Abstract P016: Lifestyle Factors Substantially Contributed to Urban-Rural Disparity in All-Cause Mortality Among the Oldest-Old in China

Abstract

Introduction: With rapid population aging, the number of the oldest old population (≥ 80 years old) will increase dramatically in the coming decades in China. In this population, previous studies have demonstrated large health disparities between urban and rural China. Using the Chinese Longitudinal Healthy Longevity Survey (CLHLS), we aim to assess the hypothesis that individual-level lifestyle factors contribute to the disparity in all-cause mortality of the oldest old between urban and rural China. Methods: The CLHLS study sampled 862 randomly selected counties and districts in 22 of the 34 provinces in China. Our study included a total of 32,999 oldest old residents (13,767 urban, 19,232 rural) from seven waves of the CLHLS: 1998, 2000, 2002, 2005, 2008, 2011-12, and 2014. Five lifestyle factors were examined: smoking, drinking, diet (fruits, vegetables, fish, eggs, salted vegetables, sugar, tea, garlic, meat, and beans), physical activity, and leisure activity (housework, fieldwork, reading, petting, majong, gardening, and watching television). All-cause mortality was ascertained through death registry and information from next of kin with a median follow up of 2.3 years (range: 1-16.5 years). We used Cox Proportional Hazard Models to examine the urban-rural disparity of all-cause mortality: the basic model including residence (rural/urban) and demographic variables (age, gender, education, occupation, marriage, co-residence, and ethnic), five separate models including each lifestyle factor and all variables in the basic model, and a model with all lifestyle factors added to the basic model. Results: There were significant differences between urban and rural participants in their smoking, drinking, physical activity, diet, and leisure activities ( P <0.005 for all). All seven Cox Regression models showed large urban-rural disparities in mortality. The basic model showed that rural mortality was 11.2% higher than urban (95% Confidence Interval: 8.2, 14.3). Adjusting for diet, physical activity, and leisure activities, separately reduced the disparity by 10.3%, 25.3%, and 34.7% respectively. Adjusting for smoking and drinking did not cause substantial changes to the disparity. When put together in the same model, these five lifestyle factors collectively reduced the disparity by 37.5%. Conclusions: In conclusion, lifestyle factors, especially diet, physical activity, and leisure activities, contributed substantially to the urban-rural disparity in all-cause mortality of the oldest old in China. Interventions and policies targeting lifestyle factors are expected to reduce the disparity in China among the oldest old population.