PMC:5664696 / 6930-11264 JSONTXT

{"project":"2_test","denotations":[{"id":"28991186-23625695-49741671","span":{"begin":411,"end":413},"obj":"23625695"},{"id":"28991186-21277616-49741672","span":{"begin":490,"end":492},"obj":"21277616"},{"id":"28991186-21153714-49741673","span":{"begin":493,"end":495},"obj":"21153714"},{"id":"28991186-27791219-49741674","span":{"begin":496,"end":498},"obj":"27791219"},{"id":"28991186-21882066-49741675","span":{"begin":499,"end":501},"obj":"21882066"},{"id":"28991186-26228349-49741676","span":{"begin":589,"end":591},"obj":"26228349"},{"id":"28991186-18521708-49741677","span":{"begin":675,"end":677},"obj":"18521708"},{"id":"28991186-11846167-49741678","span":{"begin":1350,"end":1352},"obj":"11846167"},{"id":"T73808","span":{"begin":411,"end":413},"obj":"23625695"},{"id":"T71155","span":{"begin":490,"end":492},"obj":"21277616"},{"id":"T81296","span":{"begin":493,"end":495},"obj":"21153714"},{"id":"T97051","span":{"begin":496,"end":498},"obj":"27791219"},{"id":"T43061","span":{"begin":499,"end":501},"obj":"21882066"},{"id":"T82498","span":{"begin":589,"end":591},"obj":"26228349"},{"id":"T93691","span":{"begin":675,"end":677},"obj":"18521708"},{"id":"T16423","span":{"begin":1350,"end":1352},"obj":"11846167"}],"text":"2.3. Nutritional Factors\nStudies found that the Se content in soil has a significant positive correlation with longevity. In contrast, barium (Ba) and nickel (Ni) have significant negative correlations longevity, while distributions of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), vanadium (V), zinc (Zn), lithium (Li), and iron (Fe) showed no significant correlations with longevity [16]. Of all the trace elements, Se appears most closely linked with longevity [22,23,24,25]. Food contributes a greater proportion of daily elemental intake than drinking water [26], and the Se content in food is positively correlates with the Se content in soil [27]. Because of this, we selected the Se content in soil to represent the relationship between longevity and trace elements. Soil Se can be considered as total Se (T-Se) and water-soluble (WS) Se (WS-Se). Soil WS-Se is a better indicator of environmental effects than T-Se [28]. In this study, both T-Se and WS-Se content of soil were considered. We collected background concentrations of T-Se and WS-Se from China’s Soil Environment Background Concentration Research (Ministry of Environmental Protection of the People’s Republic of China, China National Environmental Monitoring Centre 1990) [29] and other studies related to soil environmental background values in China [11,30]. We calculated soil T-Se and WS-Se in each city using the union and statistic tools in ArcGIS software. T-Se and WS-Se, for each city, is illustrated in Figure 7 and Figure 8.\nWe also noted per capita meat production (Figure 9), per capita freshwater-fish production (Figure 10), and per capita seawater fish production (Figure 11 (Shanghai and Zhoushan are regarded as one fishing ground)) to examine potential relationships between omega-3 intake and longevity. These data were collected from the statistical bulletins of each city, and the 1990 (Fishery Administration Bureau of Ministry of Agriculture 1990) and 2016 (Fishery Administration Bureau of Ministry of Agriculture 2016) China Fisheries Statistics Yearbook [31,32]. Water food production in 1990 and 2015 are illustrated in Table 1.\nTable 1 shows that fishing production increased slowly from 1990 to 2015, and seawater fishing and freshwater fishing increased 2.39 and 2.89 times, respectively. Because of the limitations of natural water food resources, aquaculture production increased sharply due to recent developments in aquaculture and biological technologies, seawater aquaculture and freshwater aquaculture increased 11.58 and 6.86 times, respectively. Individuals who were aged 85+ years had mainly eaten fishing productions rather than aquaculture productions throughout their lives, particularly at a young age. Consequently, seawater aquaculture production was not included in the seawater food production data in this research.\nIn the past, especially 20 years ago when China’s highway network was not built, and food freezing technology was not developed, sea fish were seldom transported inland. Because sea fish will quickly die and deteriorate after leaving seawater, they were almost exclusively eaten by coastal-area residents. Even today, most sea fish in China are consumed by coastal area residents. There is no accurate per capita sea fish consumption data for Chinese cities, so we launched an investigation of the frequency of sea fish consumption, per month, for the residents of 139 cities in China, as a representative sample of the whole country. It would be too difficult to obtain this data from all cities, so the 139 selected cities account for 40.3% of all cities in China, and are distributed throughout every part of the country, as illustrated in Figure 12. Frequency of sea fish consumption is related to distance from the sea. In coastal cities, residents eat sea fish 3–10 times per month, while in inland areas most consume sea fish fewer than one time per month. We evaluated the consumption of sea fish for each city according the city’s per capita sea fish consumption and seawater food production in coastal regions (Equation (2)): (2) Ci=∑i=1nFi×Ti×Pi∑i=1n(Ti×Pi)\nIn this equation, Ci is per capita sea fish consumption in city i, Fi is sea fish production in city i, Ti is the monthly frequency of sea fish consumption in city i, and Pi is the population of city i."}