The use of satellite data to measure ultraviolet-B penetrance and its potential association with age of multiple sclerosis onset.

BACKGROUND

Studies have indicated an association between low Ultraviolet B (UVB) exposure and an increased risk of developing multiple sclerosis (MS). Few studies, however, have explored whether UVB exposure is associated with the age at MS symptom onset.

OBJECTIVE

We investigated the potential association between cumulative early life ambient UVB exposure and age at MS onset, using satellite data to measure ambient UVB exposure.

METHODS

Adult onset MS patients were selected from the University of British Columbia's MS genetic database (1980-2005). Patients' places of residence from birth to age 18 years were geocoded (latitude and longitude) and assigned UVB values using NASA's Total Ozone Mapping Spectrometer (TOMS) dataset. Linear regression was used to explore the relationship between cumulative UVB exposure (measured for age periods 0-6, 7-12, 13-18, 0-12, and 0-18) and age at MS onset.

RESULTS

3226 patients were included in the analysis. Of these, 74% were female, with an overall mean symptom onset age of 33.3 years. At onset, a total of 2944 (91%) had a relapsing-remitting disease course, 254 (8%) had primary progressive and the disease course for 28 (1%) was unknown. No significant associations between cumulative early life ambient UVB exposure and age at MS onset were observed. Patient sex, MS phenotype, and immigration to Canada after age 18 were significantly associated with age of onset (p < 0.01).

CONCLUSIONS

Early life ambient UVB, as measured by satellite imagery, was not significantly associated with the age at MS onset.