Associations between serum carotenoid levels and the risk of non-Hodgkin lymphoma: a case-control study

Limited studies have investigated the effects of serum carotenoids on the risk of non-Hodgkin lymphoma (NHL), and the findings have been inconclusive. This study aims to assess the association between serum total or specific carotenoid levels and NHL risk. This 1:1 matched, hospital-based case-control study enrolled 512 newly diagnosed (within 1 month) NHL patients and 512 healthy controls who were matched by age (+/- 5 years) and sex in Urumqi, China. Serum carotenoid levels were measured by HPLC. Conditional logistic regression showed that higher serum total carotenoid levels and their subtypes (e.g. alpha-carotene, beta-carotene, beta-cryptoxanthin and lycopene) were dose-dependently associated with decreased NHL risk. The multivariable-adjusted OR and their 95 % CI for NHL risk for quartile 4 (v. quartile 1) were 0 center dot 31 (95 % CI 0 center dot 22, 0 center dot 48; P (for trend) < 0 center dot 001) for total carotenoids, 0 center dot 52 (95 % CI 0 center dot 33, 0 center dot 79; P (for trend): 0 center dot 003) for alpha-carotene, 0 center dot 63 (95 % CI 0 center dot 42, 0 center dot 94; P (for trend): 0 center dot 031) for beta-carotene, 0 center dot 73 (95 % CI 0 center dot 49, 1 center dot 05; P (for trend): 0 center dot 034) for beta-cryptoxanthin and 0 center dot 51 (95 % CI 0 center dot 34, 0 center dot 75; P (for trend): 0 center dot 001) for lycopene. A null association was observed between serum lutein + zeaxanthin and NHL risk (OR 0 center dot 89, 95 % CI 0 center dot 57, 1 center dot 38; P (for trend): 0 center dot 556). Significant interactions were observed after stratifying according to smoking status, and inverse associations were more evident among current smokers than past or never smokers for total carotenoids, alpha-carotene and lycopene (P (for heterogeneity): 0 center dot 047, 0 center dot 042 and 0 center dot 046). This study indicates that higher serum carotenoid levels might be inversely associated with NHL risk, especially among current smokers.