Psychological stress in a Japanese population with systemic lupus erythematosus: finding from KYSS study

Daily psychological stress has been proposed as a risk factor for systemic lupus erythematosus (SLE) in Western countries. However, there is little information about the relationship between daily psychological stress and the risk of SLE in a Japanese population. We examined the association between SLE and daily psychological stress.A case-control study was conducted to examine the relationship between daily psychological stress and SLE in Japanese females. The participants were 160 female SLE patients and 660 female volunteers. Unconditional logistic regression was used to compute OR and 95% confidence interval (CI), with adjustment for several covariates.Smoking (OR = 2.59; 95% CI, 1.74-3.86), walking (OR = 1.75; 95% CI, 1.81-2.56) and daily psychological stress (OR = 1.88; 95% CI, 1.14-3.10) were increased in patients with SLE after adjusting for age, region and all factors. Smokers with daily psychological stress (OR = 4.70; 95% CI = 2.53-8.77) were more prevalent than nonsmokers without daily psychological stress in SLE. The multiplicative interaction measures between smoking status and daily psychological stress did not reach statistical significance.The present study suggests the possibility that daily psychological stress as well as smoking might be associated with an increased risk of SLE.