Meta-analysis and the science of research synthesis.

Meta-analysis is the quantitative, scientific synthesis of research results. Since the term and modern approaches to research synthesis were first introduced in the 1970s, meta-analysis has had a revolutionary effect in many scientific fields, helping to establish evidence-based practice and to resolve seemingly contradictory research outcomes. At the same time, its implementation has engendered criticism and controversy, in some cases general and others specific to particular disciplines. Here we take the opportunity provided by the recent fortieth anniversary of meta-analysis to reflect on the accomplishments, limitations, recent advances and directions for future developments in the field of research synthesis.

Antidepressants for pain management in adults with chronic pain: a network meta-analysis.

BACKGROUND: Chronic pain is common in adults, and often has a detrimental impact upon physical ability, well-being, and quality of life. Previous reviews have shown that certain antidepressants may be effective in reducing pain with some benefit in improving patients' global impression of change for certain chronic pain conditions. However, there has not been a network meta-analysis (NMA) examining all antidepressants across all chronic pain conditions. OBJECTIVES: To assess the comparative efficacy and safety of antidepressants for adults with chronic pain (except headache). SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, AMED and PsycINFO databases, and clinical trials registries, for randomised controlled trials (RCTs) of antidepressants for chronic pain conditions in January 2022. SELECTION CRITERIA: We included RCTs that examined antidepressants for chronic pain against any comparator. If the comparator was placebo, another medication, another antidepressant, or the same antidepressant at different doses, then we required the study to be double-blind. We included RCTs with active comparators that were unable to be double-blinded (e.g. psychotherapy) but rated them as high risk of bias. We excluded RCTs where the follow-up was less than two weeks and those with fewer than 10 participants in each arm.  DATA COLLECTION AND ANALYSIS: Two review authors separately screened, data extracted, and judged risk of bias. We synthesised the data using Bayesian NMA and pairwise meta-analyses for each outcome and ranked the antidepressants in terms of their effectiveness using the surface under the cumulative ranking curve (SUCRA). We primarily used Confidence in Meta-Analysis (CINeMA) and Risk of Bias due to Missing Evidence in Network meta-analysis (ROB-MEN) to assess the certainty of the evidence. Where it was not possible to use CINeMA and ROB-MEN due to the complexity of the networks, we used GRADE to assess the certainty of the evidence. Our primary outcomes were substantial (50%) pain relief, pain intensity, mood, and adverse events. Our secondary outcomes were moderate pain relief (30%), physical function, sleep, quality of life, Patient Global Impression of Change (PGIC), serious adverse events, and withdrawal. MAIN RESULTS: This review and NMA included 176 studies with a total of 28,664 participants. The majority of studies were placebo-controlled (83), and parallel-armed (141). The most common pain conditions examined were fibromyalgia (59 studies); neuropathic pain (49 studies) and musculoskeletal pain (40 studies). The average length of RCTs was 10 weeks. Seven studies provided no useable data and were omitted from the NMA. The majority of studies measured short-term outcomes only and excluded people with low mood and other mental health conditions. Across efficacy outcomes, duloxetine was consistently the highest-ranked antidepressant with moderate- to high-certainty evidence. In duloxetine studies, standard dose was equally efficacious as high dose for the majority of outcomes. Milnacipran was often ranked as the next most efficacious antidepressant, although the certainty of evidence was lower than that of duloxetine. There was insufficient evidence to draw robust conclusions for the efficacy and safety of any other antidepressant for chronic pain.  Primary efficacy outcomes Duloxetine standard dose (60 mg) showed a small to moderate effect for substantial pain relief (odds ratio (OR) 1.91, 95% confidence interval (CI) 1.69 to 2.17; 16 studies, 4490 participants; moderate-certainty evidence) and continuous pain intensity (standardised mean difference (SMD) -0.31, 95% CI -0.39 to -0.24; 18 studies, 4959 participants; moderate-certainty evidence). For pain intensity, milnacipran standard dose (100 mg) also showed a small effect (SMD -0.22, 95% CI -0.39 to 0.06; 4 studies, 1866 participants; moderate-certainty evidence). Mirtazapine (30 mg) had a moderate effect on mood (SMD -0.5, 95% CI -0.78 to -0.22; 1 study, 406 participants; low-certainty evidence), while duloxetine showed a small effect (SMD -0.16, 95% CI -0.22 to -0.1; 26 studies, 7952 participants; moderate-certainty evidence); however it is important to note that most studies excluded participants with mental health conditions, and so average anxiety and depression scores tended to be in the 'normal' or 'subclinical' ranges at baseline already. Secondary efficacy outcomes Across all secondary efficacy outcomes (moderate pain relief, physical function, sleep, quality of life, and PGIC), duloxetine and milnacipran were the highest-ranked antidepressants with moderate-certainty evidence, although effects were small. For both duloxetine and milnacipran, standard doses were as efficacious as high doses. Safety There was very low-certainty evidence for all safety outcomes (adverse events, serious adverse events, and withdrawal) across all antidepressants. We cannot draw any reliable conclusions from the NMAs for these outcomes. AUTHORS' CONCLUSIONS: Our review and NMAs show that despite studies investigating 25 different antidepressants, the only antidepressant we are certain about for the treatment of chronic pain is duloxetine. Duloxetine was moderately efficacious across all outcomes at standard dose. There is also promising evidence for milnacipran, although further high-quality research is needed to be confident in these conclusions. Evidence for all other antidepressants was low certainty. As RCTs excluded people with low mood, we were unable to establish the effects of antidepressants for people with chronic pain and depression. There is currently no reliable evidence for the long-term efficacy of any antidepressant, and no reliable evidence for the safety of antidepressants for chronic pain at any time point.

Traumatic life experiences and post-traumatic stress symptoms in middle-aged and older adults with and without autistic traits.

OBJECTIVES: Research with younger adults has begun to explore associations between autism/autistic traits and vulnerability to Post Traumatic Stress Disorder (PTSD). Large scale studies and/or examination of age-effects have not been conducted. METHODS: Adults aged 50 years+ from the PROTECT study (n = 20,220) completed items about current and childhood socio-communicative difficulties characteristic of autism. Approximately 1% (n = 251) endorsed high autistic traits, henceforth the Autism Spectrum Traits (AST) group. Differences between the AST and an age-and sex-matched "Comparison Older Adults" (COA; n = 9179) group were explored for lifetime traumatic experiences and current symptoms of PTSD, depression, and anxiety. RESULTS: Almost 30% of the AST group, compared to less than 8% of the COA, reported severe trauma in childhood/adulthood, including emotional, physical or sexual abuse. Elevated current PTSD symptoms were reported by AST compared to COA. An interaction was observed between autistic traits and trauma severity; the effect of level of trauma on PTSD symptoms was significantly greater for AST versus COA participants. This interaction remained significant when controlling for current depression and anxiety symptoms. CONCLUSIONS: The findings suggest that high autistic traits may increase the likelihood of experiencing trauma across the lifespan, and the impact of severe trauma on PTSD symptoms. Older adults with high (vs. low) autistic traits may be at greater risk of experiencing PTSD symptoms in latter life. Future research should test whether the pattern of results is similar for diagnosed autistic adults.

Inhibition of Urea Transporter (UT)-B Modulates LPS-Induced Inflammatory Responses in BV2 Microglia and N2a Neuroblastoma Cells.

Urea is the major nitrogen-containing product of protein metabolism, and the urea cycle is intrinsically linked to nitric oxide (NO) production via the common substrate L-arginine. Urea accumulates in the brain in neurodegenerative states, including Alzheimer's and Huntington's disease. Urea transporter B (UT-B, SLC14A1) is the primary transport protein for urea in the CNS, identified most abundantly in astrocytes. Moreover, enhanced expression of the Slc14a1 gene has been reported under neurodegenerative conditions. While the role of UT-B in disease pathology remains unclear, UT-B-deficient mice display behavioural impairment coupled with urea accumulation, NO disruption and neuronal loss. Recognising the role of inflammation in neurodegenerative disease pathology, the current short study evaluates the role of UT-B in regulating inflammatory responses. Using the specific inhibitor UTBinh-14, we investigated the impact of UT-B inhibition on LPS-induced changes in BV2 microglia and N2a neuroblastoma cells. We found that UTBinh-14 significantly attenuated LPS-induced production of TNFα and IL-6 from BV2 cells, accompanied by reduced release of NO. While we observed a similar reduction in supernatant concentration of IL-6 from N2a cells, the LPS-stimulated NO release was further augmented by UTBinh-14. These changes were accompanied by a small, but significant downregulation in UT-B expression in both cell types following incubation with LPS, which was not restored by UTBinh-14. Taken together, the current evidence implicates UT-B in regulation of inflammatory responses in microglia and neuronal-like cells. Moreover, our findings offer support for the further investigation of UT-B as a novel therapeutic target for neuroinflammatory conditions.

Identification of the HT-29 cell line as a model for investigating MCT1 transporters in sigmoid colon adenocarcinoma.

MCT1 transporters play a crucial role in the symbiotic relationship between humans and their colonic microbiome by facilitating the transport of bacteria-derived short chain fatty acids. Expression of colonic MCT1 transporters, localized in surface epithelial cells, is regulated by luminal butyrate levels. However, MCT1 also transports lactate and can be used by cancer cells to facilitate anaerobic glycolysis. Using immunolocalization techniques, this study investigated whether changes in MCT1 during cancer varied between different colonic regions. Whilst MCT1 abundance did not significantly change in transverse colon adenocarcinoma (P = 0.363, N = 6, paired T-Test), there was an increase in MCT1 in sigmoid colon adenocarcinoma (P = 0.010, N = 21, paired T-test). Using RT-PCR and western blotting, three human intestinal cell lines were tested for their suitability as a MCT1 cancer cell model. Experiments with Caco-2 cells confirmed that they modelled normal cells, with MCT1 only expressed after exposure to butyrate. In contrast, MCT1 was expressed in the absence of butyrate in both HCT-8 and HT-29 cell lines, with consistently high levels of MCT1 protein being present in HT-29 cells. Furthermore, butyrate treatment of HT-29 cells significantly decreased both MCT1 protein abundance (P < 0.001, N = 4, unpaired T-test) and glycosylation of its' chaperone protein, CD147 (P < 0.001, N = 4, unpaired T-test). These data suggest that (i) MCT1 transporter abundance increases in sigmoid colon adenocarcinoma, and (ii) HT-29 cells are an appropriate cell model with which to investigate MCT1 function in this disease.

Localization of aquaporin-3 proteins in the bovine rumen.

Urea nitrogen salvaging is a crucial mechanism that ruminants have evolved to conserve nitrogen. Facilitative urea transporter-B proteins are known to be involved in urea transport across the rumen epithelium and thus efficiently facilitate the urea nitrogen salvaging process. Recently, functional studies have suggested that aquaglyceroporin transporters might also play a significant role in ruminal urea transport and aquaporin-3 (AQP3) protein has previously been detected in rumen tissue. In this current study, we investigated the specific localization of AQP3 transporters in the bovine rumen. First, end-point reverse-transcription PCR experiments confirmed strong AQP3 expression in both bovine rumen and kidney. Immunoblotting analysis using 2 separate anti-AQP3 antibodies detected AQP3 protein signals at 25, 32, and 42-45 kDa. Further immunolocalization studies showed AQP3 protein located in all the layers of rumen epithelium, especially in the stratum basale, and in the basolateral membranes of kidney collecting duct cells. These data confirm that AQP3 transporters are highly abundant within the bovine rumen and appear to be located throughout the ruminal epithelial layers. The physiological significance of the multiple AQP3 proteins detected and their location is not yet clear, hence further investigation is required to determine their exact contribution to ruminal urea transport.

Psychological therapies for the management of chronic and recurrent pain in children and adolescents.

BACKGROUND: This is an update of the original Cochrane review first published in Issue 1, 2003, and previously updated in 2009, 2012 and 2014. Chronic pain, defined as pain that recurs or persists for more than three months, is common in childhood. Chronic pain can affect nearly every aspect of daily life and is associated with disability, anxiety, and depressive symptoms. OBJECTIVES: The aim of this review was to update the published evidence on the efficacy of psychological treatments for chronic and recurrent pain in children and adolescents.The primary objective of this updated review was to determine any effect of psychological therapy on the clinical outcomes of pain intensity and disability for chronic and recurrent pain in children and adolescents compared with active treatment, waiting-list, or treatment-as-usual care.The secondary objective was to examine the impact of psychological therapies on children's depressive symptoms and anxiety symptoms, and determine adverse events. SEARCH METHODS: Searches were undertaken of CENTRAL, MEDLINE, MEDLINE in Process, Embase, and PsycINFO databases. We searched for further RCTs in the references of all identified studies, meta-analyses, and reviews, and trial registry databases. The most recent search was conducted in May 2018. SELECTION CRITERIA: RCTs with at least 10 participants in each arm post-treatment comparing psychological therapies with active treatment, treatment-as-usual, or waiting-list control for children or adolescents with recurrent or chronic pain were eligible for inclusion. We excluded trials conducted remotely via the Internet. DATA COLLECTION AND ANALYSIS: We analysed included studies and we assessed quality of outcomes. We combined all treatments into one class named 'psychological treatments'. We separated the trials by the number of participants that were included in each arm; trials with > 20 participants per arm versus trials with < 20 participants per arm. We split pain conditions into headache and mixed chronic pain conditions. We assessed the impact of both conditions on four outcomes: pain, disability, depression, and anxiety. We extracted data at two time points; post-treatment (immediately or the earliest data available following end of treatment) and at follow-up (between three and 12 months post-treatment). MAIN RESULTS: We identified 10 new studies (an additional 869 participants) in the updated search. The review thus included a total of 47 studies, with 2884 children and adolescents completing treatment (mean age 12.65 years, SD 2.21 years). Twenty-three studies addressed treatments for headache (including migraine); 10 for abdominal pain; two studies treated participants with either a primary diagnosis of abdominal pain or irritable bowel syndrome, two studies treated adolescents with fibromyalgia, two studies included adolescents with temporomandibular disorders, three were for the treatment of pain associated with sickle cell disease, and two studies treated adolescents with inflammatory bowel disease. Finally, three studies included adolescents with mixed pain conditions. Overall, we judged the included studies to be at unclear or high risk of bias.Children with headache painWe found that psychological therapies reduced pain frequency post-treatment for children and adolescents with headaches (risk ratio (RR) 2.35, 95% confidence interval (CI) 1.67 to 3.30, P < 0.01, number needed to treat for an additional beneficial outcome (NNTB) = 2.86), but these effects were not maintained at follow-up. We did not find a beneficial effect of psychological therapies on reducing disability in young people post-treatment (SMD -0.26, 95% CI -0.56 to 0.03), but we did find a beneficial effect in a small number of studies at follow-up (SMD -0.34, 95% CI -0.54 to -0.15). We found no beneficial effect of psychological interventions on depression or anxiety symptoms.Children with mixed pain conditionsWe found that psychological therapies reduced pain intensity post-treatment for children and adolescents with mixed pain conditions (SMD -0.43, 95% CI -0.67 to -0.19, P < 0.01), but these effects were not maintained at follow-up. We did find beneficial effects of psychological therapies on reducing disability for young people with mixed pain conditions post-treatment (SMD -0.34, 95% CI -0.54 to -0.15) and at follow-up (SMD -0.27, 95% CI -0.49 to -0.06). We found no beneficial effect of psychological interventions on depression symptoms. In contrast, we found a beneficial effect on anxiety at post-treatment in children with mixed pain conditions (SMD -0.16, 95% CI -0.29 to -0.03), but this was not maintained at follow-up.Across all pain conditions, we found that adverse events were reported in seven trials, of which two studies reported adverse events that were study-related.Quality of evidenceWe found the quality of evidence for all outcomes to be low or very low, mostly downgraded for unexplained heterogeneity, limitations in study design, imprecise and sparse data, or suspicion of publication bias. This means our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect, or we have very little confidence in the effect estimate; or the true effect is likely to be substantially different from the estimate of effect. AUTHORS' CONCLUSIONS: Psychological treatments delivered predominantly face-to-face might be effective for reducing pain outcomes for children and adolescents with headache or other chronic pain conditions post-treatment. However, there were no effects at follow-up. Psychological therapies were also beneficial for reducing disability in children with mixed chronic pain conditions at post-treatment and follow-up, and for children with headache at follow-up. We found no beneficial effect of therapies for improving depression or anxiety. The conclusions of this update replicate and add to those of a previous version of the review which found that psychological therapies were effective in reducing pain frequency/intensity for children with headache and mixed chronic pain conditions post-treatment.

STATUS OF DISINVESTMENT INITIATIVES IN LATIN AMERICA: RESULTS FROM A SYSTEMATIC LITERATURE REVIEW AND A QUESTIONNAIRE.

OBJECTIVES: Disinvestment of existing healthcare technologies that deliver low or no health benefit for their cost can be used as a tool to improve access to effective technologies, while ensuring the long-term sustainability of healthcare systems. The objective of this research was to identify disinvestment initiatives in Latin American countries (LAC). METHODS: First, a systematic literature review (SLR) was conducted. In February 2015, MEDLINE, MEDLINE In-Process, EMBASE, The Cochrane Library, and LILACS were searched for relevant journal articles, including terms related to "disinvestment," "reallocation," "obsolete technologies," and "Latin America." Additionally, a manual search of documents from Latin American health technology assessment agencies was performed. Second, an online questionnaire was sent to experts in LAC to assess whether unpublished real-life disinvestment initiatives exist. Questionnaire results were collected in September 2015. RESULTS: From the SLR, 350 records were selected for screening following de-duplication and eleven articles fulfilled inclusion criteria. Only two of these reported information on initiatives potentially identifiable as disinvestment-investment activities in Brazil and Peru. Nine respondents completed the questionnaire, and four reported that disinvestment initiatives had been conducted in their respective organizations in Argentina, Brazil, and Mexico. This lack of agreement between the SLR and the questionnaire responses shows that disinvestment initiatives are ongoing, despite being under reported. CONCLUSIONS: Many challenges need to be overcome for a disinvestment initiative to be successful, and sharing particular experiences with the international community would increase the chances of positive outcomes. The present study highlights the need for publication of such experiences in LAC.

UT-B Urea Transporter Localization in the Bovine Gastrointestinal Tract.

Facilitative UT-B urea transporters play an important role in the urea nitrogen salvaging process that occurs in the gastrointestinal tract of mammals, particularly ruminants. Gastrointestinal UT-B transporters have previously been reported in various ruminant species-including cow, sheep and goat. In this present study, UT-B transporter localization was investigated in tissues throughout the bovine gastrointestinal tract. RT-PCR analysis showed that UT-B2 was the predominant UT-B mRNA transcript expressed in dorsal, ventral and cranial ruminal sacs, while alternative UT-B transcripts were present in other gastrointestinal tissues. Immunoblotting analysis detected a strong, glycosylated ~50 kDa UT-B2 protein in all three ruminal sacs. Immunolocalization studies showed that UT-B2 protein was predominantly localized to the plasma membrane of cells in the stratum basale layer of all ruminal sac papillae. In contrast, other UT-B protein staining was detected in the basolateral membranes of the surface epithelial cells lining the abomasum, colon and rectum. Overall, these findings confirm that UT-B2 cellular localization is similar in all ruminal sacs and that other UT-B proteins are located in epithelial cells lining various tissues in the bovine gastrointestinal tract.

Differential protein abundance of a basolateral MCT1 transporter in the human gastrointestinal tract.

Bacterially derived short chain fatty acids (SCFAs), such as butyrate, are vital in maintaining the symbiotic relationship that exists between humans and their gastrointestinal microbial populations. A key step in this process is the transport of SCFAs across colonic epithelial cells via MCT1 transporters. This study investigated MCT1 protein abundance in various human intestinal tissues. Initial RT-PCR analysis confirmed the expected MCT1 RNA expression pattern of colon > small intestine > stomach. Using surgical resection samples, immunoblot analysis detected higher abundance of a 45 kDa MCT1 protein in colonic tissue compared to ileum tissue (P < 0.001, N = 4, unpaired t-test). Importantly, MCT1 abundance was found to be significantly lower in sigmoid colon compared to ascending colon (P < 0.01, N = 8-11, ANOVA). Finally, immunolocalization studies confirmed MCT1 to be abundant in the basolateral membranes of surface epithelial cells of the ascending, transverse, and descending colon, but significantly less prevalent in the sigmoid colon (P < 0.05, N = 5-21, ANOVA). In conclusion, these data confirm that basolateral MCT1 protein abundance is correlated to levels of bacterially derived SCFAs along the human gastrointestinal tract. These findings highlight the importance of precise tissue location in studies comparing colonic MCT1 abundance between normal and diseased states.

Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses.

Demand for organic milk is partially driven by consumer perceptions that it is more nutritious. However, there is still considerable uncertainty over whether the use of organic production standards affects milk quality. Here we report results of meta-analyses based on 170 published studies comparing the nutrient content of organic and conventional bovine milk. There were no significant differences in total SFA and MUFA concentrations between organic and conventional milk. However, concentrations of total PUFA and n-3 PUFA were significantly higher in organic milk, by an estimated 7 (95 % CI -1, 15) % and 56 (95 % CI 38, 74) %, respectively. Concentrations of α-linolenic acid (ALA), very long-chain n-3 fatty acids (EPA+DPA+DHA) and conjugated linoleic acid were also significantly higher in organic milk, by an 69 (95 % CI 53, 84) %, 57 (95 % CI 27, 87) % and 41 (95 % CI 14, 68) %, respectively. As there were no significant differences in total n-6 PUFA and linoleic acid (LA) concentrations, the n-6:n-3 and LA:ALA ratios were lower in organic milk, by an estimated 71 (95 % CI -122, -20) % and 93 (95 % CI -116, -70) %. It is concluded that organic bovine milk has a more desirable fatty acid composition than conventional milk. Meta-analyses also showed that organic milk has significantly higher α-tocopherol and Fe, but lower I and Se concentrations. Redundancy analysis of data from a large cross-European milk quality survey indicates that the higher grazing/conserved forage intakes in organic systems were the main reason for milk composition differences.

Composition differences between organic and conventional meat: a systematic literature review and meta-analysis.

Demand for organic meat is partially driven by consumer perceptions that organic foods are more nutritious than non-organic foods. However, there have been no systematic reviews comparing specifically the nutrient content of organic and conventionally produced meat. In this study, we report results of a meta-analysis based on sixty-seven published studies comparing the composition of organic and non-organic meat products. For many nutritionally relevant compounds (e.g. minerals, antioxidants and most individual fatty acids (FA)), the evidence base was too weak for meaningful meta-analyses. However, significant differences in FA profiles were detected when data from all livestock species were pooled. Concentrations of SFA and MUFA were similar or slightly lower, respectively, in organic compared with conventional meat. Larger differences were detected for total PUFA and n-3 PUFA, which were an estimated 23 (95 % CI 11, 35) % and 47 (95 % CI 10, 84) % higher in organic meat, respectively. However, for these and many other composition parameters, for which meta-analyses found significant differences, heterogeneity was high, and this could be explained by differences between animal species/meat types. Evidence from controlled experimental studies indicates that the high grazing/forage-based diets prescribed under organic farming standards may be the main reason for differences in FA profiles. Further studies are required to enable meta-analyses for a wider range of parameters (e.g. antioxidant, vitamin and mineral concentrations) and to improve both precision and consistency of results for FA profiles for all species. Potential impacts of composition differences on human health are discussed.

Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data: the PRISMA-IPD Statement.

IMPORTANCE: Systematic reviews and meta-analyses of individual participant data (IPD) aim to collect, check, and reanalyze individual-level data from all studies addressing a particular research question and are therefore considered a gold standard approach to evidence synthesis. They are likely to be used with increasing frequency as current initiatives to share clinical trial data gain momentum and may be particularly important in reviewing controversial therapeutic areas. OBJECTIVE: To develop PRISMA-IPD as a stand-alone extension to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Statement, tailored to the specific requirements of reporting systematic reviews and meta-analyses of IPD. Although developed primarily for reviews of randomized trials, many items will apply in other contexts, including reviews of diagnosis and prognosis. DESIGN: Development of PRISMA-IPD followed the EQUATOR Network framework guidance and used the existing standard PRISMA Statement as a starting point to draft additional relevant material. A web-based survey informed discussion at an international workshop that included researchers, clinicians, methodologists experienced in conducting systematic reviews and meta-analyses of IPD, and journal editors. The statement was drafted and iterative refinements were made by the project, advisory, and development groups. The PRISMA-IPD Development Group reached agreement on the PRISMA-IPD checklist and flow diagram by consensus. FINDINGS: Compared with standard PRISMA, the PRISMA-IPD checklist includes 3 new items that address (1) methods of checking the integrity of the IPD (such as pattern of randomization, data consistency, baseline imbalance, and missing data), (2) reporting any important issues that emerge, and (3) exploring variation (such as whether certain types of individual benefit more from the intervention than others). A further additional item was created by reorganization of standard PRISMA items relating to interpreting results. Wording was modified in 23 items to reflect the IPD approach. CONCLUSIONS AND RELEVANCE: PRISMA-IPD provides guidelines for reporting systematic reviews and meta-analyses of IPD.

Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses.

Demand for organic foods is partially driven by consumers' perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences. In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods. Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95 % CI 5, 33) %, 69 (95 % CI 13, 125) %, 28 (95 % CI 12, 44) %, 26 (95 % CI 3, 48) %, 50 (95 % CI 28, 72) % and 51 (95 % CI 17, 86) % higher, respectively. Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd. Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons.

Understanding service demand for mental health among Australians aged 16 to 64 years according to their possible need for treatment.

BACKGROUND: To inform decisions about mental health resource allocation, planners require reliable estimates of people who report service demand (i.e. people who use or want mental health services) according to their level of possible need. METHODS: Using data on 6915 adults aged 16-64 years in Australia's 2007 National Survey of Mental Health and Wellbeing, we examined past-year service demand among respondents grouped into four levels of possible need: (a) 12-month mental disorder; (b) lifetime but no 12-month mental disorder; (c) any other indicator of possible need (12-month symptoms or reaction to stressful event, or lifetime hospitalisation); (d) no indicator of possible need. Multivariate logistic regression analyses examined correlates of service demand, separately for respondents in each of levels 1-3. RESULTS: Sixteen per cent of Australian adults reported service demand, of whom one-third did not meet criteria for a 12-month mental disorder (equivalent to 5.7% of the adult population). Treatment patterns tended to follow a gradient defined by level of possible need. For example, service users with a 12-month disorder received, on average, 1.6-3.9 times more consultations than their counterparts in other levels of possible need, and had 1.9-2.2 times higher rates of psychologist consultation. Service users with a lifetime but not 12-month disorder or any other indicator of need consumed a similar average number of services to people with mild 12-month mental disorders, but received relatively fewer services involving the mental health sector. Service demand was associated with increased suicidality and psychological distress in all levels of possible need examined, and with poorer clinical and functional status for those with 12-month or lifetime disorders. CONCLUSIONS: Many Australians reporting service demand do not meet criteria for a current mental disorder, but may require services to maintain recovery following a past episode or because they are experiencing symptoms and significant psychological distress.

Descriptive inference using large, unrepresentative nonprobability samples: An introduction for ecologists.

Biodiversity monitoring usually involves drawing inferences about some variable of interest across a defined landscape from observations made at a sample of locations within that landscape. If the variable of interest differs between sampled and nonsampled locations, and no mitigating action is taken, then the sample is unrepresentative and inferences drawn from it will be biased. It is possible to adjust unrepresentative samples so that they more closely resemble the wider landscape in terms of "auxiliary variables." A good auxiliary variable is a common cause of sample inclusion and the variable of interest, and if it explains an appreciable portion of the variance in both, then inferences drawn from the adjusted sample will be closer to the truth. We applied six types of survey sample adjustment-subsampling, quasirandomization, poststratification, superpopulation modeling, a "doubly robust" procedure, and multilevel regression and poststratification-to a simple two-part biodiversity monitoring problem. The first part was to estimate the mean occupancy of the plant Calluna vulgaris in Great Britain in two time periods (1987-1999 and 2010-2019); the second was to estimate the difference between the two (i.e., the trend). We estimated the means and trend using large, but (originally) unrepresentative, samples from a citizen science dataset. Compared with the unadjusted estimates, the means and trends estimated using most adjustment methods were more accurate, although standard uncertainty intervals generally did not cover the true values. Completely unbiased inference is not possible from an unrepresentative sample without knowing and having data on all relevant auxiliary variables. Adjustments can reduce the bias if auxiliary variables are available and selected carefully, but the potential for residual bias should be acknowledged and reported.

Campbell Standards: Modernizing Campbell's Methodologic Expectations for Campbell Collaboration Intervention Reviews (MECCIR).

Introduction: The authors formed a small working group to modernize the Methodological Expectations for Campbell Collaboration Intervention Reviews (MECCIR). We reviewed comments and feedback from editors, peer reviewers of Campbell submissions, and authors; for example, that the Campbell MECCIR was long and some of the items in the reporting and conduct checklists were difficult to cross-reference. We also wanted to make the checklist more relevant for reviews of associations or risk factors and other quantitative non-intervention review types, which we welcome in Campbell. Thus, our aim was to develop a shorter, more holistic guidance and checklist of Campbell Standards, encompassing both conduct and reporting of these standards within the same checklist. Methods: Our updated Campbell Standards will be a living document. To develop this first iteration, we invited Campbell members to join a virtual working group; we sought experience in conducting Campbell systematic reviews and in conducting methods editor reviews for Campbell. We aligned the items from the MECCIR for conduct and reporting, then compared the principles of conduct that apply across review types to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-literature search extension (S) and PRISMA-2020 reporting standards. We discussed each section with the aim of developing a parsimonious checklist with explanatory guidance while avoiding losing important concepts that are relevant to all types of reviews. We held nine meetings to discuss each section in detail between September 2022 and March 2023. We circulated this initial checklist and guidance to all Campbell editors, methods editors, information specialists and co-chairs to seek their feedback. All feedback was discussed by the working group and incorporated to the Standards or, if not incorporated, a formal response was returned about the rationale for why the feedback was not incorporated. Campbell Policy: The guidance includes seven main sections with 35 items multifaceted but distinct concepts that authors must adhere to when conducting Campbell reviews. Authors and reviewers must be mindful that multiple factors need to be assessed for each item. According to the Campbell Standards, the reporting of Campbell reviews must adhere to appropriate PRISMA reporting guidelines(s) such as PRISMA-2020. How to Use: The editorial board recommends authors use the checklist during their work in formulating their protocol, carrying out their review, and reporting it. Authors will be asked to submit a completed checklist with their submission. We plan to develop an online tool to facilitate use of the form by author teams and those reviewing submissions. Providing Feedback: We invite the scientific community to provide their comments using this anonymous google form. Plan for Updating: We will update the Campbell Standards periodically in light of new evidence.

Antidepressants for pain management in adults with chronic pain: a network meta-analysis.

Background: Chronic pain is common and costly. Antidepressants are prescribed to reduce pain. However, there has not been a network meta-analysis examining all antidepressants across all chronic pain conditions, so effectiveness and safety for most antidepressants for pain conditions remain unknown. Objective: To assess the efficacy and safety of antidepressants for chronic pain (except headache) in adults. Our primary outcomes were as follows: substantial pain relief (50%), pain intensity, mood and adverse events. Our secondary outcomes were as follows: moderate pain relief (30%), physical function, sleep, quality of life, Patient Global Impression of Change, serious adverse events and withdrawal. Design: This was a systematic review with a network meta-analysis. We searched CENTRAL, MEDLINE, EMBASE, CINAHL, LILACS, AMED and PsycINFO databases for randomised controlled trials of antidepressants for chronic pain conditions up until 4 January 2022. The review was registered in PROSPERO (CRD42020171855), and the protocol was published in the Cochrane Library (https://doi.org/10.1002/14651858.CD014682). Setting: We analysed trials from all settings. Participants: We included trials in which participants had chronic pain, defined as longer than 3 months, from any condition excluding headache. Interventions: We included all antidepressants. Main outcome measures: Our primary outcome was substantial pain relief, defined as a reduction ˃ 50%. We also measured pain intensity, mood and adverse events. Secondary measures included moderate pain relief (above 30% reduction), physical function, sleep, quality of life, Global Impression of Change, serious adverse events, and withdrawal from trial. Results: We identified 176 studies with a total of 28,664 participants. Most studies were placebo-controlled (n = 83) and parallel armed (n = 141). The most common pain conditions examined were fibromyalgia (59 studies), neuropathic pain (49 studies) and musculoskeletal pain (40 studies). The average length of randomised controlled trials was 10 weeks. Most studies measured short-term outcomes only and excluded people with low mood and other mental health conditions. Across efficacy outcomes, duloxetine was consistently the highest-ranked antidepressant with moderate- to high-certainty evidence. Standard dose was equally efficacious as high dose for the majority of outcomes. Milnacipran was often ranked as the next most efficacious antidepressant, although the certainty of evidence was lower than that for duloxetine. There was insufficient evidence to draw robust conclusions for the efficacy and safety of any other antidepressant for chronic pain. Limitations: The evidence for antidepressants other than duloxetine is poor. For duloxetine, it is not clear whether the effect applies to groups with both pain and low mood, since these groups were excluded from trials. There is also insufficient evidence on long-term outcomes and on adverse effects. Conclusions: There is only reliable evidence for duloxetine in the treatment of chronic pain. Duloxetine was moderately efficacious across all outcomes at standard dose. There is also promising evidence for milnacipran, although further high-quality research is needed to be confident in these conclusions. Data for all other antidepressants were of low certainty. However, the findings should not be read as an encouragement to prescribe antidepressants where other non-pharmacological intervention could be equally effective, especially in the absence of good evidence on side effects and safety. Future work: There is a need for large, methodologically sound trials testing the effectiveness of antidepressants for chronic pain. These trials should examine long-term outcomes (> 6 months) and include people with low mood. There should also be better reporting of adverse events, tolerance of drugs, and long-term compliance. Study registration: This study is registered as PROSPERO CRD42020171855. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR128782) and is published in full in Health Technology Assessment; Vol. 28, No. 62. See the NIHR Funding and Awards website for further award information.

Chronic pain is pain that lasts for more than 3 months. Over one-third of people across the world experience chronic pain. This often has a detrimental impact on people's mood, disability and well-being. Antidepressants are often prescribed to reduce pain, but we are not sure which antidepressants work best for different types of pain, or whether they are safe. We wanted to find out whether antidepressants were effective and safe for management of chronic pain. We searched for studies that had compared any antidepressant with any other treatment for any type of chronic pain (except headache). We compared all the treatments against each other using a statistical method called network meta-analysis. This method allows us to rank the treatments in order of best to worst for each outcome. We found 176 studies that included a total of 28,664 people with chronic pain. Most of the studies (83/176) compared an antidepressant with a placebo (which looks like the real medicine but does not have any medicine in it). The evidence from our analysis suggests that: Duloxetine is the antidepressant that we have the most confidence in. It was the best antidepressant for reducing pain and improving physical function. A standard dose of duloxetine was equally as effective for reducing pain as a high dose of duloxetine. Milnacipran was also effective at reducing pain, but we are not as confident in this result as in the one for duloxetine because there were fewer studies with fewer people involved. Aside from duloxetine and milnacipran, we do not have confidence in the results from any other antidepressant included in this review, and even for duloxetine and milnacipran, we do not know the long-term effects. It is important to recognise that the lack of evidence for the majority of antidepressants in this review does not necessarily equal a lack of benefit. Rather, this means that the large, high-quality trials required for us to be certain of an antidepressant's effectiveness have not been undertaken. Altogether, although duloxetine and milnacipran are effective, the results of this review should not be read as an encouragement to prescribe antidepressants where other non-pharmacological intervention could be equally effective, especially in the absence of good evidence on side effects and safety. These conclusions were informed by our patient and public involvement group.

Regional investigation of UT-B urea transporters in the rat brain.

Recent studies have reported increased levels of urea in the aging brain and various neurological disorders. Additionally, these diseased tissues also have increased expression of the UT-B transporter that regulates urea transport in the brain. However, little is known regarding the actual UT-B protein distribution across the brain in either normal or diseased states. This current study investigated UT-B protein abundance across three regions of the rat brain - anterior, posterior and cerebellum. Endpoint RT-PCR experiments showed that there were no regional differences in UT-B RNA expression (NS, N = 3, ANOVA), whilst Western blotting confirmed no difference in the abundance of a 35 kDa UT-B protein (NS, N = 3-4, ANOVA). In contrast, there was a significant variation in a non-UT-B 100 kDa protein (P < 0.001, N = 3-4, ANOVA), which was also detected by anti-UT-B antibodies. Using the C6 rat astrocyte cell line, Western blot analysis showed that 48-h incubation in either 5 mM or 10 mM significantly increased a 30-45 kDa UT-B protein signal (P < 0.05, N = 3, ANOVA). Furthermore, investigation of compartmentalized C6 protein samples showed the 30-45 kDa signal in the membrane fraction, whilst the 100 kDa non-UT-B signal was predominantly in the cytosolic fraction. Finally, immunolocalization studies gave surprisingly weak detection of rat UT-B, except for strong staining of red blood cells in the cerebellum. In conclusion, this study confirmed that RNA expression and protein abundance of UT-B were equal across all regions of the rat brain, suggesting that urea levels were also similar. However, it also highlighted some of the technical challenges of studying urea transporters at the protein level.