Fish consumption and school grades in Swedish adolescents: a study of the large general population

Aim: To study the associations between fish intake and academic achievement as cognitive parameter among Swedish adolescents. Methods: In 2000, a questionnaire including respiratory items, socioeconomic conditions and dietary information was mailed to all schoolchildren (n = 18 158), aged 15 and living in Vastra Gotaland region of Sweden. The questionnaire was returned by 10 837 subjects. One year later, the total school grades for each subject who had completed the questionnaire and who included their full personal identification number were obtained from the national registers. Multiple linear regression models were applied to evaluate the association between fish intake and academic grades among 9448 schoolchildren, while adjusting for potential confounders, e.g. parents' education. Results: Grades were higher in subjects with fish consumption once a week compared with subjects with fish consumption of less than once a week (reference group) [increment in estimate 14.5, 95% confidence interval (CI) 11.8-17.1]. Grades were even higher in subjects with fish consumption of more than once a week compared with the reference group (increment in estimate 19.9, 95% CI 16.5-23.3). In the model stratified for parents' education, there were still higher grades among subjects with frequent fish intake in all educational strata (p < 0.01). Conclusion: Frequent fish intake among schoolchildren may provide benefits in terms of academic achievement.