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Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes : Assessment of Causal Relations

Livesey, Geoffrey; Taylor, Richard; Livesey, Helen F.; Buyken, Anette E.; Jenkins, David J.A.; Augustin, Livia S.A.; Sievenpiper, John L.; Barclay, Alan W.; Liu, Simin and Wolever, Thomas M.S., et al. (2019) In Nutrients 11(6).
Abstract

While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence,... (More)

While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.

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@article{da273550-beee-4422-90ac-a12f442537a4,
  abstract     = {<p>While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.</p>},
  articleno    = {1436},
  author       = {Livesey, Geoffrey and Taylor, Richard and Livesey, Helen F. and Buyken, Anette E. and Jenkins, David J.A. and Augustin, Livia S.A. and Sievenpiper, John L. and Barclay, Alan W. and Liu, Simin and Wolever, Thomas M.S. and Willett, Walter C. and Brighenti, Furio and Salas-Salvadó, Jordi and Björck, Inger and Rizkalla, Salwa W. and Riccardi, Gabriele and Vecchia, Carlo La and Ceriello, Antonio and Trichopoulou, Antonia and Poli, Andrea and Astrup, Arne and Kendall, Cyril W.C. and Ha, Marie Ann and Baer-Sinnott, Sara and Brand-Miller, Jennie C.},
  issn         = {2072-6643},
  keyword      = {alcohol,causation,cohort studies,diabetes,dietary fiber,epidemiology,glycemic index,glycemic load,meta-analysis,public health},
  language     = {eng},
  month        = {06},
  number       = {6},
  publisher    = {MDPI AG},
  series       = {Nutrients},
  title        = {Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes : Assessment of Causal Relations},
  url          = {http://dx.doi.org/10.3390/nu11061436},
  volume       = {11},
  year         = {2019},
}