Beyond the Average: Trends in Extreme Sodium Intake in the U.S. Population, 2003-2018

Excessive sodium consumption is a major contributor to hypertension and cardiovascular disease (CVD), yet most nutrition surveillance systems focus primarily on average intake measurements, neglecting patterns of extreme sodium consumption. Public health strategies need to consider how high sodium intake patterns evolve across the entire population over time.

The study analyzed sodium consumption patterns across US populations through NHANES data from 2003 to 2018 while focusing on percentiles and extreme consumption levels. The study evaluated the accelerations and decelerations of sodium consumption while analyzing its trends in vulnerable groups (people with self-reported hypertension, CVD, heart attack, and stroke) along with chronological time and age changes.

The analysis of NHANES data involved 60,663 participants between ages 5-80 years from eight survey cycles (2003-2018). The research used non-linear Gaussian regression to model sodium intake (mg/day) with age and the NHANES cycle treated as continuous predictor variables. We classified intake curves into four main intake patterns, increase with acceleration (IA), increase with deceleration (ID), decrease with acceleration (DA), and decrease with deceleration (DD), and estimated turning points to reflect critical risk periods in 16 selected subgroups defined by age, sex, and self-reported health conditions. We also examined temporal trends in intake extremes through individual-level and population-level data.

In most adult subgroups, we observed a non-linear pattern over time, indicating that sodium intake initially increased and then plateaued or declined around the turning point of ~20-30 years. Only girls demonstrated a steady decline in sodium intake over time, while in boys, we detected an alarming accelerating increase. The intake at upper percentiles remained extremely high: approximately 10% of the population consumed more than 5000 mg of sodium per day, which is more than twice the recommended limit of 2300 mg/day. Participants with CVD, heart attack, and stroke had a lower average intake than those without, but intake remained above recommended levels.

From 2003 to 2018, sodium intake in the U.S. showed no signs of meaningful decline, especially at the upper extreme. These findings suggest that current efforts are insufficient to meet the WHO's global target of a 30% sodium reduction by 2030.