The findings of this study indicate education was an important, if not the most important predictor of nutrient-based diet quality in the HANDLS sample. Although the parameter estimate for education was small compared to other significant predictors, it represents the change per grade completed, making education an important predictor of MAR in the HANDLS sample. Additionally, besides sex, education was the only variable that was significant in the total sample regression, as well as African American and white regression analyses. Compared to national averages, the average education of the HANDLS sample is low; 29.6% of the population did not complete a high school degree or equivalent, compared to 14.5% of the US as a whole.29
Previous analysis of a HANDLS sample revealed a median 8th
grade reading level.30
Despite the low educational attainment of the HANDLS sample, results of these analyses are consistent with other national and regional studies that found education to be a significant predictor of food and nutrient-based diet quality4,6,10
and in food and nutrient-based diet quality over time.5,7
In addition to education, the effect of race on nutrient-based diet quality cannot be discounted in this sample. Not only was race a significant predictor of MAR in the total sample regression analysis, but interaction tests indicated significant differences between races as well. MAR scores for whites were significantly higher than for African American, as were their NAR scores for thiamin, riboflavin, folate, B12, vitamin A, vitamin E, phosphorus, magnesium, copper, calcium. This finding is consistent with other studies which also reported significant differences between nutrient and food-based diet quality scores between African Americans and whites.4,6,8
Similar results were found in micronutrient intake from nationally representative NHANES data for vitamin C, potassium, and calcium.31
These differences may reflect beverage choices between races with African Americans choosing more vitamin C-fortified beverages and less potassium and calcium-rich milk and dairy products.31
Kant et al. reported that African Americans are less likely to make selections from food groups rich in these nutrients such as the fruit, vegetable, and dairy groups.31
There have been documented differences in food availability, particularly the availability of supermarkets and grocery stores in minority neighborhoods in the US(32,33
), and fast food restaurants are more prevalent in these areas.34
Although analysis on food availability has not been done in Baltimore City, these findings are consistent with high intake of fast foods previously documented in a HANDLS sample.35
Lower diet quality among African Americans examined in the HANDLS study may reflect cultural differences in selection and preparation of foods. Kittler and Sucher documented the evolution of African American soul food consisting primarily of pork, pork fat, chicken, organ meats, corn, sweet potatoes, and greens.36
Observations from the coding of dietary data in this population indicate higher intakes of soul foods such as fried chicken, pork ribs, and collard greens cooked in fat back or ham hocks for African Americans. An earlier report of the dietary patterns in a HANDLS sample created by cluster analyses revealed high intakes of fat laden foods such as fried chicken.35
These foods are rooted in the African American culture and are a way of preserving tradition.36
African Americans may view making “healthy” food choices as conforming to the dominant culture.36,37
Therefore nutrition education interventions would be helpful in this population, particularly messages aimed at individuals with low reading levels and without a high school degree.
Differences in food availability, selection, preparation, and preference, combined with differences in SES result in lower diet quality of the African American HANDLS sample, placing them at greater risk for chronic conditions and may contribute to the health disparities seen between African Americans and whites. These disparities among low-income minority populations will become more important as the US population becomes increasingly diverse, since minorities are expected to become the majority in the US by 2050.38
If changes are not made to rectify these discrepancies, it will affect the overall health of the US population.
Comparisons to other studies are difficult due to the low SES of the HANDLS population. The macronutrient intake of the HANDLS sample in this study was similar to the sample examined in the 2005-06 NHANES for protein as a percent of energy (15.9% vs. 15.9%), carbohydrate as a percent of energy (48.4% vs. 47.8%), total fat as a percent of energy (33.8% vs. 34.8%) and saturated fat as a percent of energy (11.3% vs. 11.3%).39
However the total energy intake of the HANDLS sample was less than that consumed by the 2005-06 NHANES sample, 8414 kJ vs. 9183 kJ, respectively. To our knowledge there are no current studies using the MAR for comparison. There was a study using the 1994-96 Continuing Survey of Food Intakes for Individuals; however, DRI values have changed since its publication.24
Compared to NHANES 2005-06, the HANDLS sample had lower mean intakes for all micronutrients measured in the MAR; however mean intakes for all micronutrients in the HANDLS sample were within 95% confidence intervals for the NHANES mean 2005-06 intakes.39
The mean 2005-HEI score for the HANDLS sample population was lower than the HEI-2005 scores for NHANES 2003-04 (48.7 vs. 57.5).39
HANDLS scores were also lower than the HEI-2005 scores of NHANES low-income sample (defined as <130% of the PIR) whose HEI-2005 average was 56.5.40
Similar to the results of this HANDLS sample, McCabe et al. found age, race, income, and education had statistically significant impact on 1994-96 HEI scores in African American and white adults in the Lower Mississippi Delta. However in contrast to HANDLS, income was particularly important.6
Another study using data from NHANES II and food-based measures of diet quality found whites had higher diet quality than African Americans, plus higher income and higher education were associated with better diet quality.4
Lack of a pervasive impact of income and PIR was contrary to the expected outcome of the regression analysis. In other studies, income or PIR were found to be significant predictors of diet quality, if not the most significant contributor.5,8,9
However, many of these studies analyzed nationally representative samples, while the HANDLS sample was composed of primarily of individuals with low to low-middle SES residing in an urban area. Similar to the results of this analysis, a recent study of a higher income population found education to be a stronger predictor of dietary energy density than household income.41
Therefore, differences in diet quality due to economic circumstances may disappear when samples are taken from just the low or high end of the income and PIR range.
One limitation of this study is that dietary information represents the nutrient intake from foods and not total nutrient intake. The collection of dietary supplement information began with Wave Two of the HANDLS study. Therefore, further research is necessary at the conclusion of Wave Two to determine the effect of supplementation on nutrient-based diet quality in the HANDLS sample. Another limitation is that this study did not contain the entire HANDLS sample. At the time of data analysis, baseline data were still being collected. Further research with the entire baseline sample is necessary to corroborate the results of this study. Even though the study consisted of two dietary recall interviews, the data could still be biased. Lastly, the HANDLS sample is composed of primarily low SES individuals making the application of the results limited to populations with similar characteristics.
In conclusion, to the best of our knowledge this is the first study to examine nutrient-based diet quality in an urban population of relatively low SES. Education appears to be the most important factor in predicting diet quality in this HANDLS sample. However, the effect of race cannot be discounted. Whether the racial differences in diet quality are indicative of cultural differences in food selection and preparation or of differences in SES remains unclear. Since these discrepancies in diet quality may be a contributing factor to the health disparities documented between African Americans and whites, action to help eliminate these differences is necessary as the minority populations in the US continue to grow. Culturally appropriate nutrition education to both African Americans and whites, particularly messages aimed at individuals with less than a high school education would be beneficial to improving diet quality in urban areas of low SES.