Dietary Sodium Intake and Risk of Incident Type 2 Diabetes

To fill the knowledge gap of the relation between long-term dietary sodium intake and type 2 diabetes (T2D), we evaluate the association between the frequency of adding salt to foods, a surrogate marker for evaluating the long-term sodium intake, and incident T2D risk.

A total of 402,982 participants from UK Biobank (March 13, 2006 - October 10, 2010) who were free of diabetes, chronic kidney disease, cancer, or cardiovascular disease at baseline, and had completed information on adding salt were analyzed in this study.

During a median of 11.9 years of follow-up, 13,120 incident cases of T2D were documented. Compared with participants who "never/rarely" added salt to foods, the adjusted HRs were 1.11 (95% CI, 1.06 to 1.15), 1.18 (95% CI, 1.12 to 1.24), and 1.28 (95% CI, 1.20 to 1.37) across the groups of "sometimes," "usually," and "always," respectively (P-trend<.001). We did not find significant interactions between the frequency of adding salt to foods and baseline hypertension status and other covariates on the risk of incident T2D. The observed positive association was partly mediated by body mass index, waist to hip ratio, and C-reactive protein, with a significant mediation effect of 33.8%, 39.9%, and 8.6%, respectively. The significant mediation effect of body mass index was largely driven by the body fat mass rather than the body fat-free mass.

Our findings for the first time indicate that higher frequency of adding salt to foods, a surrogate marker for a person's long-term salt taste preference and intake, is associated with a higher T2D risk.