We conducted a systematic review and meta-analysis of studies to quantify the association between body mass index (BMI) and the risks of all-cause and cardiovascular mortality in patients with type 2 diabetes. We included studies assessing the impact of BMI on all-cause and cardiovascular mortality in patients with type 2 diabetes. Data were combined using a random-effects dose-response model. Sixteen cohort studies on all-cause mortality (n = 445,125) and two studies on cardiovascular mortality (n = 92,841) were evaluated in the meta-analysis. A non-linear association was observed between BMI and all-cause mortality among patients with type 2 diabetes. With a BMI nadir of 28–30 kg/m², the risk of all-cause mortality displayed a U-shaped increase. With a BMI nadir of 29–31 kg/m², the risk of cardiovascular mortality exhibited a gradual non-linear increase for BMI > 31 kg/m². Subgroup analyses suggested that study location, diabetes duration, and smoking history may have contributed to heterogeneity among the studies. An obesity paradox exists for patients with type 2 diabetes with respect to all-cause and cardiovascular mortality. Study location, diabetes duration, and smoking history might contribute to heterogeneity among obesity paradox studies of patients with type 2 diabetes.

We aimed to investigate how body weight fluctuation affects the risk of developing type 2 diabetes by conducting a nationwide cohort study. A total of 3,855,884 participants from the National Health Insurance System health check-up data from 2012 were included in this study, and follow-up continued until 2016. Body weight was measured at least thrice between 2009 and 2012. Body weight variability (BWV) was estimated using average successive variability (ASV) indices. Cox proportional hazards regression models were used to evaluate the association of BWV with the risk of type 2 diabetes using hazard ratios (HRs) and 95% confidence intervals (CIs). Body weight fluctuation was associated with a higher risk of incident diabetes after adjustment for confounders (HR 1.10, 95% CI 1.07, 1.12 in the highest BWV quartile compared to the lowest). Regardless of the weight change status, the highest ASV quartile of BWV increased the risk for diabetes. Even subjects with a normal glucose tolerance status and those aged under 65 years had a higher risk of diabetes if their body weight highly fluctuated during the follow-up years. Our results suggest that body weight variability is an independent risk factor for diabetes. It is important to pay attention to frequent body weight fluctuations.

Objectives: We assessed thyroid-stimulating hormone (TSH) suppression effects on bone mineral density (BMD) in postmenopausal women who underwent thyroidectomy.Data sources: PubMed, EMBASE, Cochrane Library, Web of Science and SCOPUS were searched from inception to 24 February 2021.Study selection: Case-control studies were included.Data extraction and synthesis: Two authors independently reviewed the studies, extracted the data and performed meta-analysis of eligible studies.Research design and methods: Studies evaluating BMD in postmenopausal women with thyroid cancer who had thyroidectomy and levothyroxine therapy were included. Differences in BMD were presented as standardised mean differences (SMDs). Meta-analyses were conducted using a random-effects model.Results: Analysis of 16 case-control studies (426 patients and 701 controls without thyroid cancer) showed that stringent TSH suppression (TSH 10 years of follow-up (SMD −0.32; 95% CI −0.50 to −0.14). Subgroup analysis of the femoral neck showed that total thyroidectomy was related to detrimental effects on the BMD of the femoral neck (SMD −0.60; 95% CI −0.89 to −0.31; I²=90.4%), but near-total thyroidectomy was not (SMD 0.00; 95% CI −0.30 to 0.30; I²=55.6%).Conclusions: Stringent TSH suppression had deleterious effects on the BMD of the lumbar spine after thyroidectomy in postmenopausal women. Further studies are needed to determine whether stringent TSH suppression after thyroidectomy increases the fracture risk.

BACKGROUND: Optimal length of biliopancreatic (BP) and Roux limb in Roux-en-Y gastric bypass (RYGB) for improved glycemic control are not known.PURPOSE: To investigate how the lengths of the BP and Roux limbs in RYGB differentially affect postoperative glycemic outcomes in patients with type 2 diabetes.DATA SOURCES: We conducted a systematic literature search using the PubMed, Embase, and the Cochrane Library databases.STUDY SELECTION: We included studies that reported glycemic outcomes after RYGB and lengths of the BP and Roux limbs.DATA EXTRACTION: A total of 28 articles were included for data extraction. Glycemic outcomes after RYGB were assessed on the basis of two definitions: remission and improvement.DATA SYNTHESIS: We categorized the included studies into four groups according to the BP and Roux limb lengths. The type 2 diabetes remission/improvement rates were as follows: long BP–long Roux group 0.80 (95% CI 0.70–0.90)/0.81 (0.73–0.89), long BP–short Roux group 0.76 (0.66–0.87)/0.82 (0.75–0.89), short BP–long Roux group 0.57 (0.36–0.78)/0.64 (0.53–0.75), and short BP–short Roux group 0.62 (0.43–0.80)/0.53 (0.45–0.61). Meta-regression analysis also showed that a longer BP limb resulted in higher postoperative type 2 diabetes remission and improvement rates, whereas a longer Roux limb did not. There was no significant difference or heterogeneity in baseline characteristics, including diabetes-related variables, among the four groups.LIMITATIONS: Not all included studies were randomized controlled trials.CONCLUSIONS: Longer BP limb length led to higher rates of type 2 diabetes remission and improvement by 1 year after RYGB in comparisons with the longer Roux limb length.