A prospective study of sodium-lithium countertransport and hypertension in Utah.
A 7-year prospective study of a cohort of 1,458 normotensive adults from Utah pedigrees, screened from 1980 to 1985, was done to determine whether baseline levels of sodium-lithium countertransport were associated with an increased risk of future hypertension. Subsequent new hypertension (n = 39) was ascertained in 1989 from detailed follow-up medical questionnaires (67% response). Previous segregation analyses on a subset of these pedigree members who responded (n = 342) using family relationships in addition to countertransport levels have shown statistically inferred major gene segregation of sodium-lithium countertransport levels. In the normotensive adults inferred by segregation analysis to carry the recessive major gene for high sodium-lithium countertransport, new-onset hypertension occurred in 18.8% (3 of 16) compared with 3.7% (12 of 326) in the low sodium-lithium countertransport genotype group (relative risk, 4.6 [1.6, 13.9]; p = 0.03). However, an elevated baseline sodium-lithium countertransport level without genotype information from segregation analysis did not increase the risk of future hypertension in the complete cohort of adult pedigree members (relative risk, 1.02 [0.85, 1.22]). Adjustment for other risk factors reduced the relative risk to 0.90 (0.72, 1.11). We conclude that the presence of a major gene for sodium-lithium countertransport or another closely linked gene, rather than the actual level of sodium-lithium countertransport, may increase the risk of hypertension onset. High sodium-lithium countertransport levels do not increase the risk of future hypertension for individuals in whom only polygenic and environmental effects determine sodium-lithium countertransport level.(ABSTRACT TRUNCATED AT 250 WORDS)
Hunt
S C
SC
Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City.
Stephenson
S H
SH
Hopkins
P N
PN
Hasstedt
S J
SJ
Williams
R R
RR
D000328:Adult; D000368:Aged; D017920:Antiporters; D002352:Carrier Proteins / Q000097:blood; D015331:Cohort Studies; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012964:Sodium / Q000378:metabolism; D014589:Utah
D017920:Antiporters; D002352:Carrier Proteins; C045885:sodium-lithium countertransporter; D012964:Sodium