Objective To present a comprehensive review of the association between measures of body weight, waist, and fat, and different ratios of these measures, and the risk of type 2 diabetes. Design Systematic review and dose-response meta-analysis of cohort studies. Data sources PubMed, Scopus, and Web of Science up to 1 May 2021. Review methods Cohort studies looking at the association between general or central adiposity and body fat content and the risk of type 2 diabetes in the general adult population were included. Two of the authors extracted the data in duplicate. Random effects dose-response meta-analyses were performed to estimate the degree of the associations. Curvilinear associations were modelled with a one stage weighted mixed effects meta-analysis. Results 216 cohort studies with 2.3 million individuals with type 2 diabetes among 26 million participants were identified. Relative risks were 1.72 (95% confidence interval 1.65 to 1.81; n=182 studies) for an increase in body mass index of 5 units, 1.61 (1.52 to 1.70; n=78) for a 10 cm larger waist circumference, 1.63 (1.50 to 1.78; n=34) for an increase in waist-to-hip ratio of 0.1 units, 1.73 (1.51 to 1.98; n=25) for an increase in waist-to-height ratio of 0.1 units, 1.42 (1.27 to 1.58; n=9) for an increase in visceral adiposity index of 1 unit, 2.05 (1.41 to 2.98; n=6) for a 10% higher percentage body fat, 1.09 (1.05 to 1.13, n=5) for an increase in body shape index of 0.005 units, 2.55 (1.59 to 4.10, n=4) for a 10% higher body adiposity index, and 1.11 (0.98 to 1.27; n=14) for a 10 cm larger hip circumference. A strong positive linear association was found between body mass index and the risk of type 2 diabetes. Positive linear or monotonic associations were also found in all regions and ethnicities, without marked deviation from linearity at a specific cut-off value. Indices of central fatness, independent of overall adiposity, also had positive linear or monotonic associations with the risk of type 2 diabetes. Positive linear or monotonic associations were also found for total and visceral fat mass, although the number of studies was small. Conclusions A higher body mass index was associated with a greater risk of developing type 2 diabetes. A larger waist circumference, independent of overall adiposity, was strongly and linearly associated with the risk of type 2 diabetes. Systematic review registration PROSPERO CRD42021255338.

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Objective Recent studies have shown that increased dietary inflammatory index (DII) score or consumption of pro-inflammatory foods can lead to increased waist circumference (WC) as well as triglyceride (TG) concentrations in obese people. The purpose of this study is to examine the association between DII and hypertriglyceridemic waist circumference phenotype (HTGWCP) in women with overweight and obesity. Results There was a positive significant correlation between DII and HTGWCPs. In other words, with an increase in DII score or higher consumption of pro-inflammatory foods, the odds of having abnormal phenotypes including; enlarged waist normal TG (EWNT) (OR = 2.85, 95% CI 1.02 to 7.98, P for trend = 0.04), normal waist enlarged TG (NWET) (OR = 5.85, 95% CI 1.1 to 31.11, P for trend = 0.03) and enlarged waist enlarged TG (EWET) (OR = 3.13, 95% CI 0.95 to 10.27, P for trend = 0.05) increase compared to normal waist normal TG (NWNT) phenotype. In conclusion; increasing DII scores can increase abnormal phenotypes and therefore may increase WC and TG levels in overweight and obese women.

Background and objective Due to the growing global trend of obesity, it is necessary to study the diet quality as a modifiable factor to reduce the dangerous consequences of obesity. Therefore, the aim of this study was to evaluate the association between meal-based diet quality index-international (DQI-I) with obesity in adults. Methods This cross-sectional study was performed on 850 men and women in Tehran (aged 20–59 y). Dietary intakes were assessed using three 24-h dietary recalls. Meal-based Diet quality was assessed based on the construction of DQI-I. The total DQI-I score ranged from 0 to 100, with higher scores denoting better diet quality. Multiple linear regression analysis was used to examine the association of DQI-I and BMI in each meal and Logistic regression analysis was used to examine the association of DQI-I and obesity in each meal. Results The mean (± SD) of age, body mass index (BMI), waist circumference (WC) and waist to hip ratio (WHR) were 42.35(± 10.90) years, 27.32(± 5.61) kg/m2, 89.09 (± 12.04) cm and 0.86 (± 0.11), respectively. In none of the meals, after adjusting for confounders, no significant difference in BMI was observed in the both women and men groups. After controlling of confounders, there was not any relationship between meal-based DQI-I and BMI resulted from multiple linear regression analysis also there was not any significant association between meal-based DQI-I and obesity resulted from Logistic regression analysis. Conclusion In this study, we did not find any significant association between meal-specified DQI with obesity. To reach the better evaluation, more prospective studies with large sample size are needed.

We aimed to assess the association of the Nordic-style diet score with general and abdominal obesity and metabolic syndrome (MetS) in a population-based cross-sectional study of Iranian adults. Methods: We recruited 843 participants with an age range of 18 to 65 years (mean [SD] age, 44.8 [10.7] years). Dietary intake was assessed by a 168-item semiquantitative food frequency questionnaire. The Nordic-style diet score was calculated by using the median intake of 6 food groups including rye and whole grains, oatmeal, cabbage and vegetables, apples and pears, root vegetables, and fish. The odds ratio (OR) and 95% CI of obesity and MetS across tertiles of the Nordic diet score were calculated by logistic regression analysis with adjustment for age, sex, energy intake, physical activity, smoking status, education, and marital status.Results: A higher score of adherence to the Nordic-style diet score was not associated with general and central adiposity and MetS. With regard to components of the MetS, those in the second tertile of the Nordic-style diet score were at a lower risk of increased serum cholesterol concentration (OR, 0.61; 95% CI, 0.43-0.86; P = .006), and high systolic (OR, 0.65; 95% CI, 0.42-1.00; P = .05) and diastolic (OR, 0.70; 95% CI, 0.46-1.06; P = .09) blood pressure. There was no association between the Nordic-style diet score and other components of the MetS. Conclusion: This study showed that there was no significant relationship between Nordic-style diet score and abdominal and general obesity and MetS. Adopting a Nordic-style diet may be associated with lower serum cholesterol concentration and blood pressure.