PMC:5664696 / 3408-5047 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/5664696","sourcedb":"PMC","sourceid":"5664696","source_url":"https://www.ncbi.nlm.nih.gov/pmc/5664696","text":"2.1. Population\nPopulation data were obtained from the demographic database of the fifth and sixth national population census of China, carried out in 2000 and 2010, respectively (China Statistics/Beijing Info 2000, 2010) [17,18]. We used data from 345 Chinese cities in our analyses. These data included the number of individuals aged 85 years and older (the oldest available age group; 85+), and the number of individuals aged 65 years and older (65+). We used the 85+/65+ ratio as a city-level measure of longevity, as it is less sensitive to factors such as migration and birth rates which can obscure other measures of longevity.\nIt is acknowledged that the current population structure includes 65+ years old people who might have moved prior to where they lived in 2010. Since no data are available to take into account the migration of 65+ years old people prior to 2010, the assumption is that only the climate and local food of their present location affects their health status, although it is understood that where people lived in the past plays a role in their current health status. The geographical distribution of 85+/65+ ratios in Chinese cities in 2000 and 2010 are illustrated in Figure 1 and Figure 2.\nAs the population census data in south Xinjiang was not accurate [19] because investigation found the centenarians and elders count to be inaccurate as there was large gap between self-reported age and verified (actual) age [20,21]. Therefore, we deleted the data for south Xinjiang in 2000.\nTwo kinds of factors, potentially related to longevity, were collected for analysis: environmental and nutritional variables.","divisions":[{"label":"title","span":{"begin":0,"end":15}},{"label":"p","span":{"begin":16,"end":634}},{"label":"p","span":{"begin":635,"end":1221}},{"label":"p","span":{"begin":1222,"end":1513}}],"tracks":[]}