Effects of physical activity and depressive symptoms on cognitive function in older adults: National Health and Nutrition Examination Survey

Background & aims Population aging is a growing phenomenon, with cognitive impairment becoming a prevalent issue among the elderly. This study aimed to investigate the impact of physical activity and depressive symptoms on cognitive function in older adults using a nationally representative data set of U.S. older adults aged ≥ 60 years. Methods The study comprised 2713 participants aged ≥ 60 from the National Health and Nutrition Examination Survey 2011–2014. Participants were classified into two groups: Cognitive impairment and No-Cognitive impairment, determined by the results of the Digit Symbol Substitution Test (DSST). Physical activity (PA) was assessed using the Global Physical Activity questionnaire (GPAQ), while depressive symptoms were evaluated using the Patient Health Questionnaire (PHQ-9). Logistic regression analysis examined the relationship between physical activity, depressive symptoms and cognitive function. Results Multifactorial logistic regression analysis showed that high levels of physical activity were found to be significantly associated with a lower risk of cognitive impairment compared to low levels of physical activity [OR = 0.789, 95% CI:0.632 ~ 0.986, P = 0.037]. On the other hand, the presence of major depressive symptoms was significantly associated with a higher risk of cognitive impairment compared to the absence of depressive symptoms [OR = 3.482, 95% CI: 2.278 ~ 5.324, P < 0.001]. Participants in the recreational physical activity group exhibited higher Cognitive scores (P < 0.001), indicating better cognitive functioning. Conclusion High levels of Physical activity were independently associated with a lower incident cognitive impairment. Additionally, the severity of depression was positively correlated with an increased risk of cognitive impairment.