Adding salt to foods and risk of psoriasis: A prospective cohort study

Guowei Zhou; Lu Gan; Bin Zhao; Fang Fang; Hong Liu; Xiang Chen; Jiaqi Huang

doi:10.1016/j.jaut.2024.103259

Adding salt to foods and risk of psoriasis: A prospective cohort study

J Autoimmun. 2024 Jul:147:103259. doi: 10.1016/j.jaut.2024.103259. Epub 2024 Jun 1.

Authors

Guowei Zhou¹, Lu Gan², Bin Zhao², Fang Fang³, Hong Liu⁴, Xiang Chen⁵, Jiaqi Huang⁶

Affiliations

¹ Department of Dermatology, Hunan Engineering Research Center of Skin Health and Disease, Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Clinical Research Center for Cancer Immunotherapy, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Engineering Laboratory of Medical Big Data Application Technology (Central South University), Changsha, China; Furong Laboratory, Changsha, China.
² Furong Laboratory, Changsha, China; National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China; Xiangya School of Public Health, Central South University, Changsha, China; CSU-Sinocare Research Center for Nutrition and Metabolic Health, Changsha, China.
³ Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
⁴ Department of Dermatology, Hunan Engineering Research Center of Skin Health and Disease, Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Clinical Research Center for Cancer Immunotherapy, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Engineering Laboratory of Medical Big Data Application Technology (Central South University), Changsha, China; Furong Laboratory, Changsha, China. Electronic address: Hongliu1014@csu.edu.cn.
⁵ Department of Dermatology, Hunan Engineering Research Center of Skin Health and Disease, Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Clinical Research Center for Cancer Immunotherapy, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Engineering Laboratory of Medical Big Data Application Technology (Central South University), Changsha, China; Furong Laboratory, Changsha, China. Electronic address: Chenxiangck@126.com.
⁶ Furong Laboratory, Changsha, China; National Clinical Research Center for Metabolic Diseases, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China; Xiangya School of Public Health, Central South University, Changsha, China; CSU-Sinocare Research Center for Nutrition and Metabolic Health, Changsha, China. Electronic address: guowei_zhou@csu.edu.cn.

PMID: 38823158
DOI: 10.1016/j.jaut.2024.103259

Abstract

Background: High salt intake may play a critical role in the etiology of psoriasis. Yet, evidence on the association of high salt intake with risk of psoriasis is limited.

Objective: To estimate the association between frequency of adding salt to foods and risk of psoriasis.

Methods: We conducted a prospective cohort study of 433,788 participants from the UK Biobank. Hazard ratios (HRs) and their 95 % confidence intervals (CIs) for risk of psoriasis in relation to frequency of adding salt to foods were estimated using multivariable Cox proportional hazards models. We further evaluated the joint association of adding salt to foods and genetic susceptibility with risk of psoriasis. We conducted a mediation analysis to assess how much of the effect of adding salt to foods on risk of psoriasis was mediated through several selected mediators.

Results: During a median of 14.0 years of follow-up, 4279 incident cases of psoriasis were identified. In the multivariable-adjusted model, a higher frequency of adding salt to foods was significantly associated with an increased risk of psoriasis ("always" versus "never/rarely" adding salt to foods, HR = 1.25, 95 % CI: 1.10, 1.41). The observed positive association was generally similar across subgroups. In the joint association analysis, we observed that participants with a high genetic risk (above the second tertile) and the highest frequency of adding salt to foods experienced 149 % higher risk of psoriasis, when compared with participants with a low genetic risk (below the first tertile) and the lowest frequency of adding salt to foods (HR = 2.49, 95 % CI: 2.05, 3.02). Mediation analysis revealed that 1.8 %-3.2 % of the positive association between frequency of adding salt and risk of psoriasis was statistically significantly mediated by obesity and inflammatory biomarkers such as C-reactive protein and systemic immune-inflammation index (all P values < 0.004).

Conclusions: Our study demonstrated a positive association between frequency of adding salt to foods and risk of psoriasis. The positive association was independent of multiple other risk factors, and may be partially mediated through obesity and inflammation.

Keywords: Cohort study; Prospective study; Psoriasis; Salt intake.

MeSH terms

Adult
Aged
Female
Follow-Up Studies
Genetic Predisposition to Disease
Humans
Incidence
Male
Middle Aged
Proportional Hazards Models
Prospective Studies
Psoriasis* / epidemiology
Psoriasis* / etiology
Risk Factors
Sodium Chloride, Dietary* / adverse effects
United Kingdom / epidemiology

Substances

Sodium Chloride, Dietary