Influential factors on cognitive performance in middle-aged cohort: Third National Health and Nutrition Examination Survey-based study

Aging-associated cognitive decline is closely linked to illness, dementia, increased mortality, and is a major health and social issue. The purpose of this study was to determine modifiable factors associated with cognitive performance. We analyzed data from a random sample of participants of the Third National Health and Nutrition Examination Survey, which is a cross-sectional survey, of the US population, aged 20 to 59 years, who underwent computer-based neurocognitive testing. There were 5 outcome measures in 3 neurocognitive tests: the mean of simple reaction time test, the mean total latency of the symbol digit substitution test (SDST), the average number of errors of the SDST, the average trials to criterion of the serial digit learning test (SDLT), and the average total score of the SDLT. Socioeconomic status, including older age, black ethnicity, lower income ratio, and lower education level, were associated with poorer neurocognitive function in all analyzed tests. In addition, participants with poor health, nonsmokers, and nondrinkers performed worse in all administered tests compared with individuals with good health, smokers, and participants consuming alcoholic beverages. Dietary and biochemical characteristics of the blood were not consistently associated with neurocognitive performance. Our results indicate that socioeconomic factors, health-related and dietary habits, biochemical parameters of the blood, and job category were associated with neurocognitive performance in visual attention, learning, and concentration in a large, nationally representative sample of healthy, ethnically diverse 20 to 59-year-olds. Future studies are needed to understand the mechanisms of cognitive aging and the factors that contribute to its individual differences.