PFHpA alters lipid metabolism and increases the risk of metabolic dysfunction-associated steatotic liver disease in youth-a translational research framework

To address the growing epidemic of liver disease, particularly in pediatric populations, it is crucial to identify modifiable risk factors for the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Per- and polyfluoroalkyl substances (PFAS) are persistent ubiquitous chemicals and have emerged as potential risk factors for liver damage. However, their impact on the etiology and severity of MASLD remains largely unexplored in humans. This study aims to bridge the gap between human and in vitro studies to understand how exposure to perfluoroheptanoic acid (PFHpA), one of the emerging PFAS replacements which accumulates in high concentrations in the liver, contributes to MASLD risk and progression. First, we showed that PFHpA plasma concentrations were significantly associated with increased risk of MASLD in obese adolescents. Further, we examined the impact of PFHpA on hepatic metabolism using 3D human liver spheroids and single-cell transcriptomics to identify major hepatic pathways affected by PFHpA. Next, we integrated the in vivo and in vitro multi-omics datasets with a novel statistical approach which identified signatures of proteins and metabolites associated with MASLD development triggered by PFHpA exposure. In addition to characterizing the contribution of PFHpA to MASLD progression, our study provides a novel strategy to identify individuals at high risk of PFHpA-induced MASLD and develop early intervention strategies. Notably, our analysis revealed that the proteomic signature exhibited a stronger correlation between both PFHpA exposure and MASLD risk compared to the metabolomic signature. While establishing a clear connection between PFHpA exposure and MASLD progression in humans, our study delved into the molecular mechanisms through which PFHpA disrupts liver metabolism. Our in vitro findings revealed that PFHpA primarily impacts lipid metabolism, leading to a notable increase of lipid accumulation in human hepatocytes after PFHpA exposure. Among the pathways involved in lipid metabolism in hepatocytes, regulation of lipid metabolism by PPAR-a showed a remarkable activation. Moreover, the translational research framework we developed by integrating human and in vitro data provided us biomarkers to identify individuals at a high risk of MASLD due to PFHpA exposure. Our framework can inform policies on PFAS-induced liver disease and identify potential targets for prevention and treatment strategies.

Changes in plasma concentrations of per- and Polyfluoroalkyl substances after bariatric surgery in adolescents from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study

Exposure to per- and poly-fluoroalkyl substances (PFAS) is ubiquitous due to their persistence in the environment and in humans. Extreme weight loss has been shown to influence concentrations of circulating persistent organic pollutants (POPs). Using data from the multi-center perspective Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort, we investigated changes in plasma-PFAS in adolescents after bariatric surgery. Adolescents (Mean age = 17.1 years, SD = 1.5 years) undergoing bariatric surgery were enrolled in the Teen-LABS study. Plasma-PFAS were measured at the time of surgery and then 6-, 12-, and 36 months post-surgery. Linear mixed effect models were used to evaluate longitudinal changes in plasma-PFAS after the time of bariatric surgery. This study included 214 adolescents with severe obesity who had available longitudinal measures of plasma-PFAS and underwent bariatric surgery between 2007 and 2012. Underlying effects related to undergoing bariatric surgery were found to be associated with an initial increase or plateau in concentrations of circulating PFAS up to 6 months after surgery followed by a persistent decline in concentrations of 36 months (p < 0.001 for all plasma-PFAS). Bariatric surgery in adolescents was associated with a decline in circulating PFAS concentrations. Initially following bariatric surgery (0-6 months) concentrations were static followed by decline from 6 to 36 months following surgery. This may have large public health implications as PFAS are known to be associated with numerous metabolic related diseases and the significant reduction in circulating PFAS in individuals who have undergone bariatric surgery may be related to the improvement of such metabolic related diseases following bariatric surgery.

Evaluating appetite/satiety hormones and eating behaviours as predictors of weight loss maintenance with GLP-1RA therapy in adolescents with severe obesity

INTRODUCTION

Whilst glucagon-like peptide-1 receptor agonists (GLP1-RAs) are effective for treating adolescent obesity, weight loss maintenance (WLM; preventing weight regain) remains a challenge. Our goal was to investigate appetite/satiety hormones and eating behaviours that may predict WLM with exenatide (a GLP1-RA) versus placebo in adolescents with severe obesity.

METHODS

Adolescents who had ≥5% body mass index (BMI) reduction with meal replacement therapy were randomized to 52 weeks of once-weekly exenatide extended release or placebo. In this secondary analysis, eating behaviours and appetite/satiety regulation hormones post-meal replacement therapy (pre-randomization to exenatide or placebo) were evaluated as possible predictors of WLM. Percent change in BMI from randomization to 52 weeks served as the primary measure of WLM.

RESULTS

The analysis included 66 adolescents (mean age 16.0 years; 47% female). Lower leptin response to meal testing was associated with greater WLM in terms of BMI percent change in those receiving exenatide compared to placebo (p = 0.007) after adjusting for sex, age and BMI. There were no other significant predictors of WLM.

CONCLUSIONS

Prior to exenatide, lower leptin response to meals was associated with improved WLM with exenatide compared to placebo. The mostly null findings of this study suggest that GLP1-RA treatment may produce similar WLM for adolescents with obesity regardless of age, BMI, sex and eating behaviours.

Exposure to 4,4'-DDE in visceral adipose tissue and weight loss in adolescents from the Teen-LABS cohort

OBJECTIVE

Dichlorodiphenyldichloroethylene (DDE), an obesogen accumulating in adipose tissue, is released into circulation with weight loss, although its impact is underexplored among adolescents. We tested the association using an integrative translational approach of epidemiological analysis among adolescents with obesity and in vitro measures exploring the impact of DDE on adipogenesis via preadipocytes.

METHODS

We included 63 participants from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort. We assessed 4,4'-DDE in visceral adipose tissue at surgery and BMI and waist circumference at surgery and 0.5, 1, 3, and 5 years after. We conducted longitudinal analysis to estimate the interaction on weight loss between DDE and time since surgery. In vitro analysis quantified adipogenic differentiation in commercial human preadipocytes exposed to 4,4'-DDE via fluorescent staining and imaging.

RESULTS

A dose-response relationship was observed, with the low-exposure group having a greater reduction in BMI during the first year compared to higher-exposure groups and showing smaller regains compared to higher-exposure groups after the first year. In vitro analysis of preadipocytes treated with 4,4'-DDE during adipogenic differentiation for 12 days showed a concentration-dependent increase in lipid accumulation.

CONCLUSIONS

DDE could contribute to weight trajectory among adolescents undergoing bariatric surgery, potentially mediated via promoted adipogenesis in preadipocytes.

Bone mineral density in young adults 5 to 11 years after adolescent metabolic and bariatric surgery for severe obesity compared to peers

OBJECTIVE

Metabolic and bariatric surgery (MBS) is associated with decreased bone mineral density (BMD) in adults. The long-term impact of MBS during adolescence on BMD is unknown. We report bone health status 5 to 11 years after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) from the Teen-LABS study cohort.

METHODS

Between 2016 and 2022, BMD was measured by dual energy x-ray absorptiometry (DXA) in 106 young adults who had undergone MBS as adolescents. Volumetric BMD by peripheral quantitative computed tomography was measured on a subset. Ninety-one controls who had not undergone MBS were recruited for comparison.

RESULTS

In cases (RYGB: mean age 26.8 ± 1.9 years, mean BMI 42.1 ± 9.9 kg/m2, VSG: mean age 25.1 ± 2.1 years, mean BMI 37.1 ± 8.4 kg/m2), compared to controls (mean age 26.5 ± 2.7 years, mean BMI 40.2 ± 8.7 kg/m2) (age p < 0.001, BMI p = 0.02), adjusted mean DXA-BMD (g/cm2) of the RYGB (n = 58) and VSG (n = 48) groups were lower at the hip (-10.0% and -6.3%), femoral neck (-9.6% and -5.7%) and ultra-distal radius (-7.9% and -7.0%; all p < 0.001), respectively. DXA-BMD did not differ between RYGB and VSG groups. Trabecular volumetric BMD at the radius and tibia were lower in the RYGB (-30% and -26%) and VSG (-15% and -14%) groups compared to the control group (p < 0.001). Greater time since MBS was associated with lower BMD Z-scores at the hip (p = 0.05) and femoral neck (p = 0.045). Percent change in body mass index (BMI) from baseline or in the first year after MBS were not associated with bone measures at a median of 9.3 years post MBS.

CONCLUSION

BMD, especially of the hip and femoral neck, was lower in young adults who underwent MBS during adolescence compared to matched peers who had not undergone MBS. BMD Z-scores of the femoral neck were inversely associated with time since MBS but were not associated with BMI change.

Postpartum longissimus dorsi muscle loss, but not back fat, is associated with resumption of postpartum ovarian activity in dairy cattle

The objectives of this observational cohort study were to assess the effect of body condition score change, back fat depth change, and muscle diameter change on the time to commencement of luteal activity and first estrus in commercial pedigree Holstein cows. A total of 140 of 200 commercial pedigree Holstein cows were enrolled in one dairy herd in Somerset, UK, over 52 wk in 2021 to 2022. The herd used 4 automatic milking machines with in-line progesterone measurement capability to determine commencement of luteal activity and time to first estrus. Cows were followed until at least 60 d postpartum, and milk progesterone was measured daily starting from 10 DIM. Body condition scoring and ultrasound measurements of back fat depth and longissimus dorsi muscle diameter were performed on cows twice, within 7 d of both calving and 60 DIM. Other explanatory variables assessed included parity, 60-d and 305-d milk yield, and subclinical ketosis (β-hydroxybutryate ≥1.2 mmol/L). Occurrence of clinical disease <60 DIM was forced into all models as a binary variable. Data were analyzed using multivariable Cox proportionate survival analyses. Muscle loss was associated with commencement of luteal activity and time to first estrus. A reduction in muscle diameter by 1.5 to 5 mm was associated with the shortest time to the start of luteal activity and first estrus. A reduction in muscle diameter >8 mm was associated with the longest times to luteal activity and first estrus. In addition to being affected by muscle loss, commencement of luteal activity was delayed by subclinical ketosis, clinical disease, and failure to gain body condition to 60 DIM. Cows that had a BCS loss of 0.25 or more between calving and 60 DIM were at least 52 ± 22% less likely to have commenced luteal activity compared with those that gained BCS. Interestingly, cows that had no change in body condition score commenced luteal activity later than those that gained body condition score. Muscle loss was associated with time to first estrus irrespective of clinical disease status. Cows that lost >8 mm of muscle diameter showed estrus behavior later than cows that lost 1.5 to 5 mm. In conclusion, our findings indicate that extensive muscle loss postpartum was associated with a delayed start to luteal activity and first estrus, irrespective of body condition change, clinical disease, and subclinical ketosis. Marginal muscle loss and a gain in body condition, however, were associated with an earlier start to luteal activity and first estrus.

Paired Liver:Plasma PFAS Concentration Ratios from Adolescents in the Teen-LABS Study and Derivation of Empirical and Mass Balance Models to Predict and Explain Liver PFAS Accumulation

Animal studies have pointed at the liver as a hotspot for per- and polyfluoroalkyl substances (PFAS) accumulation and toxicity; however, these findings have not been replicated in human populations. We measured concentrations of seven PFAS in matched liver and plasma samples collected at the time of bariatric surgery from 64 adolescents in the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study. Liver:plasma concentration ratios were perfectly explained (r2 > 0.99) in a multilinear regression (MLR) model based on toxicokinetic (TK) descriptors consisting of binding to tissue constituents and membrane permeabilities. Of the seven matched plasma and liver PFAS concentrations compared in this study, the liver:plasma concentration ratio of perfluoroheptanoic acid (PFHpA) was considerably higher than the liver:plasma concentration ratio of other PFAS congeners. Comparing the MLR model with an equilibrium mass balance model (MBM) suggested that complex kinetic transport processes are driving the unexpectedly high liver:plasma concentration ratio of PFHpA. Intratissue MBM modeling pointed to membrane lipids as the tissue constituents that drive the liver accumulation of long-chain, hydrophobic PFAS, whereas albumin binding of hydrophobic PFAS dominated PFAS distribution in plasma. The liver:plasma concentration data set, empirical MLR model, and mechanistic MBM modeling allow the prediction of liver from plasma concentrations measured in human cohort studies. Our study demonstrates that combining biomonitoring data with mechanistic modeling can identify underlying mechanisms of internal distribution and specific target organ toxicity of PFAS in humans.

Bone mineral density 5 to 11 years after metabolic and bariatric surgery in adolescents with severe obesity compared to peers

Objective

Metabolic and bariatric surgery (MBS) is associated with decreased bone mineral density (BMD) in adults. The long-term impact of MBS during adolescence on BMD is unknown. We report bone health status 5 to 11 years after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) from the Teen-LABS study cohort.

Methods

Between 2016 and 2022, BMD was measured by dual energy x-ray absorptiometry (DXA) in 106 young adults who had undergone MBS as adolescents. Volumetric BMD by peripheral quantitative computed tomography was measured on a subset. Ninety-one controls who had not undergone MBS were recruited for comparison.

Results

Compared to controls, adjusted mean DXA-BMD of the RYGB (n = 58) and VSG (n = 48) groups were lower at the hip (-10.0% and - 6.3%), femoral neck (-9.6% and - 5.7%) and ultra-distal radius (-7.9% and - 7.0%; all p < 0.001), respectively. DXA-BMD did not differ between RYGB and VSG groups. Trabecular volumetric BMD at the radius and tibia were lower in the RYGB (-30% and - 26%) and VSG (-15% and - 14%) groups compared to the control group (p < 0.001). Greater time since MBS was associated with lower BMD Z-scores at the hip (p = 0.05) and femoral neck (p = 0.045). Percent change in body mass index (BMI) from baseline or in the first year after MSB were not associated with bone measures at a median of 9.3 years post MSB.

Conclusion

BMD, especially of the hip and femoral neck, was lower in young adults who underwent MBS during adolescence compared to matched peers who had not undergone MBS. BMD Z-scores of the femoral neck decreased with time since MBS but were not associated with BMI change.

VIDAS Enzyme-Linked Fluorescent Immunoassay for Detection of Salmonella in Foods: Collaborative Study

The VIDAS SLM method for detection of Salmonella was compared with the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Twenty laboratories participated in the evaluation. Each laboratory tested one or more of 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. No significant differences (P&lt; 0.05) were observed between the 2 methods. The 2 methods were in agreement for 99% of 1544 samples analyzed. Of the 20 samples out of agreement, 8 were VIDAS SLM positive and BAM/AOAC negative, and 12 were VIDAS SLM negative and BAM/AOAC positive. The VIDAS SLM method for detection of Salmonella in foods has been adopted first action by AOAC INTERNATIONAL.

Abstract 3118: Obesity as a risk factor for pediatric acute lymphoblastic leukemia: A report from the Children's Oncology Group

Introduction: Increases in the incidence of both obesity (a risk factor for many adulthood cancers) and acute lymphoblastic leukemia (ALL) in childhood have been observed over the past three decades, thus we sought to identify whether obesity may be an unrecognized risk factor for childhood ALL.

Methods: Demographics, anthropometrics and disease characteristics from children and young adults (aged 1-30 years) diagnosed with ALL between 2004-2017 and treated on Children’s Oncology Group (COG) frontline treatment protocols with available pre-treatment anthropometric data (n=4775, AALL17D2) were compared to National Health and Nutrition Examination Survey (NHANES) controls (n=30,107). Individuals were classified as underweight, normal weight, overweight, or obese, per standard CDC age- and sex-based pediatric and adult definitions for body mass index (BMI). Multivariate logistic regressions were performed, adjusting for sex, race/ethnicity, age, socioeconomic status and obesity status, to assess associations between BMI classification and ALL. Additional models were performed stratifying by ALL disease characteristics.

Results: ALL patients (72% B-ALL, 28% T-ALL) were more likely to be male (62%), 58% were non-Hispanic white, 9% non-Hispanic black and 24% identified as Hispanic. Among ALL patients, 5% were underweight, 58% normal weight, 17% overweight and 20% obese. Using normal weight as reference, BMI above normal weight classification was associated with ALL diagnosis (overweight, OR=1.10, 95% CI 1.00-1.20, p=0.046; obese, OR=1.15, 95% CI 1.05-1.25, p=0.002), as was underweight (OR=1.74, 95% CI 1.48-2.03, p=&lt;0.0001). When stratified by sex, the associations with overweight and obesity were only observed in males (ptrend&lt;0.0001), and when stratified by ALL immunophenotype, associations with overweight and obesity were only observed in B-ALL (ptrend&lt;0.0001). Obesity was also associated with moderate to high levels of ALL central nervous system (CNS) involvement (CNS2, OR=1.30, 95% CI 1.08-1.57, p=0.006; CNS3, OR=2.28, 95% CI 1.24-4.17, p=0.005).

Conclusions: This is the first study, to our knowledge, to show that pre-treatment overweight or obesity is associated with ALL, specifically among males and B-cell immunophenotype. Furthermore, ALL CNS involvement was associated with obesity. This study also confirmed the known association between underweight and ALL. Although the associations between BMI status and newly diagnosed ALL may be secondary to detrimental physiologic effects of ALL (i.e. underweight at time of diagnosis), they also suggest a role for inflammation, environmental exposures, or other genetic susceptibility in ALL pathogenesis. Further analyses are needed to elucidate whether other ALL disease characteristics, such as cytogenetics, may be associated with pre-treatment childhood BMI.

Citation Format: Taumoha Ghosh, Michaela Richardson, Justin Ryder, Logan Spector, Lucie Turcotte. Obesity as a risk factor for pediatric acute lymphoblastic leukemia: A report from the Children's Oncology Group [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3118.

Abstract P5-11-10: Biomarkers associated with resistance or response to CDK4/6 treatment in patients with metastatic hormone-receptive positive breast cancer

Background:

CDK4/6 inhibitor (CDKi) drugs are the current standard of care for treatment of first and second-line hormone-receptor positive/HER2 negative (HR+/HER2-) metastatic breast cancers. Numerous research efforts have commenced to understand biomarkers of response and resistance. To date, no biomarker of response has been identified. Treatment induced RB1 mutations were noted as mechanism of resistance to palbociclib and fulvestrant in about 5% of patients treated on PALOMA3 trials, whereas PI3K and ESR1 mutations emerged as potential resistance to the anti-hormonal backbone1. Additionally, FGFR1 amplification has been suggested as a resistance pathway to fulvestrant and ribociclib2. A better understanding of the molecular landscape of CDK4/6 treatment is needed. Utilizing next-gen sequencing (NGS), chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) data from HR+/HER2- patients treated at the University of Tennessee West Cancer Center, we attempted to retrospectively identify a molecular signature of resistance or response as measured by PFS.

Methods:

We analyzed 115 breast cancer patients who received CDKi treatment and 30 matched controls not exposed to CDKi and underwent comprehensive molecular profiling (Caris Life Sciences, Phoenix, AZ). A Cox proportional hazards model was built using genetic test as predictors and progression free survival (PFS) time as response. Only alterations with known pathogenic potential were considered aberrant. The R package glmnet was used to perform regularized lasso regression for feature selection on the entire data set. Important features were then used to construct Kaplan-Meier curves and perform a log-rank test for difference in PFS times.

Results:

Here we report the analysis for 2 known pathogenic biomarkers, ESR1 and TP53 based on PFS for patients who test positive versus negative. The median PFS for all patients was 234 days. Patients who harbored ESR1 mutations had reduced PFS of 180 days compared to 237 days. Patients who had P53 mutations had shorter PFS of 201 days compared to 240 days. When both groups with positive mutations were combined, the median PFS was 191 days compared to 276 days for patients without either ESR1 or P53 mutation with a p-value of 0.011. Further analysis using 4 way Kaplan Meier Curves for controls versus treated, altered versus non-altered genes, or PDL-1 expression is ongoing and will be presented at the conference.

Conclusion:

This data further support, in a real world model, the poor predictive value of ESR1 and P53 mutations on clinical outcome. Because no testing data was used, additional validation will be necessary to confirm the findings from this analysis.

References:

1. Nicholas C. Turner, Ben O'Leary, Ros Cutts, Massimo Cristofanilliet al, Genetic landscape of resistance to CDK4/6 inhibition in circulating tumor DNA (ctDNA) analysis of the PALOMA3 trial of palbociclib and fulvestrant versus placebo and fulvestrant. J Clin Oncol 36, 2018 (suppl; abstr 1001).

2. Luigi Formisano, Yao Lu, Carlos Arteaga et al. Gain of function kinase library identifies FGFR1 amplification as a mechanism of resistance to antiestrogen and CDK4/6 inhibitor in ER+ breast cancer. SABCS 2017 abstract GS6-05.

Citation Format: Mullins JN, Chaudhry A, Ryder J, Valasareddy P, Jain A, Ranganath H, Hare F, Vidal GA. Biomarkers associated with resistance or response to CDK4/6 treatment in patients with metastatic hormone-receptive positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-11-10.

Racial differences in intracerebral haemorrhage outcomes in patients with obesity

OBJECTIVE

This study was conducted to determine the role of obesity and race in intracerebral haemorrhage (ICH) outcomes.

METHODS

The Get with the guideline-Stroke database was queried for all admitted patients with spontaneous ICH. Secondary causes of ICH were excluded. Body mass index (BMI) was classified using the Center for Disease Control guidelines. Race was classified as White or non-White. Demographics, clinical, imaging data were retrieved. Outcome measures were hematoma expansion at 24 h and discharge disposition.

RESULTS

A total of 428 patients were included in our analysis. Female gender, past history of congestive heart failure, diabetes mellitus, HbA1c, blood pressure, ICH volume, ICH location, intraventricular haemorrhage and hospital length of stay deferred across BMI categories. On multivariate analysis, along with obese categories, age, ICH location and ICH volume were independent predictors of poor outcomes (hematoma expansion and poor discharge disposition). After adjusting for these variables, obesity remained a predictor of poor disposition outcome compared with normal and overweight subjects; Normal vs. Obese OR 0.26 CI 0.115-0.593 p = 0.0014; Obese vs. Overweight OR 3.79 CI 1.68-8.52 p = 0.0013. Nonetheless, obesity did not influence hematoma expansion. Overall, BMI-race classification did not influence outcomes. However, among non-Whites, the obese category had higher odds of a poor disposition outcome than normal (OR 6.84 CI 2.12-22.22 p = 0.0013) or overweight (OR 8.45 CI 2.6-27.49 p = 0.0004) categories.

CONCLUSION

An obesity paradox in ICH was not observed in our cohort. In the non-White population, patients with obesity were likely to be associated with poor disposition outcome. Similar findings were not observed in White population.

Twenty year fitness trends in young adults and incidence of prediabetes and diabetes: the CARDIA study

AIMS/HYPOTHESIS

The prospective association between cardiorespiratory fitness (CRF) measured in young adulthood and middle age on development of prediabetes, defined as impaired fasting glucose and/or impaired glucose tolerance, or diabetes by middle age remains unknown. We hypothesised that higher fitness levels would be associated with reduced risk for developing incident prediabetes/diabetes by middle age.

METHODS

Participants were from the Coronary Artery Risk Development in Young Adults (CARDIA) study who were free from prediabetes/diabetes at baseline (year 0 [Y0]: 1985-1986). CRF was quantified by treadmill duration (converted to metabolic equivalents [METs]) at Y0, Y7 and Y20 and prediabetes/diabetes status was assessed at Y0, Y7, Y10, Y15, Y20 and Y25. We use an extended Cox model with CRF as the primary time-varying exposure. BMI was included as a time-varying covariate. The outcome was development of either prediabetes or diabetes after Y0. Model 1 included age, race, sex, field centre, CRF and BMI. Model 2 additionally included baseline (Y0) smoking, energy intake, alcohol intake, education, systolic BP, BP medication use and lipid profile.

RESULTS

Higher fitness was associated with lower risk for developing incident prediabetes/diabetes (difference of 1 MET: HR 0.99898 [95% CI 0.99861, 0.99940], p < 0.01), which persisted (difference of 1 MET: HR 0.99872 [95% CI 0.99840, 0.99904], p < 0.01] when adjusting for covariates.

CONCLUSIONS/INTERPRETATION

Examining participants who had fitness measured from young adulthood to middle age, we found that fitness was associated with lower risk for developing prediabetes/diabetes, even when adjusting for BMI over this time period. These findings emphasise the importance of fitness in reducing the health burden of prediabetes and diabetes.

Dissemination and publication of research findings: an updated review of related biases

OBJECTIVES

To identify and appraise empirical studies on publication and related biases published since 1998; to assess methods to deal with publication and related biases; and to examine, in a random sample of published systematic reviews, measures taken to prevent, reduce and detect dissemination bias.

DATA SOURCES

The main literature search, in August 2008, covered the Cochrane Methodology Register Database, MEDLINE, EMBASE, AMED and CINAHL. In May 2009, PubMed, PsycINFO and OpenSIGLE were also searched. Reference lists of retrieved studies were also examined.

REVIEW METHODS

In Part I, studies were classified as evidence or method studies and data were extracted according to types of dissemination bias or methods for dealing with it. Evidence from empirical studies was summarised narratively. In Part II, 300 systematic reviews were randomly selected from MEDLINE and the methods used to deal with publication and related biases were assessed.

RESULTS

Studies with significant or positive results were more likely to be published than those with non-significant or negative results, thereby confirming findings from a previous HTA report. There was convincing evidence that outcome reporting bias exists and has an impact on the pooled summary in systematic reviews. Studies with significant results tended to be published earlier than studies with non-significant results, and empirical evidence suggests that published studies tended to report a greater treatment effect than those from the grey literature. Exclusion of non-English-language studies appeared to result in a high risk of bias in some areas of research such as complementary and alternative medicine. In a few cases, publication and related biases had a potentially detrimental impact on patients or resource use. Publication bias can be prevented before a literature review (e.g. by prospective registration of trials), or detected during a literature review (e.g. by locating unpublished studies, funnel plot and related tests, sensitivity analysis modelling), or its impact can be minimised after a literature review (e.g. by confirmatory large-scale trials, updating the systematic review). The interpretation of funnel plot and related statistical tests, often used to assess publication bias, was often too simplistic and likely misleading. More sophisticated modelling methods have not been widely used. Compared with systematic reviews published in 1996, recent reviews of health-care interventions were more likely to locate and include non-English-language studies and grey literature or unpublished studies, and to test for publication bias.

CONCLUSIONS

Dissemination of research findings is likely to be a biased process, although the actual impact of such bias depends on specific circumstances. The prospective registration of clinical trials and the endorsement of reporting guidelines may reduce research dissemination bias in clinical research. In systematic reviews, measures can be taken to minimise the impact of dissemination bias by systematically searching for and including relevant studies that are difficult to access. Statistical methods can be useful for sensitivity analyses. Further research is needed to develop methods for qualitatively assessing the risk of publication bias in systematic reviews, and to evaluate the effect of prospective registration of studies, open access policy and improved publication guidelines.

Clinical effectiveness and cost-effectiveness of bone morphogenetic proteins in the non-healing of fractures and spinal fusion: a systematic review

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of bone morphogenetic protein (BMP) for the treatment of spinal fusions and the healing of fractures compared with the current standards of care.

DATA SOURCES

Electronic databases, related journals and references from identified studies were searched in January 2006, with an updated search only for randomised controlled trials (RCTs) in November 2006.

REVIEW METHODS

A systematic review of available data was conducted. The data from selected studies were then analysed and graded according to quality and processed to give a value to the efficacy of BMP. Existing models were modified or updated to evaluate the cost-effectiveness of BMP for open tibial fractures and spinal fusion.

RESULTS

All selected trials were found to have several methodological weaknesses. Insufficient sample size in most trials, meant that patient baseline comparability between trial arms was not achieved and the statistical power to detect a moderate effect was low. Data did indicate that BMP increased fracture union among patients with acute tibial fractures and found that high-dose BMP is more effective than a lower dose for open tibial fractures. The healing rate in the BMP group was not found to be statistically significantly different from that in the autogenous bone grafting group for patients with tibial non-union fractures, but BMP reduced the number of secondary interventions in patients with acute tibial fractures compared with controls. There was very limited evidence that BMP in scaphoid non-union was safe and may help to accelerate non-union healing when used in conjunction with either autograft or allograft. There was evidence that BMP-2 is more effective than autogenous bone graft for radiographic fusion in patients with single-level degenerative disc disease. No significant difference was found when BMP-7 was compared with autograft for degenerative spondylolisthesis with spinal stenosis and spondylolysis. The use of BMP was associated with a reduced operating time, improvement in clinical outcomes and a shorter hospital stay as compared with autograft. The proportion of secondary interventions tended to be lower in the BMP group than the control, but not of statistical significance. Trial data on time to return to work postoperatively were sometimes difficult to interpret because of unclear or inappropriate data analysis methods. The incremental cost of BMP for open tibial fractures was estimated to be about 3.5 million pounds per year in the UK. The estimated incremental cost per quality-adjusted life-year (QALY) gained is 32,603 pounds. The probability that cost per QALY gained is less than 30,000 pounds for open tibial fracture is 35.5%. The cost-effectiveness ratio is sensitive to the price of BMP and the severity of open tibial fractures. The use of recombinant human bone morphogenetic protein for spinal fusion surgery may increase the cost to the UK NHS by about 1.3 million pounds per year. The estimated incremental cost per QALY gained was about 120,390 pounds. The probability that BMP is cost-effective (i.e. cost/QALY less than 30,000 pounds) was only 6.4%. From the societal perspective, the estimated total cost of using BMP for spinal fusion is about 4.2 million pounds per year in the UK.

CONCLUSIONS

Additional BMP treatment plus conventional intervention is more effective than conventional intervention alone for union of acute open tibial fractures. The cost-effectiveness of additional BMP may be improved if the price of BMP is reduced or if BMP is mainly used in severe cases. BMP may eliminate the need for autogenous bone grafting so that costs and complications related to harvesting autograft can be avoided. In non-unions, there is no evidence that BMP is more or less effective than bone graft; however, it is currently used when bone graft and other treatments have failed. The use of BMP-2 in spinal fusion surgery seems to be more effective than autogenous bone graft in terms of radiographic spinal fusion among patients with single-level degenerative disc disease. There is a lack of evidence about the effectiveness of BMP for other spinal disorders including spondylolisthesis and spinal stenosis. There was limited evidence showing that BMP is associated with greater improvement in clinical outcomes. According to the results of economic evaluation, the use of BMP for spinal fusion is unlikely to be cost-effective. The following areas would benefit from further research: clinical trials of BMP that include formal economic evaluation, a multicentre RCT of fracture non-union and of interbody and/or posterolateral spinal fusion, trials of non-tibial acute long bone fractures, and RCTs comparing BMP-2, BMP-7 and controls.

Secondary central nervous system involvement by follicular lymphoma: case report and review of the literature

BACKGROUND

We report a patient with indolent stage IV follicular lymphoma, grade 1, initially successfully treated with chemotherapy, who later developed aggressive diffuse large B-cell lymphoma in the parieto-occipital lobe 8 years after initial presentation. The differing patterns of lymphomatous involvement of the central nervous system (CNS) are briefly reviewed, with a focus on the patterns seen in secondary CNS spread by low-grade lymphomas.

CASE DESCRIPTION

A 53-year-old man was diagnosed with stage IV follicular lymphoma, grade 1, in 1996. Although initial chemotherapy was successful, he developed several recurrences of lymphoma over the following years. In May 2004, he presented with a discrete, single, massive parieto-occipital lobe brain lesion. The mass failed to regress with empiric cranial external beam radiotherapy. Because of suspicion of an unusual infection, the lesion was surgically excised in its entirety. The mass proved to be an aggressive diffuse large B-cell lymphoma, transformed from his previous follicular cell lymphoma, with retention of strong Bcl-2 and Bcl-6 immunoreactivity.

CONCLUSIONS

Parenchymal brain involvement, as opposed to dural or leptomeningeal, is a relatively uncommon pattern of spread to the CNS for systemic lymphomas. More significantly, follicular lymphomas are one of the least frequent types of indolent lymphomas to develop clinically apparent, secondary CNS spread. The presentation of an indolent follicular lymphoma with transformation to an aggressive diffuse large B-cell lymphoma within the brain parenchyma is rare. Its manifestation as a massive, singular lesion is unique and prompted diagnostic confusion.

Hematological neoplasms with first presentation as spinal cord compression syndromes: a 10-year retrospective series and review of the literature

CONTEXT

The epidural space is a well-known, albeit uncommon, location for lymphomatous involvement, estimated to occur in less than 3% of all systemic lymphomas. Initial presentation of the patient with disease in this site (i.e. primary spinal epidural lymphoma) has been considered to be "rare". When it has been reported, many studies have emphasized the occurrence of aggressive lymphomas with a poor prognosis.

DESIGN

A 10-year retrospective search of our files generated 7 patients who presented initially with back pain, incontinence and/or lower extremity weakness, and by neuroimaging studies were found to have masses causing spinal cord compression syndromes necessitating neurosurgical intervention.

RESULTS

The 7 patients included 4 males and 3 females with thoracic and lumbar epidural masses. Tumor types included high-grade non-Hodgkin lymphoma, B cell type (n = 4), indolent B cell lymphoma (n = 1), nodular sclerosing Hodgkin lymphoma (n = 1) and plasmacytoma (n = 1). Advanced disease (stage 4) was subsequently identified in all 7 patients. Despite this, survival varied greatly with therapy, from 3 weeks to almost 6 years, underscoring the need for correct classification of the lymphoma in order to optimize chemotherapeutic choices. The epidural space was the site of presentation of disease in 4% of all lymphomas diagnosed at our institution.

CONCLUSIONS

Combining all reports in the literature, epidural presentation of lymphoma is not rare. Epidural lymphomas are distinct from both primary central nervous system lymphomas and from primary dural lymphomas. A broad range of systemic hematological tumor types can present as epidural masses. A full work-up for lymphoma classification may only be possible from the tissues received at the time of the neurosurgical decompression or biopsy procedure.