Table 3.

Comparison of fixed effects and random effects estimates of relationship between a one-SD increase in the walkability index and change in each health outcome from baseline to follow-up, n=1,079 middle-aged adults who moved residential locations between 2000 and 2006

Outcome variables	Fixed effects a		Random effects b		Hausman test e
	Coefficient (SE) c,d	p-value	Coefficient (SE) c,d	p-value	p-value
Walking physical activity
Participation	−0.180 (0.139)	0.196	0.202 (0.098)	0.038**	0.003***
Exercise units	−1.126 (1.689)	0.506	4.109 (1.445)	0.004***	0.021**
Body mass index, kg/m2	−0.022 (0.077)	0.778	−0.018 (0.069)	0.793	0.000***
Waist circumference, cm	−0.232 (0.270)	0.391	−0.260 (0.242)	0.283	0.000***
Systolic blood pressure, mmHg	−0.810 (0.373)	0.032**	−0.799 (0.365)	0.029**	0.294
ln(HOMA-IR) f	−0.011 (0.015)	0.457	−0.016 (0.010)	0.104	0.005***
ln(triglycerides)	−0.017 (0.018)	0.328	−0.025 (0.015)	0.084*	0.007***
LDL cholesterol, mg/dL	−0.224 (0.992)	0.822	−1.506 (0.790)	0.057*	0.253
HDL cholesterol, mg/dL	−0.121 (0.331)	0.715	0.256 (0.284)	0.367	0.009***
ln(C-reactive protein)	0.071 (0.033)	0.032**	0.037 (0.016)	0.022**	0.057*
Atherogenic dyslipidemia	0.343 (0.231)	0.137	−0.225 (0.118)	0.057*	0.037**

SD = standard deviation, SE = standard error, HOMA-IR = homeostasis model assessment of insulin resistance, LDL = low-density lipoprotein, HDL = high-density lipoprotein

^*significant at 90 percent confidence

^**significant at 95 percent confidence

^***significant at 99 percent confidence

^aAdjusted for time (days between exams) and time-varying sociodemographic and health covariates (income, household size, marital status, employment status, smoking status, health problems that interfere with physical activity)

^bAdjusted for time (days between exams), sociodemographic and health covariates (baseline age, gender, race/ethnicity, educational attainment, income, household size, marital status, employment status, smoking status, health problems that interfere with physical activity), and reasons for moving to the current neighborhood (moved for built environment reason(s))

^cStandardized coefficients represent the association between a one-SD increase in the walkability index (i.e. increase of 7.95 units) and change in each health outcome in its specified units

^dAll standard errors clustered at the follow-up Combined Metropolitan Statistical Area (CMSA) level, with the exception of the fixed effects models for walking participation and atherogenic dyslipidemia (clustering option not available for fixed effects logistic models)

^eHausman specification test evaluates null hypothesis that consistent (fixed effects) and efficient (random effects) estimates are equal; rejection favors fixed effects over random effects

^fParticipants with diabetes at baseline (n=42) excluded from HOMA-IR regressions