Aim: To investigate differences in objectively measured patterns of sedentary behaviour (SB) among Pacific and New Zealand European (NZE) women with different body composition profiles, and to explore associations with body fat% (BF%).
Methods: Pacific (n=119) or NZE (n=159) women aged, 18-45 years were recruited according to self-reported normal or obese body mass index (BMI) categories. SB was assessed using seven-day accelerometery. Weight, height, waist and hip circumference were measured using standard protocols. BF% was assessed using whole body dual-energy x-ray absorptiometry. BF% was used to stratify women as low (<35%) or high (≥35%) BF%. Linear regression (controlled for confounders) assessed associations between SB and BF%.
Results: Pacific women with low-BF% spent more time sedentary (hours/day) compared to all other women (p<0.05): Pacific high- 9.93 ± 1.59 and low-BF% 10.37 ± 1.38 and NZE high- 9.96 ± 1.58 and low-BF% 9.69 ± 1.32 (hours/day).
NZE women with high-BF% had a higher (p<0.05) weighted median sedentary bout length (length of sedentary bout corresponding to 50% of total daily accumulated sedentary time) 20.07 ± 4.10 min compared to NZE low-BF% 17.81 ± 3.43 min and Pacific high-BF% women 18.32 ± 2.85 min.
Among NZE women, every one-hour increase in sedentary time was associated with 0.8% higher gynoid fat (p<0.05), and higher weighted median sedentary bout length (less interrupted/more prolonged SB) was associated with higher BF% (gynoid fat 0.3%, total body 0.4%, trunk 0.4%, android 0.4% and visceral fat 0.4% (p<0.05)). No significant associations between SB and BF% were found among Pacific women.
Conclusion: Pacific and NZE women in this study had high levels of SB that may be contributing to BF%. Our findings indicate breaking-up prolonged SB may assist in achieving healthier BF%. Further prospective longitudinal and randomised controlled studies, investigating the impact of SB on BF% are needed to establish causality.