Body mass index and the prevalence of prehypertension and hypertension in a Chinese rural population.

Background: To evaluate the status of overweight and obesity in a Chinese rural adult population and describe relationships between body mass index (BMI) and blood pressure according to JNC-7.
Methods: The study was conducted in 2004-2006, used a multistage cluster sampling method to select a representative sample. A total of 45,925 adults, age 35 years or older, were examined. Height, weight and blood pressure were obtained by trained doctors. Overweight and obesity were defined according to the World Health Organization classification and Chinese definition.
Results: The prevalence of overweight and obesity were 16.3% and 1.3% in males, and 24.4% and 2.7% in females (p for gender differences <0.05) according to the World Health Organization classification; The prevalence of overweight and obesity were 29.5% and 5.3% according to the Chinese definition.The prevalence of elevated blood pressure (prehypertension and hypertension) and mean levels of systolic and diastolic blood pressure increased as BMI increased. Multivariate logistic regression revealed that overweight and obesity were risk factors for prehypertension and hypertension whether in males or females.
Conclusions: Overweight and obesity has become very prevalent in the Chinese rural adult population. It is a great health problem. Our study quantifies the strong associations of BMI and elevated blood pressure. It is time to pay more attention to overweight and obese in the county of China.