Prevalence of overweight/obesity and its relationship with metabolic syndrome and fatty liver index in adult patients with type 1 diabetes. A Brazilian multicenter study

AIMS: To determine the prevalence of overweight/obesity and its relationship with metabolic syndrome (MS), fatty liver index (FLI), cardiovascular risk factors (CVRF), and diabetes-related chronic complications (DRCC) in adult patients with type 1 diabetes (T1D). METHODS: This study was conducted in 14 Brazilian public clinics in ten cities, with 1,390 patients: 802 females (57.7%), 779 (56.0%) Caucasians, aged 33.6 ± 10.8 years, age at diagnosis, 16.2 ± 9.2 years, diabetes duration, 17.4 ± 9.2 years, and HbA1c 8.8 ± 2.0%. RESULTS: Overall, 825 patients (59.4%) had normal weight, and 565 had overweight/obesity; ( 429 (30.9%) presented overweight and 136 (9.8%) presented obesity). After adjustments, overweight/obesity was associated with age, family history of overweight/obesity, total daily insulin dose, hypertension, adherence to diet, type of health care insurance, use of metformin, levels of C-reactive protein, triglycerides, uric acid and HDL-cholesterol. These patients also presented a higher prevalence of MS, FLI ≥ 60, and CVRF than patients without overweight/obesity. Overweight/obesity was not associated with DRCC and with HbA1c levels. CONCLUSIONS: Patients with T1D with overweight/obesity presented traditional risk factors for DRCC, cardiovascular diseases, MS, and non-alcoholic fatty liver disease; most of these risk factors are modifiable and can be avoided with interventions that prevent overweight/obesity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13098-023-00996-0.