Associations between exploratory dietary patterns and incident type 2 diabetes: a federated meta-analysis of individual participant data from 25 cohort studies.
European journal of nutrition 2022
Jannasch F, Dietrich S, Bishop TRP, Pearce M, Fanidi A, O'Donoghue G, O'Gorman D, Marques-Vidal P, Vollenweider P, Bes-Rastrollo M, Byberg L, Wolk A, Hashemian M, Malekzadeh R, Poustchi H, Luft VC, de Matos SMA, Kim J, Kim MK, Kim Y, Stern D, Lajous M, Magliano DJ, Shaw JE, Akbaraly T, Kivimaki M, Maskarinec G, Le Marchand L, Martínez-González MÁ, Soedamah-Muthu SS, EPIC-InterAct Consortium EPIC-InterAct Consortium, Wareham NJ, Forouhi NG, Schulze MB
PubMed ID : 35641800
In several studies, exploratory dietary patterns (DP), derived by principal component analysis, were inversely or positively associated with incident type 2 diabetes (T2D). However, findings remained study-specific, inconsistent and rarely replicated. This study aimed to investigate the associations between DPs and T2D in multiple cohorts across the world.
This federated meta-analysis of individual participant data was based on 25 prospective cohort studies from 5 continents including a total of 390,664 participants with a follow-up for T2D (3.8-25.0 years). After data harmonization across cohorts we evaluated 15 previously identified T2D-related DPs for association with incident T2D estimating pooled incidence rate ratios (IRR) and confidence intervals (CI) by Piecewise Poisson regression and random-effects meta-analysis.
29,386 participants developed T2D during follow-up. Five DPs, characterized by higher intake of red meat, processed meat, French fries and refined grains, were associated with higher incidence of T2D. The strongest association was observed for a DP comprising these food groups besides others (IRR per 1 SD = 1.104, 95% CI 1.059-1.151). Although heterogeneity was present (I = 85%), IRR exceeded 1 in 18 of the 20 meta-analyzed studies. Original DPs associated with lower T2D risk were not confirmed. Instead, a healthy DP (HDP1) was associated with higher T2D risk (IRR per 1 SD = 1.057, 95% CI 1.027-1.088).
Our findings from various cohorts revealed positive associations for several DPs, characterized by higher intake of red meat, processed meat, French fries and refined grains, adding to the evidence-base that links DPs to higher T2D risk. However, no inverse DP-T2D associations were confirmed.
It is well known that food and nutrition are important for health but there is also ongoing uncertainty on what combinations of foods are better or worse. One way to improve this understanding is to study what is known as a “dietary pattern”.
A dietary pattern is the quantity, variety, and combination of foods and beverages in a diet. For example, the Mediterranean dietary pattern is much talked about. This is based on the diet in countries such as Greece and Italy in the Mediterranean region. There is evidence that when people consume this type of a dietary pattern, that a lower risk of future type 2 diabetes is observed. But such a diet may or may not fit within different cultural and regional patterns of food consumption in a global context. Therefore it is of interest to also study other types of dietary patterns.
Dietary patterns can be based on the foods and beverages consumed in particular places, but it is also possible to generate a list of foods using statistical methods. These are known as “exploratory dietary patterns” but these have been tested much less for a link with type 2 diabetes. Also, the results of such research have not been consistent so there is remaining uncertainty. Therefore we set out to find out the nature of associations between such dietary patterns and risk of developing type 2 diabetes in different world regions.
Our research included extensive data from 25 existing studies in the world, with 400,000 participants in total and among whom nearly 30,000 people developed type 2 diabetes over time. Data were from Europe (Denmark, Finland, France, Germany, Italy, Netherlands, Spain, Sweden, Switzerland, UK), the Americas (Brazil, Mexico, Puerto Rico, USA), Eastern Mediterranean (Iran), and Western Pacific (Australia, South Korea). We standardised the dietary data and then constructed 15 different dietary patterns for all 25 studies in a consistent way.
We found that dietary patterns defined as “healthy” were generally not related to lower risk of type 2 diabetes. In contrast, five “unhealthy” dietary patterns were related to higher risk of type 2 diabetes. These dietary patterns were characterised by higher intakes of red meat, processed meat, French fries, and refined grains.
Using a large number of studies from diverse world regions, we could identify certain combinations of foods to be particularly associated with the future risk of type 2 diabetes.
This research used a novel approach which meant that data could be included from an extensive range of medical research studies from around the world, including many that had existing data but had not been able to analyse and publish the results previously. This was helpful in expanding the research to include varied populations.
Study : EPIC-InterAct