Early-life residential green spaces and traffic exposure in association with young adult body composition: a longitudinal birth cohort study of twins.

BACKGROUND: Globally, the rapid increase of obesity is reaching alarming proportions. A new approach to reduce obesity and its comorbidities involves tackling the built environment. Environmental influences seem to play an important role, but the environmental influences in early life on adult body composition have not been thoroughly investigated. This study seeks to fill the research gap by examining early-life exposure to residential green spaces and traffic exposure in association with body composition among a population of young adult twins. METHODS: As part of the East Flanders Prospective Twin Survey (EFPTS) cohort, this study included 332 twins. Residential addresses of the mothers at time of birth of the twins were geocoded to determine residential green spaces and traffic exposure. To capture body composition, body mass index, waist-to-hip ratio (WHR), waist circumference, skinfold thickness, leptin levels, and fat percentage were measured at adult age. Linear mixed modelling analyses were conducted to investigate early-life environmental exposures in association with body composition, while accounting for potential confounders. In addition, moderator effects of zygosity/chorionicity, sex and socio-economic status were tested. RESULTS: Each interquartile range (IQR) increase in distance to highway was found associated with an increase of 1.2% in WHR (95%CI 0.2-2.2%). For landcover of green spaces, each IQR increase was associated with 0.8% increase in WHR (95%CI 0.4-1.3%), 1.4% increase in waist circumference (95%CI 0.5-2.2%), and 2.3% increase in body fat (95%CI 0.2-4.4%). Stratified analyses by zygosity/chorionicity type indicated that in monozygotic monochorionic twins, each IQR increase in land cover of green spaces was associated with 1.3% increase in WHR (95%CI 0.5-2.1%). In monozygotic dichorionic twins, each IQR increase in land cover of green spaces was associated with 1.4% increase in waist-circumference (95%CI 0.6-2.2%). CONCLUSIONS: The built environment in which mothers reside during pregnancy might play a role on body composition among young adult twins. Our study revealed that based on zygosity/chorionicity type differential effects of prenatal exposure to green spaces on body composition at adult age might exist.

Association between outdoor air pollution and chronic rhinosinusitis patient reported outcomes.

BACKGROUND: The aetiology of chronic rhinosinusitis (CRS) is multifactorial with a complex interplay between environmental, microbial endogenous and genetic factors. The impact of outdoor air pollution on prevalence or severity of CRS remains largely unknown. METHODS: Real-life geolocation data (2017-2018, Belgium) from 278 CRS patients (2576 health records) using the mySinusitisCoach mobile application were analysed to calculate the patients' individual exposure to outdoor air pollutants (ozone (O3), black carbon (BC), nitrogen dioxide (NO2) and particulate matter with diameter < 2.5 µm (PM2.5)) and to associate these pollutants with the patients' sinus related symptoms measured at multiple occasions by visual analogue scale (VAS). RESULTS: The adjusted seasonal model for the spring-summer (n = 1000 health entries, N = 83 patients) population revealed an increase of 6.07 (p < 0.0001) in overall CRS symptom scoring for an interquartile range (IQR) increase in exposure to O3 (26.9 µg/m3). An increase of 1.69 (p = 0.05) in total CRS symptom scoring was observed for an IQR increase of PM2.5 (7.1 µg/m3) exposure. Sex-stratified analysis in the spring-summer population showed significant interaction between air pollution and sex with male patients having higher total CRS symptom scores for an IQR increase in exposure to PM2.5 (3.52, p = 0.001), and O3 (8.33, p < 0.0001), while no significant association with symptom severity was seen in the female patients. In the analysis stratified by comorbid asthma, CRS patients with comorbid asthma had higher total CRS symptoms for an IQR increase in exposure to PM2.5 (2.58, p = 0.04) and O3 (7.72, p < 0.0001) while the patients without comorbid asthma had no significant symptom increases. CONCLUSION: Exposure to outdoor air pollution is associated with increased symptom severity in CRS patients. The extent to which CRS patients are sensitive to outdoor air pollution exposure varies per season and depends on their sex and comorbid asthma status. mHealth technology has the potential to reveal novel insights on the patients' exposome and disease severity in the real-life situation.

Air pollution-induced placental alterations: an interplay of oxidative stress, epigenetics, and the aging phenotype?

According to the "Developmental Origins of Health and Disease" (DOHaD) concept, the early-life environment is a critical period for fetal programming. Given the epidemiological evidence that air pollution exposure during pregnancy adversely affects newborn outcomes such as birth weight and preterm birth, there is a need to pay attention to underlying modes of action to better understand not only these air pollution-induced early health effects but also its later-life consequences. In this review, we give an overview of air pollution-induced placental molecular alterations observed in the ENVIRONAGE birth cohort and evaluate the existing evidence. In general, we showed that prenatal exposure to air pollution is associated with nitrosative stress and epigenetic alterations in the placenta. Adversely affected CpG targets were involved in cellular processes including DNA repair, circadian rhythm, and energy metabolism. For miRNA expression, specific air pollution exposure windows were associated with altered miR-20a, miR-21, miR-146a, and miR-222 expression. Early-life aging markers including telomere length and mitochondrial DNA content are associated with air pollution exposure during pregnancy. Previously, we proposed the air pollution-induced telomere-mitochondrial aging hypothesis with a direct link between telomeres and mitochondria. Here, we extend this view with a potential co-interaction of different biological mechanisms on the level of placental oxidative stress, epigenetics, aging, and energy metabolism. Investigating the placenta is an opportunity for future research as it may help to understand the fundamental biology underpinning the DOHaD concept through the interactions between the underlying modes of action, prenatal environment, and disease risk in later life. To prevent lasting consequences from early-life exposures of air pollution, policy makers should get a basic understanding of biomolecular consequences and transgenerational risks.

Body fat evolution as predictor of retinal microvasculature in children.

OBJECTIVES: Microvascular changes may represent an underlying mechanism through which overweight contributes to cardiovascular disease development. Therefore, the aim of this study was to investigate whether changes in children's body fat over time are associated with the retinal microvasculature, a marker of cardiovascular aging. METHODS: In a longitudinal design, 171 healthy Flemish children (53.8% boys) were followed-up for 7 years (2008-2015), aged 2.7-8.1 years at baseline.Z-scores of body mass index (zBMI; 4.1% overweight), waist circumference (zWC) and fat mass index (zFMI by BODPOD) were obtained using standardized protocols during each visit. Retinal arteriolar (central retinal arteriolar equivalent (CRAE)) and venular equivalents (central retinal venular equivalent (CRVE)) were measured from digital retinal photographs (2015) using IVAN software. Cross-sectional and longitudinal associations between changes in body fat and retinal microvasculature were explored using multivariable regression analysis, while controlling for age, sex, mean arterial pressure, alternate retinal caliber, physical activity, diet and birth weight. RESULTS: In cross-sectional analysis, children with high zFMI had a higher CRVE, but only in boys (ß=0.25, P=0.02). In addition, boys with high zFMI had also a lower CRAE to CRVE ratio (ß=-0.26, P=0.03). No associations were seen with the CRAE, or between zBMI or zWC and the retinal microvasculature. Only changes in zFMI over time were found to be positively associated with the CRVE in boys (ß=0.38, P=0.01). CONCLUSIONS: Our analysis over a 7-year period shows that changes in body fat during childhood are already associated with the CRVE (especially in boys).

Continuous alternating inhaled antibiotic therapy in CF: A single center retrospective analysis.

INTRODUCTION: The efficacy of inhaled antibiotics to treat chronic Pseudomonas aeruginosa pulmonary infection in patients with cystic fibrosis (CF) has been well established. Few data are available on the value of continuous alternating inhaled antibiotic therapy (CAIT), a strategy increasingly used in the management of CF. OBJECTIVE: To investigate the effect of CAIT on clinical outcome in adult CF patients treated at the University Hospital Leuven. METHODS: Patients with a documented CF diagnosis who received inhaled antibiotics between March 2010 and January 2015 were retrospectively evaluated. In patients receiving CAIT patient characteristics, recorded spirometry data and number of IV antibiotic days were collected retrospectively at fixed time intervals, from 6months before to one year after the start of the 2nd inhaled antibiotic. For patients on inhaled antibiotic monotherapy (IAMT), the same data were obtained at similar intervals during the study period. RESULTS: A total of 49 of 89 patients using chronic inhaled antibiotic therapy received CAIT. Patients receiving CAIT had a lower baseline FEV1 and were more likely to be homozygous for F508del compared to patients receiving IAMT. FEV1 deteriorated on average by a factor of 0.904 per year (95% CI: 0.851-0.960) prior to the start of CAIT. The initiation of CAIT was associated with an average improvement in FEV1 by a factor of 1.148 per year (95% CI: 1.068-1.236, p=0.0002). The analysis of specific types of antibiotics revealed evidence of positive effects of adding COLI to TOBI and COLI to AZLI. We found no effect of the initiation of CAIT on the number of IV antibiotic days (p=0.80). CONCLUSION: CF patients with more advanced lung disease are more likely to receive CAIT. In this patient group, CAIT was associated with a significant improvement in FEV1. Further data are warranted to identify the value of CAIT.

Early-life house dust mite allergens, childhood mite sensitization, and respiratory outcomes.

BACKGROUND: Exposure to indoor allergens during early life may play a role in the development of the immune system and inception of asthma. OBJECTIVE: To describe the house dust mite (HDM) allergen concentrations in bedroom dust during early life and to evaluate its associations with HDM sensitization, wheezing, and asthma, from birth to school age, in 5 geographically spread European birth cohorts. METHODS: We included 4334 children from INMA-Menorca (Spain), BAMSE (Sweden), LISAplus and MAS (Germany), and PIAMA-NHS (the Netherlands). Dust samples were collected from bedrooms during early life and analyzed for Dermatophagoides pteronyssinus (Der p1) and Dermatophagoides farinae (Der f1). HDM concentrations were divided into four categories. Sensitization was determined by specific IgE. Wheezing and asthma information up to 8/10 years was collected through questionnaires. We performed mixed-effects logistic regression models and expressed associations as odds ratios with 95% confidence intervals. RESULTS: House dust mite concentrations varied across cohorts. Mean allergen concentrations were highest in INMA-Menorca (geometric mean (GM) Der p1 = 3.3 µg/g) and LISAplus (GM Der f1 = 2.1 µg/g) and lowest in BAMSE (GM Der p1 = 0.1 µg/g, Der f1 = 0.3 µg/g). Moderate and high HDM concentrations were significantly (P-values < 0.05) associated with 50-90% higher prevalence of HDM sensitization. No significant associations were observed with respiratory outcomes. CONCLUSION: Our study based on geographically spread regions, a large sample size, and a wide range of allergen concentration shows that HDM allergen concentrations vary across regions and that exposure during early life plays a role in the development of allergic sensitization but not in the development of respiratory outcomes.

Variation of DNA methylation in candidate age-related targets on the mitochondrial-telomere axis in cord blood and placenta.

BACKGROUND: Epigenetics is tissue-specific and potentially even cell-specific, but little information is available from human reproductive studies about the concordance of DNA methylation patterns in cord blood and placenta, as well as within-placenta variations. We evaluated methylation levels at promoter regions of candidate genes in biological ageing pathways (SIRT1, TP53, PPARG, PPARGC1A, and TFAM), a subtelomeric region (D4Z4) and the mitochondrial genome (MT-RNR1, D-loop). METHODS: Ninety individuals were randomly chosen from the ENVIRONAGE birth cohort to evaluate methylation concordance between cord blood and placenta using highly quantitative bisulfite-PCR pyrosequencing. In a subset of nineteen individuals, a more extensive sampling scheme was performed to examine within-placenta variation. RESULTS: The DNA methylation levels of the subtelomeric region and mitochondrial genome showed concordance between cord blood and placenta with correlation coefficients ranging from r = 0.31 to 0.43, p ≤ 0.005, and also between the maternal and foetal sides of placental tissue (r = 0.53 to 0.72, p ≤ 0.05). For the majority of targets, an agreement in methylation levels between four foetal biopsies was found (with intra-class correlation coefficients ranging from 0.16 to 0.72), indicating small within-placenta variation. CONCLUSIONS: The methylation levels of the subtelomeric region (D4Z4) and mitochondrial genome (MT-RNR1, D-loop) showed concordance between cord blood and placenta, suggesting a common epigenetic signature of these targets between tissues. Concordance was lacking between the other genes that were studied. In placental tissue, methylation patterns of most targets on the mitochondrial-telomere axis were not strongly influenced by sample location.

Mortality in non-cystic fibrosis bronchiectasis: a prospective cohort analysis.

INTRODUCTION: There is limited data on mortality and associated morbidity in non-cystic fibrosis bronchiectasis (NCFB). Our aim was to analyze the overall mortality for all newly diagnosed patients from June 2006 onwards and to evaluate risk factors for mortality in this cohort. METHODS: 245 patients who had a new diagnosis of NCFB between June 2006 and October 2012 at the University Hospital of Leuven, Belgium, were included in the analysis. Death was analyzed until end of November 2013. All patients had chest HRCT scan confirming the presence of bronchiectatic lesions and had symptoms of chronic productive cough. Univariate and multivariate Cox proportional hazard survival regression analysis was used to estimate hazard ratios (HR) and their 95% confidence intervals (CI) of variables possibly predicting mortality. RESULTS: Overall mortality in NCFB patients who had a median follow-up of 5.18 years was 20.4%. Patients with NCFB and associated chronic obstructive pulmonary disease (COPD) had a mortality of 55% in that period. Univariate analysis showed higher mortality according to age, gender, smoking history, Pseudomonas aeruginosa status, spirometry, radiological extent, total number of sputum bacteria and underlying etiology. Multivariate analysis showed significant higher mortality with increasing age (HR = 1.045; p = 0.004), with increasing number of lobes affected (HR = 1.53; p = 0.009) and when patients had COPD associated NCFB (HR = 2.12; p = 0.038). The majority of the 50 deaths were respiratory related (n = 29; 58%). CONCLUSION: NCFB patients with associated COPD disease had the highest mortality rates compared to the other NCFB patients. Additional risk factors for lower survival were increasing age and number of lobes affected.

Lymphocytic bronchiolitis after lung transplantation is associated with daily changes in air pollution.

Acute rejection represents a major problem after organ transplantation, being a recognized risk for chronic rejection and mortality. Recently, it became clear that lymphocytic bronchiolitis (LB, B-grade acute rejection) is more important than previously thought, as it predisposes to chronic rejection. We aimed to verify whether daily fluctuations of air pollution, measured as particulate matter (PM) are related to histologically proven A-grade rejection and/or LB and bronchoalveolar lavage (BAL) fluid cellularity after lung transplantation. We fitted a mixed model to examine the association between daily variations in PM(10) and A-grade rejection/LB on 1276 bronchoscopic biopsies (397 patients, 416 transplantations) taken between 2001 and 2011. A difference of 10 µg/m(3) in PM(10) 3 days before diagnosis of LB was associated with an OR of 1.15 (95% CI 1.04-1.27; p = 0.0044) but not with A-grade rejection (OR = 1.05; 95% CI 0.95-1.15; p = 0.32). Variations in PM(10) at lag day 3 correlated with neutrophils (p = 0.013), lymphocytes (p = 0.0031) and total cell count (p = 0.024) in BAL. Importantly, we only found an effect of PM10 on LB in patients not taking azithromycin. LB predisposed to chronic rejection (p < 0.0001). The risk for LB after lung transplantation increased with temporal changes in particulate air pollution, and this was associated with BAL neutrophilia and lymphocytosis. Azithromycin was protective against this PM effect.

Air pollution-associated procoagulant changes: the role of circulating microvesicles.

BACKGROUND: Epidemiological studies suggest an association between exposure to particulate matter (PM) in air pollution and the risk of venous thromboembolism (VTE). OBJECTIVES: To investigate the underlying pathophysiological pathways linking PM exposure and VTE. PATIENTS AND METHODS: We assessed potential associations between PM exposure and coagulation and inflammation parameters, including circulating microvesicles, in a group of 233 patients with diabetes. RESULTS: The numbers of circulating blood platelet-derived and annexin V-binding microvesicles were inversely associated with the current levels of PM(2.5) or PM(10), measured on the day of sampling. Recent past exposure to PM(10), up to 1 week prior to blood sampling, estimated at the patients' residential addresses, was associated with elevated high-sensitivity C-reactive protein (CRP), leukocytes and fibrinogen, as well as with tissue factor (TF)-dependent procoagulant changes in thrombin generation assays. When longer windows of past exposure were considered, up to 1 year preceding blood sampling, procoagulant changes were evident from the strongly increased numbers of red blood cell-derived circulating microvesicles and annexin V-binding microvesicles, but they no longer associated with TF. Past PM exposure was never associated with activated partial thromboplastin time (aPTT), prothrombin time (PT), or factor (F) VII, FVIII, FXII or D-dimers. Residential distance to a major road was only marginally correlated with procoagulant changes in FVIII and thrombin generation. CONCLUSIONS: Increases in the number of microvesicles and in their procoagulant properties, rather than increases in coagulation factors per se, seem to contribute to the risk of VTE, developing during prolonged exposure to air pollutants.

No exercise-induced increase in serum BDNF after cycling near a major traffic road.

Commuting by bike has a clear health enhancing effect. Moreover, regular exercise is known to improve brain plasticity, which results in enhanced cognition and memory performance. Animal research has clearly shown that exercise upregulates brain-derived neurotrophic factor (BDNF - a neurotrophine) enhancing brain plasticity. Studies in humans found an increase in serum BDNF concentration in response to an acute exercise bout. Recently, more evidence is emerging suggesting that exposure to air pollution (such as particulate matter (PM)) is higher in commuter cyclists compared to car drivers. Furthermore, exposure to PM is linked to negative neurological effects, such as neuroinflammation and cognitive decline. We carried-out a cross-over experiment to examine the acute effect of exercise on serum BDNF, and the potential effect-modification by exposure to traffic-related air pollution. Thirty eight physically fit, non-asthmatic volunteers (mean age: 43, 26% women) performed two cycling trials, one near a major traffic road (Antwerp Ring, R1, up to 260,000 vehicles per day) and one in an air-filtered room. The air-filtered room was created by reducing fine particles as well as ultrafine particles (UFP). PM10, PM2.5 and UFP were measured. The duration (∼20min) and intensity of cycling were kept the same for each volunteer for both cycling trials. Serum BDNF concentrations were measured before and 30min after each cycling trial. Average concentrations of PM10 and PM2.5 were 64.9µg/m(3) and 24.6µg/m(3) in cycling near a major ring way, in contrast to 7.7µg/m(3) and 2.0µg/m(3) in the air-filtered room. Average concentrations of UFP were 28,180 particles/cm(3) along the road in contrast to 496 particles/cm(3) in the air-filtered room. As expected, exercise significantly increased serum BDNF concentration after cycling in the air-filtered room (+14.4%; p=0.02). In contrast, serum BDNF concentrations did not increase after cycling near the major traffic route (+0.5%; p=0.42). Although active commuting is considered to be beneficial for health, this health enhancing effect could be negatively influenced by exercising in an environment with high concentrations of PM. Whether this effect is also present with chronic exercise and chronic exposure must be further elucidated.

A randomised controlled trial of azithromycin to prevent chronic rejection after lung transplantation.

Azithromycin reduces airway inflammation and improves forced expiratory volume in 1 s (FEV1) in chronic rejection or bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx). Azithromycin prophylaxis might prevent BOS. A double-blind randomised controlled trial of azithromycin (n = 40) or placebo (n = 43), initiated at discharge and administered three times a week for 2 yrs, was performed in 2005-2009 at the Leuven University Hospital (Leuven, Belgium). Primary end-points were BOS-free and overall survival 2 yrs after LTx; secondary end-points were acute rejection, lymphocytic bronchiolitis and pneumonitis rate, prevalence of pseudomonal airway colonisation or gastro-oesophageal reflux, and change in FEV1, airway and systemic inflammation over time. Patients developing BOS were assessed for change in FEV1 with open-label azithromycin. BOS occurred less in patients receiving azithromycin: 12.5 versus 44.2% (p = 0.0017). BOS-free survival was better with azithromycin (hazard ratio 0.27, 95% CI 0.092-0.816; p = 0.020). Overall survival, acute rejection, lymphocytic bronchiolitis, pneumonitis, colonisation and reflux were comparable between groups. Patients receiving azithromycin demonstrated better FEV1 (p = 0.028), and lower airway neutrophilia (p = 0.015) and systemic C-reactive protein levels (p = 0.050) over time. Open-label azithromycin for BOS improved FEV1 in 52.2% patients. No serious adverse events were noted. Azithromycin prophylaxis attenuates local and systemic inflammation, improves FEV1 and reduces BOS 2 yrs after LTx.

Co-cultures of multiple cell types mimic pulmonary cell communication in response to urban PM10.

The current authors evaluated whether a system of co-cultures of relevant cells (pneumocytes (A549), macrophages (THP-1), mast cells (HMC-1) and endothelial cells (EAHY926)) would mimic the responses to particles with a 50% cut-off aerodynamic diameter of 10 microm (PM(10)) previously reported in vivo. The role of mast cells was considered of special interest. Single cultures, bicultures (A549 + HMC-1 in a 10:1 ratio; THP-1 + HMC-1 in a 2:1 ratio) and tricultures (A549 + THP-1 + HMC-1 in a 10:2:1 ratio) were exposed to urban PM(10) (24 h at 0, 10, 30 or 100 microg x cm(-2)). Additionally, EAHY926 cells were introduced in inserts above the tricultures. The released cytokines were evaluated with a fluorescence-activated cell sorter array system. THP-1 + HMC-1 bicultures and the tricultures released more granulocyte colony-stimulating factor (G-CSF), macrophage inflammatory protein (MIP)-1beta, interleukin (IL)-1beta, IL-8, IL-6, tumour necrosis factor-alpha and MIP-1alpha in response to PM(10) than the sum of the single cultures. Tricultures with EAHY926 released more G-CSF, MIP-1alpha, IL-8 and MIP-1beta than the EAHY926 single culture. The bicultures, tricultures and tricultures with EAHY926 provide results that are consistent with the local and systemic effects previously described for particulate matter effects, i.e. inflammation, endothelial dysfunction and bone marrow cell mobilisation. Mast cells seem to play a significant role in the co-culture responses.

Genetic variation and environmental factors in biological and arterial ageing.

Arterial ageing is a complex continuously distributed phenotype, which comes about through the interaction between inherited susceptibility, life-style and environmental factors. We used an integrated approach combining methods from genetics, molecular biology and population sciences to study the role of genetic variation and environmental factors in biological ageing. The discussed work comprises four population based studies of which two had a prospective design and two integrated recently developed biomolecular markers of ageing with classical epidemiological tools. The striking variability in the age of the manifestation of cardiovascular diseases is not fully explained by conventional risk factors. Variation in biological age has been suggested. The initial telomere length of a person is mainly determined by genetic factors. In this regard, we noticed robust correlations in telomere length between fathers and daughters, between mothers and both sons and daughters, and among siblings. X-linked inheritance of telomere length is the most likely explanation for these findings. Telomere length shortens with each cell division, and exposition to harmful environmental factors results in shorter telomere length as we observed in smokers. Telomere length correlated with the distensibility of the carotid artery and oxidative stress and inflammation are major determinants of arterial and biological ageing. In this context, selenium a component of antioxidant enzymes such as glutathione peroxidase, correlated inversely with blood pressure in the population at large. Oxidative stress and inflammation are major determinants of arterial and biological ageing. If telomeres are indeed causally involved in the pathogenesis of arterial ageing, this might provide new avenues for future preventive and therapeutic strategies.

Stronger associations between daily mortality and fine particulate air pollution in summer than in winter: evidence from a heavily polluted region in western Europe.

BACKGROUND: Numerous studies have shown a strong association between daily mortality and small particulate with a diameter of <10 microm (PM10) air pollution, but the effects of season have not always been well characterised. AIM: To study the shape of the association between short-term mortality and PM10 across seasons and quintiles of outdoor temperature. DESIGN, SETTING AND PARTICIPANTS: Daily data on mortality (n = 354 357), outdoor temperature and PM10 in Flanders, Belgium, from January 1997 to December 2003, were analysed across warm versus cold periods of the year (April-September v October-March), with seasons and quintiles of outdoor temperature as possible effect modifiers. RESULTS: There was a significant (p<0.001) interaction between PM10 and period of the year in relation to mortality. To allow for non-linearity, daily mean PM10 concentrations were categorised into quartiles. Season-specific PM10 quartiles showed a strong and steep linear association between mortality and PM10 in summer and a less linear association in spring and autumn, whereas in winter the association was less strong and mortality was only increased in the highest PM10 quartile. The effect sizes expressed as the percentage increase in mortality on days in the highest season-specific PM(10) quartile versus the lowest season-specific PM10 quartile were 7.8% (95% CI 6.1 to 9.6) in summer, 6.3% (4.7 to 7.8) in spring, 2.2% (0.58 to 3.8) in autumn and 1.4% (0.06 to 2.9) in winter. An analysis by quintiles of temperature confirmed these effect sizes. CONCLUSION: The short-term effect of particulate air pollution on mortality strongly depends on outdoor temperature, even in a temperate climate.

Should pulse pressure become part of the Framingham risk score?

An increased pulse pressure suggests aortic stiffening. New evidence also suggests that pulse pressure is a more sensitive measure of risk than other indexes of blood pressure in middle-aged and older persons. The objective of the study was to relate pulse pressure to the risk of cardiovascular events in the general population, and to assess whether pulse pressure could improve the Framingham risk prediction. A total of 378 men and 391 women over the age of 50 years (mean 62.7 years) were followed. Sex-specific Framingham cardiovascular risk scores were derived from age, systolic pressure, diastolic pressure, total and HDL cholesterol, smoking status and the presence or absence of diabetes mellitus. The cutoff points used to develop a pulse pressure score were calculated by determining the percentile points corresponding to the blood pressure categories in the Framingham risk score. We calculated relative hazard rates by multiple Cox regression. After a median follow-up of 7.2 years (range: 11 months-15 years), a total of 148 cardiovascular events occurred. In Cox regression analysis, a 10 mmHg higher pulse pressure was associated with 31% (P<0.0001) increase in the risk for cardiovascular events (fatal and nonfatal) after adjustment for sex, age, total and HDL cholesterol, smoking and the presence of diabetes mellitus. After adjustment for the aforementioned risk factors, a one-point increment in the blood pressure and pulse pressure scores was associated with a 40 and 48% (both P<0.0001) increase in the risk of fatal and nonfatal cardiovascular events, respectively. When both the blood pressure and pulse pressure scores were forced into a Cox model, only the pulse pressure score remained statistically significant (P<0.0001) with a relative hazard rate of 1.37 (CI: 1.16-1.69). These prospective data suggest that pulse pressure may improve the Framingham risk prediction among middle-aged and older individuals. Further studies, especially in the Framingham cohort, are warranted.

An epidemiological re-appraisal of the association between blood pressure and blood lead: a meta-analysis.

Studies on the possible association between blood pressure and blood lead have reached divergent conclusions. In a previous meta-analysis, a doubling of the blood lead concentration was associated with a 1.0/0.6 mm Hg increase in systolic and diastolic blood pressure (BP). This meta-analysis updates the analysis originally performed in 1994. Articles on the association between BP and blood lead were identified from computer searches from January 1980 to February 2001 using the Medical Literature Analysis and Retrieval System. Of the studies reviewed, 31 provided sufficient details to be considered. The meta-analysis included 58518 subjects recruited from the general population in 19 surveys and from occupationally exposed groups in 12 studies. In all but four studies, the results were adjusted for age, and most studies took into account additional confounding factors such as body mass index and the use of alcohol and medication. Weighted joint P-values were calculated using Stouffer's procedure. The association between BP and blood lead was similar in both men and women. In the combined studies, a two-fold increase in blood lead concentration was associated with a 1.0 mm Hg rise in the systolic pressure (95% CI +0.5 to +1.4 mm Hg; P < 0.001) and with a 0.6 mm Hg increase in the diastolic pressure (95% CI +0.4 to +0.8 mm Hg; P < 0.001). On balance, this meta-analysis suggests that there can only be a weak association between BP and blood lead.