Time-series analysis of the relationship between air quality, temperature, and sudden unexplained death in Beijing during 2005-2008

Background There is a yearly increase in the rate of sudden unexplained death （SUD）, even through extensive physical examination and the testing of a large number of biomarkers, the cause of sudden death in patients previously in good health cannot be fully determined. During clinical practice, a spatial aggregation phenomenon has been observed in the incidence of sudden unexplained death. Previous research has shown that environmental factors, such as air pollution, weather conditions, etc., have a significant impact on human health. In the wake of the continuous environmental damage, the relationship between environmental factors and sudden unexplained death still needs to be studied. To study the relationship between sudden unexplained death and air quality and temperature, commonly used markers such as particulate matter of aerodynamic diameter 〈10 μm （PM10）, daily average concentration of the gaseous pollutants sulfur dioxide （SO2） and nitrogen dioxide （NO2）, and the daily average temperature were investigated. Methods The methods include collecting the data of sudden unexplained death; air quality monitoring; meteorological monitoring from January 1, 2005 to December 31, 2008; utilizing generalized additive models （GAM）; controlling the influential factors such as secular trend, seasonal trend, and Sunday dummy variable; and analyzing the correlation between daily inhalable particle concentration, daily average temperature, and the number of daily SUD. Results There was no statistical significance between the daily inhalable particle and daily incidence of sudden unexplained death. Incidence rate of sudden unexplained death had nonlinear positive correlation with daily temperature. When the temperature was 5℃ above the daily average temperature, the daily incidence of sudden unexplained death went up with the rising temperature. Conclusion Temperature may be one of the key risk factor or precipitating factor of SUD.

Common underlying diseases do not contribute in determining the causes of sudden unexplained death

Background Underlying diseases have a statistically significant positive correlation to sudden death. However, sudden unexplained death （SUD） is different from sudden death, as there is no clinical evidence to support the sudden death due to the original underlying disease, nor a lethal pathological basis to be found during autopsy. In addition, SUD are more common in young, previously healthy individuals, usually without any signs of disease, with no positive lesions found after autopsy. Therefore, a causal relationship between SUD and the underlying disease needs to be further explored. This study aimed to explore the role that common underlying diseases play in patients with SUD and to reveal the correlation between them. Methods The medical records, history and case information of 208 patients with SUD were collected for the survey. All these SUD occurred in the emergency room of Peking University Third Hospital from January 2006 to December 2009. The patients were stratified by with and without common underlying diseases. To examine possible associations between the underlying diseases and the cause of unexplained sudden death, the chi-squared and Fisher＇s exact tests were used. Results Among the 208 patients, 65 were diagnosed with common underlying diseases while 143 were not. Within these two groups, there were 45 patients for whom the clear cause of death was determined. However, there were no statistically significant differences or strong associations （x2=1.238, P 〉0.05） between the 11 patients with （16.90%） and 34 without （23.78%） common underlying disease among these 45 patients. We also found that occurrence of the common underlying diseases, such as neurological system, cardiovascular and pulmonary system diseases, are not statistically significant （P 〉0.05） in the diagnosis of the SUD. Conclusion Common underlying diseases make no obvious contributions to SUD and are not useful in diagnosing the underlying reasons for death.

Mutations of Desmoglein‑2 in Sudden Unexplained Death in the Chinese Han Population

Sudden unexplained death(SUD)remains a puzzle in forensic medicine.Desmoglein‑2(DSG2)has been linked to arrhythmogenic right ventricular cardiomyopathy which may cause life‑threatening ventricular arrhythmias and sudden death.Fatal arrhythmias resulting in sudden death also occur in the absence of morphologic cardiac abnormalities at autopsy.We hypothesized that DSG2 mutations may be responsible for certain Chinese SUD cases.We sequenced all 15 exons of DSG2 in DNA extracted from postmortem heart tissues of 25 Chinese patients dying from SUD.The primers were designed using the Primer Express 3.0 software.Direct sequencing for both sense and antisense strands was performed with a BigDye Terminator DNA sequencing kit on a 3130 Xl Genetic Analyzer.Mutation damage prediction was made using Mutation Taster,PolyPhen,and SIFT software.In 2 of 25 cases of Chinese SUD samples,two DSG2 heterozygous mutations(p.P927 L and p.T1070M)were identified,and one is probably damaging.We concluded that DSG2 mutations may be related to the occurrence of part of SUD cases in the Chinese Han population.

Analysis of the prodromal symptoms of unexplained sudden death in patients with or without underlying diseases

Background In recent years, the incidence of unexplained sudden death has risen significantly across the world. However, it occurred suddenly, often in young apparently healthy individuals and almost 50% of the patients did not have any warning signals or symptoms. Therefore, the prodromal symptoms before the incident are extremely important for early prediction of sudden death. In this article, we aimed to explore the value of prodromal symptoms for unexplained sudden death and whether the prodromal symptoms have a predictive function to unexplained sudden death （USD） without underlying diseases. Methods A total of 208 sudden death cases were selected for the survey in the Emergency Department of Peking University Third Hospital from January 2006 to December 2009 and their medical records were reviewed. The patients were divided into two groups, 65 patients had underlying diseases while 143 had not underlying diseases. In the meantime, their prodromal symptoms were collected and compared, prodromal symptoms including chest distress, dyspnea, syncope, fever, headache, vomiting, etc. Results Patients with underlying diseases were compared to those without underlying diseases associated with sudden death; there was no significant difference in gender and age distribution. Among the 208 cases, 39 cases （18.75%） had prodromal symptoms, patients with underlying diseases had prodromal symptoms in 12 cases （18.46%）, while patients without underlying diseases had prodromal symptoms in 27 cases （18.88%）. The difference between the two groups with prodromal symptoms was not statistically significant （P 〉0.05）. Conclusions Prodromal symptoms are extremely important warning signals in the occurrence of USD. It has equally important predictive value for patients both with and without underlying diseases, especially in predicting sudden death caused by cardiopulmonary and neurological diseases.

Altered Expression of Nicotinic Receptors in Perinatal Life Related to Prenatal Exposure to Toxics—An Overview of the Research Carried Out on This Topic at the “Lino Rossi” Research Center of the Milan University

The article aims to underline the impact of nicotine and pesticides on neuronal α7-nicotinic acetylcholine receptors expression in brainstem regions receiving cholinergic projections, given their fundamental role during the neuronal development. The in-depth histopathological/immunohistochemical examination of the autonomic nervous system performed at the “Lino Rossi” Research Center of the Milan University on a wide group of sudden unexpected fetal and infant deaths, highlighted the frequent hypodevelopment of brainstem structures checking the vital functions associated to altered expression of α7-nicotinic acetylcholine receptors and smoke absorption in pregnancy. A dysregulation of the catecholamine system was also observed in the cerebellar cortex of the same cases. However, in a not negligible percentage of sudden deaths with altered expression of α7-nicotinic receptors, the mothers never smoked but lived in rural areas. Specific analytical procedures showed the presence of agricultural pesticides in cerebral cortex samples of these victims. Therefore, it is possible to believe that the exposition to pesticides during pregnancy can produce the same harmful effects as nicotine on the nicotinic acetylcholine receptors. Moreover, alterations of α7-nicotinic acetylcholine receptors receptor expression were also detected in the lungs of many sudden perinatal death victims, allowing to consider even these findings as possible consequence of maternal exposure to toxic factors.