Circulating Carnitine Levels and Breast Cancer: A Matched Case-Control Study
Abstract Background: The existing epidemiologic studies on the association between carnitine and breast cancer development are scarce. This study examined the association between circulating carnitine levels and breast cancer in females.Methods: This 1:1 age-matched case-control study identified 991 female breast cancer cases and 991 female controls without breast cancer. All cases and controls were confirmed with a pathological test. We measured 16 types of whole blood carnitine levels, such as free carnitine (C0) and octadecanoylcarnitine (C18), using targeted metabolomic technology. Results: The average age for cases and controls were 50.0 years (SD: 8.7 years) and 49.5 years (SD: 8.7 years), respectively. After adjusting for covariates, each SD increase in malonylcarnitine (C3DC; OR 0.91; 95% CI 0.83-1.00), decenoylcarnitine (C10:1; OR 0.87; 95% CI 0.79-0.96) and decadienoylcarnitine (C10:2; OR 0.90; 95% CI 0.82-0.99) level was associated with decreased odds of breast cancer. However, higher butyrylcarnitine (C4) levels were associated with increased risk of breast cancer (OR 1.12; 95% CI 1.02-1.23). We observed no relationship between other carnitines with breast cancer. The false discovery rates for C3DC, C4, C10:1 and C10:2 were 0.172, 0.120, 0.064 and 0.139, respectively. Conclusions: Higher levels of C3DC, C10:1, and C10:2 were protective factors for breast cancer, whereas increased C4 levels were a risk factor for breast cancer.