Pounce & Co. : Potpourri

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Does advance contact with research participants increase response to questionnaires: an updated systematic review and meta-analysis

Background Questionnaires remain one of the most common forms of data collection in epidemiology, psychology and other human-sciences. However, results can be badly affected by non-response. One way to potentially reduce non-response is by sending potential study participants advance communication. The last systematic review to examine the effect of questionnaire pre-notification on response is 10 years old, and lacked a risk of bias assessment. Objectives Update the section of the Cochrane systematic review, Edwards et al. (2009), on pre-notification to include 1) recently published studies, 2) an assessment of risk of bias, 3) Explore if heterogeneity is reduced by: delay between pre-contact and questionnaire delivery, the method of pre-contact, if pre-contact and questionnaire delivery differ, if the pre-contact includes a foot-in-the-door manipulation, and study's the risk of bias. Methods Inclusion criteria: population: any population, intervention: comparison of some type of pre-notification, comparison group: no pre-notification, outcome: response rates. Study design randomised controlled trails. Exclusion criteria NA. Data sources Studies which cited or were included in Edwards et al. (2009); We additionally searched: CINAHL, Web of Science, PsycInfo, MEDLINE, EconLit, EMBASE, Cochrane Central, Cochrane CMR, ERIC, and Sociological Abstracts. The searches were implemented in June 2018 and May 2021. Study screening: a single reviewer screened studies, with a random 10% sample independently screened to ascertain accuracy. Data extraction data was extracted by a single reviewer twice, with a week between each extraction. Risk of Bias: within studies bias was assessed using the Cochrane Risk of Bias tool (ROB1) by a single unblinded reviewer, across studies bias was assessed using funnel plots. Synthesis Method: study results were meta-analysed with a random effects model using the final response rate as the outcome. Evaluation of Uncertainty: Uncertainty was evaluated using the GRADE approach. Results One hundred seven trials were included with 211,802 participants. Over-all pre-notification increased response, OR = 1.33 (95% CI: 1.20-1.47). However, there was a large amount of heterogeneity (I2 = 97.1%), which was not explained by the subgroup analyses. In addition, when studies at high or unclear risk of bias were excluded the effect was to reduced OR = 1.09 (95% CI: 0.99-1.20). Because of the large amount of heterogeneity, even after restricting to low risk of bias studies, there is still moderate uncertainty in these results. Conclusions Using the GRADE evaluation, this review finds moderate evidence that pre-notification may not have an effect on response rates. Funding Economic and Social Research Council. Preregistration None

Does pre-notification increase questionnaire response rates: a randomised controlled trial nested within a systematic review

BACKGROUND: Missing outcome data can lead to bias in the results of systematic reviews. One way to address missing outcome data is by requesting the data from the trial authors, but non-response is common. One way to potentially improve response rates is by sending study participants advance communication. During the update of a systematic review examining the effect of pre-notification on response rates, study authors needed to be contacted for further information. This study was nested within the systematic review by randomising authors to receive a notification of the upcoming request for information. The objective was to test if pre-notification increased response rates. METHODS: The participants were study authors included in the systematic review, whose studies were at unclear risk of bias. The intervention was a pre-notification of the request for further information, sent 1 day before the request. The outcome was defined as the proportion of authors who responded to the request for information. Authors were randomised by simple randomisation. Thirty three authors were randomised to the pre-notification arm, and 42 were randomised to the control arm. Authors were blinded to the possibility of an alternative condition. RESULTS: All authors randomised were analysed. 14/33 (42.4%) authors in the pre-notification arm had returned responses to the questionnaire, and 18/42 (42.9%) in the control arm. There was no evidence of a difference between these groups (absolute difference = - 0.5, 95% CI (- 23.4 to 22.5%), p = 1). We received no complaints about receiving the pre-notification. CONCLUSIONS: This study's results do not support the hypothesis that pre-notification increases response from study authors being contacted for a request for more information. However, the study has a low power, and the results may not generalise to other contexts, methods of administering a pre-notification, or study populations. TRIAL REGISTRATION: Registration and protocol: This trial is not registered with any trial registry. However, the protocol was posted in advance on the Open Science Framework website and is available on the Open Science Framework website: DOI: https://doi.org/10.17605/OSF.IO/MSV2W or https://osf.io/msv2w/

Triangulating evidence for the causal impact of single-intervention zinc supplement on glycaemic control for type 2 diabetes: systematic review and meta-analysis of randomised controlled trial and two-sample Mendelian randomisation

Although previous studies suggested the protective effect of Zn for type 2 diabetes (T2D), the unitary causal effect remains inconclusive. We investigated the causal effect of Zn as a single intervention on glycaemic control for T2D, using a systematic review of randomised controlled trials and two-sample Mendelian randomisation (MR). Four primary outcomes were identified: fasting blood glucose/fasting glucose, HbA1c, homeostatic model assessment for insulin resistance (HOMA-IR) and serum insulin/fasting insulin level. In the systematic review, four databases were searched until June 2021. Studies, in which participants had T2D and intervention did not comprise another co-supplement, were included. Results were synthesised through the random-effects meta-analysis. In the two-sample MR, we used single-nucleotide polymorphisms (SNP) from MR-base, strongly related to Zn supplements, to infer the relationship causally, but not specified T2D. In the systematic review and meta-analysis, fourteen trials were included with overall 897 participants initially. The Zn supplement led to a significant reduction in the post-trial mean of fasting blood glucose (mean difference (MD): -26·52 mg/dl, 95 % CI (-35·13, -17·91)), HbA1c (MD: -0·52 %, 95 % CI: (-0·90, -0·13)) and HOMA-IR (MD: -1·65, 95 % CI (-2·62, -0·68)), compared to the control group. In the two-sample MR, Zn supplement with two SNP reduced the fasting glucose (inverse-variance weighted coefficient: -2·04 mmol/l, 95 % CI (-3·26, -0·83)). From the two methods, Zn supplementation alone may causally improve glycaemic control among T2D patients. The findings are limited by power from the small number of studies and SNP included in the systematic review and two-sample MR analysis, respectively

The Rise and Fall of Debris Disks: MIPS Observations of h and chi Persei and the Evolution of Mid-IR Emission from Planet Formation

We describe Spitzer/MIPS observations of the double cluster, h and $\chi$ Persei, covering a $\sim$ 0.6 square-degree area surrounding the cores of both clusters. The data are combined with IRAC and 2MASS data to investigate $\sim$ 616 sources from 1.25-24 $\mu m$. We use the long-baseline $K_{s}$-[24] color to identify two populations with IR excess indicative of circumstellar material: Be stars with 24 $\mu m$ excess from optically-thin free free emission and 17 fainter sources (J$\sim$ 14-15) with [24] excess consistent with a circumstellar disk. The frequency of IR excess for the fainter sources increases from 4.5 $\mu m$ through 24 $\mu m$. The IR excess is likely due to debris from the planet formation process. The wavelength-dependent behavior is consistent with an inside-out clearing of circumstellar disks. A comparison of the 24 $\mu m$ excess population in h and $\chi$ Per sources with results for other clusters shows that 24 $\mu m$ emission from debris disks 'rises' from 5 to 10 Myr, peaks at $\sim$ 10-15 Myr, and then 'falls' from $\sim$ 15/20 Myr to 1 Gyr.Comment: 48 pages, 15 figures, accepted for publication in The Astrophysical Journa

The City of Collective Melancholy: Revisiting Pamuk’s Istanbul

This essay looks back upon Orhan Pamuk’s non-fiction book, Istanbul: Memories of a City (2003), and unpacks its multi-layered representation of the city as landscape. It is here that Pamuk pursues most overtly “the quest for the melancholic soul of his native city” which won him the 2006 Nobel Prize for Literature. Weaving personal memoir and historical essay into a unique narrative tapestry, Pamuk’s book explores a series of tensions that define the city’s image and identity; insider/outsider and East/West polarities, in particular, are tirelessly deconstructed. The essay examines Pamuk’s poetics and politics of memory in relation to works by other authors, notably Walter Benjamin. In conclusion, the new edition of Istanbul (2015) is discussed against the background of the social and spatial changes that have beset Turkey’s cultural capital in the interim