Understanding the natural and social factors behind regional longevity in Guangxi, China—Is centenarian ratio a good enough indicator for assessing the longevity level?

Despite a number of longevity indicators having been used in previous longevity studies, few studies have critically evaluated whether these indicators are suitable. In addition, an increasing number of studies have attempted to determine the influence of socio-economic and natural factors on regional longevity, but only certain factors were considered. The present study bridges this gap by determining the relationship between the seven longevity indicators and selecting 24 natural and socio-economic indicators in the 91 selected counties and districts in Guangxi, China. The seven longevity indicators here refer to Centenarian ratio, Longevity index, Longevity level, Aging tendency, 80+ ratio, 90+ ratio and 95+ ratio. Natural indicators in this study mainly refer to climatic ones. Socio-economic indicators can be categorized into those related to economic, education, local infrastructure, and health care facilities. These data were mainly drawn from the Meteorological Data Sharing Service System and Guangxi's sixth population census. Stepwise regression analysis has been used as the primary research method to determine the relationship between the longevity indicators and the natural, social, and economic indicators. The results show that the climate factors regarding atmospheric pressure, humidity, and rainfall are the most significant contributors to the longevity of the 60- to 90-year-old elderly in Guangxi, while the difference of mean annual temperature could have negative impacts. Also, the natural and socioeconomic factors that impact the extremely old population (those over 95 years old) in Guangxi are still not clear. This study reveals that the longevity index and longevity level are useful supplementary indexes to the centenarian ratio for assessing the regional longevity as they could help reflect the regional longevity regarding the proportion of young-old and old-old population and not just limit to those over 100 years old. The elderly (those from 60-90 years old) are more likely to be influenced by climate factors. It is, therefore, important to understand the risk of climate change for the elderly, which could provide insights for constructing a healthy aging society in the future.