Obesity is one of the most challenging global public health issues, and more than half of adults in Chia are overweight or obese. Obesity has been shown to be a risk factor for type 2 diabetes, cardiovascular disease, colon cancer and other specific cancers, and has become a serious threat and even a danger to the health and quality of life of the nation. With the mature development of bariatric surgery in the last 20 years, it is now widely recognized for its effectiveness and safety in the treatment of obesity and related metabolic diseases, as well as improving patients′ life expectancy and quality of life. However, previous data from the literatures suggest that some patients require revisional surgery after bariatric surgery, with the incidence of revisional bariatric surgery as 5% to 50%. The main reasons for revisional bariatric surgery are poor post-operative outcomes, including the lack of significant weight loss, weight regain and no significant improvement or even recurrence of associated metabolic disease, and other reasons include the development of anaemia, malnutrition and long-term chronic pain. Currently, there is only the East Asian expert consensus on revised bariatric surgery proposed by Chinese Society for Metabolic & Bariatric Surgery in 2018. However, there are still no uniform standards regarding the indications, contraindications and surgical modalities of revisional bariatric surgery in clinical practice. The authors summarize the latest researches of revisional bariatric surgery, in order to provide the guidance value for clinical practice.

Objective: To evaluate the possible mediation effect of DNA methylation in the associations between birth weight and adulthood obesity in women in China. Methods: A cross-sectional survey was conducted in 1 602 women with genetic relationship in urban area of Shanghai during March-December 2016. Information about their birth weight, birth length, current lifestyle and disease history were collected and body measurement was conducted at the interview. DNA methylation at specific sites of GNASAS, IGF2, IGF2-R, IL10 and LEP were measured using bisulphite pyrosequencing. Generalized estimating equations models with restricted cubic spline functions were used to estimate the associations of birth weight with BMI, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-hip ratio (WHtR) in adulthood, and their associations with DNA methylation were evaluated using multilevel linear models. Multilevel structural equation models were used to evaluate the mediation effect of DNA methylation. Results: A significant non-linear association was observed between birth weight and WC as well as WHtR (P<0.05). Lower birth weight was associated with higher level of methylation at IGF2-DMR (CpG1, 2), IGF2-R (CpG8, 10, 13, 16 and 17), with β coefficients and 95%CI being -4.35 (-7.30- -1.39), -4.50 (-7.59- -1.41), -2.33 (-4.60- -0.05), -1.78 (-3.88- -0.33), -2.58 (-4.82- -0.34), -2.03 (-4.00- -0.06) and -1.87 (-3.73- -0.01), respectively, but related with a lower level of methylation at LEP CpG16 (β=4.19, 95%CI: 0.37- 8.00). Lower level of methylation at IGF2-DMR (CpG7), IGF2-R (CpG3, 5, 8, 9, 10, 14, 17, 19) and LEP (CpG3, 8, 10) was associated with larger WC, with β coefficients ranging from -0.016 to -0.040 (all P<0.05). Methylation at IGF2-R CpG8 was observed to mediate the association of birth weight and WC, and could explain 3.3% of the association. Conclusion Our results suggested that DNA methylation might mediate the effect of nutrition in uteri on adulthood central obesity in women in China.