Body mass index as a moderator of the relationship between chronic disease and health-related quality of life

Objective To examine the function of body mass index（BMI）as a moderator reflecting the relationship between chronic disease and health-related quality of life（HRQOL）. Methods This study included 8 314 participants pooled from a general population-based cross-sectional survey that had been conducted in Beijing and 8 provinces of China（Jiangsu,Anhui,Gansu, Qinghai,Fujian,Jilin,Jiangxi,and Henan）. Hierarchical multiple regression was emplayed to test the moderating effect. Results In physical component summary of SF-36,the regression coefficient of interaction on chronic disease and BMI was not significantly different（β=0.084,P=0.142）,while the new ΔR2 was not significantly different （ΔR2=0.000,P=0.142） either. In mental component summary of SF-36,the interaction on chronic disease and BMI was significantly different（β=0.132, P=0.034）,so as the new ΔR2（ΔR2=0.001,P=0.034）. Compared to the standard regression coefficient,chronic disease had a greater negative impact on HRQOL than BMI on both physical and mental component summaries. Conclusion Our results indicated that BMI could moderate the association between chronic disease and HRQOL. The higher the BMI,the smaller negative impact of chronic disease on HRQOL in mental component summary was seen. Key words: Body mass index;  Noninfectious chronic disease;  Health-related quality of life; Moderating effect