Does long-term experience of nonstandard employment increase the incidence of depression in the elderly?
OBJECTIVE
Our prospective study aimed to elucidate the effect of long-term experience of nonstandard employment status on the incidence of depression in elderly population using the Korean Longitudinal Study of Ageing (KLoSA) study.


METHODS
This study used the first- to fourth-wave cohorts of KLoSA. After the exclusion of the unemployed and participants who experienced a change in employment status during the follow-up periods, we analyzed a total of 1,817 participants. Employment contracts were assessed by self-reported questions:standard or nonstandard employment. The short form of the Center for Epidemiologic Studies Depression Scale (CES-D) served as the outcome measure. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using Cox proportional hazards models to evaluate the association between standard/nonstandard employees and development of depression.


RESULTS
The mean age of the participants was 53.90 (±7.21) years. We observed that nonstandard employment significantly increased the risk of depression. Compared with standard employees, nonstandard employees had a 1.5-fold elevated risk for depression after adjusting for age, gender, CES-D score at baseline, household income, occupation category, current marital status, number of living siblings, perceived health status, and chronic diseases [HR=1.461, 95% CI= (1.184, 1.805) ]. Moreover, regardless of other individual characteristics, the elevated risk of depression was observed among all kinds of nonstandard workers, such as temporary and day workers, full-time and part-time workers, and directly employed and dispatched labor.


CONCLUSIONS
The 6-year follow-up study revealed that long-term experience of nonstandard employment status increased the risk of depression in elderly population in Korea.
Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Ageny.
Mo-Yeol
MY
Kang
Young-Joong
YJ
Kang
Woncheol
W
Lee
Jin-Ha
JH
Yoon
D000368:Aged; D003863:Depression / Q000453:epidemiology / Q000523:psychology*; D059026:Diagnostic Self Evaluation; D004651:Employment / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology / Q000523:psychology*; D009790:Occupations / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D011446:Prospective Studies; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D014478:Unemployment / Q000523:psychology