Samenvatting

Are a healthy diet and physical activity synergistically related to cognitive function in older adults?

Background. In an ageing society cognitive decline is expected to become an important health problem. Previous studies showed that a healthy lifestyle, i.e. sufficient physical activity and a healthy diet,can benefit cognitive function. In this study, we aimed to assess the (synergistic) association of physical activity and a healthy diet with cognitive functioning in 1,741 Dutch men and women aged 57-97 years.
Methods. In this cross-sectional study, data from the 2005-2006 examination wave of the Longitudinal Aging Study Amsterdam were used. Good cognitive functioning was defined as Mini-Mental State Examination score ≥27. Physical activity was assessed by the LASA Physical Activity Questionnaire and was considered sufficient if ≥ 20 min/d being moderate-intensity physically active. A healthy diet score was conducted adding up the intake of fruit, vegetables and fish. Each of the food groups were assigned a score ranging from 1 (well below guideline) to 4 (well above guideline), which were added up to determine a healthy diet (≥ 9 points). Multiple logistic regression analyses were used to examine the (synergistic) associations of physical activity and healthy diet with good cognitive functioning. All analyses were adjusted for potential genetic, chronic diseases and lifestyle confounders.
Results. Of all participants, 23% were diagnosed with cognitive impairment, 82% were physically active and 45% had a healthy diet. Physical activity (odds ratio (OR): 2.545; 95% CI: 1.289-2.162) or adherence to a healthy diet (1.831 (1.281-2.617)) were independently associated with good cognitive functioning. After adjustment for confounding, these associations remained significant. No interaction between physical activity and healthy diet was observed (p=0.17).
Conclusions. This study confirmed that physical activity and a healthy diet benefit cognitive function, although no synergistic association between the two lifestyle factors was observed. As these findings are based on a cross-sectional study, the research question should be addressed in prospective studies.