Association between urinary DINCH concentration and rheumatoid arthritis: A cross-sectional study

Area of Science:

• Environmental Health
• Rheumatology
• Toxicology

Background:

• Rheumatoid arthritis (RA) etiology involves environmental factors.
• DINCH (cyclohexane-1,2-diisononyl ester), a plasticizer, is considered safer than phthalates but its health effects, particularly on RA, are not fully understood.

Purpose of the Study:

• To investigate the association between DINCH exposure and RA risk in adults.
• To explore potential mediation by vitamin D and identify subgroups with increased susceptibility.

Main Methods:

• Utilized data from the National Health and Nutrition Examination Survey (NHANES) 2013-2018.
• Employed multivariate logistic regression, trend tests, mediation, and subgroup analyses.
• Included sensitivity analyses for missing data.

Main Results:

• Increased urinary DINCH concentration (>1.0 ng/ml) was associated with higher RA prevalence (OR = 1.44, P = 0.037).
• A potential indirect effect of DINCH on RA via vitamin D was observed (mediation effect 4.7%).
• The association was stronger in participants with low serum total vitamin D levels (OR 1.79).

Conclusions:

• Elevated urinary DINCH concentrations are associated with a higher prevalence of rheumatoid arthritis.
• Vitamin D may mediate the relationship between DINCH exposure and RA.
• Individuals with low vitamin D levels may be more vulnerable to the adverse effects of DINCH exposure on RA risk.