Diet quality indices and the risk of type 2 diabetes in the Tehran Lipid and Glucose Study

INTRODUCTION: The aim of this study was to assess the prospective association between diet quality and risk of type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS: Eligible adults (n=7268) were selected from among participants of the Tehran Lipid and Glucose Study with an average follow-up of 6.6 years. Dietary intakes were assessed using a valid and reliable semiquantitative Food Frequency Questionnaire. Anthropometrics and biochemical variables were evaluated at baseline and follow-up examinations. Dietary pattern scores were calculated for the Healthy Eating Index 2015, Mediterranean diet and the Dietary Approaches to Stop Hypertension diet. Multivariate Cox proportional hazards regression models were used to estimate the development of T2D in relation to diet quality. RESULTS: This study was conducted on 3265 men and 4003 women aged 42.4±14.6 and 40.6±13.5 years, respectively. After adjustment for potential confounders, all three diet quality scores were not associated with risk of T2D. Among individual components of the examined dietary patterns, risk of T2D increased from quartiles 1 to 4 for sodium intake (HR (95% CI) 1.00, 0.97 (0.75 to 1.25), 1.17 (0.92 to 1.49), 1.28 (1.01 to 1.62), P(trend)<0.01) and decreased from quartiles 1 to 4 for red meat intake (HR (95% CI) 1.00, 0.91 (0.72 to 1.14), 0.75 (0.58 to 0.95), 0.85 (0.67 to 1.08), P(trend)<0.01). CONCLUSION: This study emphasizes a potentially protective relationship of moderate red meat intake against development of T2D; also higher intake of sodium is related to risk of T2D.