Diet-related factors, educational levels and blood pressure in a Chinese population sample: findings from the Japan-China Cooperative Research Project.

As part of the Japan-China Cooperative Research Project of the WHO-Cardiovascular Disease and Alimentary Comparison Study, a cross-sectional study was carried out to investigate risk factors for high blood pressure (BP) in male adults in Chongqing, China. Subjects with hypertension (HT) were defined as those if they had systolic BP (SBP) > or = 140 mmHg or diastolic BP (DBP) > or = 90 mmHg or if they were receiving anti-hypertensive drug therapy. Subjects were also categorized into three groups according to their level of education, i.e., low- (< or = 6 years), intermediate- (7-9 years), or high- (> or = 10 years) level education. The results were as follows. (a) 20.3% of subjects had HT, 16.7% had hypercholesterolemia (serum total cholesterol > or = 220 mg/dl), and 23.4% were overweight (body mass index > or = 25 kg/m2). (b) After adjustment for age, SBP and DBP showed a significant positive association with body mass index, urinary sodium (Na) excretion, and total cholesterol (TC) to high-density lipoprotein (HDL) cholesterol ratio (TC/HDL). SBP and DBP tended to be negatively associated with 24 h urinary potassium (K) and magnesium (Mg) excretion. (c) Subjects with the highest educational level had the lowest prevalence of HT (11.6%), followed by those with the low (22.6%) and the intermediate (25.0%) educational levels (p<0.05). (d) Logistic regression analysis indicated that the relative risks (95%CI) of being overweight, high TC/HDL ratio, high Na excretion and lower educational level (<10 years) for risk of HT were 5.39 (2.42-11.98), 1.73 (1.13-2.63), 1.30 (1.06-1.58), and 2.56 (1.41-6.71) respectively. (e) Subjects with the highest educational level had significantly lower Na, significantly lower Na/K ratio excretion, and significantly higher K and Mg excretion values than those with intermediate or low educational levels. In conclusion, BP was strongly associated with BMI, salt intake and other diet-related factors in the study sample. The results emphasize that education plays an important role in public health for the control of high BP in the Chinese population.