Relationship between ethanol consumption and TBL2 rs17145738 on LDL-C concentration in Japanese adults: a four season 3-day weighed diet record study

BACKGROUND: LDL cholesterol (LDL-C) concentration is modified by dietary and genetic factors; however, little is known about the details of this relationship. Our aim was to investigate the associations taking into account dietary assessment methods, seasonal effects and missing values. METHODS: Study subjects completed food frequency questionnaires (FFQ) and supplied 3-day weighed dietary records (WDRs) and blood samples in four seasons. Approximately 660,000 single nucleotide polymorphisms (SNPs) were measured. Candidate SNPs related to LDL-C concentration were systematically selected. Multiple imputation was applied for missing values. A total of 312 repeated measures data were used for analyses. After adjusting for season and subjects as fixed and random effects, effects of nutrient intake and SNPs on LDL-C concentration were assessed according to three dietary assessment methods: the FFQ and first and four season 3-day WDRs (4 s-3d WDRs). RESULTS: For LDL-C concentration, ethanol consumption derived from all three dietary assessment methods was consistently associated (P < 0.09 for all). Positive and negative relationships were consistently shown with rs651007 and rs1160985 in the first and four seasons; but the latter remained after adjusting for total dietary fiber intake derived from the FFQ and 4 s-3d WDRs (P < 0.05, excepting the first 3-day WDRs). rs599839 was negatively associated after cholesterol intakes derived from the first and 4 s-3d WDRs were considered (P < 0.05 and 0.07, respectively). Each rs17145738 and ethanol consumption based on the 4 s-3d WDRs was related to LDL-C concentration (P < 0.05). Seasonal variations of LDL-C concentration were observed only in summer. CONCLUSIONS: In contrast to nutrient intake, ethanol consumption was shown to be comprehensively related to LDL-C concentration, regardless of dietary assessment methods. Taking into account seasonal effects, critical relationships with LDL-C concentration for some SNPs, after adjustment for specific nutrients, were revealed. Our findings can be used to help to interpret the relationships between dietary and genetic factors on LDL-C concentration in large-scale epidemiological studies. (10/10 keywords)