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The purpose of this study was to determine the ability of air displacement plethysmography (ADP) to estimate percentage of fat mass (%FM) in African American children. %FM was determined in 21 boys and 13 girls (11.0 +/- 1.4 y, 18.6 +/- 4.2 kg/m(2) [mean +/- SD]) by ADP (using six published densitometric equations) and dual-energy x-ray absorptiometry (DXA). Measures were done within 2 h of one another, in random order. Regardless of equation, %FM(ADP) was significantly correlated with %FM(DXA) (R(2) = 0.67-0.71, all p < 0.001). %FM(ADP) using the equation of Siri (%FM(ADP-Siri) 20.3 +/- 9.0) agreed most closely with %FM(DXA) (20.0 +/- 10.2, difference p = 0.729). Together, surface area artifact and bone mineral content per unit of bone-free fat-free mass accounted for 29% of the variance in the residual between methods. The correlation between %FM(ADP-Siri) and %FM(DXA) was not significant for those <35 kg (n = 10; R(2) = 0.084, p = 0.417). There was a trend toward %FM(ADP-Siri) underestimating %FM(DXA) in girls (-1.46 +/- 3.0%FM; p = 0.103) but not in boys (1.43 +/- 6.4%FM; p = 0.315). Predicted lung volume was 40.1% higher than measured lung volume (p < 0.001). %FM(ADP-Siri) determined using predicted lung volume was 23.5 +/- 8.9, higher than that using measured lung volume (p < 0.001) and higher than %FM(DXA) (p = 0.001). We conclude that in 9- to 14-y-old African American children and provided lung volume is measured, %FM using ADP with Siri's equation approximates that obtained by DXA. Body composition results determined by ADP in children <35 kg should be interpreted with caution.

Background: Home-based lifestyle behaviour interventions show promise for treating and preventing childhood obesity. According to family theories, engaging the entire family unit, including parents, to change their family behaviour and dynamics may be necessary to prevent the development of childhood obesity. However, little is known about how these interventions, which may change the family dynamics and weight-related behaviours of parents, affect weight outcomes in parents. Our objective was to examine the effect of a pilot home-based childhood obesity prevention intervention on measures of anthropometrics and body composition in Canadian parents. Methods: Forty-four families with children aged 1.5–5 years were randomized to one of three groups: 4 home visits with a health educator, emails, and mailed incentives (4 HV); 2 home visits, emails, and mailed incentives (2 HV); or general health emails (control). Both the 2 HV and 4 HV intervention were conducted over a period of 6 months. Body composition and anthropometric outcomes were measured at baseline and at 6 months and 18 months from baseline. Results: In parents with baseline body mass index (BMI) ≥ 25 kg/m2, the 2 HV group had significantly lower body mass and waist circumference at 6-month (CI = -5.85,-0.14 kg;-5.82,-0.30 respectively) and 18-month follow-up (CI = -7.57,-1.21 kg;-9.30,-2.50 cm respectively) when compared to control, and significantly lower BMI at 18-month follow-up when compared to control (CI = -2.59,-0.29 kg/m2). In parents with baseline BMI < 25 kg/m2, the 4 HV group had significantly lower percentage fat mass (CI = -3.94,-0.12%), while the 2 HV group had significantly lower body mass (CI = -2.56,-0.42 kg) and BMI (CI = -0.77,-0.08 kg/m2) at 6-month follow-up, both compared to control; these effects were not maintained at 18-month follow-up. Conclusions: This study provides support that a home-based childhood obesity prevention intervention may improve weight outcomes among parents. Future research should explore how home-based interventions influence family behaviour and dynamics to impact weight outcomes in children and their parents. Trial registration: Prospectively registered August 2014, clinical trial identifier NCT02223234. [ABSTRACT FROM AUTHOR]