Anthropometric and adiposity indicators and risk of type 2 diabetes: systematic review and dose-response meta-analysis of cohort studies

Abstract

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.

Fig 1

Dose-response association between body mass index and the risk of type 2 diabetes in all studies (P_{non-linearity}=0.06, n=121), healthy adults (P_{non-linearity}=0.57, n=21), men (P_{non-linearity}=0.23, n=46), women (P_{non-linearity}=0.54, n=43), young adults (P_{non-linearity}=0.03, n=6), and older adults (P_{non-linearity}=0.009, n=8). The solid line represents the non-linear dose response and the dotted lines the 95% confidence interval. The circles represent the relative risk point estimates for adiposity categories from each study with the size of the circle proportional to the inverse of the standard error

Fig 2

Dose-response association between body mass index and the risk of type 2 diabetes for all regions and ethnicities

Fig 3

Dose-response association between waist circumference and the risk of type 2 diabetes in all individuals (P_{non-linearity}=0.10, n=43), in studies which controlled for body mass index (P_{non-linearity}=0.95, n=4), in healthy individuals (P_{non-linearity}=0.51, n=8) older adults (P_{non-linearity}=0.46, n=1), men (P_{non-linearity}=0.38, n=22), and women (P_{non-linearity}=0.40, n=21). The solid line represents the non-linear dose-response and the dotted lines the 95% confidence interval. The circles represent the relative risk point estimates for adiposity categories from each study with the size of the circle proportional to the inverse of the standard error

Fig 4

Dose-response association between waist-to-hip ratio and the risk of type 2 diabetes in all individuals (P_{non-linearity}=0.17, n=19), healthy individuals (P_{non-linearity}=0.55, n=4), in studies which controlled for body mass index (P_{non-linearity}=0.40, n=1), in older adults (P_{non-linearity}=0.16, n=2), men (P_{non-linearity}<0.001, n=8), and women (P_{non-linearity}=0.10, n=10), and in the US (P_{non-linearity}=0.52; n=3), Europe (P_{non-linearity}<0.001, n=5), and Asian countries (P_{non-linearity}=0.19, n=11). The solid line represents the non-linear dose-response and the dotted lines the 95% confidence interval. The circles represent the relative risk point estimates for adiposity categories from each study with the size of the circle proportional to the inverse of the standard error

Fig 5

Dose-response association between visceral adiposity index (P_{non-linearity}<0.001, n=5) and the risk of type 2 diabetes. The solid line represents the non-linear dose-response and the dotted lines the 95% confidence interval. The circles represent the relative risk point estimates for adiposity categories from each study with the size of the circle proportional to the inverse of the standard error

Fig 6

Dose-response association between body shape index (P_{non-linearity}=0.05, n=4) and the risk of type 2 diabetes. The solid line represents the non-linear dose-response and the dotted lines the 95% confidence interval. The circles represent the relative risk point estimates for adiposity categories from each study with the size of the circle proportional to the inverse of the standard error