Context: Bitter sensitivity varies among individuals and ethnic groups partly due to polymorphisms in taste receptor genes (TAS2Rs). Although previous psychophysical studies suggest that taste status plays a role in nicotine dependence (ND), genetic evidence is lacking.
Objectives: To determine whether single nucleotide polymorphisms (SNPs) in TAS2R16 and TAS2R38 are associated with ND and if the effects differ by sex and ethnicity.
Design, setting, and participants: 2037 individuals from 602 nuclear families of African American (AA) or European American (EA) origin were recruited from the US mid-south states during 1999-2004.
Main outcome measures: ND was assessed by three measures: indexed Smoking Quantity (SQ), Heaviness of Smoking Index (HSI), and the Fagerström Test for Nicotine Dependence (FTND). Peripheral blood samples were obtained for DNA extraction and genotyping.
Results: The TAS2R38 taster haplotype PAV was inversely associated (p = 0.0165), and the non-taster haplotype AVI was positively associated (p = 0.0120), with SQ in AA smokers. The non-taster haplotype was positively associated with all ND measures in AA female smokers (p = 0.01 approximately 0.003). No significant associations were observed in the EA sample.
Conclusions: TAS2R38 polymorphisms are an important factor in determining ND in AAs. Heightened oral sensitivity confers protection against ND. Conversely, decreased sensitivity represents a risk factor for ND, especially in AA females. Together, our findings suggest that taster status plays a role in governing the development of ND and may represent a way to identify individuals at risk for developing ND, particularly in AA smokers.