Exploring body composition and metabolic health amongst NZ European, Pacific Island and Māori women participating in the women's EXPLORE study : a thesis completed as part of the requirements for Master of Science in Nutrition and Dietetics at Massey University, Albany Campus, Auckland, New Zealand

Abstract

Background: In New Zealand, 31.6% of adults are obese. Significant ethnic health inequalities exist; Pacific Islanders and Māori have the highest rates. Objectives: To investigate the body composition and metabolic health profiles of healthy NZ European, Pacific and Māori women participating in the women’s EXPLORE study. Methods/Design: Cross sectional design investigating 233 European, 91 Pacific and 84 Māori women. Different body mass index (BMI) and body fat % (BF%) defined body composition profiles were analysed for anthropometric measurements, body fat location, and metabolic biomarkers. Results: Obese (BF%) Māori women had higher android fat mass than obese (BF%) Europeans (2.53kg vs 2.23kg) with no difference in waist circumference (WC). Non-obese (BMI) Māori had higher WC than non-obese (BMI) NZ Europeans (78cm vs 73.5cm) with android fat differences. Regardless of body composition grouping, no ethnic differences were found for BF%. Obese Pacific women had higher HOMA-IR (5.12-5.45) and insulin (24.28- 23.28mU/L) than obese Europeans (2.10-2.61 and 10.07-11.24mU/L respectively), as did obese Māori (3.64-4.35 and 16.76-19.41mU/L respectively). Body composition measures with highest sensitivity across all biomarkers assessed were BF% ≥30 for Europeans, both BF% ≥30 and BMI ≥25 for Pacific, and BMI ≥25 for Māori. Conclusion: Māori and Pacific women had significantly higher glucose metabolism markers than NZ Europeans despite no differences in BF%. When comparing Māori to NZ Europeans, a higher WC was not always related to a higher android fat mass or vice versa, suggesting that WC may not be an accurate representation of abdominal fat for Māori. In spite of ethnic differences, BF% ≥30 and BMI ≥25 appear most sensitive to detect high biomarkers compared to abdominal measurements.