Duy Le, MD

Honjo K, Iso H, Inoue M, Sawada N, Tsugane S.Socioeconomic Status Inconsistency and Risk of Stroke Among Japanese Middle-Aged Women. Stroke. 2014

Inconsistency of socioeconomic status has been implicated as a risk factor for poor cardiovascular health. Honjo et al undertook a prospective cohort study evaluating inconsistency of socioeconomic status as a risk for increased incidence of all types of “stroke.”

61,595 Japanese female residents, ages 40-59 located in 15 different districts were self-administered questionnaires in 1990. They were asked to report on socio-demographic information and past medical history. 82% of the participants responded to the questionaire.  14,742 participants were deemed to be eligible and constituted the cohort group. Patients who had a malignancy, baseline cardiovascular disease were excluded from the cohort. A large number of patients were otherwise excluded were not explicitly accounted for.

The patients were measured on a scale of 1-4 in terms of highest level of education; 1) junior high; 2) high school; 3) junior college; 4) college graduate. Occupations were treated in a similar fashion where a score of 1 was assigned for manual labor; 2) sales and service; 3) office work; 4) professional and management.  Status inconsistency indicated a difference of 2 points between the level of education and the occupation. Women who were qualified for the job had a difference of less than 2 between their job and education. Patients were followed out to 20 years and the endpoint was stroke (Intra parenchymal hemorrhage, ischemic stroke, SAH) was considered an endpoint.

Baseline comparisons showed that Japanese women with higher levels of education were likely to be married, have higher self-reported psychological stress, be more physical active, less likely to be overweight and have less incidence of HTN and DM.

The results showed that there was an overall trend of Japanese women with lower education to work a manual job. Those with higher education were likely to have a professional and management job. However, there were still plenty of Japanese women with high level of education working manual jobs. The mismatch between education and career in this study is likely a specific reflection of women in the Japanese culture taking a career break in their  20’s and 30’s for family reasons and rejoining the work force in labor during their 40’s. Cox proportional hazard regression analysis was employed on the data and showed that women who were overqualified for their job had a higher stroke risk compared to women who were qualified for their job (2.06 odds ratio with [1.13,3.78 95% CI]). Women who were qualified for their job as defined above had an odds ratio of having a stroke set to a standard of 1.0. Underqualified women had an OR of 1.01 (0.69, 1.48) of having a stroke.

While the study makes an interesting finding, the generalizability of the results may be limited due to the cohort being constrained to Japanese women. The idea nonetheless is that dissatisfaction and stress at a job can potentially increase vascular events such as stroke.