Promoting Functional Health in Midlife and Old Age: Long-Term Protective Effects of Control Beliefs, Social Support, and Physical Exercise

BackgroundPrevious studies have examined physical risk factors in relation to functional health, but less work has focused on the protective role of psychological and social factors. We examined the individual and joint protective contribution of control beliefs, social support and physical exercise to changes in functional health, beyond the influence of health status and physical risk factors in middle-aged and older adults. Given that functional health typically declines throughout adulthood, it is important to identify modifiable factors that can be implemented to maintain functioning, improve quality of life, and reduce disability.
Methodology/Principal FindingsWe conducted a national longitudinal study, Midlife in the United States (MIDUS), with assessments in 1995–1996 and 2004–2006, and 3,626 community-residing adults, aged 32 to 84, were included in the analyses. Functional health (Physical Functioning subscale of the SF-36) and protective factors were measured at both occasions. While controlling for socio-demographic, health status, and physical risk factors (large waist circumference, smoking, and alcohol or drug problems), a composite of the three protective variables (control beliefs, social support, and physical exercise) at Time 1 was significantly related to functional health change. The more of these factors at Time 1, the better the health maintenance over 10 years. Among middle-aged and older adults, declines in health were significantly reduced with an increased number of protective factors.
Conclusion/SignificanceAge-related declines in health were reduced among those with more protective factors up to a decade earlier in life. Modifiable psychological, social, and physical protective factors, individually and in the aggregate, are associated with maintenance of functional health, beyond the damaging effects of physical risk factors. The results are encouraging for the prospect of developing interventions to promote functional health and for reducing public health expenditures for physical disability in later life.

研究背景
既往研究多聚焦于与功能健康（functional health）相关的躯体风险因素，却较少关注心理与社会因素的保护作用。本研究针对中老年群体，在控制健康状况与躯体风险因素影响的前提下，探讨控制感信念（control beliefs）、社会支持与体育锻炼对功能健康变化的独立及联合保护效应。鉴于功能健康在整个成年阶段通常呈衰退趋势，识别可干预的保护因素以维持机体功能、提升生活质量并减少失能，具有重要意义。

研究方法与主要结果
本研究采用美国中年发展追踪研究（Midlife in the United States, MIDUS）这一全国性纵向队列，分别于1995-1996年与2004-2006年开展评估，最终纳入3626名年龄在32至84岁之间的社区居住成年人参与分析。两次评估均对功能健康（采用SF-36量表躯体功能子量表）与保护因素进行了测量。在控制社会人口学特征、健康状况及躯体风险因素（腰围过大、吸烟、酒精或药物依赖问题）的前提下，基线（Time 1）时三类保护变量（控制感信念、社会支持与体育锻炼）的综合得分与功能健康变化显著相关。基线时具备的保护因素越多，10年间的健康维持效果越好。在中老年群体中，随着保护因素数量的增加，健康衰退程度显著降低。

研究结论与意义
相较于未积累较多保护因素的个体，在人生中最长提前十年的阶段就具备更多保护因素的群体，其随年龄增长的健康衰退程度显著降低。可干预的心理、社会与躯体保护因素，无论单独作用还是联合发挥效应，均能在抵消躯体风险因素损害作用的基础上，促进功能健康的维持。本研究结果为开发促进功能健康的干预方案、降低老年期躯体失能相关的公共卫生支出提供了积极的理论依据与实践方向。