Abstract
Objective To explore the relationship between body mass index (BMI) and blood uric acid (SUA) level in a Chinese female population.
Methods Between 2004 and 2014, we used a stratified random cluster sampling method to select a general population aged 20–80 years living in the coastal areas of Shandong Province as a research sample. According to the geographical area (Yantai, Qingdao, Weihai, Rizhao, Dongying), the degree of urbanization (city, county and township) and the state of economic development, the selected samples and the sampling process were stratified. During the sampling process, a total of 8123 women were invited and eventually completed the survey. In the process of selecting volunteers, we excluded those taking diuretic drugs and those with hyperuricemia or hypouricemia. We also excluded individuals with malignant tumors, acute infectious diseases, acute inflammatory diseases and renal insufficiency. All participants underwent a standard 75 g, 2 hour oral glucose tolerance test (OGTT) and those with abnormal indicators and participants taking hypoglycemic agents were excluded. Finally, subjects who met the criteria were given venous blood in the early morning at least 12 hours after fasting and forbidden to drink water. The required biochemical indicators were measured by an automatic biochemical analyzer and the BMI was measured by measuring the participant’s height and weight. The study was approved by the Ethics Committee of the Affiliated Hospital of Qingdao University. Statistical analyses were performed using Empowerstats software. Statistical significance was set at p<0.05. Baseline characteristics were presented as mean±SD or median (interquartile range) stratified by gender; t-tests (for normal distributions), the Kruskal-Wallis test (for non-normal distributions), and the chi-square test were used for comparison of statistical significance. The association of SUA with BMI was evaluated by linear or multivariate linear regression stratified by gender. To reveal the exact relationship between these two factors clearly, the stratified analysis, interaction test, saturation effect analysis and curve fitting were performed using EmpowerStats statistical software. Before these, covariate screening was also performed. Interaction effect was also tested to find if any other values influenced the relationship between SUA and BMI.
Results The relationship between BMI and SUA in Chinese women is not a simple linear relationship, but a U-shaped curve. When BMI decreases, the SUA content increases. As the BMI increases, the amount of SUA decreases. When the inflection point is reached, the SUA content increases with the increase in BMI.