Exposure to cigarette smoke, air pollution ups risk of juvenile idiopathic arthritis
Exposure to ozone (O3) in the second year of life and cigarette smoke (intrauterine and after birth) and maternal occupational exposure may increase the risk of juvenile idiopathic arthritis (JIA), suggests a recent study.
Intrauterine cigarette smoke exposure (odds ratio [OR], 3.43; 95 percent CI, 1.45‒8.12; p=0.005) and maternal occupational exposure (OR, 13.69; 4.4‒42.3; p<0.001) during pregnancy significantly independently predicted JIA. On the other hand, maternal employment (OR, 0.06; 0.02‒0.2; p<0.001) and ideal maternal weight gain (OR, 0.36; 0.2‒0.8; p=0.017) showed negative associations.
Furthermore, secondhand smoke exposure from birth to JIA diagnosis (OR, 3.6; 1.8‒7.3; p<0.001) and O3 exposure during the second year of life (OR, 2.76; 1.20‒6.37; p=0.017) were significant independent risk factors for the development of JIA.
A total of 66 patients with JIA and 124 age- and sex-matched healthy controls, living in Sao Paulo, Brazil, metropolitan area until JIA diagnosis, and whose mothers resided in this region during pregnancy were included in this exploratory case-control study.
The authors used a structured and reliable questionnaire (κ index for test-retest was 0.80) to analyse demographic data, gestational and perinatal-related factors, and exposure to inhalable environmental elements during pregnancy and after birth (occupational exposure to inhalable particles or volatile vapour, cigarette smoke exposure, and presence of industrial activities or gas stations near the home, work, daycare or school).
Tropospheric pollutants included particulate matter, sulphur dioxide, nitrogen dioxide, O3 and carbon monoxide.
The finding of an association between JIA and exposure to cigarette smoke and air pollution warrants further study, according to the authors.