versus chronic exposure**
**Measures have not been well validated with measures of vitamin D**

## Conclusions

**UV exposure, either sun or artificial, is important in melanoma risk**
**Cannot establish action spectrum for humans; exposures always mixed**
**Patterns of behavior vary by gender, skin type, age, and other factors**
**Age at exposure is not a simple metric; adult exposure contributes to risk**
**Need to have very clear public health messages about UV exposure**

## Collaborators

**Thomas Fears**
**DuPont Guerry IV**
**David Elder**
**Allan Halpern**
**Richard Sagebiel**
**Wallace Clark**
**Elizabeth Holly**
**Patricia Hartge**

## Use of Indoor Tanning

| Yr Survey | Location | Number |     Boys |    Girls |
| --- | --- | --- | --- | --- |
| 1989 | VA |         96 |        16 |      33 |
| 1990 | IL |     1703 |          7 |      19 |
| 1991 | MN |     1008 |        15 |      51 |
| 1992 | Norway |   15169 |        35 |      75 |
| 1993 | Sweden |     1252 |        32 |      68 |
| 1994 | IL |       658 |          1 |      16 |
| 1996 | Sweden |     2615 |          4 |      16 |
| 1996 | US |     6903 |        11 |      37 |
| 1998 | US |     1192 |          5 |      16 |
| 1999 | Sweden |     4060 |        19 |      40 |
| 1999 | US |   10079 |          2 |      14 |
| 2000 | MN & MA |     1273 |        12 |      42 |

**Lazovich d, Forster J. Eur J Cancer 2005; 41:20-27**