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

Table 4.

Regression Series for Waist Circumference 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=2155), 6–19 years old^a
Systolic blood pressure (mmHg)	−0.016^*	0.001	0.027	0.185	−0.019^*	0.013	−0.016^*	0.025	−1.268	0.205	5.4	0.198	0.010
Diastolic blood pressure (mmHg)	−0.016^*	0.001	0.049	0.052	−0.005	0.490	−0.002	0.735	−1.756	0.079	48.9	0.100	8.6×10^–5
C-reactive protein (mg/dL)	−0.016^*	0.001	0.005^*	5.5×10^–6	−2.7×10^–4	0.184	−1.3×10^–4	0.499	−2.986^*	0.003	56.9	0.058	1.2×10^–4
Total cholesterol (mmol/L)	−0.016^*	0.001	0.003	0.242	0.001	0.120	0.001	0.093	−1.131	0.258	8.5	0.024	0.003
High-density lipoprotein cholesterol (mmol/L)	−0.016^*	0.001	−0.004^*	7.4×10^–7	0.001^*	0.001	4.3×10^–4^*	0.005	3.086^*	0.002	23.1	0.178	0.004
Glycohemoglobin (%)^b	−0.009	0.127	0.002^*	0.024	2.7×10^–4	0.101	3.0×10^–4	0.077	−1.312	0.190	9.8	0.044	0.001
Metabolic risk factor (n=1,860), fasting 12- to 19-year-old subsample^a
Fasting triglycerides (mmol/L)	0.002	0.879	0.004^*	0.023	4.7×10^–4	0.471	4.7×10^–4	0.461	0.154	0.878	2.1	0.127	0.001
Fasting low-density lipoprotein cholesterol (mmol/L)	0.002	0.879	0.004	0.178	0.001	0.123	0.001	0.123	0.153	0.878	0.8	0.079	0.006
Plasma glucose (mmol/L)	0.002	0.879	−6.5×10⁻⁵	0.982	9.8×10^–5	0.870	9.0×10^–5	0.882	−0.023	0.982	0.2	0.067	2.5×10^–5
Fasting insulin (pmol/L)	0.002	0.879	0.070^*	7.4×10^–8	−0.027	0.388	−0.002	0.285	0.154	0.878	8.5	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 waist circumference while controlling for body mass index (BMI) z-score, age, gender, race/ethnicity, income, total energy intake, total alcohol intake, and smoking status. The “B path” is waist circumference and relationship to metabolic risk factors, controlling for BMI z-score, 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 BMI z-score, 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 waist circumference as a covariate.

^{^b}

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