Objective: To study the relationship between body mass index (BMI) and major cardiovascular diseases (CVD) in Chinese population and explore an optimal range of BMI among adult Chinese in terms of prevention of CVD.
Methods: Relevant data of 881 498 Chinese persons aged 18 and over in the Third National Sampling Survey on Hypertension held in 1991 were collected. The distribution of body weight and height and the relationship between BMI and prevalence of CVD were analyzed.
Results: The average BMI was 21.7 kg/m(2) +/- 3.1 kg/m(2), 21.5 kg/m(2) +/- 2.9 kg/m(2),and 21.8 kg/m(2) +/- 3.3 kg/m(2) for the whole surveyed adults, the males and females respectively. The BMI was on the upward trend along with the age, reached the peak at the age 45 approximately 54, and then on a downward trend. The mean BMI was 22.4 kg/m(2) +/- 3.3 kg/m(2) for the northern population, 21.5 kg/m(2) +/- 3.0 kg/m(2) for the western population, and 21.1 kg/m(2) +/- 2.9 kg/m(2) for the southern population with a significantly difference between any two groups (all P < 0.01). The higher the mean BMI, the greater the prevalence of hypertension, myocardial infarction and stroke. The odds ratios for hypertension, myocardial infarction and stroke among those with the BMI >/= 25.0 approximately < 28 kg/m(2) were 2.8, 3.1, and 2.6 respectively, and were 4.8, 4.0, and 2.9 respectively among those with the BMI >/= 28 kg/m(2) (all P < 0.01) in comparison with the values among those with the BMI < 25.0 kg/m(2) after adjustment for age, and smoking and drinking habits using multivariate Logistic regression model. The odds ratio for clustering of >/= 2 kinds of diseases was 2.9 approximately 4.9 among those with the BMI >/= 25 approximately < 28 kg/m(2) and 3.4 approximately 8.9 among those with the BMI >/= 28 (P < 0.01 in comparison with that among those with the BMI < 25 kg/m(2)). The risks of myocardial infarction and hypertension by BMI were greater than the risk of stroke.
Conclusion: BMI less than 25 kg/m(2) is considered as an optimal range among Chinese adults. The BMI values of 25 kg/m(2) and 28 kg/m(2) can be recommended as thresholds of overweight and obesity for Chinese adults aged >/=18 respectively.