10-year mortality following cohort study in an 80-year-old community dwelling population

在12年的随访期间，1998年参加本研究的824名受试者中，有506人死亡（总死亡率64.7%），276人存活，42人死亡（随访率94.9%）。506名死者中，128人死于心血管疾病（25.3%）、96人死于呼吸道疾病（19.0%）、87人死于癌症（17.2%）、51人死于衰老（10.1%）。研究开始时，80岁老人的牙齿数量为6.8颗，而活着的人的牙齿数量为8.3颗（P=0.026）。使用Kaplan-Meier方法评估80岁时咀嚼能力或牙齿数量与12-死亡率的关系。所有受试者根据咀嚼食物的数量（咀嚼不良，0-4；稍差，5-9；稍好，10-14；咀嚼良好，15）或牙齿数量（0;1-9;10-19;≧20）进行分类。咀嚼能力组间差异有统计学意义，牙数组间差异无统计学意义。使用Cox比例风险回归模型（根据性别进行调整），咀嚼不良受试者的总死亡率是咀嚼不良受试者的2.1倍，咀嚼不良受试者的1.4倍，咀嚼良好受试者的1.3倍。在调整性别差异后，与增加1种咀嚼食物相关的总死亡率风险降低了4.5%。同样，每增加1颗牙齿，经性别差异调整后的全因死亡率风险降低1.5%。这些发现表明，在80岁时保持咀嚼能力或保留牙齿可能与长寿有关。

During follow-up period of 12 years, 506 died(total mortality, 64.7%), 276 were alive, and 42 were lost(follow-up rate, 94.9%) out of 824 subjects who participated in the present study in 1998.Out of the 506 who died, 128 died due to cardiovascular disease(25.3%), 96 to respiratory tract disease(19.0%), 87 to cancer(17.2%), and 51 to senility(10.1%). Number of teeth at the start of the study of 80-year-old individuals was 6.8 for those who died, and 8.3 for those who remained alive(P=0.026). Association in 12-mortality with chewing ability or teeth number at age of 80 year was assessed using Kaplan-Meier methods. All subjects were classified according to the number of foods to chew(poor chewing, 0-4 ; slightly poor, 5-9 ; slightly good, 10-14 ; good chewing, 15), or number of teeth(0 ; 1-9 ; 10-19 ;≧20). There was a significant difference among groups for chewing ability, while no difference was found among groups for number of teeth. Total mortality using Cox proportional hazards regression model, which were adjusted for gender, was 2.1 times more prevalent in subjects with poor chewing, 1.4 times more prevalent in those with slightly poor chewing, and 1.3 times more prevalent in those with slightly good chewing as compared to those with good chewing. The risk for total mortality associated with increase in 1 chewable food decreased 4.5% after adjustment for gender difference. Similarly, risk of all-cause mortality adjusted for gender difference was decreased 1.5% with an increase in 1 tooth. These findings suggest that preserving chewing ability or remaining teeth at the age of 80 may be associated with longenity.