Endothelic Nitric Oxide (eNOS) Genetic Variants Associate with Physical Activity Levels among Young Caucasian Adults

Abstract

PURPOSE: Over 50% of adults do not engage in regular physical activity (PA). Genetic factors account for 32-85% of the variation in PA levels, but evidence identifying specific gene variants that influence habitual PA levels is limited. Thus, we examined associations among three genetic variants of the eNOS gene (-786T>C, rs2070744; -922A>G, rs1800779; 894G>T, rs1799983) and PA among healthy, young Caucasian adults. METHODS: Subjects (n=577, age 24.3±8.0yr, body mass index (BMI) 24.3±4.5kg·m-2) were genotyped for eNOS-786 T>C (n=308, TT n=128, TC n=147, CC n=33), -922 A>G (n=368, AA n=145, AG n=183, GG n=42), and 894 G>T (n=393, GG n=195, GT n=165, TT n=33). Subjects completed the Paffenbarger PA Questionnaire. PA phenotypes included; hr/wk spent in light, moderate and vigorous intensity PA, and sitting. Repeated measures ANCOVA tested associations among genetic variants and PA phenotypes by gender with age and BMI as covariates. Associations did not differ by gender so data are presented for the total sample. RESULTS: Adults with the eNOS 894 TT genotype reported less time in vigorous intensity PA than those with the GT and GG genotypes (4.3±1.3, 7.6±0.6, and 8.0±0.6hr/wk, respectively) (p=0.037). Adults with eNOS 894 TT genotype also reported spending more time in light intensity PA than adults with GT and GG genotypes (43.3±2.7, 36.4±1.2, and 34.5±1.1hr/wk, respectively) (p=0.009). In addition, those with eNOS 894 GT and GG genotypes reported to sit more than adults with the TT genotype (48.2±1.4, 45.9±1.3, and 38.3±3.2hr/wk, respectively) (p=0.014). CONCLUSIONS: Adults with the eNOS 894 TT genotype reported more time in light intensity PA, less time in vigorous intensity PA, and less time sitting than carriers of G allele. The vascular effects of regular episodic shear stress differs by PA intensity and may account for these eNOS 894 T>G genotype associations. However, our findings should be replicated in a prospective study designed to investigate the direct impact of PA on vascular function to determine if these suppositions are true. Supported by NIH-NINDS R01 NS40606-02 and the University of Connecticut. Center for Health, Intervention and Prevention.