研究背景

内在能力（Intrinsic capacity，IC）指个体在其整个生命历程中所拥有的全部身体机能和心理机能的综合，涵盖认知、运动、活力、心理及感官五个子领域，是维持中老年人功能发挥的关键。开展内在能力的早期评估并探索其相关因素对于促进健康老龄化具有重要意义。然而，现有研究多聚焦60岁及以上人群，针对老年早期阶段（50-59岁）人群内在能力现状及其相关因素的系统研究较为缺乏。

研究目的

通过开展基于社区的横断面研究，评估北京市房山区和江西省婺源县的社区中老年人内在能力及其子领域的现状及分布特征，分析主观和客观社会经济地位（Socioeconomic status，SES）对内在能力受损的独立和联合作用，并探索内在能力受损的其它相关因素。

研究方法

该研究采用横断面研究设计，于2023年7~9月在北京市房山区和江西省婺源县的45个社区中开展调查。通过多阶段整群目的抽样方法，招募≥50岁的社区居民作为研究对象。依托《老年人整合照护指南》（Integrated Care for Older People, ICOPE）所推荐的深入评估工具进行内在能力评估。主观社会经济地位通过MacArthur量表评估，客观社会经济地位由教育程度和职业类别构建。采用有序Logistic回归模型分析主观与客观社会经济地位与内在能力及其子领域能力受损之间的关联。采用单因素分析探索人口社会因素、行为心理因素、健康相关状况及老龄相关症状与中老年人内在能力受损的相关性，进一步采用逐步回归探讨中老年人内在能力受损的相关因素。

研究结果

1. 该研究共纳入了3,058名50岁及以上的中老年人（61.3 ± 8.05岁，女性占54.8%），其中2,333人（76.3%）存在1个及1个以上子领域能力受损，489人（16.0%）存在≥3个子领域能力受损。各子领域中，能力受损检出率最高为感官（63.5%），其次是活力（25.8%）、认知（18.4%）、心理（15.3%）和运动（11.5%）。此外，相较于北京市房山区、50~59岁、男性的个体，江西省婺源县、≥70岁、女性的个体内在能力受损检出率更高。

2. 较高的社会经济地位与中老年人较低的内在能力受损风险相关。在控制年龄、性别、婚姻状况、生活方式、医疗保险及疾病数量因素后，主观社会经济地位较高者内在能力受损风险明显较低（OR: 0.72, 95% CI: 0.60-0.87）。高等教育水平（OR: 0.54, 95% CI: 0.38-0.75）和高职业水平（OR: 0.62, 95% CI: 0.49-0.79）亦与较低的内在能力受损风险相关。进一步分析显示，社会经济地位与各子领域能力受损同样相关，尤其是教育程度对认知能力的影响最为显著，与小学及以下教育水平的个体相比，接受高等教育及以上者的认知能力受损风险明显较低（OR: 0.20, 95% CI: 0.08-0.51）。此外，与主观和客观社会经济地位均较低的个体相比，具有高教育水平且中等主观社会经济地位的个体，内在能力受损风险降低67%（OR: 0.33, 95% CI:0.18-0.60），高职业水平且中等社会经济地位者降低49%（OR: 0.51, 95% CI:0.35-0.74）。

3. 多因素分析结果显示内在能力受损与多种因素相关：≥70岁（OR: 5.15, 95% CI: 4.07-6.51）、女性（OR: 1.20, 95% CI: 1.04-1.39）、未婚（OR: 3.95, 95% CI: 1.51-10.31）、身体活动量未达到推荐标准（OR: 1.22, 95% CI: 1.05-1.41）；此外，相较于无衰弱、无社会衰弱、无疾病、无跌倒史、剩余牙齿多于20个者，衰弱（OR: 2.43, 95% CI: 2.04-2.88）、社会衰弱前期（OR: 1.47, 95% CI: 1.26-1.72）、社会衰弱期（OR: 4.76, 95% CI: 3.44-6.57）、患有≥3个疾病（OR: 1.43, 95% CI: 1.08-1.53）、过去一年中发生过跌倒（OR: 1.48, 95% CI: 1.06-2.07）、剩余牙齿数目为1~20个（OR: 1.35, 95% CI: 1.13-1.61）或0个（OR: 1.76, 95% CI: 1.18-2.61）的中老年人发生内在能力受损的风险显著增加。

研究结论

该研究结果显示，社区中老年人群中内在能力受损情况较为普遍，感官、活力和认知为最易受损的子领域。主观和客观社会经济地位与内在能力受损存在显著关联，尤其在认知子领域中表现尤为明显。此外，年龄、性别、婚姻状况、身体活动、衰弱、社会衰弱、疾病数量、跌倒历史、剩余牙齿数目是内在能力的相关因素。

Background

Intrinsic capacity (IC) refers to the composite of an individual's physical and mental capacities throughout the life course. It encompasses five subdomains: cognition, locomotion, vitality, psychology and sensory, and is critical for maintaining functional ability in middle-aged and older adults. Early assessment of IC and identification of its associated factors are essential for promoting healthy ageing. However, there is a paucity of systematic evaluations of detection rate of IC deficits among individuals in the early ageing stage (50-59 years).

Objectives

This study aimed to investigate the detection rate and distribution of IC deficits and its subdomains among community-dwelling adults aged 50 years and above, analysis the independent and joint associations of subjective and objective SES with IC deficits, and explore additional factors associated with IC deficits.

Methods

A cross-sectional study was conducted in 45 communities from Fangshan District, Beijing, and Wuyuan County, Jiangxi Province from July to September 2023. Community-dwelling adults aged 50 years and above were recruited using a multistage purposive cluster sampling method. IC was assessed using the in-depth assessment tools of the Integrated Care for Older People (ICOPE) guidelines, covering the five subdomains. Subjective SES was measured using the MacArthur Scale, while objective SES was assessed based by level of education and types of occupation. Ordered logistic regression models were used to analysis the associations between SES and IC deficits. Univariate analyses were conducted to explore the associations of social determinants, lifestyle factors, health-related conditions, and aging-related symptoms with IC deficits. Stepwise regression was then used to identify associated factors of IC deficits.

Results

1. A total of 3,058 individuals (mean age: 61.3 ± 8.05 years; 54.8% female) were included in the analysis. Of these, 2,333 (76.3%) exhibited deficits in at least one IC subdomain, with 16.0% experienced deficits in three or more subdomains. The highest detection rate of deficits was found in sensory subdomain, followed by vitality (25.8%), cognition (18.4%), psychology (15.3%), and locomotion (11.5%). Participants from Wuyuan County, those aged ≥70 years, and females were observed with higher detection rate of IC deficits compared with their counterparts.

2. Higher SES was significantly associated with a lower risk of IC deficits. After adjusting for covariates, individuals with high subjective SES (OR: 0.72, 95% CI: 0.60-0.87), high education level (OR: 0.54, 95% CI: 0.38-0.75), and high occupation level (OR: 0.62, 95% CI: 0.49-0.79) had significantly lower likelihood of IC deficits compared with their counterparts. Further analyses revealed that SES was associated with deficits across IC deficits, with the strongest association observed between level of education and cognition subdomain. Compared with individuals with low education level, those with high education had a significantly lower risk of cognition deficits (OR: 0.20, 95% CI: 0.08-0.51). Compared with individuals with both low subjective and objective SES, those with high education level and medium subjective SES had 67% lower risk (OR: 0.33, 95% CI: 0.18-0.60), and those with high occupation level and medium subjective SES had 49% lower risk (OR: 0.51, 95% CI: 0.35-0.74) of IC deficits.

3. Multivariable analyses identified several associated factors of IC deficits: age ≥70 years (OR: 5.15, 95% CI: 4.07-6.51), female (OR: 1.20, 95% CI: 1.04-1.39), unmarried status (OR: 3.95, 95% CI: 1.51-10.31), and insufficient physical activity (OR: 1.22, 95% CI: 1.05-1.41). Additional significant factors included frailty (OR: 2.43, 95% CI: 2.04-2.88), pre-social frailty (OR: 1.47, 95% CI: 1.26-1.72), social frailty (OR: 4.76, 95% CI: 3.44-6.57), ≥3 chronic conditions (OR: 1.43, 95% CI: 1.08-1.53), fall history in the past year (OR: 1.48, 95% CI: 1.06-2.07), and having 1~20 (OR: 1.35, 95% CI: 1.13-1.61) or 0 remaining teeth (OR: 1.76, 95% CI: 1.18-2.61).

Conclusion

IC deficits is highly prevalent among community-dwelling middle-aged and older adults among surveyed participants, particularly in the sensory, vitality, and cognition subdomains. Both subjective and objective SES are significantly associated with IC deficits, with particularly strong effects observed in the cognition subdomain. Additionally, age, sex, marital status, physical activity, frailty, social frailty, number of diseases, history of falls, and number of remaining teeth are important correlates of IC deficits.