U-shaped association between dietary thiamine intake and new-onset diabetes: a nationwide cohort study.

BACKGROUND

The association between dietary thiamine intake and the risk of diabetes remains unknown.

AIM

We aimed to evaluate the relation of dietary thiamine intake with new-onset diabetes and examine possible effect modifiers.

DESIGN

Prospective cohort study.

METHODS

A total of 16 272 participants who were free of diabetes at baseline were enrolled from China Health and Nutrition Survey (CHNS). Dietary nutrients intake information was collected by 3-day dietary recalls in addition to using a 3-day food-weighed method to assess cooking oil and condiment consumption. New-onset diabetes was defined as a fasting blood glucose ≥7.0 mmol/l or a glycated haemoglobin (HbA1c) ≥6.5% (48 mmol/mol) or diagnosed by a physician during the follow-up.

RESULTS

During a median follow-up duration of 9.0 years, new-onset diabetes occurred in 1101 participants. Overall, the association between dietary thiamine intake and new-onset diabetes followed a U-shape (P for non-linearity <0.001). Consistently, when thiamine intake was assessed as quartiles, compared with those in the 2-3 quartiles (0.75 to 1.10 mg/day), the significantly higher risks of new-onset diabetes were found in participants in the first quartile [adjusted hazard ratio (HR), 1.33; 95% confidence interval (CI): 1.10, 1.61] and the fourth quartile (adjusted HR, 1.39; 95% CI: 1.17, 1.67). Similar results were found when further adjusting for the intake of other major nutrients or food groups; or using the propensity score weighting to control the imbalance of covariates.

CONCLUSION

Our results suggested that there was a U-shape association between dietary thiamine intake and new-onset diabetes in general Chinese adults, with a minimal risk at 0.75-1.10 mg/day.