Linkage and association of the sodium potassium-adenosine triphosphatase (α2 and β1 genes with respiratory quotient and resting metabolic rate in the Quebec Family Study

The purpose of this study was to examine the relationship between the alpha 2 (exon 1 and exon 21-22 with BglII) and beta 1 (MspI and PvuII) genes of the sodium potassium adenosine triphosphatase and resting metabolic rate (RMR) and respiratory quotient (RQ). The sample included 582 participants from 171 families of the Quebec Family Study. RMR and RQ were adjusted for age, sex, fat mass, and fat free mass. Sib-pair analyses indicated a significant linkage between RQ and the alpha 2 exon 1 marker (P = 0.03) and the alpha(2) exon 21-22 marker (P = 0.02). No linkage was detected between the beta 1 markers and either RMR or RQ, whereas RMR was not linked with the alpha 2 makers. There was a significant interaction (P < 0.0003) between alpha 2 exon 1 carrier status and age group [younger (<45 yr) us. older (greater than or equal to 45 yr) adults] for RQ. The association between carrier status and RQ was significant in younger adults (RQ = 0.76 in carriers us. 0.80 in noncarriers, P < 0.0001) but was not in older adults (RQ = 0.81 in carriers vs. 0.80 in noncarriers). The alpha 2 exon 1 gene accounted for approximately 9.1% and 0.3% of the variance in RQ in younger and older adults, respectively. The results suggest that the sodium potassium adenosine triphosphatase alpha 2 gene may play a role in fuel oxidation, particularly in younger individuals.