Table 3.
Regression Coefficients (Fixed Effects), Random Effects, and P-values From Multivariate HLM Models That Include Only Individual-Level Characteristics As Explanatory Variables For Fruit/Vegetable Intake, Using the Third National Health and Nutrition Examination Survey 1988-1994 (NHANES III) 1
| Servings of Fruit and Vegetables Combined (N=13,281) | Servings of Fruit (N=13,310) | Servings of Vegetables (N=13,296 | ||||
|---|---|---|---|---|---|---|
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| Coeff | P-value | Coeff | P-value | Coeff | P-value | |
| Race/Ethnicity | ||||||
| Mexican American | 0.004 | 0.9783 | 0.15 | 0.1609 | -0.16 | 0.1364 |
| NH Black | -0.42 | 0.0003 | 0.06 | 0.3763 | -0.50 | <0.0001 |
| ‘Other’ | -0.30 | 0.1756 | -0.22 | 0.1609 | -0.07 | 0.6302 |
| NH White (ref) | --- | --- | --- | --- | --- | --- |
|
| ||||||
| Age (centered) | 0.03 | <0.0001 | 0.02 | <0.0001 | 0.01 | 0.0122 |
| Age (centered) squared | -0.0001 | 0.3297 | 0.0001 | 0.1181 | -0.0003 | 0.0082 |
|
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| Female | -0.71 | <0.0001 | -0.09 | 0.0944 | -0.62 | <0.0001 |
|
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| US-born | -0.85 | <0.0001 | -0.63 | <0.0001 | -0.21 | 0.0634 |
|
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| Educational Attainment | ||||||
| Grade School | -1.19 | <0.0001 | -0.70 | <0.0001 | -0.51 | <0.0001 |
| Some High School | -0.81 | <0.0001 | -0.55 | <0.0001 | -0.27 | 0.0284 |
| High School | -0.48 | <0.0001 | -0.40 | <0.0001 | -0.08 | 0.3563 |
| Post High School (ref) | --- | --- | --- | --- | --- | --- |
|
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| Family Income | ||||||
| Poor | -0.62 | 0.0009 | -0.26 | 0.0361 | -0.35 | 0.0070 |
| Low income | -0.41 | 0.0158 | -0.18 | 0.0600 | -0.23 | 0.0692 |
| Middle income | -0.31 | 0.0186 | -0.09 | 0.3374 | -0.22 | 0.0203 |
| High income (ref) | --- | --- | --- | --- | --- | --- |
|
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| Employment status | ||||||
| Employed | 0.23 | 0.2198 | 0.06 | 0.4828 | 0.18 | 0.2842 |
| Not in Labor Force | 0.27 | 0.1457 | 0.08 | 0.2585 | 0.18 | 0.2674 |
| Unemployed (ref) | --- | --- | --- | --- | --- | --- |
|
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| Region | ||||||
| Northeast | 0.12 | 0.5865 | 0.06 | 0.6639 | 0.06 | 0.6651 |
| Midwest | 0.01 | 0.9514 | 0.04 | 0.7614 | -0.02 | 0.9040 |
| South | -0.27 | 0.1407 | -0.26 | 0.0144 | -0.01 | 0.9512 |
| West (ref) | --- | --- | --- | --- | ||
|
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| Intercept | 6.44 | <0.0001 | 2.44 < | 0.0001 | 4.01 | <0.0001 |
|
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| Random Effects | ||||||
| Level 1 variance | 9.63 | <0.0001 | 3.32 | <0.0001 | 5.58 | <0.0001 |
| Level 2 variance | 1.99 | <0.0001 | 0.55 | <0.0001 | 1.09 | <0.0001 |
| Level 3 variance | 0.09 | 0.0309 | 0.05 | 0.0026 | 0.03 | 0.0723 |
|
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| ICC-level 2 (%) 2 | 17.03 | 14.06 | 16.28 | |||
| ICC- level 3 (%) 2 | 0.74 | 1.36 | 0.46 | |||
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| Fit Statistics | ||||||
| -2 Res LL | 77895.8 | 63767.9 | 70686.1 | |||
| AIC | 77901.8 | 63773.9 | 70692.1 | |||
Hierarchical linear models (HLM), or multi-level regressions, were conducted with PROC MIXED using SAS version 9.1. Level 1=individual level, level 2= tract level within counties, and level 3=county level.
ICCs = intra-class correlation coefficients, which provide an estimate of the proportion of total variance in dietary outcome that occurs between geographic areas. Level 2 ICCs provide an estimate of the proportion of variance in dietary outcome that occurs between tracts within counties while level 3 ICCs provide an estimate of the proportion of variance in dietary outcome that occurs between counties.