Rationale While the role of diet in influencing physical health is now well-established, some recent research suggests that increased consumption of fruits and vegetables could play a role in enhancing mental well-being. A limitation with much of this existing research is its reliance on cross-sectional correlations, convenience samples, and/or lack of adequate controls. Objective We aim to add to the emerging literature on the relationship between fruit and vegetable consumption and well-being by using longitudinal data from a study in the United Kingdom (UK). Method We employ panel data analytical techniques on three waves collected between 2010 and 2017 (i.e., following the same individuals over time) in the UK Household Longitudinal Survey. We also control for time-variant confounders such as diet, health, and lifestyle behaviours. Results Fixed effects regressions show that mental well-being (GHQ-12) responds in a dose-response fashion to increases in both the quantity and the frequency of fruit and vegetables consumed. This relationship is robust to the use of subjective well-being (life satisfaction) instead of mental well-being. We also document a hump-shaped relationship between fruit and vegetable consumption and age. Conclusion Our findings provide further evidence that persuading people to consume more fruits and vegetables may not only benefit their physical health in the long-run, but also their mental well-being in the short-run.

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Background Preterm birth may result in short- and long-term health problems for the child. Accurate diagnoses of preterm births could prevent unnecessary (or ensure appropriate) admissions into hospitals or transfers to specialist units. Objectives The purpose of this report is to assess the test accuracy, clinical effectiveness and cost-effectiveness of the diagnostic tests PartoSure™ (Parsagen Diagnostics Inc., Boston, MA, USA), Actim® Partus (Medix Biochemica, Espoo, Finland) and the Rapid Fetal Fibronectin (fFN)® 10Q Cassette Kit (Hologic, Inc., Marlborough, MA, USA) at thresholds ≠50 ng/ml [quantitative fFN (qfFN)] for women presenting with signs and symptoms of preterm labour relative to fFN at 50 ng/ml. Methods Systematic reviews of the published literature were conducted for diagnostic test accuracy (DTA) studies of PartoSure, Actim Partus and qfFN for predicting preterm birth, the clinical effectiveness following treatment decisions informed by test results and economic evaluations of the tests. A model-based economic evaluation was also conducted to extrapolate long-term outcomes from the results of the diagnostic tests. The model followed the structure of the model that informed the 2015 National Institute for Health and Care Excellence guidelines on preterm labour diagnosis and treatment, but with antenatal steroids use, as opposed to tocolysis, driving health outcomes. Results Twenty studies were identified evaluating DTA against the reference standard of delivery within 7 days and seven studies were identified evaluating DTA against the reference standard of delivery within 48 hours. Two studies assessed two of the index tests within the same population. One study demonstrated that depending on the threshold used, qfFN was more or less accurate than Actim Partus, whereas the other indicated little difference between PartoSure and Actim Partus. No study assessing qfFN and PartoSure in the same population was identified. The test accuracy results from the other included studies revealed a high level of uncertainty, primarily attributable to substantial methodological, clinical and statistical heterogeneity between studies. No study compared all three tests simultaneously. No clinical effectiveness studies evaluating any of the three biomarker tests were identified. One partial economic evaluation was identified for predicting preterm birth. It assessed the number needed to treat to prevent a respiratory distress syndrome case with a ‘treat-all’ strategy, relative to testing with qualitative fFN. Because of the lack of data, our de novo model involved the assumption that management of pregnant women fully adhered to the results of the tests. In the base-case analysis for a woman at 30 weeks’ gestation, Actim Partus had lower health-care costs and fewer quality-adjusted life-years (QALYs) than qfFN at 50 ng/ml, reducing costs at a rate of £56,030 per QALY lost compared with qfFN at 50 ng/ml. PartoSure is less costly than Actim Partus while being equally effective, but this is based on diagnostic accuracy data from a small study. Treatment with qfFN at 200 ng/ml and 500 ng/ml resulted in lower cost savings per QALY lost relative to fFN at 50 ng/ml than treatment with Actim Partus. In contrast, qfFN at 10 ng/ml increased QALYs, by 0.002, and had a cost per QALY gained of £140,267 relative to fFN at 50 ng/ml. Similar qualitative results were obtained for women presenting at different gestational ages. Conclusion There is a high degree of uncertainty surrounding the test accuracy and cost-effectiveness results. We are aware of four ongoing UK trials, two of which plan to enrol > 1000 participants. The results of these trials may significantly alter the findings presented here. Study registration The study is registered as PROSPERO CRD42017072696. Funding The National Institute for Health Research Health Technology Assessment programme.

There is an emerging body of evidence to suggest that nudges can motivate behaviour change. The question as to whether using nudges in tandem ‘crowds out’ the marginal effectiveness of each one has attracted little attention. Using a randomised survey experiment consisting of 1,800 farmers, we tested the impact of two nudge interventions (injunctive norm and social signalling) when used individually in isolation and also when used in combination. Our findings are indicative of limited crowd out effects and more generally suggest that there may be considerable scope for employing non-monetary interventions in combination when it comes to encouraging technology uptake.