Oral Presentation Australian & New Zealand Obesity Society 2016 Annual Scientific Meeting

Cognitive performance in normal weight and obese young women and its association with omega-3 PUFA (#59)

Rebecca Cook 1 , Helen Parker 1 2 , Cheyne Donges 3 , Nicholas O'Dwyer 1 3 , Hoi Lun Cheng 4 , Eka Cox 1 , Janet Franklin 5 , Katharine Steinbeck 4 , Manohar Garg 6 , Kieron Rooney 1 2 , Helen O'Connor 1 2
  1. Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
  2. Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
  3. School of Exercise Science, Sport and Health, Charles Sturt University, Bathurst, NSW, Australia
  4. Discipline of Child and Adolescent Health, University of Sydney, Sydney, NSW, Australia
  5. Metabolism & Obesity Services, Royal Prince Alfred Hospital, Sydney, NSW, Australia
  6. School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia

Background and significance: Low body status of omega-3 polyunsaturated fatty acids (n3PUFA) has been linked with cognitive decline in older adults. Evidence also indicates that obesity and its comorbidities may be associated with cognitive decline, however it is as yet unknown as to how these factors affect cognition in younger adults. Since n3PUFA status and obesity are both modifiable risk factors for reduced cognitive function, we sought to understand their relationship with cognition at an age and stage when they may indeed be effectively treated/modified. 

Methods: Non-smoking, healthy, young (18-35 y) normal weight (BMI 18.5-24.9kg/m2, NW) and obese weight (BMI >30kg/m2, OB) women were recruited. Participants completed anthropometric and cognitive assessments (using a validated computerised cognition testing platform, IntegNeuroTM), and provided a fasting blood sample. Performance on five cognitive domains (impulsivity, attention, information processing, memory, executive function) was reported as z-scores (normal range ±1 z-score). Omega-3 Index (O3I) was calculated as the erythrocyte membrane content of eicosapentaenoic acid plus docosahexaenoic acid as a percentage of total membrane fatty acids. Analyses used ANOVA, Chi square and Pearson correlation.

Major findings: 288 (NW: n=150, OB n=138) women (mean±SD: 25.8±5.1 y) completed all assessments. Although cognitive function was within the normal range, OB women had poorer performance on attention (NW: 0.31±1.38; OB: -0.25±1.38, p<0.001) and were more impulsive (NW: 0.36±1.14; OB: -0.07±1.07, p=0.033). Mean O3I for NW and OB were 6.8±1.7 and 5.8±1.6 respectively, p<0.001. Differences in impulsivity, but not attention, between OB and NW women were attenuated when analyses were controlled for O3I.

Conclusions: OB women had lower scores for attention and impulsivity, with O3I explaining some of the differences in impulsivity. However, as cognitive performance was in the normal range for both groups, the clinical significance for daily cognitive function warrants further investigation.