Interference of silicone breast implants on bioimpedance measurement of body fat.

BACKGROUND: No study targeting the impact of silicone breast implants on body composition measured by bioimpedance analysis was identified. OBJECTIVE: Aiming to clarify this question a prospective clinical study was designed. METHODS: Adult candidates were submitted to conventional analysis at baseline and two months after the surgical intervention. In addition, unwrapped prostheses were positioned in the axillary cavity before operation and bioimpedance was measured, both with and without application of ultrasound gel for improved conductivity (sham implantation). RESULTS: Patients (N = 20) were young and healthy (26.8 ± 3.6 years old, BMI 22.1 ± 3.7 kg/m(2)). In comparison with preoperative results, sham procedures pointed out increased body fat and body resistance (13.2 ± 5.6 vs 13.6 ± 5.4 kg, P = 0.017 and 523 ± 54 vs 569 ± 53 Ω, P = 0.003, respectively). Two-month follow-up confirmed the same pattern after surgical intervention, with minor discrepancies (13.2 ± 5.6 vs 13.8 ± 5.7 kg, P = 0.011 and 523 ± 54 vs 549 ± 62 Ω, P = 0.032, respectively). BMI remained stable and did not correlate with bioimpedance changes. CONCLUSIONS: Silicone was recognized as adipose tissue. Difference in total body fat (approximately 600 g) was consistent with used amount.