Abstract
Introduction:
Excess sodium intake is common across all age, sex, racial, and ethnic groups in the US and remains an important modifiable risk factor for elevated blood pressure (BP), a leading contributor to cardiovascular disease. While multiple 24 -hour urinary measures of sodium excretion are the preferred objective measure of sodium intake, multiple standardized, interviewer-administered 24 hour dietary recalls offer a useful surrogate measure for longitudinal group comparisons, especially unique among US Hispanics/Latinos of diverse backgrounds.
Objectives:
To assess whether dietary sodium intake was associated with change in systolic blood pressure (SBP) over six years, overall and by use of BP lowering medication.
Methods:
The Hispanic Community Health Study/Study of Latinos is an ongoing prospective population-based study of 16,415 diverse Hispanics/Latinos aged 18-74 yr from four US communities. Visit 1 (baseline) was conducted in 2008-2011, and visit 2 is currently ongoing (2014-2017). Dietary sodium intake was averaged from two interviewer-administered 24-hour diet recalls collected at visit 1. Likewise, SBP was the average from three seated measurements in visit 1 and about six years later in visit 2. Change in SBP from visit 1 to visit 2 was calculated. Using linear regression models adjusted for age, sex, study site, follow-up years, Hispanic/Latino background, education, income, nativity, diabetes, chronic kidney disease, dyslipidemia, family history of CVD, BMI, smoking, alcohol use, physical activity, and energy intake, we estimated the association of a 500 mg/day increment of sodium intake on change in SBP. Models were further stratified by self-reported use of BP lowering medication at visit 2.
Results:
The sample includes 7,904 adults who attended visit 2 by September 2016; average follow-up time was 5.8 years (SE: 0.02). At visit 1 mean age was 44.5 years (SE: 0.05); 57% were female (SE: 0.86). Overall, mean sodium intake was 3171 mg/day (SE: 33); a 500 mg/day higher sodium intake was associated with a 0.33 mmHg increase in SBP (95% CI: 0.07, 0.60). Among individuals not reporting taking BP lowering medication, mean sodium was 3,181 (SE: 34) and a 500 mg higher sodium intake was associated with a non-significant 0.29 mmHg increase in SBP (95% CI: -0.00, 0.58). Among individuals on BP lowering medication, mean sodium intake was 2,966 (SE: 50) and a 500 mg higher sodium intake was significantly associated with a 0.61 mmHg increase in SBP (95% CI: 0.11, 1.11).
Conclusions:
Among a large sample of diverse US Hispanics/Latinos, higher sodium intake was associated with small SBP increases in approximately six years. The effect of sodium on elevated SBP was stronger among individuals on BP lowering medications.