. 2012 Apr;10(2):128–136. doi: 10.1089/met.2011.0064

Table 3.

Regression Series for Body Mass Index z-Score Mediating the Relationship Between Moderate-to-Vigorous Physical Activity and Metabolic Risk Factors

	A path	P value	B path	P value	C path	P value	C′ path	P value	Sobel z-score	P value	% Mediated	R²	Partial R²for MVPA
Metabolic risk factor (n=2,155), 6–19 years old^a
Systolic blood pressure (mmHg)	7.0×10⁻⁴	0.107	0.616^*	0.017	−0.018^*	0.033	−0.013^*	0.025	1.387	0.165	5.6	0.198	0.010
Diastolic blood pressure (mmHg)	7.0×10^–4	0.107	−0.665^*	0.045	−0.004	0.610	−0.002	0.735	−1.301	0.193	33.0	0.100	8.6×10⁻⁵
C-reactive protein (mg/dL)	7.0×10^–4	0.107	−0.009	0.138	−1.4×10^–4	0.467	−1.3×10^–4	0.499	−1.122	0.262	8.1	0.058	1.2×10⁻⁴
Total cholesterol (mmol/L)	7.0×10^–4	0.107	−0.001	0.972	0.001	0.093	0.001	0.093	−0.035	0.972	0.1	0.024	0.003
High-density lipoprotein cholesterol (mmol/L)	7.0×10^–4	0.107	−0.005	0.613	4.3×10^–4^*	0.006	4.3×10^–4^*	0.005	−0.488	0.625	1.3	0.178	0.004
Glycohemoglobin (%)^b	2.4×10^–4	0.612	−0.011	0.252	0.000	0.070	0.000	0.077	−0.469	0.639	1.6	0.044	0.001
Metabolic risk factor (n=1,860), fasting 12- to 19-year-old subsample^a
Fasting triglycerides (mmol/L)	−0.001	0.362	0.016	0.507	4.5×10^–4	0.467	4.7×10^–4	0.461	−0.543	0.587	4.591	0.127	0.001
Fasting low-density lipoprotein cholesterol (mmol/L)	−0.001	0.362	−0.006	0.889	0.001	0.122	0.001	0.123	0.139	0.889	0.648	0.079	0.006
Plasma glucose (mmol/L)	−0.001	0.362	0.025	0.417	5.6×10^–5	0.926	9.0×10^–5	0.882	−0.615	0.538	27.382	0.067	2.5×10⁻⁵
Fasting insulin (pmol/L)	−0.001	0.362	−0.866	0.103	−0.027	0.328	−0.012	0.285	0.810	0.418	8.721	0.439	0.002

^{^a}

Data presented are standardized beta coefficients and P values, unless otherwise indicated. Significant results are indicated by an asterisk (^*). The “A path” is moderate-to-vigorous physical activity (MVPA; min/day) and relationship to body mass index (BMI) z-score while controlling for waist circumference, age, gender, race/ethnicity, income, total energy intake, total alcohol intake, and smoking status. The “B path” is BMI z-score and relationship to metabolic risk factors, controlling for waist circumference, age, gender, race/ethnicity, income, total energy intake, total alcohol intake, and smoking status. The “C path” is MVPA and relationship to metabolic risk factors, controlling for waist circumference, age, gender, race/ethnicity, income, total energy intake, total alcohol intake, and smoking status. The “C’ path” is identical to the C path but has the addition of BMI z-score as a covariate.

^{^b}

Glycohemoglobin was measured on 12- to 19-year-old participants only.