The influence of smoking and diet on the hypoxanthine phosphoribosyltransferase ( hprt) mutant frequency in circulating T lymphocytes from a normal human population

Abstract

The influence of the dietary antioxidants vitamin C, α- and β-carotene, lycopene, lutein/zeaxanthin, phytofluene, β-cryptoxanthin, retinal and α- and γ-tocopherol on the hypoxanthine phosphoribosyltransferase ( hprt) mutant frequency in human peripheral T lymphocytes was investigated. Twenty-five male non-smokers and 27 male smokers in the age range 50–59 years were recruited. Smokers showed a significantly higher mutant frequency compared with non-smokers (×1.5, P < 0.01). In addition, there was a significant positive relationship between hprt mutant frequency and the number of cigarettes that individuals reported smoking daily ( P < 0.01). Smokers showed significantly lower levels of plasma vitamin C and the carotenoid α-carotene than non-smokers ( P < 0.01 and P < 0.05 respectively). Both hprt mutant frequency and lymphocyte plating efficiency were weakly inversely associated with plasma vitamin C levels ( P < 0.07 and P < 0.06 respectively) suggesting that vitamin C may be protective against mutation at the hprt locus. This relationship was markedly stronger in smokers ( P < 0.01).