High Sodium Intake Associated to Increased Risk of Severe Atopic Dermatitis

Consuming too much sodium, as estimated by how much sodium is in your urine over 24 hours, is associated to active and severe atopic dermatitis (AD), according to a study published in JAMA Dermatology.

Researchers who conducted the study, of the Universities of California in San Francisco and Berkley, suggest that cutting down on sodium could be a more cost-effective and low-risk way to help manage AD.

AD, or eczema, is a chronic skin disease that is not contagious and causes inflammation, redness and irritation.

Commonly starting in childhood and often resolving before adolescence, AD can affect anyone at any age, sometimes continuing into adulthood or even appearing for the first time in adults.

According to the National Institutes of Health, around 101.27 million adults and 102.78 million children worldwide have AD.

Study researchers shared that lifestyle and environmental factors play significant roles in how common and severe AD is, but how it begins and persists has remained unclear.

Previous studies have shown show diet might be a key lifestyle factor. Eating fast food is linked to a 20% higher chance of getting AD and a 70% higher chance of severe AD in teens, research has shared.

Fast food is high in sodium, which might be connected to AD. Research has shown most of the body's sodium is stored in the skin and is linked to autoimmune and chronic inflammatory conditions like AD.

In a study from 2019, it was found that AD patients had 30 times more sodium in their affected skin than healthy people.

In this JAMA study, researchers sought to investigate whether there is an association between higher levels of sodium consumption and AD prevalence, activity and severity at the population level.

In the cross-sectional study, researchers used data from the UK Biobank, which includes over 500,000 people ages 37 to 73 from England, Scotland and Wales.

The study shared that AD affects 4% to 5% of adults, and 8% of older adults in the UK.

Folks included in the UK Biobank tend to be older, more likely female and from less deprived areas with fewer health problems, researchers shared.

Each participant's data came from a single visit between March 31, 2006, and October 1, 2010, which included questionnaires, health measurements and urine samples.

The main focus was on 24-hour urinary sodium excretion, which reflects about 90% of daily dietary sodium intake.

Data were analyzed between February 23, 2022 and March 20, 2024.

The study included 215,832 people with an average age of about 56 years, and about more than half (54.3%) were women. On average, they had about 3 grams of sodium in their urine each day.

Out of the participants, 10,839 (or 5%) had AD.

Researchers found that for each extra gram of sodium in their daily urine, the chances of having AD increased by 11%.

In addition, the risk of having active AD went up by 16%, and the severity of AD increased by 11%.

Another part of the study with 13,014 participants from the National Health and Nutrition Examination Survey showed that eating 1 gram more sodium per day, based on dietary recall, was linked to a 22% higher risk of having AD.

Researchers suggest that future investigations should look at whether variation of sodium intake over time might trigger AD flares and whether it could explain why people with AD react differently to new treatments that affect their immune system.

Overall, the study proposes that limiting how much sodium you consume could be an effective way to help treat AD in the future by being cost-effective, low-risk and available to those affected.