Gestational diabetes mellitus (GDM) is a common pregnancy complication, with complex disease mechanisms, and several risk factors may contribute to its onset. We performed an umbrella review to ...summarize the evidence from meta-analyses of observational studies on risk factors associated with GDM, evaluate whether there are indications of biases in this literature and identify which of the previously reported associations are supported by convincing evidence.
We searched PubMed and ISI Web of Science from inception to December 2018 to identify meta-analyses examining associations between putative risk factors for GDM. For each meta-analysis we estimated the summary effect size, the 95% confidence interval, the 95% prediction interval, the between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias.
Thirty eligible meta-analyses were identified, providing data on 61 associations. Fifty (82%) associations had nominally statistically significant findings (P<0.05), while only 15 (25%) were significant at P<10-6 under the random-effects model. Only four risk factors presented convincing evidence:, low vs. normal BMI (cohort studies), BMI ~30-35 kg/m2 vs. normal BMI, BMI >35 kg/m2 vs. normal BMI, and hypothyroidism.
The compilation of results from synthesis of observational studies suggests that increased BMI and hypothyroidism show the strongest consistent evidence for an association with GDM. Diet and lifestyle modifications in pregnancy should be tested in large randomized trials. Our findings suggest that women with known thyroid disease may be offered screening for GDM earlier in pregnancy.
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•Risk-benefit trade-off of walking and cycling in polluted air is poorly known.•We modelled risk-benefit trade-off of avoiding high air pollution (AP) days.•Everyday walking and ...cycling was beneficial in all cities.•Avoiding high AP days did not lead to health benefits in any of the six cities.
Regular active commuting, such as cycling and walking to and from the workplace, is associated with lower all-cause mortality through increased physical activity (PA). However, active commuting may increase intake of fine particles (PM2.5), causing negative health effects. The purpose of this study is to estimate the combined risk of PA and air pollution for all-cause mortality among active commuters who, on days with high PM2.5 levels, switch to commuting by public transportation or work from home. Towards this purpose, we developed a Health Impact Assessment model for six cities (Helsinki, London, Sao Paulo, Warsaw, Beijing, New Delhi) using daily, city-specific PM2.5 concentrations. For each city we estimated combined Relative Risk (RR) due to all-cause mortality for the PA benefits and PM2.5 risks with different thresholds concentrations. Everyday cycling to work resulted in annual all-cause mortality risk reductions ranging from 28 averted deaths per 1000 cyclists (95% confidence interval (CI): 20–38) in Sao Paolo to 12 averted deaths per 1000 cyclists (95% CI: 5–19) in Beijing. Similarly, for everyday walking, the reductions in annual all-cause mortality ranged from 23 averted deaths per 1000 pedestrians (95 CI: 16–31) in Sao Paolo to 10 averted deaths per 1000 pedestrians (95%CI: 5–16) in Beijing. Restricting active commuting during days with PM2.5 levels above specific air quality thresholds would not decrease all-cause mortality risk in any examined city. On the contrary, all-cause mortality risk would increase if walking and cycling are restricted in days with PM2.5 concentrations below 150 μg/m3 in highly polluted cities (Beijing, New Delhi). In all six cities, everyday active commuting reduced all-cause mortality when benefits of PA and risk or air pollution were combined. Switching to working from home or using public transport on days with high air pollution is not expected to lead to improved all-cause mortality risks.
The link between PM2.5 exposure and adverse health outcomes is well documented from studies across the world. However, the reported effect estimates vary across studies, locations and constituents. ...We aimed to conduct a meta-analysis on associations between short-term exposure to PM2.5 constituents and mortality using city-specific estimates, and explore factors that may explain some of the observed heterogeneity.
We systematically reviewed epidemiological studies on particle constituents and mortality using PubMed and Web of Science databases up to July 2015.We included studies that examined the association between short-term exposure to PM2.5 constituents and all-cause, cardiovascular, and respiratory mortality, in the general adult population. Each study was summarized based on pre-specified study key parameters (e.g., location, time period, population, diagnostic classification standard), and we evaluated the risk of bias using the Office of Health Assessment and Translation (OHAT) Method for each included study. We extracted city-specific mortality risk estimates for each constituent and cause of mortality. For multi-city studies, we requested the city-specific risk estimates from the authors unless reported in the article. We performed random effects meta-analyses using city-specific estimates, and examined whether the effects vary across regions and city characteristics (PM2.5 concentration levels, air temperature, elevation, vegetation, size of elderly population, population density, and baseline mortality).
We found a 0.89% (95% CI: 0.68, 1.10%) increase in all-cause, a 0.80% (95% CI: 0.41, 1.20%) increase in cardiovascular, and a 1.10% (95% CI: 0.59, 1.62%) increase in respiratory mortality per 10μg/m3 increase in PM2.5. Accounting for the downward bias induced by studies of single days, the all-cause mortality estimate increased to 1.01% (95% CI: 0.81, 1.20%). We found significant associations between mortality and several PM2.5 constituents. The most consistent and stronger associations were observed for elemental carbon (EC) and potassium (K). For most of the constituents, we observed high variability of effect estimates across cities.
Our meta-analysis suggests that (a) combustion elements such as EC and K have a stronger association with mortality, (b) single lag studies underestimate effects, and (c) estimates of PM2.5 and constituents differ across regions. Accounting for PM mass in constituent's health models may lead to more stable and comparable effect estimates across different studies.
PROSPERO: CRD42017055765.
•A meta-analysis of acute effects of PM2.5 constituents on mortality was conducted.•EC and K had the strongest and most consistent association with mortality.•Single lag studies underestimate effects.•Mortality effects of PM2.5 and constituents differ across regions.
Evidence in clinical research is accumulating and scientific publications have increased exponentially in the last decade across all disciplines. Available information should be critically assessed. ...Here, we focus on umbrella reviews, an approach that systematically collects and evaluates information from multiple systematic reviews and meta-analyses. To facilitate the design and the conduct of such a study, we provide a step-by-step guide on how to perform an umbrella review. We also present ways to report the summary findings, we describe various proposed grading criteria, and we discuss potential limitations.
There is a growing body of evidence linking ambient air temperature and adverse health effects, in the form of hospitalization or even increased mortality mainly due to respiratory and ...cardio/cerebro-vascular illnesses. In the present study, we examine the association between high ambient air temperature and cardiovascular as well as respiratory mortality for the population of the greater area of Thessaloniki, Greece, taking into account the role of particulate pollution as a potential confounder.
A mixed Poisson regression model, using a quasi-likelihood function to account for potential over-dispersion in the outcome distribution given covariates, was combined with distributed lag non-linear models, to estimate the non-linear and lag patterns in the association between mortality and daily mean temperature from 1999 to 2012.
A direct heat effect was found, as the mortality risk increased sharply above the temperature threshold of 33 °C, suggesting a significant effect of high temperatures on mortality on the same and next day of the heat events (lags 0–1) which was retained for a week, whereas a harvesting effect was noticed for the following days. Cardiovascular and respiratory mortality risk increased by 4.4% (95% CI 2.7%–6.1%) and 5.9% (95% CI 1.8%–10.3%) respectively on the same and following day of a heat event, whereas the risk dropped steeply in the following days. Particulate matter did not confound the association between high temperature and mortality in this population.
There is a significant association between mortality and hot temperatures in Thessaloniki, Greece. Reduction in exposure to increased temperatures, as part of prevention measures and strategies, should be considered for vulnerable subpopulations.
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•High ambient temperature is a known risk factor for cardio-respiratory mortality.•In Thessaloniki, this association is examined using DLNM models.•Above 33 °C, mortality risk increased for the same and next day of the heat event.•Mortality risk dropped steeply in following days, demonstrating a harvesting effect.
In many regions of the world, the relationship between ambient temperature and mortality is well-documented, but little is known about Cyprus, a Mediterranean island country where climate change is ...progressing faster than the global average. We Examined the association between daily ambient temperature and all-cause mortality risk in Cyprus. We conducted a time-series analysis with quasipoisson distribution and distributed lag non-linear models to investigate the association between temperature and all-cause mortality from 1 January 2004 to 31 December 2019 in five districts in Cyprus. We then performed a meta-analysis to estimate the overall temperature-mortality dose-response relationship in Cyprus. Excess mortality was computed to determine the public health burden caused by extreme temperatures. We did not find evidence of heterogeneity between the five districts (p = 0.47). The pooled results show that for cold effects, comparing the 1st, 2.5th, and 5th percentiles to the optimal temperature (temperature associated with least mortality, 25 ℃), the overall relative risks of mortality were 1.55 (95% CI: 1.32, 1.82), 1.41 (95% CI: 1.21, 1.64), and 1.32 (95% CI: 1.15, 1.52), respectively. For heat effects, the overall relative risks of mortality at the 95
th
, 97.5th and 99th percentiles were 1.10 (95% CI: 1.04, 1.16), 1.17 (95% CI: 1.07, 1.29), and 1.29 (95% CI: 1.11, 1.5), respectively. The excess mortality attributable to cold days accounted for 8.0 deaths (95% empirical CI: 4.5-10.8) for every 100 deaths, while the excess mortality attributable to heat days accounted for 1.3 deaths (95% empirical CI: 0.7-1.7) for every 100 deaths. The results prompt additional research into environmental risk prevention in this under-studied hot and dry region that could experience disproportionate climate change related exposures.
Implications: The quantification of excess mortality attributable to temperature extremes shows an urgent need for targeted public health interventions and climate adaptation strategies in Cyprus and similar regions facing rapid climate change. Future steps should look into subpopulation sensitivity, coping strategies, and adaptive interventions to reduce potential future risks.
Climate change is expected to increase heat-related mortality across the world. Health Impact Assessment (HIA) studies are used to quantify the impact of higher temperatures, taking into account the ...effect of population adaptation. Although air-conditioning (AC) is one of the main drivers of technological adaptation to heat, the health impacts associated with AC-induced air pollution have not been examined in detail. This study uses the city of Thessaloniki, Greece as a case study and aims to estimate the future heat-related mortality, the residential cooling demand, and the adaptation trade-off between averted heat-related and increased air pollution cardiorespiratory mortality. Using temperature and population projections under different Coupled Model Intercomparison Project Phase 6 (CIMP6) Shared Socioeconomic Pathways scenarios (SSPs), a HIA model was developed for the future heat and air pollution cardiorespiratory mortality. Counterfactual scenarios of either black carbon (BC) or natural gas (NG) being the fuel source for electricity generation were included in the HIA. The results indicate that the heat-related cardiorespiratory mortality in Thessaloniki will increase and the excess of annual heat-related deaths in 2080–2099 will range from 2.4 (95% CI: 0.0–20.9) under SSP1-2.6 to 433.7 (95% CI: 66.9–1070) under SSP5-8.5. Population adaptation will attenuate the heat-related mortality, although the latter may be counterbalanced by the higher air pollution-related mortality due to increased AC, especially under moderate SSP scenarios and coal-fired power plants. Future studies examining the health effects of warmer temperatures need to account for the impact of both adaptation and increased penetration and use of AC.
•Heat-related mortality is estimated to increase under climate change scenarios.•Recent studies demonstrated a degree of human adaptation to increased temperatures.•There is evidence that air-conditioning (AC) is one of the major the main drivers of adaptation to heat.•Air pollution mortality due to increased AC counterbalances the effect of adaptation.•Results are sensitive to Climate Change scenarios and fuel type used for electricity generation.
Diagnostic testing for primary ciliary dyskinesia (PCD) usually includes transmission electron microscopy (TEM), nasal nitric oxide, high-speed video microscopy, and genetics. Diagnostic performance ...of each test should be assessed toward the development of PCD diagnostic algorithms. We systematically reviewed the literature and quantified PCD prevalence among referrals and TEM detection rate in confirmed PCD patients. Major electronic databases were searched until December 2015 using appropriate terms. Included studies described cohorts of consecutive PCD referrals in which PCD was confirmed by at least TEM and one additional test, in order to compare the index test performance with other test(s). Meta-analyses of pooled PCD prevalence and TEM detection rate across studies were performed. PCD prevalence among referrals was 32% (95% CI: 25-39%, I
= 92%). TEM detection rate among PCD patients was 83% (95% CI: 75-90%, I
= 90%). Exclusion of studies reporting isolated inner dynein arm defects as PCD, reduced TEM detection rate and explained an important fraction of observed heterogeneity (74%, 95% CI: 66-83%, I
= 66%). Approximately, one third of referrals, are diagnosed with PCD. Among PCD patients, a significant percentage, at least as high as 26%, is missed by TEM, a limitation that should be accounted toward the development of an efficacious PCD diagnostic algorithm.
The eastern Mediterranean region is characterized by rising temperature trends exceeding the corresponding global averages and is considered a climate change hot-spot. Although previous studies have ...thoroughly investigated the impact of extreme heat and cold on human mortality and morbidity, both for the current and future climate change scenarios, the temporal trends in temperature-related mortality or the potential historical adaptation to heat and cold extremes has never been studied in this region. This study focuses on cardiovascular mortality and assesses the temporal evolution of the Minimum Mortality Temperature (MMT), as well as the disease-specific cold- and heat-attributable fraction of mortality in three typical eastern Mediterranean environments (Athens, Thessaloniki and Cyprus). Data on daily cardiovascular mortality (ICD-10 code: I00–I99) and meteorological parameters were available between 1999 and 2019 for Athens, 1999 to 2018 for Thessaloniki and 2004 to 2019 for Cyprus. Estimation of cardiovascular MMT and mortality fractions relied on time-series Poisson regressions with distributed lag nonlinear models (DLNM) controlling for seasonal and long-term trends, performed over a series of rolling sub-periods at each site. The results indicated that in Athens, the MMT decreased from 23 °C (67.5th percentile) in 1999–2007 to 21.8 °C (62nd percentile) in 2011–2019, while in Cyprus the MMT decreased from 26.3 °C (79th percentile) in 2004–2012 to 23.9 °C (66.5th percentile) in 2011–2019. In Thessaloniki, the decrease in MMT was rather negligible. In all regions under study, the fractions of mortality attributed to both cold and heat followed an upward trend throughout the years. In conclusion, the demonstrated increase in cold attributable fraction and the decreasing temporal trend of MMT across the examined sites are suggestive of maladaptation to extreme temperatures in regions with warm climate and highlight the need for relevant public health policies and interventions.
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•Adaptation to heat and cold has never been investigated in Eastern Mediterranean.•We assessed temporal trends in temperature-related CVD mortality in three sites.•Evidence of a decreasing temporal trend was observed for Minimum Mortality Temperature.•Across all sites, cold-attributable fraction of CVD mortality increased.•Results are suggestive of maladaptation to temperature extremes in warm environments.
This meta-analysis aimed to examine the association of child abuse with adult coronary heart disease risk and separately by abuse subtypes, including emotional abuse, sexual abuse, and physical ...abuse.
Data were extracted from studies published up through December 2021 and on the basis of research from PubMed, Embase, CINAHL, and PsycINFO. Studies were selected if they included adults with or without any type of child abuse and measured the risk of any type of coronary heart disease. Statistical analyses were conducted in 2022. The random effects model was used to pool the effect estimates presented by RRs with 95% CIs. Heterogeneity was assessed using Q and I2 statistics.
The pooled estimates were synthesized using 24 effect sizes from 10 studies with a sample size of 343,371 adults. Adults with child abuse were associated with a higher risk of coronary heart disease than those without (RR=1.52; 95% CI=1.29, 1.79), and the association was similar for myocardial infarction (RR=1.50; 95 % CI=1.08, 2.10) and unspecified coronary heart disease (RR=1.58; 95% CI=1.23, 2.02). Moreover, emotional (RR=1.48; 95% CI=1.29, 1.71), sexual (RR=1.47; 95% CI=1.15, 1.88), and physical (RR=1.48; 95% CI=1.22, 1.79) abuse were associated with increased risk of coronary heart disease.
Child abuse was associated with an increased risk of adult coronary heart disease. Results were generally consistent across abuse subtypes and sex. This study advocates further research on biological mechanisms linking child abuse to coronary heart disease as well as improvement in coronary heart disease risk prediction and targeted prevention approaches.
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