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Fatty acid biomarkers of dairy fat consumption and incidence of type 2 diabetes: A pooled analysis of prospective cohort studies
Journal article   Open access   Peer reviewed

Fatty acid biomarkers of dairy fat consumption and incidence of type 2 diabetes: A pooled analysis of prospective cohort studies

Fumiaki Imamura, Amanda Fretts, Matti Marklund, Andres V Ardisson Korat, Wei-Sin Yang, Maria Lankinen, Waqas Qureshi, Catherine Helmer, Tzu-An Chen, Kerry Wong, …
PLoS medicine, Vol.15(10), pp.e1002670-e1002670
10/2018
DOI: 10.1371/journal.pmed.1002670
PMCID: PMC6179183
PMID: 30303968
url
https://doi.org/10.1371/journal.pmed.1002670View
Published (Version of record) Open Access

Abstract

We aimed to investigate prospective associations of circulating or adipose tissue odd-chain fatty acids 15:0 and 17:0 and trans-palmitoleic acid, t16:1n-7, as potential biomarkers of dairy fat intake, with incident type 2 diabetes (T2D). Sixteen prospective cohorts from 12 countries (7 from the United States, 7 from Europe, 1 from Australia, 1 from Taiwan) performed new harmonised individual-level analysis for the prospective associations according to a standardised plan. In total, 63,682 participants with a broad range of baseline ages and BMIs and 15,180 incident cases of T2D over the average of 9 years of follow-up were evaluated. Study-specific results were pooled using inverse-variance-weighted meta-analysis. Prespecified interactions by age, sex, BMI, and race/ethnicity were explored in each cohort and were meta-analysed. Potential heterogeneity by cohort-specific characteristics (regions, lipid compartments used for fatty acid assays) was assessed with metaregression. After adjustment for potential confounders, including measures of adiposity (BMI, waist circumference) and lipogenesis (levels of palmitate, triglycerides), higher levels of 15:0, 17:0, and t16:1n-7 were associated with lower incidence of T2D. In the most adjusted model, the hazard ratio (95% CI) for incident T2D per cohort-specific 10th to 90th percentile range of 15:0 was 0.80 (0.73-0.87); of 17:0, 0.65 (0.59-0.72); of t16:1n7, 0.82 (0.70-0.96); and of their sum, 0.71 (0.63-0.79). In exploratory analyses, similar associations for 15:0, 17:0, and the sum of all three fatty acids were present in both genders but stronger in women than in men (pinteraction < 0.001). Whereas studying associations with biomarkers has several advantages, as limitations, the biomarkers do not distinguish between different food sources of dairy fat (e.g., cheese, yogurt, milk), and residual confounding by unmeasured or imprecisely measured confounders may exist. In a large meta-analysis that pooled the findings from 16 prospective cohort studies, higher levels of 15:0, 17:0, and t16:1n-7 were associated with a lower risk of T2D.
Dairy Products United States - epidemiology Prospective Studies Humans Middle Aged Europe - epidemiology Male Biomarkers - blood Australia - epidemiology Diabetes Mellitus, Type 2 - epidemiology Incidence Diabetes Mellitus, Type 2 - blood Taiwan - epidemiology Dietary Fats - administration & dosage Sex Factors Fatty Acids, Monounsaturated - blood Female Aged Fatty Acids - blood

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