Sodium Intake and Proteinuria/Albuminuria in the Population—Observational, Cross-Sectional Study

Abstract

Sodium effects on proteinuria are debated. This observational, cross-sectional, population-based study investigated relationships to proteinuria and albuminuria of sodium intake assessed as urinary sodium/creatinine ratio (NaCR). In 482 men and 454 women aged 35–94 years from the Moli-sani study, data were collected for the following: urinary NaCR (independent variable); urinary total proteins/creatinine ratio (PCR, mg/g), urinary albumin/creatinine ratio (ACR, mg/g), and urinary non-albumin-proteins/creatinine ratio (calculated as PCR minus ACR) (dependent variables). High values were defined as PCR ≥ 150 mg/g, ACR ≥ 30 mg/g, and urinary non-albumin-proteins/creatinine ratio ≥ 120 mg/g. Urinary variables were measured in first-void morning urine. Skewed variables were log-transformed in analyses. The covariates list included sex, age, energy intake, body mass index, waist/hip ratio, estimated urinary creatinine excretion, smoking, systolic pressure, diastolic pressure, diabetes, history of cardiovascular disease, reported treatment with antihypertensive drug, inhibitor or blocker of the renin-angiotensin system, diuretic, and log-transformed data of total physical activity, leisure physical activity, alcohol intake, and urinary ratios of urea nitrogen, potassium, and phosphorus to creatinine. In multivariable linear regression, standardized beta coefficients of urinary NaCR were positive with PCR (women and men = 0.280 and 0.242, 95% confidence interval = 0.17/0.39 and 0.13/0.35, p < 0.001), ACR (0.310 and 0.265, 0.20/0.42 and 0.16/0.38, p < 0.001), and urinary non-albumin-proteins/creatinine ratio (0.247 and 0.209, 0.14/0.36 and 0.09/0.33, p < 0.001). In multivariable logistic regression, higher quintile of urinary NaCR associated with odds ratio of 1.81 for high PCR (1.55/2.12, p < 0.001), 0.51 of 1.62 for high ACR (1.35/1.95, p < 0.001), and of 1.84 for high urinary non-albumin proteins/creatinine ratio (1.58/2.16, p < 0.001). Findings were consistent in subgroups. Data indicate independent positive associations of an index of sodium intake with proteinuria and albuminuria in the population.

Relationship between Ideal Cardiovascular Health and Incident Proteinuria: A 5 Year Retrospective Cohort Study

“…For healthy diet, lower sodium intake was related to a lower risk of proteinuria, whereas the other four components and ideal healthy dietary score did not reduce proteinuria in our study. Higher sodium intake was found to be a risk factor for hypertension and was associated with an increased incidence of proteinuria and CKD progression in previous studies [ 44 , 45 ]. The adverse effect of salt intake on the kidneys may be associated with increased blood pressure and RAAS system dysregulation [ 46 ].…”

Correlates of Calcidiol Deficiency in Adults—Cross-Sectional, Observational, Population-Based Study

“…As shown in Figure S1 of Supplementary Materials , the stratification was designed to have 100 men and 100 women for each one of the following five age-groups: 35–44, 45–54, 55–64, 65–74, and ≥75 years. The additional data collection in this target cohort included the average local solar irradiance in the month preceding the blood withdrawal as objective index of ultraviolet exposure and the measurements by automated biochemistry of serum calcidiol, serum creatinine, urine albumin, urine total protein, and urine markers of diet as reported [ 18 , 19 ]. Serum calcidiol was measured by a chemiluminescent assay (Diasorin, Saluggia, Italy) calibrated with ID-LC-MS- and ID-LC-MS/MS-traceable standard NIST-SRM 972a as per guidelines [ 7 , 8 ].…”

Association of 24-h urinary sodium excretion with microalbuminuria in a Chinese population

“…The 24-h urinary albumin excretion rate is regarded as the gold standard for measuring albuminuria. However, most of the literature has adopted the albumin/creatine ratio as an alternative due to convenience and cost 5,6 .The relationships of sodium and potassium with albuminuria have not been fully elucidated, and findings are not consistent in the literature. Several studies 7,8 have shown that sodium intake is positively correlated with urinary albumin.…”

“…The 24-h urinary albumin excretion rate is regarded as the gold standard for measuring albuminuria. However, most of the literature has adopted the albumin/creatine ratio as an alternative due to convenience and cost 5,6 .…”