Early life ambient ultraviolet B (UVB) exposure, as measured by satellite imagery, was not significantly associated with the age at multiple sclerosis (MS) onset, according to a recent study in which researchers used satellite data to measure ambient UVB exposure. Adult onset MS patients were selected from an MS genetic database (1980–2005). Patients’ places of residence from birth to age 18 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 and age at MS onset. 3,226 patients were included in the analysis (74% female, with an overall mean symptom onset age of 33.3 years). Researchers found:

• At onset, a total of 2,944 (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.