Genetic variants in the PKD1L2/BCO1 region are associated with β-carotene, lutein, and zeaxanthin: A genome-wide association study of plasma carotenoids

Abstract

Carotenoid consumption has been associated with a reduced risk of several chronic diseases. Inter-individual genetic variation may explain some of the observed differences in plasma carotenoid concentrations between individuals. Identifying genetic variants associated with circulating carotenoids in young adults may help identify individuals at increased risk for developing conditions associated with low carotenoids later in life. We hypothesize that common genetic variants are associated with circulating carotenoid concentrations in a population of young adults. A genome-wide association study (GWAS) on plasma carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, and zeaxanthin) was conducted in Caucasians (n = 393) from the Toronto Nutrigenomics and Health Study. Replication cohorts included individuals of Caucasian (n = 193), East Asian (n = 436) and South Asian (n = 135) ethnicity. Linear regression adjusted for age, sex, BMI, total serum cholesterol, dietary carotenoid intake and population structure were used to identify associations between genetic variants and plasma carotenoids. Associations that met the threshold for genome-wide significance (p < 5 × 10^-8) in unadjusted and partially adjusted models were not observed in the replication cohorts. No variants achieved genome-wide significance in fully adjusted models. Previously identified associations between variation in the PKD1L2/BCO1 region and β-carotene, lutein and zeaxanthin were replicated in the GWAS cohort (p < .05). Established variation in the PKD1L2/BCO1 region is associated with plasma carotenoids. These variants may help to identify individuals who require greater amounts of these antioxidants and to provide precision nutrition recommendations for optimal intake of various carotenoids.