Data_Sheet_1_Associations between dietary copper intake, general obesity and abdominal obesity risk: A nationwide cohort study in China.docx

ObjectiveCopper plays a crucial role in redox reactions. The aims of this research are to examine the effects of copper consumption on general obesity and abdominal obesity risk.
MethodsOverall, data of 13,282 participants were obtained from the China Health and Nutrition Survey (1997–2011). A combination of individual 24-h recall and household survey was used to assess dietary intake. Time-dependent mixed effect Cox regression model treating family as a random effect were used to assess the associations between quintiles of copper intake, general obesity and abdominal obesity risk. Obesity was defined by BMI ≥ 28 kg/m2, and abdominal obesity was defined as waist circumference ≥85 cm in men and ≥80 cm in women.
ResultsDuring follow-up, 1,073 and 4,583 incident cases of general obesity and abdominal obesity occurred respectively. There were U-shaped associations of dietary copper intakes with general obesity and abdominal obesity (P for nonlinearity <0.001). In the general obesity track, compared with quintile 3 (reference category), participants in the top quintile and bottom quintile showed higher general obesity risk (HR, 2.00; 95%CI: 1.63, 2.45 for the top quintile, HR, 1.34; 95%CI: 1.08, 1.68 for the bottom quintile). In the abdominal obesity track, compared with quintile 3, the top quintile and bottom quintile were also associated with a significantly increased risk of abdominal obesity (HR, 1.68; 95%CI: 1.52, 1.87 for the top quintile, HR, 1.36; 95%CI: 1.22, 1.52 for the bottom quintile).
ConclusionsWe demonstrated U-shaped associations between dietary copper, general and abdominal obesity risk in Chinese and emphasized the importance of maintaining appropriate copper intake level for the prevention of obesity.