Table 3.

Linear regression results for the association between leptin and MRI brain volume measures.

Brain Volume Measure (per SD)	Model 1*		Model 2**		Model 3***
	Beta (SE)	P-value	Beta (SE)	P-value	Beta (SE)	P-value
Total cerebral brain, %	0.029 (0.028)	0.31	0.036 (0.035)	0.30	0.039 (0.036)	0.28
Total gray matter, %	−0.0023 (0.027)	0.93	0.043 (0.034)	0.21	0.045 (0.035)	0.20
Total white matter, %	0.025 (0.028)	0.38	0.016 (0.035)	0.66	0.018 (0.036)	0.61
Hippocampus, %	0.0017 (0.028)	0.95	−0.0039 (0.035)	0.91	−0.028 (0.036)	0.43
White matter hyperintensities, cm3 (ln-transformed)	0.020 (0.028)	0.49	−0.042 (0.035)	0.23	−0.044 (0.036)	0.23

Abbreviations: SD, standard deviation; SE, standard error

Note: Leptin is natural log-transformed and standardized within each sex. Brain volume measures are expressed per standard deviation increment of age and age-squared-adjusted residuals. The interaction between leptin and BMI for each outcome was assessed using Model 1. There are no statistically significant interactions between leptin and BMI category for any of the brain volume outcome measures.

^*Adjusted for age at MRI, age-squared, sex, systolic blood pressure, ln-insulin, ln-fasting blood glucose, and years between clinic exam and MRI.

^**Adjusted for model 1 covariates plus body mass index (kg/m²).

^***Adjusted for model 2 covariates plus APOE4.