Healthy lifestyle habits and cognitive performance in middle-aged and older adults

Background: Dementia affects approximately 55 million people worldwide, and this number is estimated to reach 139 million cases by 2050. A healthy diet, physical activity, quality sleep, and abstinence from tobacco contribute to reducing the risk of dementia. However, little is known about the role of a healthy lifestyle in cognitive performance in diverse populations from low- to middle-income countries, where social determinants can negatively impact health behaviors and cognition. Methods: This cross-sectional study used data from the ELSI-Brasil, a representative study of the Brazilian population aged 50 years or older. Variables were collected through self-report. The independent variables were sleep quality (quality and sleep problems), alcohol consumption (current use and frequency), smoking (current status and history), physical activity (type and frequency of activities), and  diet (frequency of consumption of fruits, vegetables, legumes, and meats). Binary lifestyle variables were created and a Healthy Lifestyle Index (HLI) score was computed. The dependent variables were memory, verbal fluency, and global cognition. Linear regression models were conducted, adjusted for age, gender, ethnicity, marital status, education, family income, hypertension, cholesterol, diabetes, and depression. The R software was used to conduct the analyses. Results: The sample included 8,168 participants (mean age: 63.2 years; 56.2% women; 47.0% Black) (Table 1). Regarding lifestyle components, being physically active was associated with global cognition (β=0.133 [0.087-0.178], p<0.001), memory (β=0.132 [0.085-0.180], p<0.001) and verbal fluency (β=0.114 [0.070-0.157], p<0.001). Eating a healthy diet was associated with greater global cognition (β=0.062 [0.005-0.119], p=0.035) and memory performance (β=0.069 [0.009-0.129], p=0.025). Healthy sleep was associated with greater global cognition (β=0.066 [0.019-0.112], p=0.006) and memory performance (β=0.058 [0.011-0.105], p=0.016). No smoking and healthy alcohol consumption did not show significant associations. Regarding the HLI, higher scores were associated with greater global cognition (β=0.935 [95% CI: 0.682-1.188], p<0.001), memory (β=0.910 [0.651-1.168], p<0.001), and verbal fluency performance (β=0.726 [0.468-0.985], p<0.001) (Table 2, Figure 1). Conclusions: A healthy lifestyle was associated with greater global and domain-specific cognitive performance, particularly being physically active, eating a healthy diet, and having good quality sleep, in Brazilian adults aged 50 years or older.