Our data suggest that slightly more than one-third of U.S. adults without diabetes had a family history of diabetes in 2005–2008 but that fewer than half reported receiving a physician’s or health professional’s advice during the past year about diabetes risk–reducing behavioral changes. Although there is substantial evidence that diabetes can be prevented by healthy lifestyle changes, our data show that no more than one-half of U.S. adults without diabetes reported trying to perform these risk-reducing behaviors in the past 12 months. However, when physician advice was received, >70% of U.S. adults without diabetes reported following the advice and engaging in one or more of these behavioral changes. In contrast, a smaller percentage of people who did not receive physician advice acknowledged making these changes.
Consistent with prior studies (11
), our study confirms independent associations of physician advice and diabetes risk factors, including familial risk for diabetes, with diabetes risk–reducing behaviors in the general adult U.S. population without diabetes. However, the effect of family history of diabetes on risk-reducing behavior changes was diminished after accounting for all commonly known associated risk factors for diabetes.
Family history is an important risk factor that reflects inherited genetic susceptibility, shared environment, and common behaviors. Valdez et al. (7
) reported that approximately one of every three adults in the U.S. population has a moderate or high familial risk of diabetes. People with a family history of diabetes have been found to have two to six times higher risk of having type 2 diabetes (16
). Studies have suggested that the use of family history as a screening tool to detect diabetes and cardiovascular diseases is an inexpensive method of extracting genomic information (17
). Regardless, a recent study on the impact of a positive family history and genetic risk variants on the incidence of diabetes reported a difference in diabetes incidence according to family history in the early years of intervention but that this difference disappeared upon follow-up (18
). Our data suggest that people with a reported family history of diabetes participate more in risk-reducing behavior changes than those with no family history (without accounting for all commonly known associated risk factors, including the reception of physician advice). This could be because FHx+ individuals are more aware of their risk of diabetes than are FHx− individuals (19
In agreement with other studies (20
), our data suggest a strong effect of physician advice on the adoption of risk-reducing behavioral changes in the previous year, which varied by demographic characteristics. However, the prevalence of performing risk-reducing behaviors did not differ by family history of diabetes for those who received and followed physician advice on behavioral changes. Given the high percentage of people performing these behaviors if in receipt of advice, our data suggest that this advice was effective but that the knowledge of a positive family history did not increase the already high percentage of people adopting the preventive behaviors. A prior study on lifestyle modification to improve blood pressure control in individuals with diabetes concluded that physician advice is effective at changing hypertension-related lifestyle factors among people with diabetes, regardless of sex or race/ethnicity (11
). Studies also reported that patients with type 2 diabetes might visit their family physicians up to nine times yearly (21
), giving physicians and other health care professionals many opportunities to assess and to encourage patients to engage in risk-reducing behaviors. In spite of the influence of family history in risk-reducing behavior changes and the important role of physician advice on lifestyle changes, our data suggest that more than one-half of people at high risk (i.e., with a positive family history of diabetes) had not received physician advice on lifestyle changes in the past 12 months. Using our data and data from a recent CDC diabetes report (1
), we estimate that there are >49 million people aged ≥20 years who do not have diabetes but who are at high risk because of a positive family history who have not received physician advice on lifestyle changes or recommended interventions. These findings indicate a great challenge in diabetes prevention, particularly for high-risk individuals.
Previous studies have reported that numerous factors may influence the routine provision of physician advice on lifestyle changes, for example, lack of time for counseling, physician training and education, limited staff support, reimbursement for preventive services, knowledge of successful strategies, community resources, limited English proficiency, and perceived success rate (11
). Despite these barriers, adoption of these risk-reducing behaviors could be substantially promoted if physician advice is provided (22
). Therefore, as physicians are increasingly encouraged to offer preventive care, effective strategies need to be developed to promote lifestyle changes and to help physicians overcome barriers to promoting a healthy lifestyle.
Strengths and limitations
This study has several strengths. First, we conducted this study using data from a nationally representative sample of the U.S. population, making our estimates generalizable to the entire population of U.S. adults without diabetes. Second, NHANES provides substantial data on biological and lifestyle factors, all of which were collected using standard laboratory and physical measurements. Finally, our study includes 4 years of data and, thus, a large sample size, powering our statistical ability to detect associations. However, there are several limitations. First, NHANES is cross-sectional, so we could not formally assess the temporal relation between physician advice and family history with behavior changes or assess these factors in relation to diabetes incidence. We were only able to evaluate how risk-reducing behaviors associated with family history and how much of this association is due to physician advice. We accessed the association of family history on reports of behavioral changes for the preceding 12 months. Nevertheless, it is unclear whether these lifestyle changes would continue long term. Second, there may be substantial social desirability bias introduced by self-reported responses regarding lifestyle changes and the receipt of physician advice. There are no separate methods in NHANES to validate self-reported variables, including family history of diabetes. Third, family history of diabetes could only be defined based on first-degree relatives, since information for other relatives was not asked in the 2005–2008 NHANES. As reported in a previous study (23
), differences in the definition of family history between studies may lead to inconsistent findings. Fourth, the terms “physician advice” and “physician counseling” may not be interpreted consistently (11
). Therefore, there should be some caution when comparing our estimates of the effect of physician advice on the adoption of diabetes risk reduction behaviors with the findings of other studies. In addition, other factors affect the influence of physician advice, such as the use of effective counseling techniques, the duration of counseling, how often patients have physician visits and get counseled, and the physician’s attitude and perceptions (24
). These factors were not considered in the current study. Finally, the results of this study may be influenced by the misclassification of diabetes (25
). We did not use measures of fasting plasma glucose or results from glucose tolerance tests because these tests were performed in only a subset of NHANES participants, which would have largely reduced our sample size. Therefore, we defined diabetes by self-report and by using the new HbA1c
criteria recently recommended by the American Diabetes Association (14
In conclusion, our data suggest that family history of diabetes and advice from a health professional both influence the adoption of diabetes risk–reducing behaviors. Our data also indicated that people with family history are more likely to have a discussion with their doctors on behavior changes. There is room for improvement regarding the proportion of adults who actually receive such advice. However, once the advice is provided, familial risk does not seem to affect the adoption of these behaviors. It appears likely that the continued development of practical methods and effective strategies to promote behavioral changes is needed to contain, and perhaps reverse, the modern epidemic of diabetes.