Mortality patterns and biological status in Pietrzykowice against the backdrop of historical events and social transitions: A biodemographic study of 19th-century rural Galicia

The 19^th century was a period of profound historical and social dynamics in Galicia, significantly impacting the biological status of its inhabitants. This study aimed to characterize the mortality patterns of the population in Pietrzykowice (Stary Zywiec parish) through a biodemographic analysis of parochial registers. The research material comprised death records from the All Saints Parish in Stary Zywiec, spanning the years 18001899 (N = 1,894 females and N = 2,010 males). The reliability of the registers was formally verified. Life tables were constructed assuming both the stationary and the stable population models. Key metrics calculated included neonatal and infant mortality rates, alongside an analysis of seasonal patterns and causes of death. The study incorporated measures of the opportunity for natural selection to evaluate the impact of differential mortality. The Chi-squared test was used to determine the statistical significance of sex-based and seasonal distributions. Sex-specific and temporal differences in e_x estimates were verified using standard error tables and nomographic methods. To assess sex-based disparities in neonatal and post-neonatal mortality, a z-test for two proportions was employed. For all statistical tests, the significance level was set at <i>p</i> < 0.05. Life expectancy at birth (e₀) was 23.87 years for females and 21.20 years for males, while e₂₀ reached 33.69 years for females and 34.40 years for males in stationary population model. A statistically significant disadvantage in newborn life expectancy e₀ was observed for males, whose values fell considerably below those recorded for females. Analysis of the three measures of the opportunity for natural selection revealed high mortality rates among the younger age groups, and suggesting that only a relatively small proportion of individuals reached their full reproductive potential. Neonatal and infant mortality rates differences were statistically significant, reaching 54.36 and 129.15 for females, and 60.00 and 172.33 for males respectively. Significant seasonality in mortality was observed, although sex-based differences in seasonal patterns were not statistically significant. The distribution of causes of death varied significantly by quarter (season) and age category. Furthermore, causes of death showed significant differentiation between sexes. The 19^th-century inhabitants of Pietrzykowice exhibited low life expectancy relative to more affluent regions, such as Greater Poland (Wielkopolska). The population was also characterized by high early childhood mortality. The findings indicate that mortality patterns were highly diversified by season, sex, and age, suggesting a complex interplay between environmental factors and biological susceptibility in shaping the demographic profile of this rural community.