. Author manuscript; available in PMC: 2015 Sep 1.

Published in final edited form as: Int J Vitam Nutr Res. 2014;84(0):286–294. doi: 10.1024/0300-9831/a000215

Table 3.

Coefficients from the Ordinary Least Squares (OLS) Regression

Variables	β (SE) from OLS for Folate Levels
Variables	Serum folate	RBC folate
A. Unadjusted model for full sample
Tested after versus before fortification	9.10^*** (0.79)	190.64^*** (20.60)

Observations	356	356

B. Unadjusted model for subsample with data on all covariables
Tested after versus before fortification	9.40^*** (1.01)	186.93^*** (25.41)

Observations	262	262

C. Adjusted model for subsample with data on all covariables
Tested after versus before fortification	8.67^*** (1.04)	180.14^*** (26.78)

Observations¹	262	262

Note: The Table reports the OLS regression coefficients (β) and standard errors (SE) in parentheses.

^***

p < 0.01.

The adjusted model (Model C) controls for the following covariates: maternal age, marital status, number of children, wanting more children, smoking cigarettes, drinking alcoholic beverages, contraception use, educational attainment, employment status, and frequency of gynecological visits. The sample size declined to 262 observations when adjusting for these variables since some observations had missing data on one or more of these variables. As a reference, we also show the results from the unadjusted model (Model B) that was estimated in the subsample with complete data on all covariables (adjusted for in model C).