# Prevalence and sociodemographic correlates of antinuclear antibody testing by indirect immunofluorescence or solid-phase assays in a Spanish population: the Camargo Cohort

## TL;DR

This study examines how common antinuclear antibodies are in a Spanish population and how they relate to factors like age, gender, and lifestyle.

## Contribution

The study provides new insights into ANA prevalence and its association with sociodemographic and biobehavioral factors in a low-risk population.

## Key findings

- ANA prevalence was higher with indirect immunofluorescence compared to solid-phase assays.
- ANA prevalence increased with age, in females, and in those with higher C-reactive protein levels.
- Sedentary lifestyle and non-alcohol use were linked to higher ANA prevalence.

## Abstract

Autoantibodies are the hallmark of autoimmunity, and specifically, antinuclear antibodies (ANA) are one of the most relevant antibodies present in systemic autoimmune diseases (AID). In the present study, we evaluate the relationship between ANA and sociodemographic and biobehavioral factors in a population with a low pre-test probability for systemic AID. ANA were determined in serum samples at baseline visit from 2997 participants from the Camargo Cohort using indirect immunofluorescence assay, and two solid phase assays (SPA), addressable laser bead immunoassay, and fluorescence enzyme immunoassay. Sociodemographic and biobehavioral features of the subjects were obtained at baseline visit using a structured questionnaire. The prevalence of ANA positive results was significantly higher when indirect immunofluorescence assay was used as screening method in comparison with SPAs, being higher in females, older subjects, and those with higher C-reactive protein levels. Considering biobehavioral features, the prevalence was higher in those individuals with a sedentary lifestyle, and in ex- and non-alcohol users. Moreover, considering the relevance of the antibody load using ANA Screen, the prevalence of the antibody load also increased with age, especially in females. In conclusion, the prevalence of ANA varies depending on sociodemographic and biobehavioral features of the subjects, which could be relevant specifically in a population with a low pre-test probability for systemic AIDs.

The online version contains supplementary material available at 10.1007/s12026-023-09430-z.