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Association of Glycaemic Index and Glycaemic Load With Risk of Type 2 Diabetes
abstract
This abstract is available on the publisher's site.
Access this abstract now Full Text Available for ClinicalKey SubscribersBACKGROUND
The association between the glycaemic index and the glycaemic load with type 2 diabetes incidence is controversial. We aimed to evaluate this association in an international cohort with diverse glycaemic index and glycaemic load diets.
METHODS
The PURE study is a prospective cohort study of 127 594 adults aged 35-70 years from 20 high-income, middle-income, and low-income countries. Diet was assessed at baseline using country-specific validated food frequency questionnaires. The glycaemic index and the glycaemic load were estimated on the basis of the intake of seven categories of carbohydrate-containing foods. Participants were categorised into quintiles of glycaemic index and glycaemic load. The primary outcome was incident type 2 diabetes. Multivariable Cox Frailty models with random intercepts for study centre were used to calculate hazard ratios (HRs).
FINDINGS
During a median follow-up of 11.8 years (IQR 9.0-13.0), 7326 (5.7%) incident cases of type 2 diabetes occurred. In multivariable adjusted analyses, a diet with a higher glycaemic index was significantly associated with a higher risk of diabetes (quintile 5 vs quintile 1; HR 1.15 [95% CI 1.03-1.29]). Participants in the highest quintile of the glycaemic load had a higher risk of incident type 2 diabetes compared with those in the lowest quintile (HR 1.21, 95% CI 1.06-1.37). The glycaemic index was more strongly associated with diabetes among individuals with a higher BMI (quintile 5 vs quintile 1; HR 1.23 [95% CI 1.08-1.41]) than those with a lower BMI (quintile 5 vs quintile 1; 1.10 [0.87-1.39]; p interaction=0.030).
INTERPRETATION
Diets with a high glycaemic index and a high glycaemic load were associated with a higher risk of incident type 2 diabetes in a multinational cohort spanning five continents. Our findings suggest that consuming low glycaemic index and low glycaemic load diets might prevent the development of type 2 diabetes.
FUNDING
Full funding sources are listed at the end of the Article.
Additional Info
Disclosure statements are available on the authors' profiles:
Associations of the glycaemic index and the glycaemic load with risk of type 2 diabetes in 127 594 people from 20 countries (PURE): a prospective cohort study
Lancet Diabetes Endocrinol 2024 Apr 05;[EPub Ahead of Print], V Miller, DA Jenkins, M Dehghan, K Srichaikul, S Rangarajan, A Mente, V Mohan, S Swaminathan, R Ismail, M Luz Diaz, RM Ravindran, K Zatonska, A Bahonar, Y Altuntas, R Khatib, P Lopez-Jaramillo, A Yusufali, K Yeates, J Chifamba, R Iqbal, R Yusuf, E Catherina Swart, H Bo, G Han, X Li, KF Alhabib, A Rosengren, A Avezum, F Lanas, S YusufFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Does what you eat increase your risk of diabetes?
This age-old question of “is it nature or nurture?” continues to plague us, especially regarding diseases like diabetes. First, we thought diabetes was due to poor diet. Then we moved to “it’s all genetics” that is driving diabetes. Presently, we are perhaps ending up on a hybrid model where both genetics and lifestyle play an important role in diabetes.
In this paper, the authors wanted to determine whether diet affects the development of diabetes. They used data from the PURE (Prospective Urban and Rural Epidemiology) study to examine the relationship between diet and the development of diabetes. They had data from dietary questionnaires from 127,594 individuals in 20 different countries. None of these individuals had diabetes at the beginning of the trial. The authors also had data on all the cases of diabetes that developed during the study.
Since they were looking for diabetes, it made sense to categorize the foods that the participants ate based on the glycemic index. Foods with a high glycemic index release glucose quickly, thus they increase blood glucose levels rapidly. Therefore, the pancreas would have to work harder to keep the blood glucose levels at an acceptable level. So, the participants’ diets were categorized based on glycemic index.
Another important factor to consider is how much of the high glycemic index food the participants ate. A very small amount of a very high glycemic index food would not cause a huge stress on the pancreas. However, a large amount of that same food would greatly stress the pancreas. Therefore, the glycemic load is also an important consideration. The glycemic load incorporates the glycemic index with the amount that is being eaten.
The participants were divided into five groups (quintiles) going from the lowest to the highest glycemic index and glycemic loads. The authors compared the lowest glycemic index and glycemic load group with the highest group and found a higher incidence of diabetes in the highest group. Therefore, patients eating the highest glycemic index foods and those with the highest glycemic load had the highest risk of diabetes.
When the authors looked at the glycemic index, there was a 15% increase in diabetes in quintile 5 versus quintile 1 (HR, 1.15; 95% CI, 1.03–1.29). When they looked at glycemic load, there was a 21% increase between the highest and the lowest groups (HR, 1.21; 95% CI, 1.06–1.37).
Interestingly, they also categorized the patients based on their body mass index. A stronger association was observed between glycemic index and the risk of developing diabetes among patients with a high BMI compared with those with a lower BMI. For patients with high BMI, there was a 23% statistically significant increase in the risk of developing diabetes. However, for the lower BMI group, the patients with high glycemic index only had a statistically significant 10% increase in the risk of developing diabetes.
So, this means that patients who are obese or have high BMI are more sensitive to the glycemic index. So is it nature or nurture? I think it is both. We have genes that can predispose us to diabetes; then, our lifestyle, in this case, our diet, pushes us over the top.
This should give us great hope because it means that if we eat foods with low glycemic indices and reduce the amount we eat, then maybe we won’t stress out our pancreases, and they can stay functioning much longer. Perhaps we can explain it this way to our patients. It’s like rain; a little rain is good, but a big downpour is not good — the drainage can’t handle it, so it floods. For glucose, a little is great but a lot is not good so let’s be smart about our food choices so that we don’t stress out our pancreas.