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A recent cross-sectional study explored the association between dietary sodium intake and atopic dermatitis.

A recent cross-sectional study explored the association between dietary sodium intake and atopic dermatitis (AD) in adults, using data from the UK Biobank and the National Health and Nutrition Examination Survey (NHANES).

“Lifestyle and environmental factors are important contributors to AD prevalence and activity, but the role of specific exposures that drive the onset and persistence of AD remain poorly understood,” researcher wrote online in JAMA Dermatology. “Identifying specific modifiable exposures is a high priority for patients and their caregivers, who cite the unpredictability of the disease course as a major contributor to the burden of disease.”

The study included 215,832 participants from the UK Biobank, aged 37-73 years, who provided spot urine samples to estimate their 24-hour sodium excretion. Researchers calculated sodium intake using the sex-specific International Cooperative Study on Salt, Other Factors, and Blood Pressure equation, which incorporates body mass index (BMI), age, and urine concentrations of potassium, sodium, and creatinine.

The findings of the study showed that the mean estimated 24-hour urine sodium excretion was 3.01 g/day among participants, with 5.0% diagnosed with AD. Multivariable logistic regression analysis revealed that each 1-g increase in estimated 24-hour urine sodium excretion was associated with a 11% increase in the odds of having AD (AOR, 1.11; 95% CI; 1.07-1.14), a 16% increase in the odds of having active AD (AOR, 1.16; 95% CI; 1.05-1.28), and a 11% increase in the odds of more severe AD (AOR, 1.11; 95% CI; 1.07-1.15).

In a validation cohort of 13,014 NHANES participants, a 1-g per day higher dietary sodium intake, estimated using dietary recall questionnaires, was associated with a 22% higher risk of current AD (AOR, 1.22; 95% CI; 1.01-1.47).

These findings suggest that higher dietary sodium intake is significantly associated with increased prevalence, activity, and severity of AD. The study emphasizes the potential for dietary sodium restriction as a low-cost and low-risk intervention for managing AD.

“These findings suggest that restriction of dietary sodium intake may be a cost-effective and low-risk intervention for AD,” the study authors said.

This study also highlights the need for further research to explore the mechanisms by which sodium intake influences AD and to evaluate whether reducing dietary sodium could help mitigate the disease’s burden.

“Future work should examine whether variation of sodium intake over time might trigger AD flares and whether it helps to explain heterogeneity in response to new immunomodulatory treatments for AD,” they concluded. “Reduced sodium intake was recommended as a treatment for AD more than a century ago,12 but there have yet to be studies examining the association of dietary sodium reduction with skin sodium concentration or AD severity.”