John O. Warner

Prof. John O. Warner

Section of Paediatrics, Imperial College London, London SW7 2BU, UK
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Research Focus & Metrics

Academic Career Length

37Years (1990-Present)

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

Representative Publications

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17 August 2017 in Nutrients
Verified
Journal Article
Open access
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DMDaniel Munblit
Daniel Munblit
DPDIEGO PERONI
DIEGO PERONI
ABAlba Boix-Amorós
Alba Boix-Amorós
PHPeter S. Hsu
Peter S. Hsu
BLBelinda Van't Land
Belinda Van't Land
John O. WarnerJohn O. Warner
John O. Warner
There is conflicting evidence on the protective role of breastfeeding in relation to the development of allergic sensitisation and allergic disease. Studies vary in methodology and definition of outcomes, which lead to considerable heterogeneity. Human milk composition varies both within and between individuals, which may partially explain conflicting data. It is known that human milk composition is very complex and contains variable levels of immune active molecules, oligosaccharides, metabolites, vitamins and other nutrients and microbial content. Existing evidence suggests that modulation of human breast milk composition has potential for preventing allergic diseases in early life. In this review, we discuss associations between breastfeeding/human milk composition and allergy development.

11 September 2020 in Journal of Medical Internet Research
Verified
Journal Article
Open access
NNNikita A Nekliudov
Nikita A Nekliudov
OBOleg Blyuss
Oleg Blyuss
KCKa Yan Cheung
Ka Yan Cheung
LPLoukia Petrou
Loukia Petrou
JGJon Genuneit
Jon Genuneit
DMDaniel Munblit
Daniel Munblit
Background: The COVID-19 pandemic has potentially had a negative impact on the mental health and well-being of individuals and families. Anxiety levels and risk factors within particular populations are poorly described. Objective: This study aims to evaluate confidence, understanding, trust, concerns, and levels of anxiety during the COVID-19 pandemic in the general population and assess risk factors for increased anxiety. Methods: We launched a cross-sectional online survey of a large Russian population between April 6 and 15, 2020, using multiple social media platforms. A set of questions targeted confidence, understanding, trust, and concerns in respondents. The State-Trait Anxiety Inventory was used to measure anxiety. Multiple linear regressions were used to model predictors of COVID-19–related anxiety. Results: The survey was completed by 23,756 out of 53,966 (44.0% response rate) unique visitors; of which, 21,364 were residing in 62 areas of Russia. State Anxiety Scale (S-Anxiety) scores were higher than Trait Anxiety Scale scores across all regions of Russia (median S-Anxiety score 52, IQR 44-60), exceeding published norms. Time spent following news on COVID-19 was strongly associated with an increased S-Anxiety adjusted for baseline anxiety level. One to two hours spent reading COVID-19 news was associated with a 5.46 (95% CI 5.03-5.90) point difference, 2-3 hours with a 7.06 (95% CI 6.37-7.74) point difference, and more than three hours with an 8.65 (95% CI 7.82-9.47) point difference, all compared to less than 30 minutes per day. Job loss during the pandemic was another important factor associated with higher S-Anxiety scores (3.95, 95% CI 3.31-4.58). Despite survey respondents reporting high confidence in information regarding COVID-19 as well as an understanding of health care guidance, they reported low overall trust in state and local authorities, and perception of country readiness. Conclusions: Among Russian respondents from multiple social media platforms, there was evidence of higher levels of state anxiety associated with recent job loss and increased news consumption, as well as lower than expected trust in government agencies. These findings can help inform the development of key public health messages to help reduce anxiety and raise perceived trust in governmental response to this current national emergency. Using a similar methodology, comparative surveys are ongoing in other national populations.

29 February 2024 in Archives of Disease in Childhood
Verified
Journal Article
Closed access
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John O. WarnerJohn O. Warner
John O. Warner
Many additives, some of which have no nutritional value, can be legally used in processed foods. They intensify colour, thicken, increase shelf life and enhance flavour. Regulatory authorities issue approvals as safe within acceptable quantitative limits. Ultra-processed foods (UPFs) contain combinations of all these additives and are particularly attractive to children.Many publications suggest that artificial colourants, benzoate preservatives, non-caloric sweeteners, emulsifiers and their degradation derivatives have adverse effects by increasing risks of mental health disorders, attention deficit hyperactivity disorder, cardiovascular disease, metabolic syndrome and potential carcinogenic effects.A systematic review has established that artificial azo dye food colourants (AFCs) and sodium benzoate preservative cause disturbed behaviour in children. AFCs and benzoates in animal models have neurotoxic properties through gut microbial generation of toxic metabolites. Observational studies show associations between high emulsifier intake and cardiovascular disease. Animal models and in vitro studies have highlighted neurotoxic, cytotoxic, genotoxic and carcinogenic effects. High intake of non-caloric sweeteners has been linked to cardiovascular disease and depression in adults and is linked to childhood obesity.Little research has focused on children who are the largest consumers of UPFs. Potentially, they are a ticking time bomb for adult obesity, metabolic syndrome, cardiovascular diseases, mental health disorders and cancers. Based on risk/benefit analysis, azo dye AFCs should be banned. Benzoates, emulsifiers and sweeteners require assessment of quantitative limits and cumulative effects of combinations. Consumers purchasing UPFs require information through ingredient health warnings and recommendations to use natural unprocessed foods which have well-described health-promoting properties.

27 January 2016 in Allergy
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Journal Article
Open access
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RBRobert Boyle
Robert Boyle
MTM. L.‐K. Tang
M. L.‐K. Tang
WCW. C. Chiang
W. C. Chiang
MCM. C. Chua
M. C. Chua
IIIntan Hakimah Ismail
Intan Hakimah Ismail
KKKaren Knipping
Karen Knipping
Background Prevention guidelines for infants at high risk of allergic disease recommend hydrolysed formula if formula is introduced before 6 months, but evidence is mixed. Adding specific oligosaccharides may improve outcomes. Objective To evaluate whether partially hydrolysed whey formula containing oligosaccharides (0.8 g/100 ml) (pHF‐OS) can prevent eczema in high‐risk infants [ISRCTN65195597]. Methods We conducted a parallel‐group, multicentre, randomized double‐blind controlled trial of pHF‐OS vs standard cow's milk formula. Infants with a family history of allergic disease were randomized (stratified by centre/maternal allergy) to active (n = 432) or control (n = 431) formula until 6 months of age if formula was introduced before 18 weeks. Primary outcome was cumulative incidence of eczema by 12 months in infants randomized at 0–4 weeks (375 pHF‐OS, 383 control). Secondary outcomes were cumulative incidence of eczema by 12 or 18 months in all infants randomized, immune markers at 6 months and adverse events. Results Eczema occurred by 12 months in 84/293 (28.7%) infants allocated to pHF‐OS at 0‐4 weeks of age, vs 93/324 (28.7%) control (OR 0.98 95% CI 0.68, 1.40; P = 0.90), and 107/347 (30.8%) pHF‐OS vs 112/370 (30.3%) control in all infants randomized (OR 0.99 95% CI 0.71, 1.37; P = 0.94). pHF‐OS did not change most immune markers including total/specific IgE; however, pHF‐OS reduced cow's milk‐specific IgG1 (P < 0.0001) and increased regulatory T‐cell and plasmacytoid dendritic cell percentages. There was no group difference in adverse events. Conclusion pHF‐OS does not prevent eczema in the first year in high‐risk infants. The immunological changes found require confirmation in a separate cohort.

14 August 2014 in BMC Medicine
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Journal Article
Open access
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KJKelsey Dj Jones
Kelsey Dj Jones
BHBarbara Hünten-Kirsch
Barbara Hünten-Kirsch
ALAhmed Mr Laving
Ahmed Mr Laving
CMCaroline W Munyi
Caroline W Munyi
MNMoses Ngari
Moses Ngari
JBJames Berkley
James Berkley
Environmental enteric dysfunction (EED) is an acquired syndrome of impaired gastrointestinal mucosal barrier function that is thought to play a key role in the pathogenesis of stunting in early life. It has been conceptualized as an adaptive response to excess environmental pathogen exposure. However, it is clinically similar to other inflammatory enteropathies, which result from both host and environmental triggers, and for which immunomodulation is a cornerstone of therapy. In this pilot double-blind randomized placebo-controlled trial, 44 children with severe acute malnutrition and evidence of EED were assigned to treatment with mesalazine or placebo for 28 days during nutritional rehabilitation. Primary outcomes were safety and acceptability of the intervention. Treatment with mesalazine was safe: there was no excess of adverse events, evidence of deterioration in intestinal barrier integrity or impact on nutritional recovery. There were modest reductions in several inflammatory markers with mesalazine compared to placebo. Depression of the growth hormone - insulin-like growth factor-1 axis was evident at enrollment and associated with inflammatory activation. Increases in the former and decreases in the latter correlated with linear growth. Intestinal inflammation in EED is non-essential for mucosal homeostasis and is at least partly maladaptive. Further trials of gut-specific immunomodulatory therapies targeting host inflammatory activation in order to optimize the growth benefits of nutritional rehabilitation and to address stunting are warranted. Funded by The Wellcome Trust. Registered at Clinicaltrials.gov NCT01841099 .

24 May 2017 in Nutrients
Verified
Journal Article
Open access
PDF file
DMDaniel Munblit
Daniel Munblit
MTMarina Treneva
Marina Treneva
DPDIEGO PERONI
DIEGO PERONI
SCSilvia Colicino
Silvia Colicino
LCLi Yan Chow
Li Yan Chow
John O. WarnerJohn O. Warner
John O. Warner
The role of breastfeeding in improving allergy outcomes in early childhood is still unclear. Evidence suggests that immune mediators in human milk (HM) play a critical role in infant immune maturation as well as protection against atopy/allergy development. We investigated relationships between levels of immune mediators in colostrum and mature milk and infant outcomes in the first year of life. In a large prospective study of 398 pregnant/lactating women in the United Kingdom, Russia and Italy, colostrum and mature human milk (HM) samples were analysed for immune active molecules. Statistical analyses used models adjusting for the site of collection, colostrum collection time, parity and maternal atopic status. Preliminary univariate analysis showed detectable interleukin (IL) 2 and IL13 in HM to be associated with less eczema. This finding was further confirmed in multivariate analysis, with detectable HM IL13 showing protective effect OR 0.18 (95% CI 0.04–0.92). In contrast, a higher risk of eczema was associated with higher HM concentrations of transforming growth factor β (TGFβ) 2 OR 1.04 (95% CI 1.01–1.06) per ng/mL. Parental-reported food allergy was reported less often when IL13 was detectable in colostrum OR 0.10 (95% CI 0.01–0.83). HM hepatocyte growth factor (HGF) was protective for common cold incidence at 12 months OR 0.19 (95% CI 0.04–0.92) per ng/mL. Data from this study suggests that differences in the individual immune composition of HM may have an influence on early life infant health outcomes. Increased TGFβ2 levels in HM are associated with a higher incidence of reported eczema, with detectable IL13 in colostrum showing protective effects for food allergy and sensitization. HGF shows some protective effect on common cold incidence at one year of age. Future studies should be focused on maternal genotype, human milk microbiome and diet influence on human milk immune composition and both short- and long-term health outcomes in the infant.