Association of Dietary Carbohydrate Intake with Changes in Cardiometabolic Risk Markers During Breast Cancer Treatment: A Prospective Cohort Study

Abstract Background Cardiovascular disease is the leading cause of death among breast cancer survivors, and chemotherapy is associated with adverse metabolic changes. Whether dietary carbohydrate intake during treatment independently tracks with cardiovascular risk factor changes remains unknown. Methods In this prospective cohort study, 100 women with histologically confirmed breast cancer were recruited before initiating chemotherapy and followed for six months. Dietary carbohydrate intake was assessed using nine 24-hour dietary records collected throughout treatment. Anthropometric, lipid, glycemic, and hepatic markers were measured at baseline and at six months. Linear regression models were used to examine associations between carbohydrate intake (% of total energy) and study outcomes. Model 1 used change scores (follow-up minus baseline) as the dependent variables, whereas Model 2 used follow-up values as the dependent variables and adjusted for age, tumor stage, physical activity, baseline BMI, and the corresponding baseline outcome value. Results Mean carbohydrate intake was 47 ± 4.71% of total energy. In the adjusted model, higher carbohydrate intake was independently associated with greater increases in waist circumference (β = 0.123, P = 0.015), fat mass (β = 0.153, P = 0.015), visceral adiposity index (β = 0.053, P = 0.014), triglycerides (β = 0.637, P = 0.010), fasting insulin (β = 0.127, P = 0.014), and AST (β = 0.393, P = 0.001). Associations with LDL-cholesterol, HDL-cholesterol, blood pressure, fasting blood glucose, HbA1c, HOMA-IR, and ALT were not statistically significant. Conclusion Dietary carbohydrate intake during chemotherapy was independently associated with unfavorable anthropometric, lipid, glycemic, and hepatic changes in women with breast cancer. These findings suggest that dietary carbohydrate intake may be relevant to cardiometabolic health during breast cancer treatment and warrants further investigation.