Background: Malnutrition remains a significant ongoing issue in Canada. Phase angle (PhA) from bioelectric impedance analysis (BIA) may be a surrogate marker for nutritional status. PhA results are confounded by age, gender, and BMI. Thus, standardized PhA (SPhA) is a better approach for monitoring. 

Objectives: Our primary objective was to determine PhA in a sample of Canadian, overweight/obese, community-dwelling adults categorized by age, gender, and BMI. Our secondary objective was to compare PhA of our sample to a reference population matched for age, gender, and BMI.  Our tertiary objective was to determine if PhA could be improved in response to a nutrition and lifestyle change intervention.

Methods: Overweight/obese adults attending a comprehensive weight management intervention underwent body composition analysis via BIA to determine PhA.  Participants’ PhA were matched for age, gender, and BMI based on reference values.  Z-scores, or SPhAs, were calculated to compare Canadian values to a reference population, then dichotomized into low or average/high PhA groups (< -1 SD or ≥ 1 SD, respectively).

Results: Baseline data was collected on seventy-two participants (mean PhA 5.3±0.8°).  Fifty-five participants had three-month data (mean PhA 5.2±0.7°, p=NS).  Overall, 40.3% had low SPhA, compared to 59.7% with average SPhA at baseline.  At 3 months, 38.2% had low SPhA, versus 61.8% with average SPhA value (p=NS).   

Conclusions:  When SPhA is used as a surrogate marker of malnutrition, 40% of participants are classified as malnourished at baseline and 38% at three months.  Three months is likely not enough time to see changes in PhA with this intervention. Future research will assess how changes in body weight influences SPhA.

Phase angle and malnutrition in Canadian community-dwelling adults