Physical Activity and Abdominal Fat Distribution in Greenland

PURPOSE: We examined how total volume of physical activity and reallocation of time spent at various objectively measured intensities of physical activity (PA) were associated with overall and abdominal fat distribution in adult Inuit in Greenland.

METHODS: Data were collected as part of a countrywide cross-sectional health survey in Greenland. A combined accelerometer and heart rate monitor measured total physical activity energy expenditure (PAEE) and intensities of PA (N=1536). Visceral- and subcutaneous adipose tissue (VAT, SAT) was assessed by ultrasonography. Isotemporal substitution modeling was used to analyse the association between substitution of 1-hour of sedentary time to light or moderate intensity PA and 1-hour light intensity PA to moderate or vigorous intensity PA in relation to BMI, waist circumference (WC), SAT and VAT.

RESULTS: A negative linear association was found for total PAEE and BMI, WC, VAT and SAT. Exchanging 1-hour of sedentary time with light intensity PA was associated with lower WC (-0.6 cm., p=0.01), SAT (-0.08 cm., p<0.001) and VAT (-0.04 cm., p=0.359). Exchanging light intensity PA with vigorous intensity PA resulted in -6.1 cm. lower WC (p<0.001), -0.7 cm. lower VAT (p=0.018) and -0.7 cm. lower SAT (p<0.001). When further adjusting for BMI the associations were attenuated; however, most of them remained significant, and the directions were mostly unchanged. Both 1,5, and 10 minutes bouts of MVPA were negatively associated with overall and abdominal fat distribution.

CONCLUSION: PAEE is associated with lower BMI, WC and abdominal fat among Greenland Inuit. The importance of promoting an upward shift of the whole PA intensity distribution and to spur even short bouts of MVPA to limit excessive accumulation of SAT and VAT is highlighted.