Showing papers in "Epidemiology in 2008"
TL;DR: In a population-based sample of middle-aged adults, subjective reports of habitual sleep are moderately correlated with actigraph-measured sleep, but are biased by systematic over-reporting.
Abstract: Recent epidemiologic studies have found that sleep duration is associated with obesity, diabetes, hypertension and mortality. These studies have used self-reported habitual sleep duration, which has not been well validated. We model the extent to which self-reported habitual sleep reflects average objectively measured sleep. Eligible participants at the Chicago site of Coronary Artery Risk Development in Young Adults Study were invited to participate in a 2003-2004 ancillary sleep study; 82% (n=669) agreed. Sleep measurements collected in two waves included: 3-days of wrist actigraphy, a sleep log, and standard questions about usual sleep duration. Average measured sleep was 6 hours, and subjective reports averaged 0.80 hours longer than measured sleep. Subjective reports were not well calibrated, increasing on average by 31 minutes for each additional hour of measured sleep. Our model suggests that persons sleeping 5 and 7 hours over-reported, on average, by 1.3 and 0.3 hours respectively. Overall, there was a correlation of 0.45 between reported and measured sleep duration. The extent of overestimation, calibration and correlation varied by personal and sleep characteristics. Although asking about sleep duration seems uncomplicated, the correlation between self-reported and objectively-measured sleep in this population was moderate and systematically biased.
1,177 citations
TL;DR: Potential approaches to this problem include being cautious about newly discovered effect sizes, using analytical methods that correct for the anticipated inflation, ignoring the magnitude of the effect (if not necessary), conducting large studies in the discovery phase, using strict protocols for analyses, pursuing complete and transparent reporting of all results, placing emphasis on replication, and being fair with interpretation of results.
Abstract: Newly discovered true (non-null) associations often have inflated effects compared with the true effect sizes. I discuss here the main reasons for this inflation. First, theoretical considerations prove that when true discovery is claimed based on crossing a threshold of statistical significance and the discovery study is underpowered, the observed effects are expected to be inflated. This has been demonstrated in various fields ranging from early stopped clinical trials to genome-wide associations. Second, flexible analyses coupled with selective reporting may inflate the published discovered effects. The vibration ratio (the ratio of the largest vs. smallest effect on the same association approached with different analytic choices) can be very large. Third, effects may be inflated at the stage of interpretation due to diverse conflicts of interest. Discovered effects are not always inflated, and under some circumstances may be deflated-for example, in the setting of late discovery of associations in sequentially accumulated overpowered evidence, in some types of misclassification from measurement error, and in conflicts causing reverse biases. Finally, I discuss potential approaches to this problem. These include being cautious about newly discovered effect sizes, considering some rational down-adjustment, using analytical methods that correct for the anticipated inflation, ignoring the magnitude of the effect (if not necessary), conducting large studies in the discovery phase, using strict protocols for analyses, pursuing complete and transparent reporting of all results, placing emphasis on replication, and being fair with interpretation of results.
1,176 citations
TL;DR: There is an important mortality effect of heat across Europe from June through August; it is limited to the first week following temperature excess, with evidence of mortality displacement.
Abstract: BACKGROUND: Epidemiologic studies show that high temperatures are related to mortality, but little is known about the exposure-response function and the lagged effect of heat. We report the associations between daily maximum apparent temperature and daily deaths during the warm season in 15 European cities. METHODS: The city-specific analyses were based on generalized estimating equations and the city-specific results were combined in a Bayesian random effects meta-analysis. We specified distributed lag models in studying the delayed effect of exposure. Time-varying coefficient models were used to check the assumption of a constant heat effect over the warm season. RESULTS: The city-specific exposure-response functions have a V shape, with a change-point that varied among cities. The meta-analytic estimate of the threshold was 29.4 degrees C for Mediterranean cities and 23.3 degrees C for north-continental cities. The estimated overall change in all natural mortality associated with a 1 degrees C increase in maximum apparent temperature above the city-specific threshold was 3.12% (95% credibility interval = 0.60% to 5.72%) in the Mediterranean region and 1.84% (0.06% to 3.64%) in the north-continental region. Stronger associations were found between heat and mortality from respiratory diseases, and with mortality in the elderly. CONCLUSIONS: There is an important mortality effect of heat across Europe. The effect is evident from June through August; it is limited to the first week following temperature excess, with evidence of mortality displacement. There is some suggestion of a higher effect of early season exposures. Acclimatization and individual susceptibility need further investigation as possible explanations for the observed heterogeneity among cities.
777 citations
TL;DR: The findings suggest that the discrepancies between the Women's Health Initiative and Nurses’ Health Study ITT estimates could be largely explained by differences in the distribution of time since menopause and length of follow-up.
Abstract: Causal inferences are drawn from both randomized experiments and observational studies. When estimates from both types of studies are available, it is reassuring to find that they are often similar.1–3 On the other hand, when randomized and observational estimates disagree, it is tempting to attribute the differences to the lack of random treatment assignment in observational studies.
This lack of randomization makes observational effect estimates vulnerable to confounding bias due to the different prognosis of individuals between treatment groups. The potential for confounding may diminish the enthusiasm for other desirable features of observational studies compared with randomized experiments – greater timeliness, less restrictive eligibility criteria, longer follow-up, and lower cost. However, even though randomization is the defining difference between randomized experiments and observational studies, further differences in both design and analysis are commonplace. As a consequence, observational-randomized discrepancies cannot be automatically attributed to randomization itself.
In this paper we assess the extent to which differences other than randomization contribute to discrepant observational versus randomized effect estimates in the well-known example of postmenopausal estrogen plus progestin therapy and the risk of coronary heart disease (CHD). Specifically, we explore discrepancies attributable to different distributions of time since menopause, length of follow-up, and analytic approach.
The published findings on this topic can be briefly summarized as follows. Large observational studies suggested a reduced risk of CHD among postmenopausal hormone users. Two of the largest observational studies were based on the Nurses’ Health Study (NHS)4, 5 in the United States and on the General Practice Research Database6 in the United Kingdom. More recently, the Women’s Health Initiative (WHI) randomized trial7 found a greater incidence of coronary heart disease among postmenopausal women in the estrogen plus progestin arm than in the placebo arm (68% greater in the first two years after initiation, 24% greater after an average of 5.6 years).8, 9
The present paper does not address the complex clinical and public health issues related to hormone therapy, including risk-benefit considerations. Rather, we focus on methodologic issues in the analysis of observational cohort studies. Specifically, we reanalyze the NHS observational data to yield effect estimates of hormone therapy that are directly comparable with those of the randomized WHI trial except for the fact that hormone therapy was not randomly assigned in the NHS. We do this by mimicking the design of the randomized trial as closely as possible in the NHS. As explained below, our approach requires conceptualizing the observational NHS cohort as if it were a sequence of nonrandomized “trials.” Because the randomized trial data were analyzed under the intention-to-treat (ITT) principle, we analyze our NHS “trials” using an observational analog of ITT (see below).
A recent re-analysis of the General Practice Research Database using this strategy could not adjust for lifestyle factors and it yielded wide confidence intervals.10 Further, the estrogen used by women in that study was not the conjugated equine estrogen used by the women in the NHS and WHI studies. Our analysis of the NHS data incorporates lifestyle factors and includes women using the same type of estrogen as in the WHI randomized trial.
682 citations
TL;DR: This study shows that certain chemical species modify the association between PM2.5 and mortality and illustrates that mass alone is not a sufficient metric when evaluating health effects of PM exposure.
Abstract: Background:Although the association between exposure to particulate matter (PM) mass and mortality is well established, there remains uncertainty about which chemical components of PM are most harmful to human health.Methods:A hierarchical approach was used to determine how the association between d
363 citations
TL;DR: The hypothesis that high vitamin D status provides protection against type 2 diabetes is supported, and the relative odds between the highest and lowest quartiles was 0.28, suggesting a reduced risk of type 1 diabetes in their highest vitamin D quartile.
Abstract: Background:Low vitamin D status has been suggested as a risk factor for type 2 diabetes. Although the epidemiologic evidence is scarce, 2 recent studies have suggested an association. The present study investigated the relation of serum vitamin D with type 2 diabetes incidence using pooled data from
323 citations
TL;DR: Although coarse particles seem to be more hazardous duringSaharan dust days, differences in chemical composition did not explain these observations and further investigation is needed to understand the role of coarse particles and the mechanism by which Saharan dust increases mortality.
Abstract: Background:Winds from the Sahara-Sahel desert region regularly transport large amounts of dust to the Americas, North Africa, and Europe. The presence of high dust concentrations for long periods of time, and the interaction between dust and man-made air pollution, raise concerns about adverse healt
305 citations
TL;DR: There is strong support for air pollution effects on the development of lung function in children and adolescents but further research is needed on the relevance of specific pollution sources, particularly with regard to susceptible populations and relevant exposure periods throughout life.
Abstract: Lung function is an important measure of respiratory health and a predictor of cardiorespiratory morbidity and mortality. Over the past 2 decades, more than 50 publications have investigated long-term effects of ambient air pollution on lung function with most finding adverse effects. Several studies have also suggested effects from traffic-related air pollution. There is strong support for air pollution effects on the development of lung function in children and adolescents. It remains unclear whether subjects with slower development of lung function compensate by prolonging the growth phase, or whether they end their development at a lower plateau, thus entering the decline phase with a reduced lung function. In adults, the evidence for long-term air pollution effects is mostly based on cross-sectional comparisons. One recent longitudinal study observed that decreasing pollution attenuated the decline of lung function in adults. Earlier inconclusive cohort studies were based on limited data. There is great diversity in study designs, markers of air pollution, approaches to the measurement of exposure, and choices in lung function measures. These limit the comparability of studies and impede quantitative summaries. New studies should use individual-level exposure assessment to clarify the role of traffic and to preclude potential community-level confounding. Further research is needed on the relevance of specific pollution sources, particularly with regard to susceptible populations and relevant exposure periods throughout life.
302 citations
TL;DR: Residents of neighborhoods with better walkability, availability of healthy foods, greater safety, and more social cohesion may be mechanisms that link neighborhoods to hypertension.
Abstract: Background:The goal of this study was to investigate cross-sectional associations between features of neighborhoods and hypertension and to examine the sensitivity of results to various methods of estimating neighborhood conditions.Methods:We used data from the Multi-Ethnic Study of Atherosclerosis
283 citations
TL;DR: Measurement of the indicator bacteria Enterococci in recreational water using a rapid QPCR method predicted swimming-associated GI illness at freshwater beaches polluted by sewage discharge and children at 10 years or younger were at greater risk for GI illness following exposure.
Abstract: Background:Culture-based methods of monitoring fecal pollution in recreational waters require 24 to 48 hours to obtain results. This delay leads to potentially inaccurate management decisions regarding beach safety. We evaluated the quantitative polymerase chain reaction (QPCR) as a faster method to
274 citations
TL;DR: Exposure to moderate levels of locally emitted air pollution from traffic early in life appears to influence the development of airway disease and sensitization in preschool children.
Abstract: Background:Urban air pollution can trigger asthma symptoms in children, but there is conflicting evidence on effects of long-term exposure on lung function, onset of airway disease and allergic sensitization.Methods:The spatial distribution of nitrogen oxides from traffic (traffic-NOx) and inhalable
TL;DR: This study provides evidence of increased mortality due to elevated apparent temperature exposure, with no confounding or effect modification due to air pollution.
Abstract: Background:Extreme temperatures have been associated with increased mortality worldwide. The extent to which air pollutants may confound or modify this association remains unclear.Methods:We examined the association between mean apparent temperature and total mortality in 9 cities across the United
TL;DR: E Epidemiologists need to be aware of potential problems that occur when the same data set is used to select a multilocus risk model from a wide range of possible models and then estimate the accuracy of the final model ("over-fitting").
Abstract: The estimated effect of a marker allele from the initial study reporting the marker-allele association is often exaggerated relative to the estimated effect in follow-up studies (the "winner's curse" phenomenon). This is a particular concern for genome-wide association studies, where markers typically must pass very stringent significance thresholds to be selected for replication. A related problem is the overestimation of the predictive accuracy that occurs when the same data set is used to select a multilocus risk model from a wide range of possible models and then estimate the accuracy of the final model ("over-fitting"). Even in the absence of these quantitative biases, researchers can over-state the qualitative importance of their findings--for example, by focusing on relative risks in a context where sensitivity and specificity may be more appropriate measures. Epidemiologists need to be aware of these potential problems: as authors, to avoid or minimize them, and as readers, to detect them.
TL;DR: A simple noniterative procedure is proposed for computing the combined effect size under this model and it is suggested that this could represent a more convincing alternative to the random effects model.
Abstract: We introduce a quality-effects approach that combines evidence from a series of trials comparing 2 interventions. This approach incorporates the heterogeneity of effects in the analysis of the overall interventional efficacy. However, unlike the random-effects model based on observed between-trial heterogeneity, we suggest adjustment based on measured methodological heterogeneity between studies. We propose a simple noniterative procedure for computing the combined effect size under this model and suggest that this could represent a more convincing alternative to the random effects model.
TL;DR: Data from 9 study regions near a ferrochromium factory in Liaoning Province, China are consistent with increased stomach cancer risk in a population exposed to Cr+6 in drinking water.
Abstract: In 1987 investigators in Liaoning Province China reported that mortality rates for all cancer stomach cancer and lung cancer in 1970-1978 were higher in villages with hexavalent chromium (Cr/+6)-contaminated drinking water than in the general population. The investigators reported rates but did not report statistical measures of association or precision. Using reports and other communications from investigators at the local Jinzhou Health and Anti-Epidemic Station we obtained data on Cr/+6 contamination of groundwater and cancer mortality in 9 study regions near a ferrochromium factory. We estimated: (1) person-years at risk in the study regions based on census and population growth rate data (2) mortality counts based on estimated person-years at risk and previously reported mortality rates and (3) rate ratios and 95% confidence intervals. The all-cancer mortality rate in the combined 5 study regions with Cr/+6-contaminated water was negligibly elevated in comparison with the rate in the 4 combined study regions without contaminated water (rate ratio = 1.13; 95% confidence interval = 0.86-1.46) but was somewhat more elevated in comparison with the whole province (1.23; 0.97-1.53). Stomach cancer mortality in the regions with contaminated water was more substantially elevated in comparison with the regions without contaminated water (1.82; 1.11-2.91) and the whole province (1.69; 1.12-2.44). Lung cancer mortality was slightly elevated in comparison with the unexposed study regions (1.15; 0.62-2.07) and more strongly elevated in comparison with the whole province (1.78; 1.03-2.87). Mortality from other cancers combined was not elevated in comparison with either the unexposed study regions (0.86; 0.53-1.36) or the whole province (0.92; 0.58-1.38). While these data are limited they are consistent with increased stomach cancer risk in a population exposed to Cr/+6 in drinking water. (authors)
TL;DR: Evidence is found for an association of exposure to black smoke and traffic with lung cancer incidence in people who had never smoked.
Abstract: Background: Most studies on the association between lung cancer and air pollution have investigated mortality. There have been few studies of lung cancer incidence. Methods: We used data from the ongoing Netherlands Cohort Study on Diet and Cancer for 114,378 subjects with follow-up from September 1986 to December 1997. Exposure to black smoke, nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter ≥2.5 μm (PM2.5) and traffic intensity variables (intensity on nearest road, intensity in a 100 m buffer, and an indicator variable for living close to a major road) were estimated at the home address. We conducted Cox proportional hazard analyses in the full cohort adjusting for age, sex, smoking status, and area-level socioeconomic status. We also carried out case-cohort analyses using more potential confounders on a subset of study participants for whom complete information from the baseline questionnaire had been processed. Results: Adjusted analyses included 1940 cases for the full cohort and 1295 cases for the case-cohort analysis. Relative risks (RRs) for the overall air pollution concentrations were slightly below unity, and for the traffic variables RRs were slightly elevated. Risk was elevated among people who never smoked cigarettes (40,114 participants; 252 cases), with RRs of 1.47 (95% confidence interval ≤ 1.01-2.16) for overall black smoke concentration, 1.11 (0.88-1.41) for traffic intensity on nearest road, and 1.55 (0.98-2.43) for living near a major road. Conclusions: We found evidence for an association of exposure to black smoke and traffic with lung cancer incidence in people who had never smoked. No associations were found for the full cohort, or for other categories of smoking. Copyright © 2008 by Lippincott Williams & Wilkins.
TL;DR: Results are presented that allow the researcher in certain cases to determine the direction of the bias that arises when control for confounding is inadequate and the directed acyclic graph causal framework is described.
Abstract: We present results that allow the researcher in certain cases to determine the direction of the bias that arises when control for confounding is inadequate. The results are given within the context of the directed acyclic graph causal framework and are stated in terms of signed edges. Rigorous definitions for signed edges are provided. We describe cases in which intuition concerning signed edges fails and we characterize the directed acyclic graphs that researchers can use to draw conclusions about the sign of the bias of unmeasured confounding. If there is only one unmeasured confounding variable on the graph, then nonincreasing or nondecreasing average causal effects suffice to draw conclusions about the direction of the bias. When there are more than one unmeasured confounding variable, nonincreasing and nondecreasing average causal effects can be used to draw conclusions only if the various unmeasured confounding variables are independent of one another conditional on the measured covariates. When this conditional independence property does not hold, stronger notions of monotonicity are needed to draw conclusions about the direction of the bias.
TL;DR: Even without extremes in apparent temperature, an association between temperature and mortality in California that was independent of air pollution was observed.
Abstract: Background:Elevated temperature has been associated with increased mortality. Few epidemiologic studies, however, have considered air pollutants as potential confounders or effect modifiers. None has focused on California, where the climate is generally mild and pollution levels tend to be high—an i
TL;DR: Diabetes prevention efforts may need to consider features of residential environment, including diet, physical activity, and body mass index, which suggested that these variables partly mediated observed associations.
Abstract: Objective:Little is known about the influence of the built environment, and in particular neighborhood resources, on health. We hypothesized that neighborhood resources for physical activity and healthy foods are associated with insulin resistance.Methods:Person-level data (n = 2026) came from 3 sit
TL;DR: Exposure to cell phones prenatally and postnatally was associated with behavioral difficulties such as emotional and hyperactivity problems around the age of school entry, which may be noncausal and may be due to unmeasured confounding.
Abstract: Background:The World Health Organization has emphasized the need for research into the possible effects of radiofrequency fields in children We examined the association between prenatal and postnatal exposure to cell phones and behavioral problems in young childrenMethods:Mothers were recruited to
TL;DR: To the degree that the association of birth weight with adult survival is causal, the U-shaped association between birth weight and adult mortality suggests that population increases in birth weight may not necessarily lead to improved health in adulthood.
Abstract: Background:Small size at birth is associated with subsequent cardiovascular disease and diabetes, and large size is associated with obesity and cancer. The overall impact of these opposing effects on mortality throughout the lifespan is unclear because causes of death change with age.Methods:We inve
TL;DR: It is conjecture that selection bias due to censoring by death may be the main explanation for the reversal of the relative rate with increasing age.
Abstract: We conducted a systematic review of published prospective studies that estimated the association between smoking and the incidence of Alzheimer disease and dementia. The relative rate for smokers versus nonsmokers ranged from 0.27 to 2.72 for Alzheimer disease (12 studies) and from 0.38 to 1.42 for dementia (6 studies). The minimum age at entry (range: 55-75 years) explained much of the between-study heterogeneity in relative rates. We conjecture that selection bias due to censoring by death may be the main explanation for the reversal of the relative rate with increasing age.
TL;DR: Short- and long-term residential exposures to traffic-related pollutants in Oslo were associated with reduced peak expiratory flow and forced expiratories flow at 25% and 50% in 9- to 10-year-old children, especially in girls, with weaker associations after adjusting for a contextual socioeconomic factor.
Abstract: Background:Long-term exposure to outdoor air pollution has typically been estimated on the aggregate level, and more individual measures of exposure are needed. We investigated the associations with lung function of residential outdoor air pollution in early life, total lifetime, and days before lun
TL;DR: The number of cholera cases increased with both high and low rainfall in the weeks preceding hospital visits, suggesting that factors associated with river level are on the causal pathway between high rainfall and incidence of choledera.
Abstract: Background: The incidence of cholera in Bangladesh shows clear seasonality, suggesting that weather factors could play a role in its epidemiology. We estimated the effects of rainfall on the incidence of cholera in Dhaka, Bangladesh. Methods: We examined time-series patterns of the weekly number of hospital visits due to cholera in relation to weekly rainfall from 1996 to 2002. We used Poisson regression models, adjusted for seasonal variation, between-year variation, public holidays, and temperature. The role of river level on the rainfall-cholera relationship was also examined by incorporating river-level terms into the models. Results: The weekly number of cholera cases increased by 14% (95% confidence interval = 10.1%–18.9%) for each 10-mm increase above the threshold of 45 mm for the average rainfall, over lags 0 to 8 weeks. Conversely, the number of cholera cases increased by 24% (10.7%–38.6%) for a 10-mm decrease below the same threshold of average rainfall, over lags 0 to 16 weeks. River level partly explained the association between high rainfall and the number of cholera cases. Conclusions: The number of cholera cases increased with both high and low rainfall in the weeks preceding hospital visits. These results suggest that factors associated with river level are on the causal pathway between high rainfall and incidence of cholera.
Journal Article•
TL;DR: In this article, the authors examined whether declining selenium levels over time are associated with cognitive decline in a cohort of community-dwelling French elderly, and they found that cognitive decline was associated with decreases of plasma SE over time.
Abstract: Background: Because brain oxidative stress is a cause of cognitive impairment, selenium, which is an antioxidant, may protect against cognitive decline. The aim of the study was to examine whether declining selenium levels over time are associated with cognitive decline in a cohort of community-dwelling French elderly. Methods: During 1991–1993, 1389 subjects (age 60–71 years) were recruited into a 9-year longitudinal study with 6 waves of follow-up. Cognitive functions were evaluated by neuropsychologic tests. To take into account the entire set of cognitive measurements and the within-subject correlations between measures, we analyzed mixed linear and logistic models to study associations between selenium change and cognitive decline. Results: After controlling for potential confounders, cognitive decline was associated with decreases of plasma selenium over time. Among subjects who had a decrease in their plasma selenium levels, the greater the decrease in plasma selenium, the higher the probability of cognitive decline. Among subjects who had an increase in their plasma selenium levels, cognitive decline was greater in subjects with the smallest selenium increase. There was no association between short-term (2-year) selenium change and cognitive changes. Conclusion: Selenium status decreases with age and may contribute to declines in neuropsychologic functions among aging people.
TL;DR: It is proposed that the Medicare files can be used to construct on-going cohorts for tracking the risk of air pollution over time and risks similar to those in the previously published reports, which incorporated more extensive information on individual-level confounders.
Abstract: Background:The American Cancer Society study and the Harvard Six Cities study are 2 landmark cohort studies for estimating the chronic effects of fine particulate air pollution (PM2.5) on mortality. Using Medicare data, we assessed the association of PM2.5 with mortality for the same locations inclu
TL;DR: Helmet use may provide some protection from head injury among skiers and snowboarders involved in falls or collisions, and odds ratios for head, face, and neck injury among helmeted compared with unhelmeted persons.
Abstract: BACKGROUND:: The extent to which helmet use reduces the risk of injury in ski- and snowboard-related accidents is unclear. We studied the association of helmet use with injuries of the head, face, and neck among skiers and snowboarders involved in falls and collisions. METHODS:: We conducted a case-control study, using ski patrol injury reports for the years 2000-2005 from 3 ski resorts in the western United States. We identified all skiers and snowboarders involved in falls or collisions who received care from the ski patrol. Helmet use among persons with injuries of the head (n = 2537), face (n = 1122), or neck (n = 565) was compared with helmet use among those involved in falls and collisions who received care for injuries below the neck (n = 17,674). We calculated odds ratios for head, face, and neck injury among helmeted compared with unhelmeted persons. RESULTS:: The adjusted odds ratios were 0.85 for head injury (95% confidence interval = 0.76-0.95), 0.93 for facial injury (0.79-1.09), and 0.91 for neck injury (0.72-1.14). CONCLUSIONS:: Helmets may provide some protection from head injury among skiers and snowboarders involved in falls or collisions. Language: en
TL;DR: The susceptibility of the elderly to die of ambient ozone was confirmed and other vulnerable subpopulations including women, blacks, and those with atrial fibrillation were identified, particularly marked in cities with lower ozone concentrations.
Abstract: Background:Daily increases in ambient ozone have been associated with increased mortality. However, little is known about which subpopulations are more susceptible to death related to ozone.Methods:We conducted a case-only study in 48 US cities to identify subpopulations particularly vulnerable to o
TL;DR: Prenatal and early-life exposures to CO, PM10, and NO2 have a negative effect on pulmonary function in subgroups of asthmatic children, including children who were African American, those diagnosed with asthma before the age of 2 years, and those exposed to maternal smoking during pregnancy.
Abstract: Background:Prenatal and early life periods represent critical windows for oxidant pollutant-induced lung remodeling. The objective of this study was to examine the association of prenatal and lifetime exposures to air pollutants with pulmonary function in a cohort of children with asthma.Methods:Pre
TL;DR: A decrease in air temperature, particularly the average temperature of the last 5 days, was associated with an increase in both C-reactive protein and interleukin-6, whereas fibrinogen seemed to react to temperature changes after 3 days, suggesting a biologic mechanism for the observed seasonal variation in death from ischemic heart disease and stroke in the elderly.
Abstract: Background:Temperature changes have been associated with increased cardiovascular risk, but the role of inflammatory markers in this relationship is not well understood. The objective of this study was to analyze the association between air temperature and C-reactive protein, interleukin-6 and fibri