Ultraviolet radiation exposure of children and adolescents in Durban, South Africa

Photochemistry and Photobiology, Mar 2003 by Guy, Caradee, Diab, Roseanne, Martincigh, Bice

CONCLUSIONS

In the light of skin cancer statistics in South Africa and the importance of early childhood UVR exposure, it was considered important to measure the UVR dose of children and adolescents. This study was conducted in the city of Durban for a 1 week period in summer for three age groups of children and adolescents (4-6 years, 69 years and 13-14 years). This study is believed to be the first of its kind in South Africa.

UVR-sensitive PSF was used to provide a measure of UVR dose in accordance with studies done elsewhere in England and Australia. Participants kept daily journals describing their activities, which provided some insight into the role of behavior patterns in determining UVR dose.

The mean and median PSFB doses for all ages over the study period were 2.1 and 1.2 SED units, respectively. No significant statistical differences were found between PSFB doses as a function of age, although it was noted that males generally received higher UVR doses than females.

The variability in individual PSFB doses was found to be dependent on the nature of activities in which an individual was engaged. This was reflected in the differences in PSFB doses on weekdays when compared with weekends. Most of the activities on days with highest PSFB dose were related to swimming or beach activities.

On average, subjects received a UVR dose of 4.6% of the ambient daily erythemal UVR. This factor was used to estimate the potential dose of an individual over the full annual cycle. This estimate assumes that the subject's outdoor behavior patterns remained relatively unchanged throughout the year. Based on the dose in joules per square meter required to induce minimal, marked and painful erythema for different skin types as suggested by B. L. Diffey (personal communication), it was estimated that there are 139 days in a typical year when individuals with skin type I are likely to experience minimal erythema and 97 and 32 days for individuals with skin types II and III, respectively.

Individual UVR dose was found to be largely dependent on the activity of the individual, although it is expected that random human movement and variation in the orientation of the anatomic site toward the direct solar beam will influence the PSFB dose. Future work will focus on quantifying this relationship.

Acknowledgements-We acknowledge the National Research Foundation and CANSA for funding, Prof. Brian Diffey for comments on the calibration curve, Dr. Greg Bodeker for helpful discussion and data, Dr. Glenda Matthews for assistance with statistical analyses, Dr. Arnold Prause for provision of the UVR data and the anonymous reviewers for their constructive comments.

REFERENCES

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2. Kalicharran, S., R. D. Diab and F. Sokolic (1993) Trends in total ozone over southern African stations between 1979 and 1991. Geophys. Res. Lett. 20(2), 2877-2880.