Stress and inflammatory biomarkers and symptoms are associated with bioimpedance measures

Abstract Background This large cross‐sectional, multi‐centre study evaluated the association of body composition measurements by a novel dual frequency bioimpedance device (BIA‐ACC) with chronic stress/inflammation biomarkers and the presence of medically unexplained symptoms (MUS). Materials and methods Participants were adult Caucasians of both sexes and included 10 416 lean subjects with no MUS (Group A), 58 710 lean subjects with MUS (Group B) and 30 445 overweight/obese subjects with no MUS and excessive fat mass (FM) (Group C). Results Total body extracellular water (ECW) was higher, while intracellular water (ICW) was lower in Group B than both other groups ( P < 0·01). Group A had significantly lower FM and higher skeletal mass (SK) and phase angle (PA) than Group B and lower circulating high sensitivity (hs) CRP levels than both other groups. hsCRP was higher in Group C than Group A though ( P < 0·01). Salivary cortisol in Group B was lower in the morning and higher in the evening than both other groups ( P < 0·001), indicating circadian rhythm obliteration or reversal in this group. ECW correlated positively with serum hsCRP and 8 p.m. salivary cortisol, but negatively with 8 a.m. salivary cortisol, while PA correlated positively with 8 a.m. and negatively with 8 p.m. salivary cortisol and serum hsCRP. Both 8 a.m. and 8 p.m. salivary cortisol and serum hsCRP were associated with the presence of MUS and BIA‐ACC measurements, including ECW, ICW, FM, SK and PA. Conclusions MUS is an index of chronic stress and inflammation and BIA‐ACC may provide a useful, bloodless and rapid tool in the clinical setting, distinguishing patients with chronic stress/inflammation from healthy subjects and monitoring their response to treatment.