Objective: To evaluate the relationship between frequency of pruritic symptoms experienced over a 1-month period and psychological stress.
Design: Cohort study.
Setting: Population-based study in Japan.
Participants: A total of 2224 participants at least 18 years old and without psychiatric disorders participated in the Japan Health Diary Study (October 2003), a cohort study comprising a representative sample in Japan.
Main outcome measures: Frequency of pruritic symptoms assessed by self-reported health diaries over the 1-month period and subsequent psychological stress measured using the Japanese version of the Perceived Stress Scale.
Results: The 2224 participants had a mean age of 44.6 years, 1212 (54.5%) were women, and 70 (3.1%) presented with pruritic symptoms. Multivariable analysis showed that patients with pruritic symptoms had significantly higher psychological stress than those without pruritic symptoms (beta coefficient, 2.33; 95% confidence interval [CI], 0.53-4.14; P = .01). Furthermore, a linear trend was observed between increased psychological stress and increased severity of pruritic symptoms, with beta coefficients for the first, second, and third tertiles for symptoms of 0.81 (95% CI, -1.97 to 3.59), 1.77 (95% CI, -0.82 to 4.37), and 4.86 (95% CI, 1.29 to 8.43), respectively (P value for trend, .004).
Conclusion: Our results suggest that frequency of pruritic symptoms is associated with psychological stress in the general population.