Publications by authors named "Leffondre K"

Article Synopsis
  • The study investigated the link between air pollution and cataract surgery incidence in older adults in Bordeaux, France.
  • Researchers followed 829 participants aged 65 and older from 1999-2017, monitoring their cataract surgeries and estimating their long-term air pollution exposure.
  • Results showed that long-term exposure to nitrogen dioxide (NO) at levels ≥40 μg/m was significantly associated with increased incidence of cataract surgery, suggesting that meeting air quality standards could benefit public health.
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Background: While genetic, hormonal, and lifestyle factors partially elucidate the incidence of breast cancer, emerging research has underscored the potential contribution of air pollution. Polychlorinated biphenyls (PCBs) and benzo[a]pyrene (BaP) are of particular concern due to endocrine-disrupting properties and their carcinogenetic effect.

Objective: To identify distinct long term trajectories of exposure to PCB153 and BaP, and estimate their associations with breast cancer risk.

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  • A study investigated how exposure to various air pollutants affects mortality in dialysis patients, using data from 90,373 patients in France between 2012 and 2020.
  • The research found that higher pollution levels were linked to increased all-cause deaths and specifically higher rates of infectious mortality among these patients.
  • Results indicate that air pollution could be a significant factor in the rising deaths related to chronic kidney disease (CKD) globally, with stronger effects observed in women and patients with fewer comorbidities.
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  • The study investigates the link between social deprivation and the incidence of kidney replacement therapy (KRT) among children and young adults in France, showing a correlation between higher social deprivation and increased KRT rates.
  • Analyzed data from 2010 to 2015, including 672 children who started KRT, revealing that 38.8% were from the most deprived areas, with higher incidence rates as deprivation increased.
  • Results indicate that social health inequalities emerge even at the initiation of KRT, emphasizing the importance of addressing these inequalities in chronic kidney disease management.
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  • A study involving 5170 older adults aimed to determine if genetic factors influence how lifestyle choices affect the risk of developing dementia.* -
  • Researchers used the Lifestyle for BRAin health risk score (LIBRA) to assess modifiable lifestyle factors, finding that higher scores correlated with increased dementia incidence, regardless of genetic predisposition.* -
  • The results suggest that lifestyle interventions could be beneficial in preventing dementia, regardless of an individual's genetic risk factors like the APOE ε4 allele.*
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Introduction: Pre-emptive access to the kidney transplant (KT) waiting list remains limited in France, with only 3.9% of patients on pre-emptive KT and 5.6% of patients registered at the time of initiation of dialysis.

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  • Recent research indicates that patients undergoing hemodialysis with an arteriovenous (AV) graft may experience higher hospitalization rates compared to those with an AV fistula, particularly regarding vascular access-related issues.
  • The study analyzed data from nearly 18,800 patients in France who started hemodialysis with a catheter, utilizing advanced statistical models to account for factors like recurring hospitalizations and patient comorbidities.
  • Results show that while AV grafts are linked to increased overall and cause-specific hospitalization rates, this association is less pronounced in patients with certain comorbid conditions, such as diabetes.
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Background: The trajectories of haemoglobin in patients with chronic kidney disease (CKD) have been poorly described. In such patients, we aimed to identify typical haemoglobin trajectory profiles and estimate their risks of major adverse cardiovascular events (MACE).

Methods: We used 5-year longitudinal data from the CKD-REIN cohort patients with moderate to severe CKD enrolled from 40 nationally representative nephrology clinics in France.

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Chronic exposure to air pollution may have adverse effects on neurodegenerative diseases. Glaucoma, the second leading cause of blindness worldwide, is a neurodegenerative disease of the optic nerve, characterized by progressive thinning of the retinal nerve fiber layer (RNFL). We investigated the relationship of air pollution exposure with longitudinal changes of RNFL thickness in the Alienor study, a population-based cohort of residents of Bordeaux, France, aged 75 years or more.

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Background: Sheltered homeless families suffer from deleterious living conditions such as housing instability (i.e., moving from one shelter to another) that could be an additional barrier to healthcare utilization.

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We investigated the shape of the relationship between longitudinal uric acid (UA) and the hazard of kidney failure and death in chronic kidney disease (CKD) patients, and attempted to identify thresholds associated with increased hazards. We included CKD stage 3-5 patients from the CKD-REIN cohort with one serum UA measurement at cohort entry. We used cause-specific multivariate Cox models including a spline function of current values of UA (cUA), estimated from a separate linear mixed model.

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Article Synopsis
  • Long-term exposure to nitrogen dioxide (NO) air pollution is associated with an increased risk of breast cancer, based on a study conducted within the French E3N cohort of 5222 breast cancer cases and matched controls.
  • The study utilized a land use regression model to estimate annual mean concentrations of NO for each participant, finding that each interquartile range increase in NO levels correlated with an odds ratio (OR) of 1.09 for breast cancer risk.
  • Results showed consistent effects for postmenopausal women, while no significant association was found for premenopausal women, suggesting that long-term NO exposure could be a relevant factor in breast cancer risk, particularly for certain demographics.
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Background And Objectives: Late stages of CKD are characterized by significant symptom burden. This study aimed to identify subgroups within the 5-year trajectories of symptom evolution in patients with CKD and to describe associated patient characteristics and outcomes.

Design, Setting, Participants, & Measurements: Among 2787 participants (66% men) with eGFR <60 ml/min per 1.

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  • The COVID-19 pandemic led to global kidney transplantation (KT) moratoriums, creating uncertainty about their effects on the life expectancy of KT candidates.
  • A study simulated various populations of French KT candidates, analyzing potential outcomes based on moratorium lengths of 0 to 24 months, using data from nearly 64,000 patients.
  • Findings indicated that even a short 2.5-month moratorium predicted additional waiting list time and deaths, with significant impacts observed for moratoriums longer than 9 months, suggesting that extending the moratorium could have severe consequences for patient outcomes.
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Introduction: Socioeconomic status (SES) is recognized as an important determinant of kidney health. We aimed to evaluate the association of social deprivation with different indicators at kidney replacement therapy (KRT) initiation in the French pediatric metropolitan population.

Methods: All patients with end-stage kidney disease (ESKD) who started KRT before 20 years old in France between 2002 and 2015 were included.

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Objective: To identify and critically appraise risk prediction models for living donor solid organ transplant counselling.

Study Design And Setting: We systematically reviewed articles describing the development or validation of prognostic risk prediction models about living donor solid organ (kidney and liver) transplantation indexed in Medline until April 4, 2021. Models were eligible if intended to predict, at transplant counselling, any outcome occurring after transplantation or donation in recipients or donors.

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Molecular studies suggest that cadmium due to its estrogenic properties, might play a role in breast cancer (BC) progression. However epidemiological evidence is limited. This study explored the association between long-term exposure to airborne cadmium and risk of BC by stage, grade of differentiation, and histological types at diagnosis.

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Background: Long-term behavioral and health risk factors constitute a primary focus of research on the etiology of chronic diseases. Yet, identifying critical time-windows during which risk factors have the strongest impact on disease risk is challenging. To assess the trajectory of association of an exposure history with an outcome, the weighted cumulative exposure index (WCIE) has been proposed, with weights reflecting the relative importance of exposures at different times.

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Background: Kidney transplantation (KT) is the optimal treatment for children with end-stage kidney disease. The aim of this study was to evaluate the impact of preemptive kidney transplantation (PKT) and of pretransplant dialysis duration on graft survival among French pediatric kidney transplant recipients.

Methods: We analyzed all first pediatric kidney-only transplantations performed in France between 1993 and 2012.

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Background: Benzo[a]pyrene (BaP) is an endocrine-disrupting pollutant formed during incomplete combustion of organic materials. It has been recognized as a reproductive and developmental toxicant, however epidemiological evidence of the long-term effect of ambient air BaP on breast cancer (BC) is limited. Thus we evaluated associations between ambient air BaP exposure and risk of BC, overall and according to menopausal status and molecular subtypes (estrogen receptor negative/positive (ER-/ER+) and progesterone receptor negative/positive (PR-/PR+)), stage and grade of differentiation of BC in the French E3N cohort study.

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Article Synopsis
  • The study investigates the link between exposure to PCB153, a common environmental pollutant, and the risk of breast cancer, highlighting that genetic and hormonal factors do not fully account for all cases.
  • Researchers analyzed data from over 5,000 breast cancer cases and matched controls within the French E3N cohort, utilizing atmospheric concentration models to estimate cumulative PCB153 exposure for participants.
  • Findings indicate a significant increase in breast cancer risk associated with PCB153 exposure, particularly in postmenopausal women and for ER-positive breast cancer types, suggesting environmental factors may play a crucial role in breast cancer development.
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Background: No study to our knowledge has examined the use of observational data to emulate a clinical trial whereby patients at the time of kidney transplant proposal are randomly assigned to an awaiting transplantation or transplantation group. The main methodologic issue is definition of the baseline for dialyzed patients assigned to awaiting transplantation, resulting in the inability to use common propensity score-based approaches. We aimed to use time-dependent propensity score to better appraise the benefit of transplantation.

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Background: Several models have been proposed to predict kidney graft failure in adult recipients but none in younger recipients. Our objective was to propose a dynamic prediction model for graft failure in young kidney transplant recipients.

Methods: We included 793 kidney transplant recipients waitlisted before the age of 18 years who received a first kidney transplantation before the age of 21 years in France in 2002-13 and survived >90 days with a functioning graft.

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