Abstract P221: Relationship of Dietary Carbohydrate and Fiber Intake to Risk of Cardiovascular Disease Mortality in Japanese: NIPPON DATA80
Authors: Miyazawa Itsuko , Miura Katsuyuki , Miyagawa Naoko , Kondo Keiko , Kadota Aya , Okuda Nagako , Fujiyoshi Akira , Chihara Izumi , Nakamura Yoshikazu , Hozawa Atsushi , Kita Yoshikuni , Yoshita Katsushi , Okamura Tomonori , Okayama Akira , Ueshima Hirotsugu 
Published: July 2021

Aims:
The association between carbohydrate intake and cardiovascular disease (CVD) risk has been investigated; however, it remains unclear. Carbohydrate quality is considered to be more important than its amount. Carbohydrate consists of fiber and available carbohydrate which includes starch and sugar. The aim of this study was to examine the relationship of each of carbohydrate, available carbohydrate, starch and fiber intake to the long-term CVD mortality risk in Japanese population. We also examined the relationship of the ratios of carbohydrate, available carbohydrate or starch-to-fiber to CVD risk.

Methods:
We prospectively followed 8,925 participants (3,916 men and 5,009 women) aged 30-79 years without CVD who participated in the National Nutrition Survey in 1980 from 300 randomly selected areas in Japan. The participants were followed for 24 years. To identify the cause of death, the National Vital Statistics database of Japan was used. Food intake survey using weighed food records over three days in each household was conducted. The nutrient intake reported for each household was proportionally allocated to each household member according to the mean consumption rate by age and sex in 1995. Ratios of carbohydrate, available carbohydrate or starch intake (g/day) divided by dietary fiber intake (g/day) were also calculated. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) for CVD mortality by sex-specific quartiles of fiber (g/1000kcal), carbohydrate (%kcal), available carbohydrate (%kcal), starch (%kcal) and their ratios. HRs were adjusted for age, sex, lifestyle factors (smoking status, drinking status, BMI, medication of hypertension, past history of diabetes mellitus), and dietary factors (intakes of sodium, saturated fatty acids and long-chain n-3 polyunsaturated fatty acids).

Results:
During 24-years of follow up, 823 CVD deaths were observed (419 men and 404 women). Adjusted HR for CVD mortality was lower in the highest quartile (Q4) of fiber intake (0.71, 95%CI: 0.57-0.89,
P
-trend 0.003) compared with the lowest (Q1). However, carbohydrate, available carbohydrate and starch intake were not associated with CVD mortality (Adjusted HR for Q4 compared with Q1: 1.00, 95%CI: 0.76-1.32,
P
-trend 0.875; 1.07, 0.82-1.40, 0.757; 0.92, 0.71-1.20, 0.619; respectively). The ratios of carbohydrate, available carbohydrate or starch-to-fiber were all positively associated with CVD mortality (Adjusted HR for Q4 compared with Q1: 1.40, 95%CI: 1.13-1.73,
P
-trend 0.003; 1.33, 1.08-1.64, 0.006; 1.23, 0.99-1.52, 0.032; respectively).

Conclusions:
Dietary fiber intake was inversely related to long-term CVD mortality risk in Japanese. The ratios of carbohydrate, available carbohydrate or starch-to-fiber were positively associated with long-term CVD mortality risk; they might be useful indexes to predict future CVD risk.