1,721,086 research outputs found
Assessment of solar UV exposure in the Italian population
Full text linkSolar ultraviolet radiation (UVR) has influenced the evolution
of life on earth and likely caused the development of different skin
pigmentation in humans: those inhabiting low latitudes, with high
UVR intensity, have darker skin pigmentation for protection from
the deleterious effects of UVR, while those in higher latitudes
have developed fair skin to maximize vitamin D production from
much lower ambient UVR. In the last centuries, however, there has been an increase in
human migration from its original areas and human skin
pigmentation is no longer necessarily suited to the environment
where it lives. Dark-skinned populations at low latitudes have
very low incidence of melanoma skin cancer (MSC) and non
melanoma skin cancer (NMSC, such as squamous cell carcinoma,
SCC, and basal cell carcinoma, BCC) but their migration to high
latitudes has seen an increase in the incidence of rickets and
osteomalacia; meanwhile, fair-skinned populations who have
migrated to low latitudes have experienced a rapid rise in the
incidence of MSC and NMSC. Furthermore, changes in habits and
attitudes have meant that many people all over the globe are now
exposed to more, or less, UVR than ever before.
In addition, the documented stratospheric ozone downward
trend due to chlorofluorocarbons (CFCs) has been associated with
an increase of solar ultraviolet radiation B (UVB) at the earth’s
surface, even though UVR changes are also associated with
fluctuations in cloud cover and atmospheric pollution. If ambient
UVR increases, in the absence of changes in personal attitudes
and sun protection, there will be an increase in health diseases due
to excessive UVR exposure. The only positive human benefit from a moderate degree of
solar UVR exposure is the production of vitamin D required for
skeletal health. Recently, there has been a debate within the
scientific community regarding the health duality of UVR.
Various articles have suggested that low vitamin D can be
considered a risk factor for breast, prostate and colon cancers. Kimlin’s research group (Australia) is currently focusing on the
positive and negative effects of UVR on human health in order to
quantify the correct exposure of populations. For such reasons,
evaluation of the personal solar UVR doses on different body
parts and the search for related easy to measure biological
indicators can be helpful in the study of the best levels of
exposure and the understanding of what is still unknown. The purpose of this study was to suggest and test a
methodology for the measuring of personal solar UVR doses and
search for possible biological indicators of its effects. We chose
polysulphone (PS) dosimetry as the main investigative
methodology. Several field experiments were performed, five of
them with groups of volunteers (in vivo) selected among the
Italian population (schoolchildren, sun bathers, vineyard growers,
skiers and hikers), presented and discussed here.
The main result was the data collection of personal UVR
exposures, added to the global dataset as Exposure Ratio (ER)
between the erythemally weighed dose measured by the PS
dosimeter and the corresponding ambient dose on a horizontal
plane measured by a radiometer. Mean (median) values of ER on the chest for schoolchildren,
sun bathers and hikers were respectively 0.07 (0.07), 0.19 (0.19)
and 0.11 (0.07). Since the schoolchildren ER turned out to be the
lowest, we asked whether the dose allowed a sufficient production
of vitamin D, discovering that some children of the sample
showed inadequate modalities of exposure (probably recovered
during the summer months). The study on sun bathers, decided so
as to supply indications on the relationship between the absorbed
doses and the development of the photodermatoses, evidenced that
the latter were not linked to high values of Exposure Ratio but
they rather depended on the genetic characteristics of the
individuals, which probably reacted to the exposure not through
the production of melanin but with an increase in the dilation of
blood vessels, leading to skin reddening.
ER on the forehead for skiers and hikers showed an average
value of 1.01 (1.03) and 0.27 (0.24) respectively, with the difference due to snow albedo. The study on vineyard growers,
carried out in three different seasons (spring, summer and
autumn), supplied an average value of 0.71 (0.69) for the nape and
of 0.46 (0.42) for the arm, with an elevated variability due to the
different atmospheric conditions and to the different duties
between one season and another.
The study also proposed a methodology combining the use of
colorimetric parameters, skin temperature and additional
information (such as the amount of free radicals in the skin) that
were collected during the experiments. All data were analyzed by
means of well known statistical multivariate approaches, namely
PCA (Principal Component Analysis) and Cluster Analysis, useful
when variables are not only correlated but also numerous. Finally,
to interpret the results, an empirical model for the estimation of
short and long term doses was proposed
- …
