Breastfeeding is protective against many long-term diseases, yet the mechanisms involved are unknown. Leptin gene (LEP) is reported to be associated with body mass index (BMI). On the other hand, breastfeeding duration has been found to be associated with DNA methylation (DNAm) of the LEP gene. Therefore, epigenetic regulation of LEP may represent the mechanism underlying the protective effect of breastfeeding duration against obesity. In the Isle of Wight Birth Cohort, peripheral blood DNAm at 23 cytosine-phosphate-guanine sites (CpGs) in the LEP locus in 10-year-old (n = 297) samples and 16 CpGs in 18-year-old (n = 305) samples, were generated using the Illumina Infinium MethylationEPIC and HumanMethylation450 Beadchips respectively and tested for association with breastfeeding duration (total and exclusive) using linear regression. To explore the association between breastfeeding durations and genome-wide DNAm, epigenome-wide association studies (EWASs) and differential methylation region (DMR) analyses were performed. BMI trajectories spanning the first 18 years of life were used as the outcome to test the association with breastfeeding duration (exposure) using multi-nominal logistic regression. Mediation analysis was performed for significant CpG sites. Both total and exclusive breastfeeding duration were associated with DNAm at four LEP CpG sites at 10 years (P value < 0.05), and not at 18 years. Though no association was observed between breastfeeding duration and genome-wide DNAm, DMR analyses identified five significant differentially methylated regions (Sidak adjusted P value < 0.05). Breastfeeding duration was also associated with the early transient overweight trajectory. Furthermore, DNAm of LEP was associated with this trajectory at one CpG site and early persistent obesity at another, though mediation analysis was not significant. Breastfeeding duration is associated with LEP methylation at age 10 years and BMI trajectory. LEP DNAm is also significantly associated with BMI trajectories throughout childhood, though sample sizes were small. However, mediation analysis did not demonstrate that DNAm of LEP explained the protective effect of breastfeeding against childhood obesity.

Several small studies have shown associations between breastfeeding and genome-wide DNA methylation (DNAm). We performed a comprehensive Epigenome-Wide Association Study (EWAS) to identify associations between breastfeeding and DNAm patterns in childhood. We analysed DNAm data from the Isle of Wight Birth Cohort at birth, 10, 18 and 26 years. The feeding method was categorized as breastfeeding duration >3 months and >6 months, and exclusive breastfeeding duration >3 months. EWASs using robust linear regression were performed to identify differentially methylated positions (DMPs) in breastfed and non-breastfed children at age 10 (false discovery rate of 5%). Differentially methylated regions (DMRs) were identified using comb-p. The persistence of significant associations was evaluated in neonates and individuals at 18 and 26 years. Two DMPs, in genes SNX25 and LINC00840, were significantly associated with breastfeeding duration >6 months at 10 years and was replicated for >3 months of exclusive breastfeeding. Additionally, a significant DMR spanning the gene FDFT1 was identified in 10-year-old children who were exposed to a breastfeeding duration >3 months. None of these signals persisted to 18 or 26 years. This study lends further support for a suggestive role of DNAm in the known benefits of breastfeeding on a child’s future health.

Background Routine group and save (G&S) testing is frequently performed prior to cholecystectomy, despite growing evidence that a targeted approach is safe and avoids unnecessary investigations. This retrospective cohort study explored frequency of testing in our unit, rates of peri-operative blood transfusion and pre-operative risk factors for requiring transfusion. Methods Health records of 453 consecutive adults who underwent cholecystectomy in a UK NHS trust were reviewed for blood transfusion up to 30 days post-operatively. We compared the need for transfusion against patient demographics, indication and urgency of surgery, and the number of prior emergency hospital attendances with gallstone complications. Logistic regression determined whether prior attendances with complications of gallstones independently predicted the need for transfusion. Results Peri-operative blood transfusions within 30 days of operation occurred in 1.1% of cases, with no requirement for uncrossmatched blood. Patients who received a blood transfusion tended to have higher American Society of Anesthesiologists (ASA) grades (p = 0.017), were more likely to have an underlying primary haematological malignancy (20.0% vs. 0.2%; p = 0.022) and prior emergency hospital attendances with gallstone complications (median 4 vs. 1; p < 0.001). Logistic regression showed each prior emergency attendance was associated with 4.6-fold odds of transfusion (p = 0.019). Receiver operating characteristic curve analysis showed an area under the curve of 0.92. Three or more attendances predicted need for transfusion with 60.0% sensitivity and 98.0% specificity. 74% of patients had at least one G&S sample taken pre-operatively, costing the trust approximately £3,800 per year in materials. Conclusions The findings of this study suggest that pre-operative G&S testing prior to cholecystectomy is not routinely required. Increased frequency of prior emergency hospital attendances with gallstone complications and co-morbidities associated with coagulopathies were pre-operative risk factors for post-operative blood transfusion. More selective testing could provide large financial savings for health institutions without compromising patient safety.