Nutritional status is associated with cognition and grip strength among older adults: A 10-y longitudinal study in Ghana and South Africa

Objectives

The current study examined the association between nutritional status and changes in cognition and grip strength among older Ghanaian and South African adults over time using three waves of data from the WHO Study on global AGEing and adult health (SAGE).

Methods

In total, 6113 and 3623 records of adults aged 60+ y were assessed from Ghanaian and South African datasets, respectively. These were extracted from three waves of the SAGE, conducted between 2007 and 2019. The six-item Mini Nutritional Assessment–Short Form questionnaire, five cognitive performance tests, and dynamometer were used to measure nutritional status, cognition, and handgrip strength, respectively. Data were analyzed by one-way analysis of variance and linear mixed models.

Results

After adjusting for all significant covariates, participants at risk of malnutrition (Ghana 3.05 [Standard error (SE) = 0.56], P < 0.0001; South Africa 3.79 [SE = 1.58], P = 0.016) and those with adequate nutritional status (Ghana 6.36 [SE = 0.59], P < 0.0001; South Africa 8.30 [SE = 1.56], P < 0.0001) had significantly higher cognitive scores compared with malnourished participants. In both Ghana and South Africa, handgrip strength was significantly different between the categories of nutritional status in all three study waves (analysis of variance Ghana W1: P < 0.0001, W2: P = 0.0007, W3: P = 0.0043; South Africa P < 0.0001 for all). Significantly higher handgrip strength was measured in participants either classified at risk of malnutrition (Ghana; 2.69 [SE = 0.47], P < 0.0001; South Africa; 4.18 [SE = 2.02], P = 0.038) or those with adequate nutritional status (Ghana; 4.27 [SE = 0.51], P < 0.0001; South Africa; 9.76 [SE = 1.97], P < 0.0001) compared with participants classified as malnourished in both countries. After adjustment for covariates, these differences remained significant in Ghana, but only for those with adequate nutritional status in South Africa.

Conclusions

This study confirmed a positive longitudinal association between nutritional status and both cognitive function and hand grip strength for older adults in Ghana and South Africa. These findings highlight the importance of nutritional intervention to promote access to adequate, nutritious diets as people in low- and middle-income countries age.