Association of carbohydrate, rice, noodle and bread consumption and atrial fibrillation risk in a Japanese urban population: a prospective cohort study.
Total and simple carbohydrate intakes were associated with increased atrial fibrillation risk in men but not women in a Japanese urban population, while no association was found between staple food consumption and AF risk in either sex.
Key Findings
Results
High total carbohydrate intake was associated with increased atrial fibrillation risk in men.
HR for Q4 vs Q1 was 2.51 (95% CI: 1.06 to 5.96) in men
5229 adult participants were included with a mean age of 56.9 years; 46.5% were men
226 individuals developed AF during 68,668 person-years of follow-up (mean 13.1 years)
Multivariable-adjusted Cox regression models were used after adjusting for confounding factors
No significant association was found in women (HR for Q4 vs Q1: 1.33, 95% CI: 0.27 to 6.65)
Results
High simple carbohydrate intake was associated with increased atrial fibrillation risk in men.
HR for Q4 vs Q1 was 3.29 (95% CI: 1.33 to 8.13) in men for simple carbohydrate intake
The association between simple carbohydrates and AF risk was stronger than the association for total carbohydrates in men
In women, the association for simple carbohydrates was not statistically significant (HR for Q4 vs Q1: 2.75, 95% CI: 0.74 to 10.26)
The paper notes findings imply the association between carbohydrate intake and AF risk is 'influenced by the type of carbohydrates'
Results
Complex carbohydrate intake showed a negative (protective) directional association with AF risk in men, though women's results were inconclusive.
The paper states 'a positive association between high intake of simple carbohydrates and AF risk in men whereas the association was negative for complex carbohydrate intakes'
In women, complex carbohydrate HR for Q4 vs Q1 was 1.04 (95% CI: 0.38 to 2.83), indicating no significant association
The results in the women's group were described as 'inconclusive'
Assessment used Food Frequency Questionnaire data from a population-based prospective cohort study
Results
No significant association was found between staple food consumption (rice, noodles, or bread) and atrial fibrillation risk in either men or women.
Staple foods examined included rice, noodles, and bread
No association was observed in either sex
This finding is notable given that rice is a primary carbohydrate source in the Japanese diet
The study population was a Japanese urban population assessed via Food Frequency Questionnaire
Methods
226 participants developed atrial fibrillation over a mean follow-up of 13.1 years in a cohort of 5229 adults.
Total follow-up was 68,668 person-years
Mean age of participants was 56.9 years
46.5% of participants were men
This was a population-based prospective cohort study of a Japanese urban population
What This Means
This research suggests that eating high amounts of carbohydrates—particularly simple carbohydrates like sugars—may be linked to a higher risk of developing atrial fibrillation (an irregular heart rhythm) in Japanese men. Researchers followed over 5,000 adults in Japan for an average of 13 years and tracked who developed atrial fibrillation, finding that men in the highest quarter of simple carbohydrate consumption had more than three times the risk of AF compared to those in the lowest quarter. In contrast, complex carbohydrates appeared to have the opposite directional relationship in men, and results in women were not statistically significant.
Interestingly, despite rice, noodles, and bread being major carbohydrate sources in the Japanese diet, none of these specific staple foods were individually linked to AF risk in either men or women. This suggests that the overall type and quantity of carbohydrates consumed—rather than any single food—may matter more for heart rhythm health.
This research matters because atrial fibrillation is a common heart condition associated with stroke and other serious complications, and dietary factors that could influence its risk are of broad public health interest. The sex-specific differences found here highlight that the relationship between diet and heart health may differ between men and women, warranting further investigation in diverse populations.
Khairan P, Kato Y, Kokubo Y, Arafa A, Nakao Y, Matsumoto C, et al.. (2026). Association of carbohydrate, rice, noodle and bread consumption and atrial fibrillation risk in a Japanese urban population: a prospective cohort study.. BMJ open. https://doi.org/10.1136/bmjopen-2025-109639