Habitual fish consumption and glycated haemoglobin: The EPIC-Norfolk Study

Objective: To investigate the association between habitual fish consumption and a continuous measure of glycaemia. Design: Cross-sectional study. Setting: EPIC-Norfolk, a population-based cohort study of diet and chronic disease. Subjects and methods: In all, 4500 men and 5509 women, aged 40-78 y, without self-reported diabetes. Diet was assessed by a semiquantitative food frequency questionnaire, and glycaemia was measured by glycated haemoglobin. Results: In women only, in analyses adjusted for age, the HbA1c level was positively associated with eating fried fish and inversely associated with eating oily fish (b=0.036, 95% confidence interval (CI): 0.0033, 0.069; and b=-0.046, 95% CI:-0.086, -0.0064 respectively). These associations were attenuated by adjustment for family history of diabetes, smoking status and physical activity level, but the association with fried fish remained statistically significant (b=0.033, 95% CI: 0.00056, 0.066). Adjusting for total energy, alcohol, fruit and vegetable intakes resulted in further attenuation and both associations were no longer statistically significant. In men, there was no evidence that HbA1c level was associated with fish consumption. Conclusions: The study found no evidence of an association between fish consumption and HbA1c after taking other lifestyle factors into account.