Overall, in the unadjusted analyses, there was weak evidence of an association between social support and diabetes outcomes. In addition, there was no evidence of an association between race/ethnicity and diabetes self-care behaviors, although racial/ethnic minorities had poorer diabetes control compared with whites, similar to prior NHANES studies30
and other meta-analytic studies.31
This population-based study thus differed from previous studies reporting differences in diabetes self-management by race/ethnicity.32-34
However, considering interactions of social support with each of the racial/ethnic groups suggested that future research evaluating these groups separately as well as contrasting groups may be warranted. The association of social support with the outcomes was most markedly different for blacks, with increased odds of performing 3 out of the 5 self-care behaviors (controlling weight, controlling fat/calories, and exercising) as well as decreased diastolic BP. This pattern of improving diabetes outcomes was not observed for the other 2 racial/ethnic groups, with the exception of whites having decreased LDL cholesterol with increased social support scores.
These results are consistent with previous research examining social support within the black community, such as a greater reliance on informal social networks17
and the importance of familial support for those with diabetes.10
In addition, previous research on social support within NHANES found that African Americans had higher scores on several social support measures compared with whites and Hispanics.35
Thus, perhaps the development of social ties and/or utilization of social support within specific cultural communities are unique enough to impact health in different ways—a topic that deserves further exploration. While it remains unclear why the same patterns of social support did not emerge for Latinos or whites in this study, future research into how social support influences health behaviors and outcomes comparing various racial/ethnic groups is needed; for example, investigating whether the positive effects of peer, Internet, and phone-based social support interventions among individuals with diabetes4
are applicable across races/ethnicities.
Furthermore, we found that social support was associated with A1C levels among whites, but in the opposite direction than anticipated (ie, increased social support was associated with higher A1C). Although social support is theorized to influence health behaviors as well as psychological and biological pathways,2
the potential causal link between social support and improved self-care behaviors is likely tighter than the link between social support and improved diabetes clinical outcomes, and the biological pathways activated through social support are not well understood. Moreover, the clinical outcomes in this cross-sectional analysis were probably vulnerable to reverse causality—that is, individuals with worse A1C might be receiving or relying more on social support than those with better blood sugar control. Therefore, future longitudinal studies examining the influence of social support among several racial/ethnic groups may be able to take further steps toward establishing causality and better understanding how race/ethnicity and social support work together to influence clinical outcomes.
There are several study limitations to note. First, a fully validated measure, such as the social network index, might have captured more subtle differences in social integration or support across races/ethnicities. The index in this analysis captured a count of the types of support in one's life, which is more general than a scale.36
The index created assumed that each type of support contributes equally and interchangeably to the index, an assumption that cannot be verified within this scope of this study. Furthermore, this index combined aspects of support and networks into a single measure, which is different from previous studies on this topic. Although both networks and support are theorized to similarly influence self-efficacy and, in turn, self-care behaviors and clinical outcomes, they may exert a different influence on the outcomes in this study.2
Different aspects of social support not included in NHANES, such as tangible support for getting to doctor's appointments,37
might also have an important influence on diabetes outcomes.
Furthermore, the findings are also based on a relatively small sample size. However, despite overall small numbers that may have limited statistical power, these comparisons were made within a nationally representative NHANES survey with oversampling of racial/ethnic minorities, which likely increases the generalizability of the results. In addition, the self-care behaviors were captured through self-report in the survey and could be over-reported because of social desirability, which has been suggested in other studies.38
Differences in self-report by race/ethnicity would impact our group comparisons most significantly. Moreover, more detailed reporting of self-care outcomes in future studies (ie, beyond reducing the outcomes to binary assessments) might provide more information about the relationship between social support and health behaviors. Finally, although there are several outcomes of interest in this study, we knowingly did not adjust for multiple comparisons,39
given that this was an initial analysis to examine differences in social support in diabetes care by race/ethnicity with an expectation that findings would be replicated in future confirmatory analyses.