Interscapular fat is strongly associated with insulin resistance.

Abstract

Subcutaneous abdominal adipose tissue (SCAAT), visceral adipose tissue (VAT), fat in the neck area [interscapular fat (IF)], and liver fat (LF) are associated with metabolic traits related to insulin resistance. Whole-body magnetic resonance imaging and spectroscopy offer a unique approach to quantify fat depots in larger cohorts. The objective was to study 1) the impact of the aforementioned fat depots on insulin sensitivity in a cross-sectional design and 2) changes in these fat depots and in insulin sensitivity during a lifestyle intervention (LI). One hundred eighty-seven subjects were included in the cross-sectional study. Follow-up data during LI were available in 172 subjects. Body fat depots were quantified by whole-body magnetic resonance imaging, and representative reference slices at the umbilical level (SCAAT, VAT) and at the level of the shoulder joint (IF) were analyzed. LF was measured by (1)H-magnetic resonance spectroscopy. Insulin sensitivity was estimated from an oral glucose tolerance test. Cross-sectionally, SCAAT, VAT, IF, and LF were negatively associated with IS (all P < 0.0001). The change in insulin sensitivity during LI was associated with the changes in these fat depots (all P < 0.001). In a multivariate model, the change in insulin sensitivity during LI adjusted for gender, age, LF, and IF at baseline was associated with change in IF (P < 0.01) and with change in LF (P < 0.0001). IF represents a subcutaneous fat depot determining whole-body IS, both cross-sectionally and during LI. The impact of LF and IF on insulin sensitivity appears to be independent from each other. Additional studies are needed to clarify the metabolic properties of IF.