Weather extremes and perinatal mortality - Seasonal and ethnic differences in northern Sweden, 1800-1895

BACKGROUND

Many studies have shown the impact of heat and cold on total and age-specific mortality, but knowledge gaps remain regarding weather vulnerability of very young infants. This study assessed the association of temperature extremes with perinatal mortality (stillbirths and deaths in the first week of life), among two ethnic groups in pre-industrial northern Sweden.

METHODS

We used population data of indigenous Sami and non-Sami in selected parishes of northern Sweden, 1800-1895, and monthly temperature data. Multiple logistic regression models were conducted to estimate the association of cold (<10th percentile of temperature) and warmth (>90th percentile) in the month of birth with perinatal mortality, adjusted for cold and warmth in the month prior birth and period, stratified by season and ethnicity.

RESULTS

Perinatal mortality was slightly higher in Sami than in non-Sami (46 vs. 42 / 1000 live and stillbirths), but showed large variations across the region and over time. Both groups saw the highest perinatal mortality in autumn. For Sami, winter was a high-risk time as well, while for non-Sami, seasonality was less distinct. We found an association between exposure to cold and perinatal mortality among winter-born Sami [Odds ratio (OR) 1.91, 95% confidence interval (CI) 1.26-2.92, compared to moderate temperature], while there was little effect of cold or warmth during other seasons. Non-Sami, meanwhile, were affected in summer by warmth (OR 0.20, CI 0.05-0.81), and in autumn by cold (OR 0.39, CI 0.19-0.82).

CONCLUSIONS

In this pre-industrial, subarctic setting, the indigenous Sami's perinatal mortality was influenced by extreme cold in winter, while non-Sami seemed to benefit from high temperature in summer and low temperature in autumn. Climate vulnerability of these two ethnic groups sharing the same environment was shaped by their specific lifestyles and living conditions.

For the good of the nation: scientific discourses endorsing the medicalization of childbirth in Peru, 1900-1940

Over the course of the twentieth century, a series of changes occurred in the understanding of childbirth, which went from being a natural reproductive phenomenon belonging to the female, domestic sphere to a professional medical matter handled in an institutional setting. Through procedures like the use of anesthesia, Cesarean sections, ultrasound and other techno-scientific interventions, rapid and significant improvements and changes took place in the health and life of society and of women. The medicalization of childbirth in the early twentieth century was part of a broader process of constructing the state and institutionalizing the patriarchy that was common throughout the region.

Biological and Cultural Causes of Seasonality of Deaths in Historical Populations From Poland

Seasonal fluctuations in mortality and their causes in the nineteenth century Polish rural populations: wealthy, agriculturally and economically advanced populations from Wielkopolska, and poor populations from Silesia and Galicia (southern Poland) were described. Data-sources included parish death registers from the Roman Catholic parish of Dziekanowice in the region of Wielkopolska, Prussian statistical yearbooks for the Pozna Province as well as information from previous publications regarding Silesia and Galicia. The 19th century patterns were compared with those in present-day Poland. The occurrence of seasonality of deaths was assessed with: the Chi-squared test, the Kolmogorov-Smirnov test, and the Autoregressive Integrated Moving Average Models (ARIMA). In all populations there was a winter maximum of the number of deaths, while the minimum occurred in early summer. In the poor populations of Silesia and Galicia another statistically significant increase in the incidence of deaths was observed in the early spring. In the rich and modern villages of Wielkopolska there was no spring increase in the number of deaths, however, in all populations of Wielkopolska, irrespective of a particular pattern, a secondary mortality peak occurred in the late summer and autumn. Statistical tests used in this study did not show any clear differences in the distribution of the seasonality of deaths between the populations of Wielkopolska on the one hand, and the populations from Galicia and Silesia, on the other hand. The statistical significance of differences was, however, evident between populations representing the two distinguished by secondary peaks death seasonality patterns. Seasonal death increase split the populations under study into two groups according to the criterion of wealth.

The effect of Rh-negative disease on perinatal mortality: some evidence from the Skellefteå region, Sweden, 1860-1900

The Rh-negative gene is a well-known cause of perinatal mortality. In this article, we analyze the possible role of Rh disease in perinatal mortality and stillbirths in a particular historical setting: the Skellefteå region in northern Sweden between 1860 and 1900. The data used for the study cover 23,067 children born to 4,943 women. The exact impact is not possible to establish using historical data, but the typical pattern of the disease allows us to make estimations. The expected levels based on knowledge of blood group distribution, the risk of sensitization from Rh incompatability, and the risk of perinatal mortality in births by sensitized mothers are compared with the observed levels. The results show that Rh disease was important for perinatal mortality and clustering of deaths within families.

[Hoogendoorn and the medical registry]

Dirk Hoogendoorn (1914-1990) was a solo general practitioner in the village of Wijhe (eastern part of the Netherlands) from 1941, during the time of the German occupation, until 1971. From the very beginning, he combined his practice with the recording of disease patterns. He first concentrated on infectious diseases, especially whooping cough, which was the subject of his doctoral thesis. He later set up registries in two regional hospitals. When his initiative expanded to a national organisation, he became its advisor. He nonetheless continued to produce statistics on a variety of disorders as well as on surgical procedures, even more so after his retirement. The subjects ranged from traffic accidents and tonsillectomies to the discrepancy between increased body height and the unchanging height of the tennis net, but he had the most affinity with the practice of obstetrics. He stirred up much emotion by showing that a decrease in perinatal mortality was proceeding slower in the Netherlands than in other European countries, especially by suggesting a causal relationship between this lag and the high rate of Dutch home deliveries. This debate has continued to this day.

Peruvian contributions to the study on human reproduction at high altitude: from the chronicles of the Spanish conquest to the present

Humans have lived in the Peruvian Andes for about 12,000 years providing adequate time for adaptation to high altitude to have occurred. The arrival of the Spanish conquistadors in the 16th century potentially altered this process through genetic admixture. Early records revealed a potential for reduced fertility and a high perinatal and neonatal mortality amongst the early Spanish inhabitants who settled at high altitude when compared to the native Inca population. It appears that fertility is reduced during acute exposure at high altitude but is normal in populations born and living at high altitude. On the other hand, perinatal and neonatal mortality is presently still high at elevated altitudes, even after taking into account socio-economic status. The rates of perinatal and neonatal mortality are, however, lower in populations that have resided at high altitude for longer; populations inhabiting the southern Andes have a longer antiquity at high altitude and lower rates of fetal and neonatal deaths than those in the central Andes with a shorter residence at high altitude. Clearly, antiquity and genetics are important components in determining survival and quality of life at high altitude.