Table 4.

Regression results of testing the effect of salivary testosterone on total surface area

Predictors	Estimates	SE	Std. Beta	Standardized SE	Standardized CI	Statistic	P  *
Males (N = 160 id; 122 twinid; Observations = 306)
Testosterone	12.41	53.01	0.00	0.02	−0.03– 0.04	0.23	0.815
Testosterone: age (linear)	121.86	520.48	0.05	0.19	−0.32– 0.42	0.23	0.815
Testosterone: age (quadratic)	248.65	493.50	0.09	0.18	−0.27– 0.45	0.50	0.614
Females (N = 131 id; 103 twinid; Observations = 255)
Testosterone	−85.97	60.40	−0.03	0.02	−0.08– 0.01	−1.42	0.155
Testosterone: age (linear)	−476.88	542.68	−0.17	0.20	−0.571– 0.23	−0.88	0.38
Testosterone: age (quadratic)	469.84	490.05	0.18	0.19	−0.19– 0.55	0.96	0.338
Effect of salivary testosterone on change of surface area from birth to year 1
Males (N = 68 twinid; Observations = 89)
Testosterone	4.66	78.64	0.01	0.11	−0.2 – 0.21	0.06	0.953
Females (N = 59 twinid; Observations = 72)
Testosterone	−142.91	69.09	−0.19	0.09	−0.38 – −0.01	−2.07	0.039 *

^* P value <0.05 “*” and <0.002 “**” (P value for significance after correction for multiple comparison).