OBJECTIVETo investigate the effects of rs10916581, a common single nucleotide polymorphism (SNP) located in the promoter region of pre-miR-320b-2, on coronary heart disease (CHD) risk and circulating microRNA-320b (miR-320b) level. To explore potential factors influencing circulating miR-320b level.

METHODSRs10916581 was genotyped in a case-control study with 1 507 CHD cases and 1 379 age- and sex-frequency-matched controls. The cases were consecutively recruited from 3 hospitals (Tongji Hospital, Union Hospital, and Wugang Hospital) in Wuhan city (Hubei, China) between May 2004 and October 2009 and all the controls resided in Wuhan communities. A subgroup of 174 CHD cases and 181 non-diabetes controls without acute infection were randomly selected and their circulating miR-320b levels were detected using quantitative reverse transcriptase polymerase chain reaction assays. The association of rs10916581 with CHD susceptibility was analyzed with multivariable logistic regression model. Generalized linear regression model was used to explore the associations of rs10916581 and some other factors with circulating miR-320b level.

RESULTSIn single-factor logistic regression analysis, no association was found between rs10916581 and CHD risk. After adjustment for age, sex, BMI, smoking status, hypertension, diabetes, total triglyceride, total cholesterol/high density lipoprotein (TC/HDL-C), the result did not materially alter(compared with CC genotype, the OR (95%CI) of CHR in the subjects carried CT, TT, CT+TT genotypes were 0.94 (0.76-1.15), 0.99 (0.74-1.33) and 0.95 (0.78-1.16) ). No significant interactions were observed between the conventional risk factors of CHD (age, gender, smoking status, BMI, hypertension, diabetes, CHD family history) and rs10916581 on CHD risk (P > 0.05). Rs10916581 showed no significant association with circulating miR-320b level in cases, controls or total population (β(95%CI) was -0.028 (-0.495-0.440), 0.250 (-0.226-0.727) and 0.134 (-0.218-0.486) respectively, P > 0.05). However, circulating miR-320b level was negatively associated with BMI (β (95%CI) was -0.140 (-0.261--0.020), P = 0.022) while positively associated with TC/HDL(β (95%CI) was 0.620 (0.261-0.979), P = 0.001) in cases, and in total population, its circulating level tended to be lower in diabetes or hypertension patients (β(95%CI) was -1.025 (-1.696--0.354) and -0.594 (-1.138--0.049) respectively, P = 0.003, 0.033 respectively) and was positively associated with TC/HDL-C (β(95%CI) was 0.108 (0.027-0.190), P = 0.009).

CONCLUSIONThe common SNP (rs10916581) in the promoter region of pre-miR-320b-2 might have little contribution to the CHD predisposition in Chinese Han population, and it might not affect circulating miR-320b level. Conventional CHD risk factors (BMI, TC/HDL-C, hypertension and diabetes) might have effects on its circulating level.