dismutase (SOD) activity were determined in 170 children and adolescents with T1DM. Principal component analysis was used to investigate clustering of clinical and laboratory variables associated with elevated oxidative stress and reduced antioxidative defense biomarkers. Results Factor analysis extracted 7 factors, interpreted as: (1) “demo- graphic factor” including age, BMI, waist and hip circumferences, systolic and diastolic blood pressure; (2) “proatherogenic factor” that included total and LDL-cholesterol and triglycerides; (3) “liver function factor” including AST, ALT and ©GT; (4) “disease duration factor” with positive loading of age at diabetes onset and negative loading of diabetes duration; (5) “metabolic control factor” that included glucose and HbA1c; (6) “reno-inflammatory factor” with positive loadings of hsCRP and GFR and negative loading of urea; and (7) “antiatherogenic factor” that included HDL-cholesterol. High AOPP levels were independently predicted by “proatherogenic” (OR: 2.05; 95%CI: 1.31-3.21; Pb0.01) and “metabolic control” (OR: 2.13; 95%CI: 1.32-3.41; Pb0.01) factors. “Reno-inflammatory” factor was significant predictor of increased PAB (OR: 2.19; 95%CI: 1.34-3.58; Pb0.01). Regarding antioxidative defense markers, reduced SH- groups were predicted by “disease duration factor” (OR: 1.62; 95% CI: 1.03-2.53; Pb0.05), while “demographic factor” predicted lower SOD activity (OR: 1.81; 95%CI: 1.17-2.78; Pb0.01). Conclusions Metabolic control and disease duration, dyslipidemia and low- grade inflammation are conditions associated with oxidative stress in paediatric T1DM patients. doi:10.1016/j.cca.2019.03.630 T304 Effect of surgically induced weight loss on serum adiponectin levels and its association with the gene expression in visceral adipose tissue of morbidly obese individuals R. Yadav a , S. Aggarwal b , A. Singh a , R. Mir a a Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India b Department of Surgical Disciplines, Laproscopic and Bariatric Surgery, All India Institute of Medical Sciences, New Delhi, India Background-aim Obesity and its co-morbidities are the major health problems in the modern world. One of the major co-morbidity is the insulin resistance. Bariatric surgery has recently emerged as a promising treatment approach in alleviating many of the co-morbidities seen in morbidly obese individuals. Adiponectin is the major adipokine secreted by adipose tissue which has a role in regulating glucose and lipid metabolism in our body. Thus we have undertaken our study in order to monitor the serum levels of adiponectin, both pre- and post- operatively to ascertain the effect of weight reduction on it and its correlation with the gene expression in visceral adipose tissue of morbidly obese individuals. Methods For our study, a total of 20 individuals were recruited from the department of surgical disciplines; AIIMS, New Delhi. Out of these; 15 were obese (BMIN30); admitted for Bariatric surgery and 5 were non-obese (BMIb25) individuals admitted for surgery like cholecys- tectomy. Blood samples were collected from all the subjects pre- operatively and followed post-operatively only in obese individuals at the time of discharge and at third to sixth month follow-up. Serum level of Adiponectin was analysed using Luminex bead assay technology. The expression of adiponectin was also assessed in adipose tissue biopsy samples obtained at the time of surgery from all the subjects using real time PCR. Results We found a significant difference in the serum Adiponectin levels in obese (15.17 μg/ml) and non-obese individuals (23.30 μg/ml); p value b0.05. The levels also improved significantly with weight loss after bariatric surgical procedure in obese individuals at three to six month (average 4.7 month) follow up (20.53 μg/ml); p value b0.05 but not at immediate post-op period (17.38 μg/ml). These levels also correlated with the improvement in the biochemical parameters like lipid profile and fasting insulin. Moreover, the serum Adiponectin levels also correlated with their gene expression in visceral adipose tissue with a significant difference between obese and non-obese groups. Conclusions From our study, it is concluded that surgical weight reduction markedly improves the metabolic profile in the obese individuals thereby averting the complications in them. doi:10.1016/j.cca.2019.03.631 T305 Incidence of diabetes mellitus type 2 in the European population chronically exposed to arsenic R. Barbir c , B. Michalke g , M. Lucio g , B. Tariba c , M. Vučić Lovrenčić f , V. Šerić d , S. Canecki-Varžić e , S. Ljubić a , L. Smirčić Duvnjak h , A. Krivohvalek b , I. Vinković Vrček c a Department of Diabetes and Endocrinology, University Hospital Merkur, Zagreb, Croatia b Institute of Public Health “Dr. Andrija Štampar”, Zagreb, Croatia c Analytical Toxicology and Mineral Metabolism Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia d Deparment for Clinical laboratory diagnostics, University Hospital Centre Osijek, Osijek, Croatia e Department of Diabetes, Endocrinology and Metabolism Disorders, University Hospital Centre Osijek, Osijek, Croatia f Department of Medical Biochemistry and Laboratory Medicine, Univer- sity Hospital Merkur, Zagreb, Croatia g Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum Mün- chen – German Research Center for Environmental Health, München, Germany h Vuk Vrhovac University Clinic, Merkur University Hospital, Zagreb, Croatia Abstracts / Clinica Chimica Acta 493 (2019) S268–S310