Review and statistical analysis of activity values reported for coastal sands worldwide.

The activity of natural radionuclides is unevenly distributed across the Earth's crust, with certain areas exhibiting significantly higher levels than others, known as High Background Radiation Areas (HBRAs). This study presents a statistical analysis of reported activity values for coastal sands globally. Through this statistical analysis, costal sands were classified into four categories based on their activity levels, providing a standardized framework to compare the natural radioactivity of these sands. This classification is a valuable tool for identifying populations exposed to different radiation levels, which is essential for the study of stochastic effects. The study proposes thresholds to define HBRAs as regions with activity values exceeding 203 Bq/kg for 238U, 517 Bq/kg for 232Th, or 960 Bq/kg for 40K. Regions with lower values are classified as NonHBRAs. Further subdivision of these categories resulted in four distinct regions: NonHBRA-, NonHBRA+, HBRA-, and HBRA+. The activity values for these subdivisions are 92 Bq/kg and 2,903 Bq/kg for 238U, 94 Bq/kg and 7,230 Bq/kg for 232Th, and 901 Bq/kg and 2,298 Bq/kg for 40K. By calculating the external dose rates from the reported activity data, a threshold of 357 nGy/h was identified as the dose boundary separating NonHBRAs from HBRAs. The values for the subdivisions resulted 101 nGy/h and 3,867 nGy/h. The study also explores the content of these natural radionuclides in relation to their bearing minerals and discusses correlations between the reported activity values and the characteristics of the sands. Additionally, the activity of the anthropogenic radionuclide 137Cs (reported values ranging from the detection limit to 63 Bq/kg) is examined.

RNA-sequencing predicts a role of androgen receptor and aldehyde dehydrogenase 1A1 in osteosarcoma lung metastases.

One-third of pediatric patients with osteosarcoma (OS) develop lung metastases (LM), which is the primary predictor of mortality. While current treatments of patients with localized bone disease have been successful in producing 5-year survival rates of 65-70%, patients with LM experience poor survival rates of only 19-30%. Unacceptably, this situation that has remained unchanged for 30 years. Thus, there is an urgent need to elucidate the mechanisms of metastatic spread in OS and to identify targetable molecular pathways that enable more effective treatments for patients with LM. We aimed to identify OS-specific gene alterations using RNA-sequencing of extremity and LM human tissues. Samples of extremity and LM tumors, including 4 matched sets, were obtained from patients with OS. Our data demonstrate aberrant regulation of the androgen receptor (AR) pathway in LM and predicts aldehyde dehydrogenase 1A1 (ALDH1A1) as a downstream target. Identification of AR pathway upregulation in human LM tissue samples may provide a target for novel therapeutics for patients with LM resistant to conventional chemotherapy.

Factors Affecting Adherence, Intake, and Perceived Palatability of Oral Nutritional Supplements: A Literature Review.

Oral nutritional supplements (ONS) are a clinically effective and relatively inexpensive way to supplement the diet of patients with, or at risk of, undernutrition. Good adherence is a primary determinant of the effectiveness of ONS. However adherence can be problematic for those with the greatest clinical need, such as undernourished older adults. This review aimed to appraise the available literature for the factors (contextual, personal and product related) affecting patient adherence and perceived palatability of ONS, identify areas requiring improvement and uncover gaps in the evidence to guide the focus of future research. Contextual factors identified were healthcare staff and the timing of administration. Personal factors included sensory changes and motivation which alter experience of and desire to consume ONS. The product's sensory characteristics determined palatability and intake, but undesirable attributes, such as off-flavours, can stem from nutritional ingredients. The contribution made by aroma to older adults' experience of ONS was a comparatively under-researched area. Further research should address this evidence gap to optimise the flavour, aroma profile and palatability for undernourished older consumers, thereby optimising intake. A combined multidisciplinary effort involving strategic expansion of research, industry development and clinical practice should simultaneously address the factors identified, to provide the best approach to improve adherence.

The relation between stimulated salivary flow and the temporal consumption experience of a liquid oral nutritional supplement.

Use of oral nutritional supplements (ONS) in undernourished patients has proven clinical benefits, but this can be hampered by low adherence due to poor experience of palatability. Many patients, particularly older patients, experience hyposalivation which can cause taste changes and reduce the enjoyment of foods. The aim of this study was to investigate differences in the temporal consumption experience (comprising sensory perception, in-mouth aroma release and subjective appetite) of a clinically relevant portion of ONS, for groups differing in saliva flow rates (SFR). The SFR (mL/min) of thirty healthy individuals was measured on three occasions. This data was used to categorise individuals into three groups using quartile analysis: low flow (LF) (0.3-0.6 mL/min, n = 5), medium flow (MF) (0.7-1.2 mL/min, n = 16) and high flow (HF) (1.3-1.8 mL/min, n = 9). Over the consumption of eight 15 mL sips of ONS, individuals rated their sensory perception and subjective appetite perception using line scales. Additionally, in-mouth aroma release was measured for each sip, using atmospheric pressure chemical ionisation (APCI). Compared with the MF and HF group, the LF group reported a significantly greater increase of mouth-drying over increased sips (p = 0.02). The LF group also experienced significantly higher aftertaste perception (p < 0.001), and more intense in-mouth aroma release (p = 0.015), compared with the HF group. These findings occurred concurrently with relatively lower hunger sensations in the LF and MF group. Many patients who are prescribed ONS likely experience reduced salivary flow rates. The unique sensory experiences of these individuals should be considered in order to optimise palatability and nutritional intake.

An alternative methodology to determine 210Pb activity soil profiles.

Unsupported 210Pb (Pbexc) is generated in air and is subsequently deposited on soil surface. The Pbexc can be used for sediment dating, soil erosion/sedimentation and air mass studies. In many cases, 210Pb activity determination (gamma ray 46.5 keV) cannot be performed due to the lack of efficiency calibration curve, especially when radioactive patron source is not available. This work presents an alternative methodology to obtain the 210Pb activity values, based on the activity definition and the attenuation coefficient determinations and assuming that soil samples coming from depth higher than 25 cm only contain 210Pb generated in the soil (Pbexc free, i.e., for those soil layers the 210Pb activity is equal to the 226Ra activity, at secular equilibrium). The proposed methodology was evaluated using soils from La Plata region, Argentina. The same soil samples were also analyzed in a second laboratory by the conventional methodology. The obtained results indicated that the proposed procedure can be used as a good alternative in cases where a calibration sample is not available.

Effects of replacing diet beverages with water on weight loss and weight maintenance: 18-month follow-up, randomized clinical trial.

BACKGROUND: Beneficial effects of replacing diet beverages (DBs) with water on weight loss, during a 24-week hypoenergetic diet were previously observed. However, it is not known whether this difference is sustained during a subsequent 12-month weight maintenance period. OBJECTIVE: To evaluate effects of replacing DBs with water on body weight maintenance over a 12-month period in participants who undertook a 6-month weight loss plan. DESIGN: Seventy-one obese and overweight adult women (body mass index (BMI): 27-40 kg m-2; age: 18-50 years) who usually consumed DBs in their diet were randomly assigned to either substitute water for DBs (water group: 35) or continue drinking DBs five times per week (DBs group: 36) after their lunch for the 6-month weight loss intervention and subsequent 12-month weight maintenance program. RESULTS: A total of 71 participants who were randomly assigned were included in the study by using an intention-to-treat analysis. Greater additional weight loss (mean±s.d.) in the water group was observed compared with the DBs group after the 12-month follow-up period (-1.7±2.8 vs -0.1±2.7 kg, P=0.001). BMI decreased more in the water group than in the DBs group (-0.7±1 vs -0.05±1.1 kg m-2, P=0.003). There was also a greater reduction in fasting insulin levels (-0.5±1.4 vs -0.02±1.5 mmol l-1, P=0.023), better improvement in homeostasis model assessment of insulin resistance (-0.2±0.4 vs -0.1±0.3, P=0.013) and a greater decrease in 2-h postprandial plasma glucose (-0.2±0.3 vs -0.1±0.3 mmol l-1, P<0.001) in the water group compared with the DBs over the 12-month weight maintenance period. CONCLUSIONS: Replacement of DBs with water after the main meal in women who were regular users of DBs may cause further weight reduction during a 12-month weight maintenance program. It may also offer benefits in carbohydrate metabolism including improvement of insulin resistance over the long-term weight maintenance period.

Investigating anthelmintic efficacy against gastrointestinal nematodes in cattle by considering appropriate probability distributions for faecal egg count data.

The Faecal Egg Count Reduction Test (FECRT) is the most widely used field-based method for estimating anthelmintic efficacy and as an indicator of the presence of anthelmintic resistant nematodes in cattle, despite never having been validated against the gold standard of controlled slaughter studies. The objectives of this study were to assess the normality of cattle faecal egg count (FEC) data and their transformed versions, since confidence intervals used to aid the interpretation of the FECRT, are derived from data assumed to be normally distributed, and violation of this assumption could potentially lead to the misclassification of anthelmintic efficacy. Further, probability distributions and associated parameters were evaluated to determine those most appropriate for representing cattle FEC data, which could be used to estimate percentage reductions and confidence limits. FEC data were analysed from 2175 cattle on 52 farms using a McMaster method at two different diagnostic sensitivities (30 and 15 eggs per gram (epg)) and a sensitive centrifugal flotation technique (SCFT) with a sensitivity of 1 epg. FEC data obtained from all egg count methods were found to be non-normal even upon transformation; therefore, it would be recommended that confidence or credible intervals be generated using either a Bootstrapping or Bayesian approach, respectively, since analyses using these frameworks do not necessarily require the assumption of normality. FEC data obtained using the SCFT method were best represented by distributions associated with the negative binomial and hence arithmetic means could be used in FECRT calculations. Where FEC data were obtained with less sensitive counting techniques (i.e. McMaster 30 or 15 epg), zero-inflated distributions and their associated central tendency were the most appropriate and would be recommended to use, i.e. the arithmetic group mean divided by the proportion of non-zero counts present; otherwise apparent anthelmintic efficacy could be misrepresented.

Impact of structurally modifying hyaluronic acid on CD44 interaction.

CD44 is a widely-distributed type I transmembrane glycoprotein that binds hyaluronic acid (HA) in most cell types, including primary tumor cells and cancer-initiating cells and has roles in cell migration, cell-cell, and cell-matrix adhesion. HA-derived conjugates and nanoparticles that target the CD44 receptor on cells have been reported for targeted delivery of therapeutics and imaging agents. Altering crucial interactions of HA with CD44 active sites holds significant importance in modulating targeting ability of hyaluronic acid to other cancer types that do not express the CD44 receptor or minimizing the interaction with CD44+ cells that are not target cells. The approach adopted here was deacetylation of the N-acetyl group and selective sulfation on the C6-OH on the HA polymer, which form critical interactions with the CD44 active site. Major interactions identified by molecular modeling were confirmed to be hydrogen bonding of the C6-OH with Tyr109 and hydrophobic interaction of the N-acetyl group with Tyr46, 83 and Ile 92. Modified HA was synthesized and characterized and its interactions were assessed by in vitro and molecular modeling approaches. In vitro techniques included flow cytometry and fluorescence polarization, while in silico approaches included docking and binding calculations by a MM-PBSA approach. These studies indicated that while both deacetylation and sulfation of HA individually decrease CD44 interaction, both chemical modifications are required to minimize interaction with CD44+ cells. The results of this study represent the first step to effective retargeting of HA-derived NPs for imaging and drug delivery.

Antenatal Weight Management: Women's Experiences, Behaviours, and Expectations of Weighing in Early Pregnancy.

The current emphasis on obstetric risk management helps to frame gestational weight gain as problematic and encourages intervention by healthcare professionals. However pregnant women have reported confusion, distrust, and negative effects associated with antenatal weight management interactions. The MAGIC study (MAnaging weiGht In pregnanCy) sought to examine women's self-reported experiences of usual-care antenatal weight management in early pregnancy and consider these alongside weight monitoring behaviours and future expectations. 193 women (18 yrs+) were recruited from routine antenatal clinics at the Nottingham University Hospital NHS Trust. Self-reported gestation was 10-27 weeks, with 41.5% (n = 80) between 12 and 14 and 43.0% (n = 83) between 20 and 22 weeks. At recruitment 50.3% of participants (n = 97) could be classified as overweight or obese. 69.4% of highest weight women (≥30 kg/m2) did not report receiving advice about weight, although they were significantly more likely compared to women with BMI < 30 kg/m2. The majority of women (regardless of BMI) did not express any barriers to being weighed and 40.8% reported weighing themselves at home. Women across the BMI categories expressed a desire for more engagement from healthcare professionals on the issue of bodyweight. Women are clearly not being served appropriately in the current situation which simultaneously problematizes and fails to offer constructive dialogue.

Approximate total Fe content determined by Mössbauer spectrometry: Application to determine the correlation between gamma-ray-emitter activities and total content of Fe phases in soils of the Province of Buenos Aires, Argentina.

Pearson correlation coefficients between 40K, 226Ra and 232Th activities and the total Fe phase fractions yielded by Mössbauer spectroscopy have been calculated for soils of the Province of Buenos Aires, Argentina. Total fractions of Fe phases have been obtained from the relative fractions reported in previous works weighted by the Fe soil content and the recoilless-fraction of each Fe phase. An approximate method based on the relationship between the Mössbauer spectral absorption area (obtained from the 57Fe Mössbauer data) and the total Fe concentration (determined by colorimetric methods, after microwave assisted acid digestion of soil samples) has been used for the first time to determine the Fe concentration in soils with an accuracy of 15%. Protocol to extend the method for unknown samples is also discussed. The determined new coefficients differ from those reported previously. A significant and positive correlation between the total fraction of Fe2+ and the 40K activity values has been obtained. This result validates the hypothesis put forward in a previous work, i.e., that illite captures the 40K existing in the soil. In addition, with the new approximation, the Pearson correlation coefficients for the other natural radionuclides give values that indicate that the methodology reported here is appropriate to study the correlations between the activity values with the total fractions of Fe phases.

Does oral carbohydrate supplementation improve labour outcome? A systematic review and individual patient data meta-analysis.

BACKGROUND: Labour is a period of significant physical activity. The importance of carbohydrate intake to improve outcome has been recognised in sports medicine and general surgery. OBJECTIVES: To assess the effect of oral carbohydrate supplementation on labour outcomes. SEARCH STRATEGY: MEDLINE (1966-2014), Embase, the Cochrane Library and clinical trial registries. SELECTION CRITERIA: Randomised controlled trials (RCT) of women randomised to receive oral carbohydrate in labour (<6 cm dilated), versus placebo or standard care. DATA COLLECTION AND ANALYSIS: Authors were contacted to provide data. Individual patient data meta-analyses were performed to calculate pooled risk ratios (RR) and 95% confidence intervals (CI). MAIN RESULTS: Eight RCTs met the inclusion criteria. Six authors responded, four supplied data (n = 691). Three studies used isotonic drinks (one placebo-controlled, two compared with standard care), and one an advice booklet regarding carbohydrate intake. The mean difference in energy intake between the intervention and control groups was small [three studies, 195 kilocalories (kcal), 95% CI 118-273]. There was no difference in the risk of caesarean section (RR 1.15, 95% CI 0.83- 1.61), instrumental birth (RR 1.26, 95% CI 0.96-1.66) or syntocinon augmentation (RR 0.99, 95% CI 0.86-1.13). Length of labour was similar (mean difference -3.15 minutes, 95% CI -35.14 to 41.95). Restricting the analysis to primigravid women did not affect the result. Oral carbohydrates did not increase the risk of vomiting (RR 1.09, 95% CI 0.78-1.52) or 1-minute Apgar score <7 (RR 1.23, 95% CI 0.82-1.83). AUTHORS' CONCLUSION: Oral carbohydrate supplements in small quantities did not alter labour outcome. TWEETABLE ABSTRACT: Oral carbohydrate does not affect labour. But the difference between intervention and control equals 10 teaspoons sugar.

Enhanced MAPK signaling drives ETS1-mediated induction of miR-29b leading to downregulation of TET1 and changes in epigenetic modifications in a subset of lung SCC.

Non-small-cell lung cancer is the leading cause of cancer death worldwide and is comprised of several histological subtypes, the two most common being adenocarcinoma (AC) and squamous cell carcinoma (SCC). Targeted therapies have successfully improved response rates in patients with AC tumors. However, the majority of SCC tumors lack specific targetable mutations, making development of new treatment paradigms for this disease challenging. In the present study, we used iterative non-negative matrix factorization, an unbiased clustering method, on mRNA expression data from the cancer genome atlas (TCGA) and a panel of 24 SCC cell lines to classify three disease segments within SCC. Analysis of gene set enrichment and drug sensitivity identified an immune-evasion subtype that showed increased sensitivity to nuclear factor-κB and mitogen-activated protein kinase (MAPK) inhibition, a replication-stress associated subtype that showed increased sensitivity to ataxia telangiectasia inhibition, and a neuroendocrine-associated subtype that showed increased sensitivity to phosphoinositide 3-kinase and fibroblast growth factor receptor inhibition. Additionally, each of these subtypes exhibited a unique microRNA expression profile. Focusing on the immune-evasion subtype, bioinformatic analysis of microRNA promoters revealed enrichment for binding sites for the MAPK-driven ETS1 transcription factor. Indeed, we found that knockdown of ETS1 led to upregulation of eight microRNAs and downregulation of miR-29b in the immune-evasion subtype. Mechanistically, we found that miR-29b targets the DNA-demethylating enzyme, TET1, for downregulation resulting in decreased 5-hmC epigenetic modifications. Moreover, inhibition of MAPK signaling by gefitinib led to decreased ETS1 and miR-29b expression with a corresponding increase in TET1 expression and increase in 5-hmC. Collectively, our work identifies three subtypes of lung SCC that differ in drug sensitivity and shows a novel mechanism of miR-29b regulation by MAPK-driven ETS1 expression which leads to downstream changes in TET1-mediated epigenetic modifications.

Limiting antenatal weight gain improves maternal health outcomes in severely obese pregnant women: findings of a pragmatic evaluation of a midwife-led intervention.

BACKGROUND: Antenatal obesity in pregnancy is associated with complications of pregnancy and poor obstetric outcomes. Although most guidance on pregnancy weight is focused on the prepregnancy period, pregnancy is widely viewed as a period where women are open to lifestyle change to optimise their health. METHODS: The hospital-based Bumps and Beyond intervention invited all pregnant women with a body mass index (BMI) >35 kg m(-2) to take part in a programme of health education around diet and exercise, accompanied by one-to-one guidance and monitoring of dietary change. This service evaluation compares 89 women who completed at a programme of seven sessions with healthy lifestyle midwives and advisors (intervention) versus a group of 89 women who chose not to attend (non-intervention). RESULTS: Mean (SD) weight gain in the intervention group [4.5 (4.6) kg] was less than in the non-intervention group [10.3 (4.4) kg] between antenatal booking and 36 weeks of gestation (< 0.001). This was associated with a 95% reduction in the risk of gestational hypertension during pregnancy and a general reduction in pregnancy complications. There was no effect of the intervention upon gestational diabetes or complications in labour other than post-partum haemorrhage (reduced by 55%). The impact of the intervention on gestational weight gain was greater in women with BMI >40 kg m(-2) at booking. There were no adverse effects of the intervention, even though 21% of the intervention group lost weight during their pregnancy. CONCLUSIONS: Intensive, personalised weight management intervention may be an effective strategy for the prevention of hypertensive disorders during pregnancy.

Efficacy of diclazuril and toltrazuril in the prevention of coccidiosis in dairy calves under field conditions.

A blinded, controlled, randomised field study was undertaken on two commercial dairy farms in Germany to compare the efficacy of the anticoccidials, diclazuril and toltrazuril in the prevention of bovine coccidiosis. A total of 86 calves aged between five and six weeks were randomly allocated to two treatment and one untreated control groups. Calves were monitored for 78 days post-treatment by clinical observation, bodyweight gain, faecal oocyst counts (FOCs) and coccidia species differentiation. Strategic treatments had no significant effect on bodyweight gains (P>0.05). Whilst the number of diarrhoea days was similar for all three groups from days 1 to 41, there was a significant difference in the number and percentage of diarrhoea days from day 42 with the diclazuril-treated group showing only one diarrhoea day compared with 9 days (P=0.0195) and 18 days (P=0.0027) for the control and toltrazuril-treated groups, respectively. FOCs in control calves fluctuated throughout the period of study indicating continued coccidia challenge. FOCs in the diclazuril-treated calves declined to low levels post-treatment, increasing to occasional counts >500 oocysts per gram of faeces (OPG) between days 27 and 42, but thereafter remained low. Calves treated with toltrazuril also showed low FOCs until day 40 but then showed several peaks of oocyst output >500 OPG coinciding with days of diarrhoea.

Comparative efficacy of diclazuril (Vecoxan®) and toltrazuril (Baycox bovis®) against natural infections of Eimeria bovis and Eimeria zuernii in French calves.

A blinded, randomized, controlled, multi-centric field study was conducted on French dairy farms (n = 9) to evaluate the long term efficacy of metaphylactic, single oral treatments with either 1 mg/kg body weight (BW) of diclazuril (Vecoxan®), or 15 mg/kg BW of toltrazuril (Baycox®) against natural infections with Eimeria zuernii and/or Eimeria bovis, compared to untreated control animals. A total of 199 calves from nine commercial farms aged between 21 and 55 days old at the start of study were included and randomly allocated to one of three groups. Calves on all farms were observed for a period of 78 days post treatment, using both parasitological (oocyst excretion), and clinical parameters (faecal score and body weight). The assessment of efficacy was based on both control of oocyst excretion, and on the average daily weight gains throughout the study. During the whole study period, the mean number of days with diarrhoea (≥ 2) was similar (0.7 days) between treated groups. Excretion in the untreated group peaked at 21 days after treatment. In both the diclazuril and toltrazuril-treated groups, mean oocyst excretion decreased dramatically in the five days following treatment. Thereafter, particularly towards the end of the study period, oocyst counts and percentage levels of E. zuernii were highest in the toltrazuril-treated group. In pooled data from all trial sites, the average daily weight gain was significantly (p = 0.01) higher (+ 0.057 kg/day) in the diclazuril group when compared to the toltrazuril group, and the average body weight gain of the diclazuril treated group was 4.4 kg higher than the toltrazuril group. On eight of the nine trial sites, the average daily gain was greater in the diclazuril group than in the toltrazuril group. This study demonstrates that, over an extended observation period of 78 days, metaphylactic treatment with both diclazuril and toltrazuril reduces the impact of coccidiosis, but greater performance benefits based on average daily weight gains, were achieved following the use of diclazuril.

Bilothorax as a rare sign of intra-abdominal bile leak in a patient without peritonitis.

We present the case of a 60-year-old patient who developed a right-sided bilothorax following para-aortic lymph node sampling. Bilothorax is a very rare condition, with most of the reported cases resulting from direct flow of bile from the biliary system to the pleural space through a fistula or other defect in the diaphragm. In this case, there was no obvious communication found between peritoneal and pleural spaces. Our patient proceeded to an exploratory laparotomy following this finding in the absence of peritonitis. Bilothorax should be considered in patients who develop a progressive pleural effusion following upper gastrointestinal surgery, particularly if it involves manipulation of the biliary system.

Role of carcinoembryonic antigen as a marker for colorectal liver metastases.

Carcinoembryonic antigen (CEA), a marker for colorectal adenocarcinoma, can monitor disease progression and treatment response. This study aims to determine the accuracy of CEA in the detection and resectability of colorectal liver metastases. Patients with primary colorectal cancer were divided into three groups: resectable hepatic metastases (group 1), unresectable metastases (group 2), and disease-free cases (group 3). The CEA concentration was recorded pre- and post-hepatectomy in group 1 and on radiological confirmation of disease state in the other groups. It was expressed as median (95% confidence interval [CI]), with predictors of concentration determined. Group 1 (n=141) had pre-operative CEA of 8.9 (4.6-13.1), with 38.1% of patients being normal. Maximum tumour diameter correlated with CEA level (r=0.41, P<0.0001). Post-hepatectomy CEA was 2.3 (1.9-2.7; P<0.0001), with 81.1% of patients being normal. Group 2 (n=158) had CEA of 20.6 (9.4-31.9). Group 3 (n=361) had CEA of 2.0 (1.8-2.2). Sensitivity of CEA pre- and post-hepatectomy was 61.2% and 69.3%, respectively, while specificity was 79.8% for both groups. Concentration was elevated in hepatic colorectal metastases but is not a marker of resectability. A CEA reduction post-resection indicates that it may be used as an indicator of treatment response, while CEA is increased by tumour burden and lesion size.

Timing of the introduction of complementary feeding and risk of childhood obesity: a systematic review.

The World Health Organisation recommends exclusive breastfeeding until 6 months of age and continued breastfeeding until 2 years of age or beyond. Appropriate complementary foods should be introduced in a timely fashion, beginning when the infant is 6 months old. In developing countries, early or inappropriate complementary feeding may lead to malnutrition and poor growth, but in countries such as the United Kingdom and United States of America, where obesity is a greater public health concern than malnutrition, the relationship to growth is unclear. We conducted a systematic review of the literature that investigated the relationship between the timing of the introduction of complementary feeding and overweight or obesity during childhood. Electronic databases were searched from inception until 30 September 2012 using specified keywords. Following the application of strict inclusion/exclusion criteria, 23 studies were identified and reviewed by two independent reviewers. Data were extracted and aspects of quality were assessed using an adapted Newcastle-Ottawa scale. Twenty-one of the studies considered the relationship between the time at which complementary foods were introduced and childhood body mass index (BMI), of which five found that introducing complementary foods at <3 months (two studies), 4 months (2 studies) or 20 weeks (one study) was associated with a higher BMI in childhood. Seven of the studies considered the association between complementary feeding and body composition but only one study reported an increase in the percentage of body fat among children given complementary foods before 15 weeks of age. We conclude that there is no clear association between the timing of the introduction of complementary foods and childhood overweight or obesity, but some evidence suggests that very early introduction (at or before 4 months), rather than at 4-6 months or >6 months, may increase the risk of childhood overweight.