Date Published: April 25, 2019
Publisher: Public Library of Science
Author(s): Yaoyue Hu, Peng Li, Pekka Martikainen, Eric van Exel.
No consensus has been reached on whether depression decreases or increases with age in later life. Majority of the evidence comes from Western societies, while little is known about this relationship and its rural-urban disparities in the Chinese context.
Three waves of data from 15,501 Chinese adults aged 45–85 years from the China Health and Retirement Longitudinal Study, Chinese sister study of Health and Retirement Study, were used. Depression caseness was identified using the 10-item Center for Epidemiologic Studies Depression Scale (score ≥12). Urbanisation levels were determined by combining rural-urban residence and rural-urban Hukou (a household registration system). Odds ratios and predicted probabilities of depression caseness were estimated using generalised linear mixed models.
For both men and women and across all ages, the crude predicted probability of depression caseness was the highest in the rural group, followed by the semi-urban group, and the lowest in the urban group. The probability was stable over age among urban men (around 0.05), but it increased at an accelerated rate with age among semi-urban men (0.25 at age 85, 95% confidence interval [CI]: 0.13–0.44) and rural men (0.29 at age 85, 95% CI: 0.22–0.39). Among women the age pattern was similar between the urbanisation groups: the probability increased with age, reached a peak at ages 75–80 (urban women: 0.16, 95% CI: 0.13–0.20; semi-urban women: 0.28, 95% CI: 0.20–0.39; rural women: 0.41, 95% CI: 0.36–0.46), and decreased slightly afterwards. These differences were significantly attenuated when socio-demographic characteristics and physical disability, but not when behaviour-related factors, were controlled for.
The age trajectories of later-life depression caseness varied by gender and urbanisation levels, and were not U-shaped as in many Western societies. The increasing depression caseness with age and the large rural disadvantage were substantially driven by socio-demographic characteristics and physical disability.
Depression, China’s fourth leading cause of disability, has been increasingly recognised as a serious public health concern in its older population.[2, 3] According to a recent meta-analysis of 32 studies, the prevalence of depressive symptoms was approximately 10% higher among rural older Chinese aged 60 and over (29.2%) than among their urban counterparts (20.5%). This rural-urban disparity contradicts observations from Western societies or other eastern Asian countries where no substantial rural-urban difference or even an urban disadvantage was found.
More than half of our sample were rural Hukou holders living in rural areas; whereas the share of rural and urban Hukou holders living in urban areas was similar (Table 1). Depression caseness was more common among the less urbanised groups and among women. Urban men and women also differed from their less urbanised counterparts that they received more education, were retired, had more household amenities, and engaged in social activities more often. Additionally, more urban men were overweight and obese but less of them were current smokers than semi-urban and rural men.
In this study using a large nationally representative sample of middle-aged and older Chinese adults, we found that, across all ages, rural men and women had the highest probability of depression caseness, followed by the semi-urban ones, and the urban ones had the lowest probability. The age trajectories of depression caseness differed between urbanisation groups among men but were highly similar among women. The probability of depression caseness did not change with age among urban men, however it increased more rapidly at older ages among semi-urban and rural men. Among women, the probability increased with age at a decelerated rate with a peak at ages 75–80. After controlling for socio-demographic factors, the probability became decreasing with age. The rural-urban disparities in the age trajectories of depression caseness largely reduced when socio-demographic characteristics and physical disability were adjusted for, whereas behaviour-related factors only played a lesser role.