Effects of weight cycling on coronary risk factors

Interest in the health hazards of weight loss and regain (weight cycling) is growing. This study examined the relationship between weight cycling during ages 21 to 35 and changes in coronary risk factors (systolic blood pressure, diastolic blood pressure, total cholesterol, and HDL cholesterol) during ages 35 to 40. We followed up 264 blue-collar workers from the time they were 21 to 40 years of age working for one company. Analysis of covariance was applied including the number of weight cycles during ages 21 to 35 as the independent variable and the changes in coronary risk factors between age 35 and 40 as the dependent variables. The covariates were adjusted for body mass index (BMI) at age 35, increase in BMI between ages 35 and 40, value of coronary disease risk factors at age 35, and smoking status at age 40. The results showed that increase in systolic and diastolic blood pressure was not significantly related to the number of weight cycles. For total and HDL cholesterol, interaction was seen between smoking status and the number of weight cycles, and the effects of weight cycle on cholesterol levels were examined by smoking status. The change in total cholesterol among frequent cyclers was not significantly different from that among non-cyclers. Though the increment of HDL cholesterol in frequent cyclers was significantly larger than that in non-cyclers for non-smokers, an inverse relationship was seen for heavy smokers (not significant). Our results showed the effects of weight cycling on changes in coronary risk factors only for HDL cholesterol based on analysis by smoking status. As the present study was conducted on a small population, interaction between weight cycling and smoking status on HDL cholesterol should be confirmed using a larger population.