Winter Mortality Research Articles

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders.

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

Interannual variability in size-selective winter mortality of young-of-the-year striped bass

Abstract Early life stages of fish are characterized by high size-selective mortality rates, with selection generally acting against smaller, slow-growing individuals. Here, we investigate, for the St. Lawrence River striped bass (Morone saxatilis) population, how size of young-of-the-year juveniles (YOYs) affected survival from the pre-wintering period until the following spring, by comparing their otolith daily growth trajectory to that of one-year-old juveniles (OYOs). Otolith growth in the first 50 d after hatch was faster in post- than in pre-winter juveniles in both years, indicating that fast-growing individuals were more likely to survive to the next spring. A larger back-calculated size at age 1 in the 2016 year class compared to that observed in 2017 also suggests interannual variability in size-selective overwinter survival. Our results indicate that the design of YOY abundance surveys aimed at predicting annual recruitment strength needs to account for the effect of size-dependent mortality until the end of the first winter of life, as high abundance of relatively small YOYs in autumn may not necessarily translate into a large number of OYOs in the following spring and thus into high recruitment.

An improved definition of official excess winter mortality statistics as the basis for detailed analysis and monitoring

In official statistics, excess winter mortality, the number of additional deaths in a winter period, is typically defined as the difference between mortality in a winter period relative to the nonwinter periods before and after. We note two limitations of this approach: (1) the data for the period after winter is available only later, so estimates of excess winter mortality are not timely; (2) unusually high or low numbers of deaths in the non-winter periods can affect estimates. We propose an alternative statistic based on the application of standard seasonal adjustment procedures. We compare the approaches and present some illustrative analyses. The new statistic provides a more objective and timely official series, but is susceptible to revisions, which are shown to be small in practice. We recommend it as the basis of more detailed monitoring and modelling.

What should be the baseline when calculating excess mortality? New approaches suggest that we have underestimated the impact of the COVID-19 pandemic and previous winter peaks

Excess mortality has been used to measure the impact of COVID-19 over time and across countries. But what baseline should be chosen? We propose two novel approaches: an alternative retrospective baseline derived from the lowest weekly death rates achieved in previous years and a within-year baseline based on the average of the 13 lowest weekly death rates within the same year. These baselines express normative levels of the lowest feasible target death rates. The excess death rates calculated from these baselines are not distorted by past mortality peaks and do not treat non-pandemic winter mortality excesses as inevitable.We obtained weekly series for 35 industrialized countries from the Human Mortality Database for 2000–2020. Observed, baseline and excess mortalities were measured by age-standardized death rates. We assessed weekly and annual excess death rates driven by the COVID-19 pandemic in 2020 and those related to seasonal respiratory infections in earlier years. There was a distinct geographic pattern with high excess death rates in Eastern Europe followed by parts of the UK, and countries of Southern and Western Europe. Some Asia-Pacific and Scandinavian countries experienced lower excess mortality. In 2020 and earlier years, the alternative retrospective and the within-year excess mortality figures were higher than estimates based on conventional metrics. While the latter were typically negative or close to zero in years without extraordinary epidemics, the alternative estimates were substantial. Cumulation of this "usual" excess over 2–3 years results in human losses comparable to those caused by COVID-19.Challenging the view that non-pandemic seasonal winter mortality is inevitable would focus attention on reducing premature mortality in many countries. As SARS-CoV-2 is unlikely to be the last respiratory pathogen with the potential to cause a pandemic, such measures would also strengthen global resilience in the face of similar threats in the future.

Snow and land use alter pheasant survival in South Dakota

AbstractWe examined survival of ring‐necked pheasants (Phasianus colchicus) occupying fragmented landscapes within the Prairie Pothole Region in South Dakota, USA, where severe winter weather events historically limited pheasant population growth through increased mortality. Recent landscape transformations could further affect overwinter adult female survival by reducing critical winter resources. Assessing the influence of time‐dependent landscape features on survival at small focal scales may reveal spatially important relationships. We captured and monitored 321 adult female pheasants from 2017–2019 and recorded 110 pheasant winter mortalities. Female pheasant winter survival was 0.66 (85% CI = 0.62–0.70) and was inversely correlated to snow depth. We generated Cox proportional hazard models to determine risk of mortality associated with landscape features. Pheasants using landscapes other than perennial cover (i.e., emergent wetland, tall vegetation, woody, food plots) experienced a 2.22 times greater risk of raptor predation than pheasants using perennial cover. Additionally, pheasants experienced a 58% reduced risk of weather mortality when using emergent wetlands. We analyzed resource selection ratios to understand how perceived landscape risks at the population level scaled down to land use selection at the individual level. Female pheasants selected for emergent wetlands, showed no selection for woody features, and avoided tall vegetation (non‐aquatic herbaceous vegetation >75 cm) during severe winters. Pheasants would greatly benefit from conservation of emergent wetlands and integrating perennial cover into harvested cropland.

Apparent winterkill of Painted Turtle (<i>Chrysemys picta</i>)

Around the margin of an artificial pond in Ottawa, Ontario, we found 25 Painted Turtles (Chrysemys picta) that appeared to have died over the course of two winters (17 during the first winter and eight during the second). We examined meteorological data to try to determine the cause of the mortality. Summer and fall rains were only slightly below normal in both years, suggesting water levels should have been close to normal. The winter air temperature was warmer than normal and winter snowfall was slightly above normal in both years. Unseasonable weather does not appear to be responsible for the winter mortality and the pond’s maximum depth of 1.7 m should prevent freezing to the bottom. It is possible that the artificial nature of the pond creates suboptimal overwintering habitat, rendering the site an ecological trap; however, there is no direct evidence to support this theory. It is also possible that winter mortality of turtles is widespread at temperate wetlands, but that dead turtles were more detectable at this site because of the bare shoreline around the pond. Winter mass mortality events, if common, may represent an additional threat to turtle populations, which are declining from various anthropogenic threats.

A Time-Series Study for Effects of Ozone on Respiratory Mortality and Cardiovascular Mortality in Nanchang, Jiangxi Province, China.

ObjectiveMost evidence comes from studies show that ambient ozone(O3) pollution has become a big issue in China. Few studies have investigated the impact of ozone spatiotemporal patterns on respiratory mortality and cardiovascular mortality in Nanchang city. Thus, this study aimed to explore the health effect of ozone exposure on respiratory mortality and cardiovascular mortality in Nanchang, Jiangxi Province.MethodsUsing the daily mortality data, atmospheric routine monitoring data and meteorological data in Nanchang from 2014 to 2020, we performed a generalized additive model (GAM) based on the poisson distribution in which time-series analysis to calculate the risk correlation between respiratory mortality and cardiovascular mortality and ozone exposure level (8h average ozone concentration, O3-8h). Besides, analyses were also stratified by season, age and sex.ResultsIn the single-pollutant model, for every 10 μg/m3 increase in ozone, respiratory mortality increased 1.04% with 95% confidence interval (CI) between 0.04 and 1.68%, and cardiovascular mortality increased 1.26% (95%CI: 0.68 ~ 1.83%). In the multi-day moving average lag model, the mortality of respiratory diseases and cardiovascular diseases reached a relative risk peak on the cumulative lag5 (1.77%,95%CI: 0.99 ~ 2.57%) and the cumulative lag3 (1.68%,95%CI: 0.93 ~ 2.45%), respectively. The differences were statistically significant (P < 0.05). Results of the stratified analyses showed the effect value of respiratory mortality in people aged ≥65 years was higher than aged <65 years, whereas the greatest effect of cardiovascular mortality in people aged <65 years than aged ≥65 years. Ozone had a more profound impact on females than males in respiratory diseases and cardiovascular diseases. In winter and spring, ozone had a obvious impact on respiratory mortality, and effects of ozone pollution on cardiovascular mortality were stronger in summer and winter. There was a statistically significant difference of respiratory mortality in winter and spring and of cardiovascular mortality in summer and winter (P < 0.05).ConclusionsIn the long run, the more extreme the pollution of ozone exposure, the higher the health risk of residents' respiratory mortality and cardiovascular mortality. Therefore, the government should play an important role in the prevention and control ways of decreasing and eliminating the ozone pollution to protect the resident's health. The findings provide valuable data for further scientific research and improving environmental policies in Nanchang city.

System Complexity in Influenza Infection and Vaccination: Effects upon Excess Winter Mortality.

Unexpected outcomes are usually associated with interventions in complex systems. Excess winter mortality (EWM) is a measure of the net effect of all competing forces operating each winter, including influenza(s) and non-influenza pathogens. In this study over 2400 data points from 97 countries are used to look at the net effect of influenza vaccination rates in the elderly aged 65+ against excess winter mortality (EWM) each year from the winter of 1980/81 through to 2019/20. The observed international net effect of influenza vaccination ranges from a 7.8% reduction in EWM estimated at 100% elderly vaccination for the winter of 1989/90 down to a 9.3% increase in EWM for the winter of 2018/19. The average was only a 0.3% reduction in EWM for a 100% vaccinated elderly population. Such outcomes do not contradict the known protective effect of influenza vaccination against influenza mortality per se—they merely indicate that multiple complex interactions lie behind the observed net effect against all-causes (including all pathogen causes) of winter mortality. This range from net benefit to net disbenefit is proposed to arise from system complexity which includes environmental conditions (weather, solar cycles), the antigenic distance between constantly emerging circulating influenza clades and the influenza vaccine makeup, vaccination timing, pathogen interference, and human immune diversity (including individual history of host-virus, host-antigen interactions and immunosenescence) all interacting to give the observed outcomes each year. We propose that a narrow focus on influenza vaccine effectiveness misses the far wider complexity of winter mortality. Influenza vaccines may need to be formulated in different ways, and perhaps administered over a shorter timeframe to avoid the unanticipated adverse net outcomes seen in around 40% of years.

Dormice (Gliridae) in the diet of predators in Eurasia: a review

Dormice are widely distributed through Eurasia and Africa, but their abundance varies considerably. In many regions, dormice are rare, and their role in ecosystems is considered to be unimportant. The aim of this study was to evaluate the significance of dormice in the diet of predators in the Palaearctic (excluding Japan). A total of 540 sources, containing information on dormice in the diet of predators was analysed. Countries of Southern and Central Europe had the largest numbers of target sources. Dormice were recorded in the diet of 57 predator species: 21 mammals, 13 owls, 18 diurnal birds and 5 reptiles. Owls hunting in the forests, particularly the Tawny Owl (Strix aluco), are the main dormouse predators. The highest proportion of dormice in the diet of predators was recorded in the Mediterranean region, where Edible Dormice (Glis glis) are abundant and some other dormouse species are sympatric. In particular periods, dormice may be an alternative prey for predators such as Tawny Owl and even Lynx (Lynx lynx). It was supposed previously that predation was an important cause of high winter mortality in dormice, but analysis of publications showed that dormice were rather seldom recorded in the winter diet of predators. Thus, the exact impact of predators on winter mortality of dormice remains unclear. The role of dormice in the diet of predators depends on dormouse abundance. In areas where dormice are rare, it is trivial. However, predators catching even individual females, may have a significant impact on dormouse reproductive success.

Climatic conditions and prevalence of melanistic snakes-contrasting effects of warm springs and mild winters.

Climate change is one of the greatest challenges that wildlife is facing. Rapid shifts in climatic conditions may accelerate evolutionary changes in populations as a result of strong selective pressure. Most studies focus on the impact of climatic conditions on phenologies and annual cycles, whereas there are fewer reports of empirical support for climate-driven changes in the phenotypic variability of free-living populations. We investigated whether climatic variables explain the prevalence of colour polymorphism in a population of the grass snake (Natrix natrix) with two morphotypes, the melanistic and non-melanistic ones, in the period 1981-2013. We found that the prevalence of the black phenotype was negatively related to spring temperature and winter harshness, expressed as the number of snow days. According to the thermal melanism hypothesis, a high predation rate during warmer springs may override relaxed thermal benefits and vice versa, i.e. black individuals may perform better than typical ones when thermal conditions in spring are unfavourable. In turn, because they are smaller, melanistic individuals may be exposed to a higher risk of winter mortality, particularly during longer winters. We highlight the need for more studies on the effects of climatic conditions on temporal variation in melanism prevalence in other populations and species as well as in various geographic regions.

Fungal ectoparasites increase winter mortality of ladybird hosts despite limited effects on their immune system.

Winter represents a challenging period for insects inhabiting temperate regions. A plethora of studies have investigated how environmental conditions such as temperature affect insect overwintering success. However, only a few studies have focused on biotic factors and the mechanisms affecting the overwintering performance of insects. Here, we investigated the effects of the parasitic fungus Hesperomyces virescens on the overwintering performance and immune system functioning of the invasive ladybird Harmonia axyridis. Winter survival was significantly lower for infected than for uninfected ladybirds. Body mass loss during overwintering tends to be higher for infected individuals compared to uninfected ones and for larger ladybirds. In addition, parasitic infection reduced post-winter longevity without food in male but not female ladybirds. Total haemocyte and protein concentration as well as antimicrobial activity against Escherichia coli significantly decreased during ladybird overwintering. However, haemolymph parameters were only poorly affected by Hesperomyces infection, with the exception of antimicrobial activity against E. coli that tended to be higher in infected ladybirds. Interestingly, none of the pre-winter haemolymph parameters were good predictors of ladybird winter survival. Overall, our results indicate that energy exhaustion unrelated to immune system challenge is the most probable explanation for increased overwintering mortality in infected ladybirds.

Trends in Excess Winter Mortality (EWM) from 1900/01 to 2019/20-Evidence for a Complex System of Multiple Long-Term Trends.

Trends in excess winter mortality (EWM) were investigated from the winter of 1900/01 to 2019/20. During the 1918–1919 Spanish flu epidemic a maximum EWM of 100% was observed in both Denmark and the USA, and 131% in Sweden. During the Spanish flu epidemic in the USA 70% of excess winter deaths were coded to influenza. EWM steadily declined from the Spanish flu peak to a minimum around the 1960s to 1980s. This decline was accompanied by a shift in deaths away from the winter and spring, and the EWM calculation shifted from a maximum around April to June in the early 1900s to around March since the late 1960s. EWM has a good correlation with the number of estimated influenza deaths, but in this context influenza pandemics after the Spanish flu only had an EWM equivalent to that for seasonal influenza. This was confirmed for a large sample of world countries for the three pandemics occurring after 1960. Using data from 1980 onward the effect of influenza vaccination on EWM were examined using a large international dataset. No effect of increasing influenza vaccination could be discerned; however, there are multiple competing forces influencing EWM which will obscure any underlying trend, e.g., increasing age at death, multimorbidity, dementia, polypharmacy, diabetes, and obesity—all of which either interfere with vaccine effectiveness or are risk factors for influenza death. After adjusting the trend in EWM in the USA influenza vaccination can be seen to be masking higher winter deaths among a high morbidity US population. Adjusting for the effect of increasing obesity counteracted some of the observed increase in EWM seen in the USA. Winter deaths are clearly the outcome of a complex system of competing long-term trends.

Variation of lipids and fatty acids in noble scallop Chlamys nobilis under low temperature stress

Low temperature is an important stress factor for warm-water marine mollusks. It is well known that lipids play an important role in the resistance of low temperature stress in mollusks. The noble scallop Chlamys nobilis is an important economic warm-water bivalve. It has been cultured in the waters of southern China since the 1980s. However, C. nobilis often experiences regional mass mortality in winter. In the present study, the variation of lipids and fatty acids in C. nobilis were studied in differentiated temperatures (water temperature was gradually decreased from 27 °C to 15, 13 and 11 °C). The results demonstrated that lipid peroxidation increased at low temperatures, gills were damaged at 13 and 11 °C, and the condition index decreased only at 11 °C. Moreover, the level of triglycerides and total cholesterol in digestive glands increased significantly at 15 and 13 °C, and the triglycerides in adductor muscles also increased significantly at low temperatures. Furthermore, the level of ∑n-6 PUFA in digestive glands and adductor muscles increased significantly, the level of ∑n-3 PUFA and EPA + DHA in adductor muscles increased significantly, whereas the level of ∑n-3 PUFA and EPA + DHA in digestive glands decreased significantly at 13 and 11 °C. This is the first report on the variations of lipids and fatty acids in mollusks under chronic low temperature stress. The present results also showed that both lipids and PUFA played important roles in animal resistance to low temperature stress, which can provide guidance for improving low temperature tolerance of bivalves.

Non-linear response of temperature-related mortality risk to global warming in England and Wales

Climate change is expected to lead to changes in seasonal temperature-related mortality. However, this impact on health risk does not necessarily scale linearly with increasing temperature. By examining changes in risk relative to degrees of global warming, we show that there is a delayed emergence of the increase in summer mean mortality risk in England and Wales. Due to the relatively mild summer mean temperatures under the current climate and the non-linearity of the exposure–response relationships, minimal changes in summer mean risk are expected at lower levels of warming and an escalation in risk is projected beyond 2.5 °C of global warming relative to pre-industrial levels. In contrast, a 42% increase in mortality risk during summer heat extremes is already expected by 2 °C global warming. Winter attributable mortalities, on the other hand, are projected to decrease largely linearly with global warming in England and Wales.

Therapeutic potential of gasotransmitters for cold stress-related cardiovascular disease

Abstract Growing evidence has shown that exposure to low ambient temperature poses a huge challenge to human health globally. Actually, cold stress is closely associated with a higher incidence of cardiovascular morbidity and mortality in winter or in cold regions. Cellular and molecular mechanisms underlying cardiovascular complications in response to cold exposure have yet to be fully clarified. Considering that cold exposure is an important risk of cardiovascular complications, it is necessary to clarify the molecular mechanism of cold stress-induced cardiovascular diseases and to develop effective intervention strategies. Hydrogen sulfide (H2S), nitric oxide (NO), and carbon monoxide (CO) are well-known gasotransmitters that are endogenously produced in many biological systems. Accumulating studies have demonstrated that these gasotransmitters play a critical role in a wide spectrum of physiological and/or pathophysiological processes by regulating numerous signaling pathways. These gas signal molecules are emerging as important players in cardiovascular homeostasis, and disruption of these gasotransmitters is critically implicated in cardiovascular anomalies, such as hypertension, atherosclerosis, myocardial ischemia, heart failure, and stroke. Also, evidence is emerging that H2S, NO, and CO may be involved in the pathologies of cold stress-induced cardiovascular ailments. In this review, we aim to highlight and discuss the recent advances towards the development of gasotransmitters-based therapeutics for cold stress-related cardiovascular pathogenesis. We believe that the effects of H2S, NO, and CO on cardiovascular regulation under cold environment will attract tremendous interest in the near future as they serve as novel regulators of cardiovascular biology in cold environment.

Significant genes in response to low temperature in Fenneropenaeus chinensis screened through multiple transcriptome group comparisons

Fenneropenaeus chinensis is a migratory marine species with a suitable growth at 18–30°C. To prolong breeding season and reduce mortality in winter, breeding new shrimp varieties with cold tolerance is essential. Genes upregulated and highly expressed at low temperature are reasonable candidate genetic markers for the breeding of cold tolerant strain variants. This study screened genes with these features by comparing multiple low-vs. normal-temperature transcriptome groups. The results showed that nine genes were upregulated and highly expressed at low temperature in more than seven of the nine comparison groups. Six of them were identified as genes encoding transcription factor ATF2, RNA recognition motif domain-containing protein, cytochrome b5-like protein, troponin C, tubulin alpha-1, and 18S/5.8S/28S rRNA, respectively. Cold-inducible upregulations of ATF2, cytochrome b5, and rRNAs were novel findings in this study. The other three novel genes were predicted to encode a membrane-bound extracellular protein and two lncRNAs. Four of the screened genes were verified by real time RT-PCR, and their expression levels were consistent with the sequencing results, demonstrating the accuracy of the transcriptome sequencing data. Function analysis showed that ATF2 might be the master transcription factor regulating the expressions of proteins involved in cellular responses to cold. The other genes played a role in events such as enhancing translation, increasing energy, inhibiting apoptosis, and preserving cell integrity. The expression features of these nine genes suggested that they were of great significance to the cold tolerance of shrimp.

Effect of winter canola cultivar on seed yield, oil, and protein content

AbstractWinter canola (Brassica napus L.) production has increased in the United States over the past several decades; however, there is little research in the southeastern United States on its agronomic production and growth characteristics under different nitrogen (N) fertilizer rates. The objectives of this study were to determine the effects of N rates on winter mortality, yield, oil and protein content, and seedpod shatter resistance across cultivars. Canola was grown in a randomized split complete block design with four replicates under five different N rates (0, 56, 112, 168, and 224 kg N ha−1) with four different cultivars (Hekip, Inspiration, and Edimax CL or Phoenix CL). Seed yield was very low for the 2017–2018 season, likely due to extreme cold conditions in winter and/or frost at flowering. There was high winter mortality during this period, but Edimax CL had significantly lower mortality (79.7%) than Inspiration (85.7%) and Hekip (83.9%). In the following year, more mild temperatures led to low mortality and greater yields, where rates of 112, 168, and 224 kg N ha−1 had the greatest yields (1,612–1,857 kg ha−1) with no significant differences according to cultivar. In 2018, shatter resistance was greatest for the rates of 112, 168, and 224 kg N ha−1 and was positively related to N rate. Across both years, Inspiration had greater shatter resistance. In 2019, the lowest N rate (0 kg N ha−1) and Phoenix CL had significantly greater oil contents (48.4 and 47.3%, respectively), whereas the highest N rate (224 kg N ha−1) with no particular cultivar had a significantly greater protein content (21.0%).

Study of life cycle of green apple aphid (aphis pomi de geer) infesting apple orchards in Kashmir valley

Keeping in view the havoc caused by green apple aphid on Apple industry in last couple of years and observing the resistance against insecticides in this pest. Severe infestation causes curling, stunting and weakening of terminals and increase risk of winter mortality. A common strategy to control this pest in conventional apple orchards in Kashmir is the use of one or more application of insecticides. But wide spectrum insecticides have led to resistance and resurgence in this pest. It also upsets natural biodiversity and affects population abundance of predators This study was devised and aimed at determining the life history of this devastating pest during May to November months on apple host. The data on total life period (pre-reproductive, reproductive and post-reproductive periods) was recorded. The total progeny produced and total nymphal period was also calculated. The detailed biology of the pest has been recorded for the first time in Apple orchards of Kashmir province of J&K. This study will be of immense importance in carving out a sustainable future IPM strategy against this pest.

Thermal comfort in naturally ventilated dwellings in the central Mexican plateau

A third of Mexico's population (35 M people) lacks decent housing. Current efforts to improve housing focus on structural strength and security rather than thermal comfort. However, as 59% of the population earns less than the median income, the building itself must provide adequate internal temperatures, i.e., the range between the minimum temperature suggested by WHO of 18 °C, and the maximum temperatures suggested by the CIBSE TM59:2017 criteria. Despite the perception of being a “warm” country, 38% of the Mexican population lives in places where the external temperatures often drop to 0 °C in winter falling to −6 °C during seasonal cold fronts. This is worrying, as a lack of adequate protection from low indoor temperatures is associated with high excess winter mortality rates. Hence, we undertake one of the first Class-II thermal comfort studies in a cold climate in Mexican homes. For eleven months, hourly indoor environmental and occupancy data, complemented with language-localised bi-monthly thermal comfort surveys, were matched against the Adaptive and PMV thermal comfort models. We find that only 42% of the living room occupied hours were within acceptability ranges, dropping to 22% in winter. Finally, we find that current strategies for achieving homeostatic heat balance are garment based (i.e., extra blankets or clothing), in addition to electric heaters to a lesser extent. Hence, we find that Mexican houses are presently not capable of providing adequate internal thermal environments during cold periods, suggesting the need for an extensive insulation programme.

Central heating and winter mortality in China: A national study based on 364 Chinese locations

The association between temperature and mortality has been widely investigated, however, studies on the effects of central heating on mortality risk are sparse. We applied a variant of difference-in-differences (DID) approach to assess the effects of central heating on winter mortality in China, and further analyzed the modification effect of central heating on the temperature-mortality association. Central heating was negatively associated with winter mortality (OR: 0.42, 95% CI: 0.39, 0.46) with higher effects on females and the elderly. Compared with cardiovascular or cerebrovascular diseases, central heating had a much greater effect on respiratory diseases. Every week less in central heating duration was associated with a 3.32% (95% CI: 3.03%, 3.61%) increased risk in total mortality. We found the temperature effect was much more pronounced among the locations without central heating (ER: 5.01%, 95% CI: 4.68%, 5.34%) than those with central heating (ER: 0.01%, 95% CI: −0.74%, 0.75%). The analysis suggests that central heating significantly decreases winter mortality in northern China, which may partly be achieved by attenuating the mortality caused by temperature. Therefore, central heating should be developed in some regions of southern China to reduce the mortality risk of low temperature in winter.