Comparative studies of diet-related factors and blood pressure among Chinese and Japanese: results from the China-Japan Cooperative Research of the WHO-CARDIAC Study. Cardiovascular Disease and Alimentary Comparison.

We aimed to compare the differences in diet-related factors and their associations with blood pressure (BP) between Chinese and Japanese. A total of 1,151 Chinese (M/F: 551/600) and 1,681 Japanese (782/899), aged 48-56 years, were studied using a multi-center cross-sectional study design. This work was a constituent part of the World Health Organization (WHO) Cardiovascular Disease and Alimentary Comparison (CARDIAC) Study. Measurements included in the present report were BP, body mass index (BMI), serum total cholesterol (TC), 24-h urinary sodium, potassium, calcium, magnesium, creatinine, 3-Methylhistidine (3MH, a marker of animal protein intake) and taurine (a marker of seafood intake) excretion levels. Results were as follows: (a) Japanese men had a significantly higher prevalence of hypertension than the Chinese (34.4% vs. 20.5%, p<0.01). After adjustment for age, Japanese men had a significantly higher mean systolic and diastolic BP (SBP, DBP), and Japanese women had a significantly higher DBP than the Chinese subjects overall (p<0.01, respectively). (b) Japanese had significantly higher mean BMI, TC and sodium excretion, and lower mean magnesium excretion than Chinese (p<0.01). (c) In the Japanese sample, multiple linear regression analyses (using a stepwise procedure) showed that SBP had a significant positive association with BMI and sodium excretion, and a significant negative association with magnesium excretion, while DBP had a significant positive association with BMI and a significant negative association with the 3MH to creatinine ratio (3MH/Cre). In the Chinese sample, both SBP and DBP showed a significant positive association with BMI and sodium, and a significant negative association with 3MH/Cre. In conclusion, Japanese had significantly higher mean BP than Chinese. The differences in BP may have been partly attributable to differences in various diet-related factors, particularly in BMI, sodium, magnesium-rich foods and animal protein intake, between the two populations.