Christopher Penfold

Dr. Christopher Penfold

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Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 September 2015 in International Journal of Obesity
Verified
Journal Article
Open access
PRP J Rogers
P J Rogers
PHP S Hogenkamp
P S Hogenkamp
CGC de Graaf
C de Graaf
SHSuzanne Higgs
Suzanne Higgs
ALA Lluch
A Lluch
DMD J Mela
D J Mela
By reducing energy density, low-energy sweeteners (LES) might be expected to reduce energy intake (EI) and body weight (BW). To assess the totality of the evidence testing the null hypothesis that LES exposure (versus sugars or unsweetened alternatives) has no effect on EI or BW, we conducted a systematic review of relevant studies in animals and humans consuming LES withad libitumaccess to food energy. In 62 of 90 animal studies exposure to LES did not affect or decreased BW. Of 28 reporting increased BW, 19 compared LES with glucose exposure using a specific ‘learning’ paradigm. Twelve prospective cohort studies in humans reported inconsistent associations between LES use and body mass index (−0.002 kg m−2per year, 95% confidence interval (CI) −0.009 to 0.005). Meta-analysis of short-term randomized controlled trials (129 comparisons) showed reduced total EI for LES versus sugar-sweetened food or beverage consumption before anad libitummeal (−94 kcal, 95% CI −122 to −66), with no difference versus water (−2 kcal, 95% CI −30 to 26). This was consistent with EI results from sustained intervention randomized controlled trials (10 comparisons). Meta-analysis of sustained intervention randomized controlled trials (4 weeks to 40 months) showed that consumption of LES versus sugar led to relatively reduced BW (nine comparisons; −1.35 kg, 95% CI –2.28 to −0.42), and a similar relative reduction in BW versus water (three comparisons; −1.24 kg, 95% CI –2.22 to −0.26). Most animal studies did not mimic LES consumption by humans, and reverse causation may influence the results of prospective cohort studies. The preponderance of evidence from all human randomized controlled trials indicates that LES do not increase EI or BW, whether compared with caloric or non-caloric (for example, water) control conditions. Overall, the balance of evidence indicates that use of LES in place of sugar, in children and adults, leads to reduced EI and BW, and possibly also when compared with water.

28 January 2018 in Nutrients
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Journal Article
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Angeliki PapadakiAngeliki Papadaki
Angeliki Papadaki
PAPlease close this account Please close this account
Please close this account Please close this account
ZTZoi Toumpakari
Zoi Toumpakari
CEClare England
Clare England
MRManmita Rai
Manmita Rai
GFGene Feder
Gene Feder
The aim of this study was to examine the validity of the English version of the PREvencion con DIetaMEDiterranea (PREDIMED) 14-item Mediterranean Diet Adherence Screener (MEDAS), a brief questionnaire assessing adherence to the Mediterranean diet (MedDiet), which was used in the PREDIMED trial for assessment and immediate feedback. This instrument (MEDAS) was administered to 96 adults with a high cardiovascular risk (66% women, mean age 68.3 ± 6.0 years), recruited from general practices in Bristol, UK. Participants then completed a 3-day estimated food record, and the MEDAS was administered again one month later. A MedDiet score (range = 0–14) was calculated from the MEDAS’ administrations and food record to assess concurrent validity and test-retest reliability. Predictive validity was assessed by examining the association of the MEDAS-derived score with cardiometabolic risk factors and dietary intakes derived from the food records. The MEDAS-derived MedDiet score was higher by 1.47 points compared to food records (5.47 vs.4.00, p < 0.001), correlated moderately with the record-derived score (r = 0.50, p < 0.001; ICC = 0.53, p < 0.001) and there was borderline fair agreement between the two methods (κ = 0.19, 95% CI 0.07–0.31, p = 0.002; 95% limits of agreement −2.2, 5.1). Exact agreement within score categories and gross misclassificationwere 45.8% and 21.9%, respectively. The distribution of dietary intakes, reported on the food records by the MEDAS-derived total MedDiet score, was in the expected direction, but no association was observed with cardiometabolic risk factors. The two administrations of the MEDAS produced similar mean total MedDiet scores (5.5 vs. 5.4, p = 0.706), which were correlated (r and ICC = 0.69, p < 0.001) and agreed fairly (κ = 0.38, 95% CI 0.24–0.52, p < 0.001; 95% limits of agreement −3.1, 3.2). The English version of the MEDAS has acceptable accuracy and reliability for assessing MedDiet adherence among individuals with a high cardiovascular risk, in the UK, and can be used to rank individuals according to MedDiet adherence in research and practice.

1 January 2017 in Diabetes & Metabolism Journal
Verified
Journal Article
Open access
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Jinyue YuJinyue Yu
Jinyue Yu
PSPeige Song
Peige Song
RPRachel Perry
Rachel Perry
CPChristopher Penfold
Christopher Penfold
ACAshley R. Cooper
Ashley R. Cooper
Yu J, et al. Diabetes Metab J. 2017 Aug;41(4):251-262. https://doi.org/10.4093/dmj.2017.41.4.251

17 December 2014 in BMC Cancer
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Journal Article
Open access
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ANAndrew Robert Ness
Andrew Robert Ness
AWAndrea Waylen
Andrea Waylen
KHKatrina Hurley
Katrina Hurley
MJMona Jeffreys
Mona Jeffreys
CPChristopher Penfold
Christopher Penfold
STSteven J Thomas
Steven J Thomas
Head and neck cancer is an important cause of ill health. Survival appears to be improving but the reasons for this are unclear. They could include evolving aetiology, modifications in care, improvements in treatment or changes in lifestyle behaviour. Observational studies are required to explore survival trends and identify outcome predictors. We are identifying people with a new diagnosis of head and neck cancer. We obtain consent that includes agreement to collect longitudinal data, store samples and record linkage. Prior to treatment we give participants three questionnaires on health and lifestyle, quality of life and sexual history. We collect blood and saliva samples, complete a clinical data capture form and request a formalin fixed tissue sample. At four and twelve months we complete further data capture forms and send participants further quality of life questionnaires. This large clinical cohort of people with head and neck cancer brings together clinical data, patient-reported outcomes and biological samples in a single co-ordinated resource for translational and prognostic research.

15 May 2017 in Systematic Reviews
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Journal Article
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RPrachel perry
rachel perry
VLVerity Leach
Verity Leach
PDPhilippa Davies
Philippa Davies
CPChristopher Penfold
Christopher Penfold
ANAndy Ness
Andy Ness
RCRachel Churchill
Rachel Churchill
Fibromyalgia (FM) is a chronic, debilitating pain disorder. Dissatisfaction with conventional medicine can lead people with FM to turn to complementary and alternative medicine (CAM). Two previous overviews of systematic reviews of CAM for FM have been published, but they did not assessed for risk of bias in the review process. Five databases Medline, Embase, AMED (via OVID), Web of Science and Central were searched from their inception to December 2015. Reference lists were hand-searched. We had two aims: the first was to provide an up-to-date and rigorously conducted synthesis of systematic reviews of CAM literature on FM; the second was to evaluate the quality of the available systematic review evidence using two different tools: AMSTAR (Shea et al. BMC Med Res Methodol 15; 7:10, 2007) and a more recently developed tool ROBIS (Whiting et al. J Clin Epidemiol 69:225-34, 2016) specifically designed to assess risk of bias in systematic reviews. Any review that assessed one of eight CAM therapies for participants diagnosed with FM was considered. The individual studies had to be randomised controlled trials where the intervention was compared to placebo, treatment as usual or waitlist controls to be included. The primary outcome measure was pain, and the secondary outcome measure was adverse events. We identified 15 reviews that met inclusion criteria. There was low-quality evidence that acupuncture improves pain compared to no treatment or standard treatment, but good evidence that it is no better than sham acupuncture. The evidence for homoeopathy, spinal manipulation and herbal medicine was limited. Overall, five reviews scored 6 or above using the AMSTAR scale and the inter-rater agreement was good (83.6%), whereas seven reviews achieved a low risk of bias rating using ROBIS and the inter-rater agreement was fair (60.0%). No firm conclusions were drawn for efficacy of either spinal manipulation or homoeopathy for FM. There is limited evidence for topical Capsicum, but further research is required. There is some evidence to support the effectiveness of acupuncture for FM, but further high-quality trials are needed to investigate its benefits, harms and mechanisms of action, compared with no or standard treatment. PROSPERO CRD42016035846 .

16 May 2018 in Clinical Otolaryngology
Verified
Journal Article
Open access
PDF file
STSteven J Thomas
Steven J Thomas
CPChristopher Penfold
Christopher Penfold
AWAndrea Waylen
Andrea Waylen
ANAndrew R Ness
Andrew R Ness
Head and neck cancers are the sixth most common cancers worldwide and an important cause of ill health.(1) Each year about 9000 cases are reported in the UK.(2) Survival is poor and despite advances in treatment, has not improved until recently.(3) The majority of head and neck cancers are squamous cell carcinomas, affecting the larynx, oropharynx and oral cavity. The aetiology is changing and this has implications for prevention and treatment. Twenty years ago, tobacco and alcohol consumption were considered to be the established risk factors and it was estimated that these risk factors accounted for about 75% of cases.(4) More recently human papillomavirus (HPV) has emerged as a likely cause of oropharyngeal cancer.(4) Here we argue that each cancer site is predicted differently by smoking, alcohol and sexual behaviour. We also suggest that these risk factors do not fully explain the changing pattern of disease observed in the UK.