Case Studies: Health

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The SoDa Service has one set of data for UV in the world. This climatic data set has been used several times in health studies. For instance, they were used in the following scientific publication about multiple sclerosis:

1. S.-M. Orton, PhD, 2. L. Wald, PhD, 3. C. Confavreux, MD, 4. S. Vukusic, PhD, 5. J.P. Krohn, MSc, 6. S.V. Ramagopalan, PhD, 7. B.M. Herrera, PhD, 8. A.D. Sadovnick, PhD and 9. G.C. Ebers, MD, FMedSci, 2010. Association of UV radiation with multiple sclerosis prevalence and sex ratio in France. Published in Neurology, Copyright © 2011 by AAN Enterprises, Inc.

Individual sun exposure can be assessed using meteorological satellite measurements. A study was performed to compare measurements of UVA and UVB exposure of children recorded with personal dosimeters with assessment through a detailed questionnaire and satellite measurements. Methods: 25 families with one index child participated in the study. Participants filled a questionnaire detailing daily activities, geographical location and circumstances of sun exposure. Corresponding satellite measurements of local UVA and UVB irradiation were obtained from the SoDa Service, and namely the database HelioClim. Results: Out of 353 days of sun exposure, 437 episodes were recorded with a dosimeter. Median duration of each session was 2 hours, 62% of exposures occurring between 11 a.m. and 3 p.m. There was a good correlation between measurements from dosimeter and satellite (r=0.48 for UVA; r=0.40 for UVB, Spearman correlation p<0.0001). Dosimeter records tend to underestimate the total exposure measured from the dosimeter (difference per session: 40 Wh/m2 UVA, 1.5 Wh/m2 UVB). The correlation was better for exposure in the sun (r=0.5 and 0.43 for UVA and UVB respectively), on the beach (r=0.57 and 0.42), at the seashore (r=0.64 and 0.40). Multivariate analysis adjusting for weather, exposure duration, horizontal or vertical use of dosimeter, shade, environment and activity showed that satellite measurements were only significantly influenced by the weather. Dosimeter records were essentially influenced by the type of use (81% in UVA and 73% in UVB decrease of measure when dosimeter was worn on the belt), exposures in the shade (54% decrease for both UVA and UVB), environment (60% decrease for UVA and 34% for UVB for exposure in the country side). When adjusting for all variables, there was a significant independent correlation between dosimeter and satellite measurements (p<0.0001 for UVA and UVB). Conclusion: Satellite measurements give a good estimate of individual UVA and UVB exposure, independently of exposure conditions and could be used to estimate actual exposure. Poster P-113 presented at The 6th World Congress on Melanoma, Sept 6-10 2005, Vancouver, BC, Canada. Authors: M. Boniol (IARC, Lyon, France), MS. Cattaruzza* (Dept of Public Health, “La Sapienza” University, Rome, Italy), L. Wald (Ecole des Mines de Paris, Sophia Antipolis, France), MA. Richard (Dermatologie, Hopital Ste Marguerite, Marseille, France), MT. Leccia (Dermatologie, CHU Grenoble, France), F. Truchetet (Dermatologie, Thionville, France), C. Renoirte (Institut Jules Bordet, Brussels, Belgium), P. Vereecken (Dermatologie, Hopital Erasme, Brussels, Belgium), P. Autier (Institut Jules Bordet, Brussels, Belgium), JF. Doré (INSERM U590 Lyon, France). Date: September 2005.

Matthieu Boniol, from IARC (International Agency for Research on Cancer), an institute of the World Health Organisation (WHO), and his co-workers, from the French research institute INSERM UMR 453, are comparing UV radiation data delivered by the SoDa Service to outputs from digital dosimeters that have been brought all day long by volunteers during their summer vacations. The study evidences the relationship between skin cancer, sun bathing habits, social parameters and typology of individuals. Date: January 2005.

UK researchers from the University of Southampton, Royal London Hospital and Princess Anne Hospital Study Group, have studied the insufficiency of vitamin D in women of childbearing age. There is increasing evidence that the risk of osteoporotic fracture in later life may be determined, in part, by environmental influences during intrauterine and early postnatal growth. By studying a cohort of children, from birth to age of nine and their mothers during pregnancy, and by using UV data delivered by the SoDa Service, these researchers have found that maternal vitamin D insuffiency is common during pregnancy and is associated with reduced skeletal growth of the offspring during childhood; this relationship is mediated in part through umbilical venous calcium concentration. Vitamin D supplementation of pregnant women, especially during winter months, may lead to long-lasting reductions in the risk of osteoporotic fracture among their offspring. More on this story at the MRC Environmental Epidemiology Unit web site.  Reference: Javaid MK, Crozier SR, Harvey NC, Dennison EM, Boucher BJ, Arden NK, Godfrey KM, Cooper C, and the Princess Anne Hospital Study Group, 2005, Maternal vitamin D status during pregnancy and childhood bone mass at age nine years: A longitudinal observational study. To be submitted. Date: January 2005.