High sodium intake and sodium to potassium ratio may be linked to subsequent increase in vascular damage in adults aged 40 years and older: the Korean multi-rural communities cohort (MRCohort)

Abstract

Purpose Subclinical vascular damage is a chronic intermediate process in cardiovascular disease (CVD) and high sodium (Na) has been regarded as an adverse factor in subclinical vascular health; however, the longitudinal relationship between Na intake and subclinical vascular damage has not been studied. We aimed to evaluate the longitudinal relationship of dietary Na intake and sodium to potassium ratio (Na:K) with brachial-ankle pulse wave velocity (baPWV) and carotid intima media thickness (cIMT) in healthy adults aged 40 years and older in Korea.

Methods The present study was based on participants (n=2145 for baPWV analysis and n=2494 for cIMT analysis) who visited three times during 2005–2013 (median 5.3 years of follow-up). We used both dietary Na intake and Na:K at baseline and its average (baseline, 2nd, 3rd), which was obtained from food frequency questionnaire (FFQ) as exposure at every visit. baPWV and cIMT levels at the third visit and change from baseline to the third visit were used to represent the level of subclinical vascular damage.

Results After adjustment for potential confounders, significant positive relationships between dietary Na intake and both baPWV3rd and cIMT3rd were observed (baPWV: p for trend≤0.0001 for Naaverage; cIMT: p for trend=0.013 for Naaverage). Compared with Na:Ks less than 1.0, the levels of both baPWV and cIMT were higher for participants with Na:Ks over 1.0 (baPWV: p for trend=0.0002 for Na:Kaverage; cIMT: p for trend=0.005 for Na:Kaverage). Similar significant trends were shown in relationships between dietary Na intake and Na:K and changes in baPWV and cIMT levels.

Conclusions In conclusion, dietary Na intake and Na:K may be positively linked to subsequent baPWV and cIMT levels in adults aged 40 years and older in Korea. Our findings may provide informative evidence on subclinical vascular damage, particularly for populations with relatively high dietary Na intake and low dietary K intake.