Exploring physical activity profiles of Māori, Pacific and European women from Aotearoa New Zealand : implications for body composition and metabolic health : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Sciences at Massey University, Auckland, New Zealand

Abstract

Background: Regular physical activity provides extensive health benefits, and is a key modifiable risk factor for chronic disease. Aims and objectives: The research aim was to robustly explore the physical activity profiles of Māori, Pacific and European women aged 16-45 years, living in New Zealand, to understand ethnic differences in their physical activity profiles and its consequences on body composition and metabolic health markers. Objectives were to: investigate the challenges of collecting hip-worn accelerometer data; determine ethnic differences in physical activity levels, and associated disease risk of being overweight-obese; investigate whether substituting sedentary behaviour with equal time in physical activity can predict improved health markers; examine recreational physical activity preferences to make ethnic-specific suggestions for meeting physical activity guidelines. Methods: Participants were 406 healthy premenopausal Māori, Pacific and European women aged 16-45 years, stratified by body composition profile and ethnicity. Physical activity data were collected using hip-worn accelerometers and Recent Physical Activity Questionnaire. Body composition was assessed using anthropometry, air displacement plethysmography and dual-energy x-ray absorptiometry. Metabolic biomarkers were measured from venous blood samples. Results: Accelerometer wear compliance was 86%, but discomfort (67%) and embarrassment (45%) hindered wear. European women (92.7%) returned more valid data than Māori (82.1%) or Pacific (73.0%, p < 0.04) women. More overweight-obese European (67%) than Māori (49%) or Pacific (32%, p < 0.001) women achieved physical activity guidelines. Achieving guidelines was strongly associated for Māori, inversely with total and regional fat percentages and clustered cardiometabolic risk score (p < 0.01) and positively with body lean percentage (p = 0.21), and for European women inversely with regional fat percentages and positively with body lean percentage (p ≤ 0.036). Substituting sedentary time with moderate-vigorous physical activity predicted improvements (p < 0.05) in total (14.8%) and android (12.5%) fat percentages, BMI (15.3%) and insulin (42.2%) for overweight-obese Māori women, and waist-to-hip ratio (6.4%) among Pacific women. Recreational physical activity preferences varied by ethnicity, possibly due to cultural/ethnic factors. Suggestions to increase physical activity were: family/whanaubased team activities for Māori women; community/church-linked games and fitness sessions for Pacific women; adding variety to existing activities for European women. Conclusions: Ethnicity played a major role in: collecting data; amounts/types of physical activity performed; implications of physical activity on health markers. Tailoring physical activity recommendations for specific ethnic groups could have major positive health implications for New Zealand women.