We found that adults with obesity have lower prevalence of use of yoga therapy, and similar prevalence of use of several CAM modalities, including relaxation techniques, natural herbs, massage, chiropractic medicine, tai chi, and acupuncture, compared to normal-weight individuals. After adjustment for sociodemographic factors, insurance status, medical conditions, and health behaviors, adults with obesity were generally less likely to use most individual CAM modalities, although the magnitude of these differences were quite modest in many cases.
Despite the estimated 1.3 billion dollars spent on weight loss supplements in 2001 (31
), we found low prevalence of use of natural herbs overall by adults with obesity. These results were surprising given the results of a recently published national survey that found the prevalence of use of nonprescription weight loss supplements to be 8.7% overall, and use by adults with obesity substantially higher than that of normal-weight individuals (32
). One potential explanation for our different findings may be the way that supplements were categorized in our study. Because the NHIS grouped use of nonvitamin/nonmineral supplements under the heading of natural herbs, if a respondent did not categorize their weight loss supplement as a natural herb, data would not have been collected on their use of the supplement. Our results also contrast data reported from the National Health and Nutrition Examination Survey (NHANES) which found that higher BMI is associated with lower use of dietary supplements overall (33
). However, NHANES included use of multivitamin/multimineral supplements in their definition of dietary supplements, whereas our study focused specifically on use of natural herbs. Therefore, these differing categorizations limit direct comparisons of the relationship between BMI and dietary supplement use between the surveys.
We had expected adults with obesity to have the same or higher use of CAM given their increased burden of disease and greater use of conventional medical care. One potential explanation for lower use of some CAM therapies, including yoga and massage, by adults with obesity may be related to their reduced participation in healthy lifestyle behaviors. Previous studies have suggested that CAM users are more likely to engage in physical activity (34
), and our results are consistent with these findings. However, even after we adjusted for physical activity level and smoking status, we found lower use of yoga, massage, tai chi, and acupuncture with higher BMI categories, suggesting that additional factors are influencing the use of these CAM therapies by adults with obesity. Interestingly, among respondents who had used any CAM therapy, we did not detect any difference in the rating of the importance of CAM use for maintaining health and well-being between weight categories.
Our study could not explicitly examine whether respondents were using CAM therapies in place of conventional care. However, in the 40% of adults using CAM to treat a specific medical condition, <50% used CAM in combination with conventional medical care. We found that adults with obesity were slightly more likely to use CAM in combination with conventional care.
We found the strongest relationship between obesity and low use of CAM for yoga therapy. One potential explanation is that most types of yoga are more difficult to perform with a large body habitus, and therefore may create situations of self-doubt, discomfort, and embarrassment (36
), discouraging adoption and extended use by adults with obesity. Likewise, slightly lower use of massage therapy by adults with obesity, may reflect avoidance of therapies that require body exposure and manipulation by a provider. Interestingly, use of chiropractic, which also focuses on the body, did not differ by weight category. Further understanding of differences in patterns of use by adults with obesity might help us better understand the particular health-care expectations and needs, as well as the potential barriers to care of this population. Patterns of utilization of CAM by adults with obesity are of particular interest as evidence is emerging on the efficacy of CAM for treatment of some medical conditions related to obesity, such as low back pain and hypertension (9
). However, based upon our results, it does not appear that out-of-pocket expenditures for CAM therapies augment health-care costs attributable to obesity.
Disclosure rates of CAM use to conventional medical providers were somewhat higher among adults with obesity, although overall rates of disclosure were low, ranging from 21 to 34%. This low rate for disclosure is concerning for adults with obesity, since they are somewhat more likely to use CAM in combination with conventional medical treatments, and thus may be at greater risk for potential adverse events, such as drug–herb interactions.
There are several potential limitations of our data. First, the self-reporting methodology of NHIS may have led to error or misclassification. For example, adults with obesity tend to underestimate their weight and hence BMI, thus any differences we found across BMI categories were likely underestimated. Second, given the relative low prevalence of respondents with moderate and extreme obesity, we were likely underpowered to detect differences between obesity categories. In addition, since it is challenging to categorize the vast number of non-conventional therapies used in the United States, it is difficult to capture the true prevalence of use of CAM.
In summary, our study suggests that despite their increased burden of disease, adults with obesity are not using CAM therapies at higher rates than normal-weight individuals. Adults with higher BMIs are less likely to use yoga and somewhat less likely to use most other individual modalities after adjustment for several potential confounders. Further research is needed to improve our understanding of the role of CAM in the treatment of obesity and obesity related conditions.