Occupational psychosocial stressors and ergonomic strain during pregnancy and sex-specific risk of childhood asthma

OBJECTIVES: Previous studies have indicated that maternal occupational psychosocial stressors may affect the risk of asthma in the offspring, but their results are inconsistent. Maternal occupational ergonomic strain is associated with predictors of fetal lung development, including preterm birth and low birthweight; however, it is not known, whether ergonomic strain during pregnancy is a risk factor for asthma in offspring. The aim was to investigate maternal psychosocial stressors and ergonomic strain during pregnancy relative to the risk of offspring asthma.

METHODS: Live- and firstborn singletons (1996-2018) and their mothers were identified from Danish nationwide registers. Job code at time of conception was assigned to each mother and linked with exposure estimates from job exposure matrices (JEMs) of psychosocial stressors and ergonomic strain. Diagnoses of childhood asthma were retrieved from the Danish National Patient Register. Incidence rate ratios (IRR) of asthma were estimated using Poisson regression; adjusted for maternal asthma, age at conception, socioeconomic position, and body mass index, and calendar year.

RESULTS: Maternal employment in occupations with low decision authority (IRR: 1.08, 95% CI 1.00-1.16) and high ergonomic strain (IRR: 1.09, 95% CI 1.02-1.16) was associated with increased risk of asthma among male offspring. Largely similar, but less consistent, associations were observed among female offspring due to low decision authority.

CONCLUSION: We found a minor increased risk of asthma among offspring whose mothers worked in an occupation with low decision authority or high ergonomic strain, most pronounced among male offspring.