Environmental Effects on Cognitive Decline in Older Adults: Insights for Long-Term Care Services

Background/Purpose:
Cognitive decline among older adults draws more attention as the population in the United States is aging rapidly. The current population reports (2014) estimated that the population aged 65 and over would reach 83.7 million in 2050, which is nearly doubled compared to the aging population in 2012 (43.1 million). As people get older, they are more vulnerable to experience cognitive decline, which may lead to cognitive impairment or even dementia. While many studies have been conducted to explore individual factors associated with cognitive decline among older adults, it is also important to pay attention to the impact of environmental factors. According to the Ecological Model of Aging (Lawton & Nahemow, 1973), cognitive decline is not determined by one single factor, but rather is the result of a dynamic interplay among serval factors, including biological, psychological, social resources, and environmental factors. Thus, the current study intended to explore what specific environmental factors, such as neighborhood socioeconomic status, physical and social environment, and healthcare accessibility, are associated with older adults’ cognitive functioning in the US.

Methods:
The study employed a longitudinal design drawing data from Health and Retirement Study (HRS) to examine the environmental factors associated with cognitive decline among older adults in the US. HRS is a large, nationally representative longitudinal panel survey of more than 37,000 individuals aged 50 and over in 23,000 households. The total sample in the current study included 19,632 adults aged 65 and above from wave 3 to wave 13 living in 1,250 counties, which consist of 85,858 observations. A generalized equation modeling with exchangeable correlation structure was used to understand the impact of the environmental effects by controlling individual factors, such as gender, age, education, marital status, household income, physical and mental status, and health behaviors.

Results:
The preliminary findings suggested that environmental factors can affect older adults' cognitive functioning. Controlling for individual characteristics, respondents living in a county with better healthcare quality were associated with better cognitive functioning (ß = 0.34, p < .05); respondents living in the rural area were associated with lower cognitive functioning compared to respondents living in urban areas ( ß = 0.19, p < .5). Older adults living in a county with a higher poverty rate were associated with lower cognitive functioning (ß = -0.02, p < .001). Lastly, older adults living in a county with a higher rate of low food accessibility had a lower cognitive functioning (ß = -0.05, p < .05).

Conclusions and Implications:
Overall, the study found that environmental factors, such as geographical locations, poverty rate, healthcare quality, and food accessibility, were associated with older adults' cognitive functioning. The findings indicates the cognitive disparities among neighborhoods and shed light on what resources are needed and where they should be allocated. Social workers and other healthcare practitioners also need to rethink intervention strategies and create an aging-friendly environment to improve cognitive functioning among older adults so that older adults can live independently as long as possible.