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The Cochrane Database of Systematic... Jan 2022Paediatric flat feet are a common presentation in primary care; reported prevalence approximates 15%. A minority of flat feet can hurt and limit gait. There is no... (Review)
Review
BACKGROUND
Paediatric flat feet are a common presentation in primary care; reported prevalence approximates 15%. A minority of flat feet can hurt and limit gait. There is no optimal strategy, nor consensus, for using foot orthoses (FOs) to treat paediatric flat feet.
OBJECTIVES
To assess the benefits and harms of foot orthoses for treating paediatric flat feet.
SEARCH METHODS
We searched CENTRAL, MEDLINE, and Embase to 01 September 2021, and two clinical trials registers on 07 August 2020.
SELECTION CRITERIA
We identified all randomised controlled trials (RCTs) of FOs as an intervention for paediatric flat feet. The outcomes included in this review were pain, function, quality of life, treatment success, and adverse events. Intended comparisons were: any FOs versus sham, any FOs versus shoes, customised FOs (CFOs) versus prefabricated FOs (PFOs).
DATA COLLECTION AND ANALYSIS
We followed standard methods recommended by Cochrane.
MAIN RESULTS
We included 16 trials with 1058 children, aged 11 months to 19 years, with flexible flat feet. Distinct flat foot presentations included asymptomatic, juvenile idiopathic arthritis (JIA), symptomatic and developmental co-ordination disorder (DCD). The trial interventions were FOs, footwear, foot and rehabilitative exercises, and neuromuscular electrical stimulation (NMES). Due to heterogeneity, we did not pool the data. Most trials had potential for selection, performance, detection, and selective reporting bias. No trial blinded participants. We present the results separately for asymptomatic (healthy children) and symptomatic (children with JIA) flat feet. The certainty of evidence was very low to low, downgraded for bias, imprecision, and indirectness. Three comparisons were evaluated across trials: CFO versus shoes; PFO versus shoes; CFO versus PFO. Asymptomatic flat feet 1. CFOs versus shoes (1 trial, 106 participants): low-quality evidence showed that CFOs result in little or no difference in the proportion without pain (10-point visual analogue scale (VAS)) at one year (risk ratio (RR) 0.85, 95% confidence interval (CI) 0.67 to 1.07); absolute decrease (11.8%, 95% CI 4.7% fewer to 15.8% more); or on withdrawals due to adverse events (RR 1.05, 95% CI 0.94 to 1.19); absolute effect (3.4% more, 95% CI 4.1% fewer to 13.1% more). 2. PFOs versus shoes (1 trial, 106 participants): low to very-low quality evidence showed that PFOs result in little or no difference in the proportion without pain (10-point VAS) at one year (RR 0.94, 95% CI 0.76 to 1.16); absolute effect (4.7% fewer, 95% CI 18.9% fewer to 12.6% more); or on withdrawals due to adverse events (RR 0.99, 95% CI 0.79 to 1.23). 3. CFOs versus PFOs (1 trial, 108 participants): low-quality evidence found no difference in the proportion without pain at one year (RR 0.93, 95% CI 0.73 to 1.18); absolute effect (7.4% fewer, 95% CI 22.2% fewer to 11.1% more); or on withdrawal due to adverse events (RR 1.00, 95% CI 0.90 to 1.12). Function and quality of life (QoL) were not assessed. Symptomatic (JIA) flat feet 1. CFOs versus shoes (1 trial, 28 participants, 3-month follow-up): very low-quality evidence showed little or no difference in pain (0 to 10 scale, 0 no pain) between groups (MD -1.5, 95% CI -2.78 to -0.22). Low-quality evidence showed improvements in function with CFOs (Foot Function Index - FFI disability, 0 to 100, 0 best function; MD -18.55, 95% CI -34.42 to -2.68), child-rated QoL (PedsQL, 0 to 100, 100 best quality; MD 12.1, 95% CI -1.6 to 25.8) and parent-rated QoL (PedsQL MD 9, 95% CI -4.1 to 22.1) and little or no difference between groups in treatment success (timed walking; MD -1.33 seconds, 95% CI -2.77 to 0.11), or withdrawals due to adverse events (RR 0.58, 95% CI 0.11 to 2.94); absolute difference (9.7% fewer, 20.5 % fewer to 44.8% more). 2. PFOs versus shoes (1 trial, 25 participants, 3-month follow-up): very low-quality evidence showed little or no difference in pain between groups (MD 0.02, 95% CI -1.94 to 1.98). Low-quality evidence showed no difference between groups in function (FFI-disability MD -4.17, 95% CI -24.4 to 16.06), child-rated QoL (PedsQL MD -3.84, 95% CI -19 to 11.33), or parent-rated QoL (PedsQL MD -0.64, 95% CI -13.22 to 11.94). 3. CFOs versus PFOs (2 trials, 87 participants): low-quality evidence showed little or no difference between groups in pain (0 to 10 scale, 0 no pain) at 3 months (MD -1.48, 95% CI -3.23 to 0.26), function (FFI-disability MD -7.28, 95% CI -15.47 to 0.92), child-rated QoL (PedsQL MD 8.6, 95% CI -3.9 to 21.2), or parent-rated QoL (PedsQL MD 2.9, 95% CI -11 to 16.8).
AUTHORS' CONCLUSIONS
Low to very low-certainty evidence shows that the effect of CFOs (high cost) or PFOs (low cost) versus shoes, and CFOs versus PFOs on pain, function and HRQoL is uncertain. This is pertinent for clinical practice, given the economic disparity between CFOs and PFOs. FOs may improve pain and function, versus shoes in children with JIA, with minimal delineation between costly CFOs and generic PFOs. This review updates that from 2010, confirming that in the absence of pain, the use of high-cost CFOs for healthy children with flexible flat feet has no supporting evidence, and draws very limited conclusions about FOs for treating paediatric flat feet. The availability of normative and prospective foot development data, dismisses most flat foot concerns, and negates continued attention to this topic. Attention should be re-directed to relevant paediatric foot conditions, which cause pain, limit function, or reduce quality of life. The agenda for researching asymptomatic flat feet in healthy children must be relegated to history, and replaced by a targeted research rationale, addressing children with indisputable foot pathology from discrete diagnoses, namely JIA, cerebral palsy, congenital talipes equino varus, trisomy 21 and Charcot Marie Tooth. Whether research resources should continue to be wasted on studying flat feet in healthy children that do not hurt, is questionable. Future updates of this review will address only relevant paediatric foot conditions.
Topics: Child; Flatfoot; Foot Orthoses; Humans; Pain; Pain Measurement; Quality of Life
PubMed: 35080267
DOI: 10.1002/14651858.CD006311.pub4 -
The Cochrane Database of Systematic... Jan 2022Paediatric flat feet are a common presentation in primary care; reported prevalence approximates 15%. A minority of flat feet can hurt and limit gait. There is no... (Review)
Review
BACKGROUND
Paediatric flat feet are a common presentation in primary care; reported prevalence approximates 15%. A minority of flat feet can hurt and limit gait. There is no optimal strategy, nor consensus, for using foot orthoses (FOs) to treat paediatric flat feet.
OBJECTIVES
To assess the benefits and harms of foot orthoses for treating paediatric flat feet.
SEARCH METHODS
We searched CENTRAL, MEDLINE, and Embase to 01 September 2021, and two clinical trials registers on 07 August 2020.
SELECTION CRITERIA
We identified all randomised controlled trials (RCTs) of FOs as an intervention for paediatric flat feet. The outcomes included in this review were pain, function, quality of life, treatment success, and adverse events. Intended comparisons were: any FOs versus sham, any FOs versus shoes, customised FOs (CFOs) versus prefabricated FOs (PFOs).
DATA COLLECTION AND ANALYSIS
We followed standard methods recommended by Cochrane.
MAIN RESULTS
We included 16 trials with 1058 children, aged 11 months to 19 years, with flexible flat feet. Distinct flat foot presentations included asymptomatic, juvenile idiopathic arthritis (JIA), symptomatic and developmental co-ordination disorder (DCD). The trial interventions were FOs, footwear, foot and rehabilitative exercises, and neuromuscular electrical stimulation (NMES). Due to heterogeneity, we did not pool the data. Most trials had potential for selection, performance, detection, and selective reporting bias. No trial blinded participants. We present the results separately for asymptomatic (healthy children) and symptomatic (children with JIA) flat feet. The certainty of evidence was very low to low, downgraded for bias, imprecision, and indirectness. Three comparisons were evaluated across trials: CFO versus shoes; PFO versus shoes; CFO versus PFO. Asymptomatic flat feet 1. CFOs versus shoes (1 trial, 106 participants): low-quality evidence showed that CFOs result in little or no difference in the proportion without pain (10-point visual analogue scale (VAS)) at one year (risk ratio (RR) 0.85, 95% confidence interval (CI) 0.67 to 1.07); absolute decrease (11.8%, 95% CI 4.7% fewer to 15.8% more); or on withdrawals due to adverse events (RR 1.05, 95% CI 0.94 to 1.19); absolute effect (3.4% more, 95% CI 4.1% fewer to 13.1% more). 2. PFOs versus shoes (1 trial, 106 participants): low to very-low quality evidence showed that PFOs result in little or no difference in the proportion without pain (10-point VAS) at one year (RR 0.94, 95% CI 0.76 to 1.16); absolute effect (4.7% fewer, 95% CI 18.9% fewer to 12.6% more); or on withdrawals due to adverse events (RR 0.99, 95% CI 0.79 to 1.23). 3. CFOs versus PFOs (1 trial, 108 participants): low-quality evidence found no difference in the proportion without pain at one year (RR 0.93, 95% CI 0.73 to 1.18); absolute effect (7.4% fewer, 95% CI 22.2% fewer to 11.1% more); or on withdrawal due to adverse events (RR 1.00, 95% CI 0.90 to 1.12). Function and quality of life (QoL) were not assessed. Symptomatic (JIA) flat feet 1. CFOs versus shoes (1 trial, 28 participants, 3-month follow-up): very low-quality evidence showed little or no difference in pain (0 to 10 scale, 0 no pain) between groups (MD -1.5, 95% CI -2.78 to -0.22). Low-quality evidence showed improvements in function with CFOs (Foot Function Index - FFI disability, 0 to 100, 0 best function; MD -18.55, 95% CI -34.42 to -2.68), child-rated QoL (PedsQL, 0 to 100, 100 best quality; MD 12.1, 95% CI -1.6 to 25.8) and parent-rated QoL (PedsQL MD 9, 95% CI -4.1 to 22.1) and little or no difference between groups in treatment success (timed walking; MD -1.33 seconds, 95% CI -2.77 to 0.11), or withdrawals due to adverse events (RR 0.58, 95% CI 0.11 to 2.94); absolute difference (9.7% fewer, 20.5 % fewer to 44.8% more). 2. PFOs versus shoes (1 trial, 25 participants, 3-month follow-up): very low-quality evidence showed little or no difference in pain between groups (MD 0.02, 95% CI -1.94 to 1.98). Low-quality evidence showed no difference between groups in function (FFI-disability MD -4.17, 95% CI -24.4 to 16.06), child-rated QoL (PedsQL MD -3.84, 95% CI -19 to 11.33), or parent-rated QoL (PedsQL MD -0.64, 95% CI -13.22 to 11.94). 3. CFOs versus PFsO (2 trials, 87 participants): low-quality evidence showed little or no difference between groups in pain (0 to scale, 0 no pain) at 3 months (MD -1.48, 95% CI -3.23 to 0.26), function (FFI-disability MD -7.28, 95% CI -15.47 to 0.92), child-rated QoL (PedsQL MD 8.6, 95% CI -3.9 to 21.2), or parent-rated QoL (PedsQL MD 2.9, 95% CI -11 to 16.8).
AUTHORS' CONCLUSIONS
Low to very low-certainty evidence shows that the effect of CFOs (high cost) or PFOs (low cost) versus shoes, and CFOs versus PFOs on pain, function and HRQoL is uncertain. This is pertinent for clinical practice, given the economic disparity between CFOs and PFOs. FOs may improve pain and function, versus shoes in children with JIA, with minimal delineation between costly CFOs and generic PFOs. This review updates that from 2010, confirming that in the absence of pain, the use of high-cost CFOs for healthy children with flexible flat feet has no supporting evidence, and draws very limited conclusions about FOs for treating paediatric flat feet. The availability of normative and prospective foot development data, dismisses most flat foot concerns, and negates continued attention to this topic. Attention should be re-directed to relevant paediatric foot conditions, which cause pain, limit function, or reduce quality of life. The agenda for researching asymptomatic flat feet in healthy children must be relegated to history, and replaced by a targeted research rationale, addressing children with indisputable foot pathology from discrete diagnoses, namely JIA, cerebral palsy, congenital talipes equino varus, trisomy 21 and Charcot Marie Tooth. Whether research resources should continue to be wasted on studying flat feet in healthy children that do not hurt, is questionable. Future updates of this review will address only relevant paediatric foot conditions.
Topics: Child; Flatfoot; Foot Orthoses; Humans; Pain; Pain Measurement; Quality of Life
PubMed: 35029841
DOI: 10.1002/14651858.CD006311.pub3 -
La Medicina Del Lavoro Oct 2023Per- and poly-fluoroalkyl substances (PFASs) are a large, complex group of synthetic chemicals humans can be exposed to from occupational or environmental sources. In... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Per- and poly-fluoroalkyl substances (PFASs) are a large, complex group of synthetic chemicals humans can be exposed to from occupational or environmental sources. In this systematic review and meta-analysis, we examined the association between PFAS exposure, particularly Perfluorooctanoic Acid (PFOA), and Perfluorooctane Sulfonic Acid (PFOS), and risk of kidney, liver, and testicular cancer.
METHODS
We systematically searched PubMed to identify cohort and case-control studies reported after the Monograph of the International Agency for Research on Cancer and the Toxicological Profile of the Agency for Toxic Substances and Disease Registry. We assessed the quality of the studies by using a modified version of the Newcastle-Ottawa Scale (NOS). Forest relative risk (RR) plots were constructed for liver, kidney, and testicular cancer. We conducted stratified analyses by geographic region, study design, quality score, outcome, years of publication, exposure source, and PFAS type. A random-effects model was used to address heterogeneity between studies.
RESULTS
Fifteen studies, including ten cohort studies, three case-control studies nested in a cohort, and two case-control studies were included after removing duplicate and irrelevant reports. We found an association between overall PFAS exposure and the risk of kidney cancers (RR=1.18, 95% CI =1.05-1.32; I =52.8%, 11 studies). Also, we showed an association between high-level exposure to PFAS and kidney cancer (RR=1.74, 95% CI =1.23-2.47; p=0.005) and testicular cancer (RR=2.22, 95% CI =1.12-4.39; p=0.057). There was no association with liver cancer. We found no heterogeneity by geographical region, PFAS type, study design, outcome, quality score, year of publication, or exposure source. Only two studies reported results among women.
CONCLUSIONS
We detected an association between overall PFAS exposure and kidney cancer and high doses of PFAS with testicular cancer. However, bias and confounding cannot be excluded, precluding a conclusion in terms of causality.
Topics: Female; Humans; Male; Testicular Neoplasms; Kidney; Liver; Kidney Neoplasms; Carcinoma, Renal Cell; Fluorocarbons
PubMed: 37878255
DOI: 10.23749/mdl.v114i5.15065 -
Communications Medicine Oct 2023Heterogeneity in type 2 diabetes presentation and progression suggests that precision medicine interventions could improve clinical outcomes. We undertook a systematic...
BACKGROUND
Heterogeneity in type 2 diabetes presentation and progression suggests that precision medicine interventions could improve clinical outcomes. We undertook a systematic review to determine whether strategies to subclassify type 2 diabetes were associated with high quality evidence, reproducible results and improved outcomes for patients.
METHODS
We searched PubMed and Embase for publications that used 'simple subclassification' approaches using simple categorisation of clinical characteristics, or 'complex subclassification' approaches which used machine learning or 'omics approaches in people with established type 2 diabetes. We excluded other diabetes subtypes and those predicting incident type 2 diabetes. We assessed quality, reproducibility and clinical relevance of extracted full-text articles and qualitatively synthesised a summary of subclassification approaches.
RESULTS
Here we show data from 51 studies that demonstrate many simple stratification approaches, but none have been replicated and many are not associated with meaningful clinical outcomes. Complex stratification was reviewed in 62 studies and produced reproducible subtypes of type 2 diabetes that are associated with outcomes. Both approaches require a higher grade of evidence but support the premise that type 2 diabetes can be subclassified into clinically meaningful subtypes.
CONCLUSION
Critical next steps toward clinical implementation are to test whether subtypes exist in more diverse ancestries and whether tailoring interventions to subtypes will improve outcomes.
PubMed: 37798471
DOI: 10.1038/s43856-023-00360-3 -
Children (Basel, Switzerland) Nov 2021Brain tumors are the second most common neoplasm in the pediatric age. Pesticides may play an etiologic role, but literature results are conflicting. This review... (Review)
Review
Parental Pesticide Exposure and Childhood Brain Cancer: A Systematic Review and Meta-Analysis Confirming the IARC/WHO Monographs on Some Organophosphate Insecticides and Herbicides.
BACKGROUND
Brain tumors are the second most common neoplasm in the pediatric age. Pesticides may play an etiologic role, but literature results are conflicting. This review provides a systematic overview, meta-analysis, and IARC/WHO consideration of data on parental exposure to pesticides and childhood brain tumors.
METHODS
We searched PubMed, SCOPUS, and Google Scholar for literature (1 January 1966-31 December 2020) that assessed childhood brain tumors and parental exposure to pesticides. We undertook a meta-analysis addressing prenatal exposure, exposure after birth, occupational exposure, and residential exposure. A total of 130 case-control investigations involving 43,598 individuals (18,198 cases and 25,400 controls) were included.
RESULTS
Prenatal exposure is associated with childhood brain tumors (odds ratio, OR = 1.32; 95% CI: 1.17-1.49; I = 41.1%). The same occurs after birth exposure (OR = 1.22; 95% CI: 1.03-1.45, I = 72.3%) and residential exposure to pesticides (OR = 1.31; 95% CI: 1.11-1.54, I = 67.2%). Parental occupational exposure is only marginally associated with CBT (OR = 1.17, 95% CI: 0.99-1.38, I = 67.0%).
CONCLUSIONS
There is an association between CBT and parental pesticides exposure before childbirth, after birth, and residential exposure. It is in line with the IARC Monograph evaluating the carcinogenicity of diazinon, glyphosate, malathion, parathion, and tetrachlorvinphos.
PubMed: 34943292
DOI: 10.3390/children8121096 -
Journal of Oral and Maxillofacial... 2021Causative linkages of tobacco use with oral potentially malignant disorders and cancers of oral cavity have been studied. Oral squamous cell carcinoma is one of the most... (Review)
Review
Causative linkages of tobacco use with oral potentially malignant disorders and cancers of oral cavity have been studied. Oral squamous cell carcinoma is one of the most common cancers in India. The International Agency for Research on Cancer (IARC) monograph found a significant association between smokeless tobacco (SLT) use and oral cancer. However, only a few limited studies have been represented on the IARC monograph. Published meta-analyses have provided pooled risk estimates for oral cancers caused by tobacco, both on global and regional levels. This systematic review was aimed at summarizing all the available studies exclusively in India by collecting data from PubMed and Medline. Emphasis was laid on cohort and case-control studies, and a few cross-sectional studies for premalignant lesions were also discussed. A significant association was noticed on SLT and premalignant and malignant oral cavity lesions.
PubMed: 34703140
DOI: 10.4103/0973-029X.325258 -
Environment International Dec 2022The World Health Organization (WHO) and the International Labour Organization (ILO) are the producers of the WHO/ILO Joint Estimates of the Work-related Burden of... (Meta-Analysis)
Meta-Analysis
The effect of occupational exposure to welding fumes on trachea, bronchus and lung cancer: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury.
BACKGROUND
The World Health Organization (WHO) and the International Labour Organization (ILO) are the producers of the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury (WHO/ILO Joint Estimates). Welding fumes have been classified as carcinogenic to humans (Group 1) by the WHO International Agency for Research on Cancer (IARC) in IARC Monograph 118; this assessment found sufficient evidence from studies in humans that welding fumes are a cause of lung cancer. In this article, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from trachea, bronchus, and lung cancer attributable to occupational exposure to welding fumes, to inform the development of WHO/ILO Joint Estimates on this burden of disease (if considered feasible).
OBJECTIVES
We aimed to systematically review and meta-analyse estimates of the effect of any (or high) occupational exposure to welding fumes, compared with no (or low) occupational exposure to welding fumes, on trachea, bronchus, and lung cancer (three outcomes: prevalence, incidence, and mortality).
DATA SOURCES
We developed and published a protocol, applying the Navigation Guide as an organizing systematic review framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including Medline, EMBASE, Web of Science, CENTRAL and CISDOC. We also searched grey literature databases, Internet search engines, and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.
STUDY ELIGIBILITY AND CRITERIA
We included working-age (≥15 years) workers in the formal and informal economy in any Member State of WHO and/or ILO but excluded children (<15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies, and other non-randomized intervention studies with an estimate of the effect of any (or high) occupational exposure to welding fumes, compared with occupational exposure to no (or low) welding fumes, on trachea, bronchus, and lung cancer (prevalence, incidence, and mortality).
STUDY APPRAISAL AND SYNTHESIS METHODS
At least two review authors independently screened titles and abstracts against the eligibility criteria at a first review stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. If studies reported odds ratios, these were converted to risk ratios (RRs). We combined all RRs using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence, and strength of evidence, using the Navigation Guide tools and approaches adapted to this project. Subgroup (e.g., by WHO region and sex) and sensitivity analyses (e.g., studies judged to be of "high"/"probably high" risk of bias compared with "low"/"probably low" risk of bias) were conducted.
RESULTS
Forty-one records from 40 studies (29 case control studies and 11 cohort studies) met the inclusion criteria, comprising over 1,265,512 participants (≥22,761 females) in 21 countries in three WHO regions (Region of the Americas, European Region, and Western Pacific Region). The exposure and outcome were generally assessed by job title or self-report, and medical or administrative records, respectively. Across included studies, risk of bias was overall generally probably low/low, with risk judged high or probably high for several studies in the domains for misclassification bias and confounding. Our search identified no evidence on the outcome of having trachea, bronchus, and lung cancer (prevalence). Compared with no (or low) occupational exposure to welding fumes, any (or high) occupational exposure to welding fumes increased the risk of acquiring trachea, bronchus, and lung cancer (incidence) by an estimated 48 % (RR 1.48, 95 % confidence interval [CI] 1.29-1.70, 23 studies, 57,931 participants, I 24 %; moderate quality of evidence). Compared with no (or low) occupational exposure to welding fumes, any (or high) occupational exposure to welding fumes increased the risk dying from trachea, bronchus, and lung cancer (mortality) by an estimated 27 % (RR 1.27, 95 % CI 1.04-1.56, 3 studies, 8,686 participants, I 0 %; low quality of evidence). Our subgroup analyses found no evidence for difference by WHO region and sex. Sensitivity analyses supported the main analyses.
CONCLUSIONS
Overall, for incidence and mortality of trachea, bronchus, and lung cancer, we judged the existing body of evidence for human data as "sufficient evidence of harmfulness" and "limited evidence of harmfulness", respectively. Occupational exposure to welding fumes increased the risk of acquiring and dying from trachea, bronchus, and lung cancer. Producing estimates for the burden of trachea, bronchus, and lung cancer attributable to any (or high) occupational exposure to welding fumes appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates. PROTOCOL IDENTIFIER: https://doi.org/10.1016/j.envint.2020.106089.
Topics: Humans; Adolescent; Lung Neoplasms; World Health Organization; Cost of Illness
PubMed: 36402034
DOI: 10.1016/j.envint.2022.107565 -
NTP Monograph Dec 2019Traffic-related air pollution (TRAP) contributes significantly to ambient air pollution, especially in urban settings. Air pollution has been established as a risk... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Traffic-related air pollution (TRAP) contributes significantly to ambient air pollution, especially in urban settings. Air pollution has been established as a risk factor for hypertension and cardiovascular disease in adults, but this effect is less studied in other susceptible populations. There is increasing evidence that air pollution may adversely affect hypertensive disorders of pregnancy (e.g., gestational hypertension, preeclampsia, eclampsia).
OBJECTIVE
Because reports indicate that air pollution may be linked to hypertensive disorders, the National Toxicology Program (NTP) conducted a systematic review to evaluate whether exposure to TRAP during pregnancy is associated with hypertensive disorders of pregnancy.
METHODS
A systematic review protocol was developed and utilized for this evaluation that followed the Office of Health Assessment and Translation approach for conducting literature-based health assessments. This evaluation considered a range of traffic-related air pollutant measurements (e.g., fine particulate matter [PM2.5]) and traffic measures (e.g., proximity to major roads) in the literature search. Confidence ratings and level-of-evidence conclusions were developed for bodies of evidence for a given exposure measure when there was sufficient evidence (i.e., more than three studies). Changes in blood pressure during pregnancy, gestational hypertension, preeclampsia, eclampsia, or hemolysis, elevated liver enzyme levels, and low platelet count (HELLP) syndrome were considered as measures of hypertension. Hazard conclusions were developed using a two-step process. First, confidence ratings were developed for individual air pollutants (e.g., PM2.5, nitrogen oxides [NOx]) and traffic measures (traffic density and proximity to major roads). Overall hazard conclusions were then developed for TRAP, considering the combined bodies of evidence across different individual measures of traffic-related pollutants.
RESULTS AND EVIDENCE SYNTHESIS
The literature search and screening process identified 18 relevant epidemiological studies and one relevant animal study (from 344 potentially relevant references) that met the objective and the inclusion criteria. The human bodies of evidence for traffic-related PM2.5 and NO2 present a consistent pattern of findings that exposure to these pollutants is associated with the development of hypertensive disorders of pregnancy. There is a similar pattern of findings, but a smaller effect size, for bodies of evidence that residing in high-traffic density regions or in close proximity to major roads are associated with developing hypertensive disorders during pregnancy. There is a moderate level of evidence in the combined human body of evidence based primarily on the TRAP air pollutant studies with support from the traffic measures studies. There is an inadequate level of evidence in the animal body of evidence due to the lack of experimental animal studies identified for these measures. Evidence for other traffic-related pollutants that were identified (i.e., carbon monoxide [CO], black carbon [BC], and elemental carbon [EC]), including one animal study for CO, were few in number or provided inconsistent results across studies, and level-of-evidence conclusions were not reached.
DISCUSSION AND CONCLUSION
NTP concludes that exposure to TRAP is presumed to be a hazard to pregnant women for developing hypertensive disorders of pregnancy. This conclusion was based on moderate confidence and moderate level of evidence in the combined body of evidence from human studies reporting on multiple measures of TRAP exposure (traffic-related PM2.5 and NO2) with support from studies on traffic measures (residing in high-traffic density regions or in close proximity to major roads during pregnancy). (This section of the abstract has been abridged.).
Topics: Air Pollutants; Animals; Humans; Hypertension, Pregnancy-Induced; Traffic-Related Pollution; Vehicle Emissions
PubMed: 33560269
DOI: 10.22427/NTP-MGRAPH-7 -
Journal of the National Cancer... Jul 2020Whether low-dose ionizing radiation can cause cancer is a critical and long-debated question in radiation protection. Since the Biological Effects of Ionizing Radiation...
Whether low-dose ionizing radiation can cause cancer is a critical and long-debated question in radiation protection. Since the Biological Effects of Ionizing Radiation report by the National Academies in 2006, new publications from large, well-powered epidemiological studies of low doses have reported positive dose-response relationships. It has been suggested, however, that biases could explain these findings. We conducted a systematic review of epidemiological studies with mean doses less than 100 mGy published 2006-2017. We required individualized doses and dose-response estimates with confidence intervals. We identified 26 eligible studies (eight environmental, four medical, and 14 occupational), including 91 000 solid cancers and 13 000 leukemias. Mean doses ranged from 0.1 to 82 mGy. The excess relative risk at 100 mGy was positive for 16 of 22 solid cancer studies and 17 of 20 leukemia studies. The aim of this monograph was to systematically review the potential biases in these studies (including dose uncertainty, confounding, and outcome misclassification) and to assess whether the subset of minimally biased studies provides evidence for cancer risks from low-dose radiation. Here, we describe the framework for the systematic bias review and provide an overview of the eligible studies.
Topics: Epidemiologic Studies; Humans; Neoplasms, Radiation-Induced; Radiation Protection; Radiation, Ionizing; Risk
PubMed: 32657348
DOI: 10.1093/jncimonographs/lgaa009