Further evidence for population specific differences in the effect of DNA markers and gender on eye colour prediction in forensics.

The genetics of eye colour has been extensively studied over the past few years, and the identified polymorphisms have been applied with marked success in the field of Forensic DNA Phenotyping. A picture that arises from evaluation of the currently available eye colour prediction markers shows that only the analysis of HERC2-OCA2 complex has similar effectiveness in different populations, while the predictive potential of other loci may vary significantly. Moreover, the role of gender in the explanation of human eye colour variation should not be neglected in some populations. In the present study, we re-investigated the data for 1020 Polish individuals and using neural networks and logistic regression methods explored predictive capacity of IrisPlex SNPs and gender in this population sample. In general, neural networks provided higher prediction accuracy comparing to logistic regression (AUC increase by 0.02-0.06). Four out of six IrisPlex SNPs were associated with eye colour in the studied population. HERC2 rs12913832, OCA2 rs1800407 and SLC24A4 rs12896399 were found to be the most important eye colour predictors (p < 0.007) while the effect of rs16891982 in SLC45A2 was less significant. Gender was found to be significantly associated with eye colour with males having ~1.5 higher odds for blue eye colour comparing to females (p = 0.002) and was ranked as the third most important factor in blue/non-blue eye colour determination. However, the implementation of gender into the developed prediction models had marginal and ambiguous impact on the overall accuracy of prediction confirming that the effect of gender on eye colour in this population is small. Our study indicated the advantage of neural networks in prediction modeling in forensics and provided additional evidence for population specific differences in the predictive importance of the IrisPlex SNPs and gender.

Epidemiology and chronobiology of out-of-hospital cardiac arrest in a subpopulation of southern Poland: A two-year observation.

BACKGROUND: Although recent studies indicate temporal variations in the incidence of out-of-hospital cardiac arrest (OHCA), the Polish experience in this research is scarce to date. We evaluated the epidemiology of OHCA and circadian, weekly and seasonal variations of OHCA frequency among the adult population of the Opole district, Poland. METHODS: The retrospective analysis of 815 OHCA cases with presumed cardiac etiology was made based on dispatch cards from the Emergency Medical Center in Opole registered during a 2 year period (2006-2007). RESULTS: The incidence of OHCA in the studied population was 1.56/1000 inhabitants per year. Mean age of the group was 69.2 ± 14.2 years, with the majority of men (63%), younger than women (66.1 vs. 74 years, p = 0.0001). The OHCA occurrence increased with age reaching a peak between 71 and 75 years. The incidence of OHCA stayed at stable low levels between 22:00 and 4:59 and started to increase at 5:00, with trimodal peaks: 8:00-10:59, 14:00-15:59 and 18.00-21.59. The lowest number of OHCA occurred from 00:00 to 5:59, the highest from 6:00 to 11:59 (13% vs. 32.4%, p < 0.001). The day with the lowest occurrence of OHCA was Friday, the highest Saturday (10.9% vs. 16%, p = 0.01). Summer was the season of the lowest incidence of OHCA, while winter - the highest (22.6% vs. 26%, p = 0.04). These seasons were the warmest and the coldest one, respectively (average temperature 18.5°C vs. 0°C, p < 0.001). CONCLUSIONS: Circadian and less marked, weekly variability in OHCA occurrence were confirmed. Existing seasonal differences may be affected by temperature. This is the first Polish analysis of a large subpopulation, which also includes seasonal temperature data.