A comparison of Geriatric Depression Scale scores in older Australian and Japanese women

AIMS: The aim of this study was to compare the prevalence of depressive symptoms in Australian and Japanese populations of community-dwelling older women using the Geriatric Depression Scale (GDS-15). In addition, the relationship between lifestyle and health factors and higher ratings of depressive symptoms was also examined to determine if there were culturally consistent risk factors associated with higher depressive symptom scores. METHODS: A total of 444 community based women aged between 65 and 77 years completed a depressive symptom measure (GDS-15) and provided information on common lifestyle factors. The Australian sample (n = 222) were drawn from the Women's Healthy Ageing Project and the age-matched, Japanese sample from the Kumamoto Ageing Study of Mental Health (n = 222). The GDS was chosen to; (1) reduce the impact of physical symptoms associated with old age and, (2) reduce the inflation in scores that may result from the Japanese tendency to endorse somatic items more often than Western adults. RESULTS: Mean GDS total scores were significantly higher for the Japanese population 3.97 ± 3.69 compared with 1.73 ± 2.7 for Australian women. The percentages of women scoring in the normal; mild and moderate ranges for depression were 91, 7 and 2% for Australia and 67, 24 and 9% for Japan. Scores remained significantly higher for the Japanese cohort when controlling for lifestyle and health factors associated with depression. The analysis of lifestyle and health characteristics showed that the greatest difference between cohorts was in the area of living status, with more Australian women living with their partner and more than three times as many Japanese women living with their children. When the data for the countries was considered independently employment status affected the likelihood of higher depression scores in the Australian sample while heart disease and poor sleep impacted the risk for the Japanese population. CONCLUSIONS: Significantly more Japanese women scored within the mild and moderate ranges on the GDS compared with their Australian peers, even when controlling for possible confounding factors. Of the lifestyle and health factors assessed in this analysis no single variable was a common risk factor for higher depressive scores for both countries. The presence of cultural influences that may impact the risk of experiencing depressive symptoms, and culture specific patterns of item endorsement on depressive symptom measures, needs to be explored in more detail.