Table 4.

Meta-regression analysis of variables predicting serum and plasma levels of leptin.

Variables	R	Adjusted R2	P
Age
Serum	-0.065	-0.103	0.679
Plasma	0.114	-0.078	0.599
Sex
Serum	0.324	0.107	0.198
Plasma	0.089	0.195	0.089
Assay approaches
Serum	-0.272	-0.099	0.500
Plasma	0.053	-0.109	0.927
Design
Serum	-0.0003	-0.123	0.990
Plasma	-0.452	0.113	0.164