Abstract
BACKGROUND: Coenzyme Q10 (CoQ10) is a ubiquitous molecule in living organisms serving as a cofactor in energy production. Epidemiological studies have reported low CoQ10 levels being associated with an increased risk of various cancers. We conducted the first study to evaluate the association of CoQ10 concentrations with lung cancer risk. METHODS: A nested case-control study including 201 lung cancer cases and 395 matched controls from the Southern Community Cohort Study was conducted. Plasma CoQ10 levels were measured using high-performance liquid chromatography with photo-diode array detection. Conditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between plasma CoQ10 levels and lung cancer risk. RESULTS: Plasma CoQ10 concentration was inversely associated with the risk of lung cancer. After adjusting for age, sex, race, and socioeconomic status, the OR (95% CI) comparing the third to first tertile was 0.57 (0.36-0.91, P for trend = 0.02). Further adjustments for smoking, alcohol, chronic obstructive pulmonary disease, and body mass index attenuated the point estimate slightly (OR = 0.60, 95% CI = 0.34-1.08, P for trend = 0.11), comparing third to first tertiles. Stratified analyses identified a significant inverse association between plasma CoQ10 levels and lung cancer risk in current smokers, but not in former/never smokers. The association was more evident in cases who were diagnosed within 1 year of blood draw than in cases diagnosed after 1 year. CONCLUSIONS: Low plasma CoQ10 was significantly associated with increased lung cancer risk, particularly among current smokers. The stronger association seen shortly following the blood draw suggests that CoQ10 may be related to disease progression.