Familial correlations from genes and shared environment for urine, plasma, and intraerythrocytic sodium

Abstract

Spouse-spouse, sib-sib, and parent-offspring correlations were calculated for urinary, plasma, and intracellular sodium levels on over 1,900 persons aged 3-86 years in 98 Utah kindreds. For 36 hours prior to their clinic visit, 31% of the sample was salt-loaded with salt tablets, while the rest followed their normal diet. For those on their normal diet, urine creatine-, age-, and sex-adjusted urinary sodium excretion from a timed 12-hour overnight sample showed similar and significant correlations between spouses (r = .29), sibs less than 20 years old (r = .38), and parent-offspring pairs for offspring less than 20 years old (r = .29). This contrasted with the lower correlations between sibs 20 years of age and older (r = .10) and parent-offspring pairs for offspring 20 years of age and older (r = .13), presumed to live in different households. Adult plasma sodium sib-sib (r = .13) and parent-offspring (r = .15) correlations were similar to the urinary sodium correlations, while the spouse-spouse (r = .48), the sib-sib (r = .64), and the parent-offspring (r = .63) correlations for those presumed to live in the same household nearly doubled. Intracellular sodium correlations for the adult sibs (r = .32) and offspring (r = .36) were over twice as large as for urinary or plasma sodium, although the spouse-spouse correlation (r = .37) remained large also.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic studies of cation tests and hypertension.

“…All values had been adjusted for potential confounders such as body size, anthropometries, and urinary creatinine excretion before correlation analyses were performed. 34 As shown in Table 2, similar low-level correlations were observed for urinary sodium in spouses and siblings living together, and less for siblings living apart. This suggests that environmental factors rather than genes play the prominent role in the familial correlations for urinary sodium.…”

Predictors of an increased risk of future hypertension in Utah. A screening analysis.

“…10 We have also provided some evidence that intracellular sodium is genetically controlled. 34 - 35 However, in this study we could find no indication of a prospective relation to hypertension.…”