Tipping the scales: the effect of literacy on obese patients' knowledge and readiness to lose weight.

Objectives: The purpose of this study was to determine the association between the literacy level of overweight/obese patients and their weight-loss knowledge, attitudes, and readiness.

Methods: Structured patient interviews and a literacy screening instrument were administered in two primary care clinics at a university-based public hospital.

Results: A convenience sample of 210 overweight or obese adult outpatients (body mass index [greater than or equal to]25 kg/[m.sup.2] or [greater than or equal to]30 kg/[m.sup.2], respectively) were enrolled. Mean respondent age was 52 years; 74% were female, and 76% were black. Two thirds of patients read below a 9th grade level. Half of patients across all literacy levels reported currently attempting weight loss. There was a significant relation between literacy level and weight-loss knowledge, attitudes, and readiness (P < 0.05).

Conclusions: Patients with low literacy were significantly less likely to understand the adverse health consequences of obesity and the need to lose weight and to report being ready to lose weight. Patient education and counseling for weight loss should be tailored for patients with low literacy skills.

Key Words: health literacy, literacy, obesity, public hospital, weight loss

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The incidence of obesity has increased dramatically in the United States; almost two thirds of adults (58 to 64%) are now overweight or obese. (1,2) Rates of obesity are highest for vulnerable populations, for example, those with low literacy, low incomes, minorities, the elderly, and the uninsured. (2) Nationally, there is a higher prevalence of obesity in southern states, particularly among patients cared for in public hospitals. (3) These patients often have low literacy, which may affect their understanding of the health consequences of obesity and appropriate weight loss strategies.

Low literacy is an underrecognized problem in the United States that has been associated with poor health and poor health outcomes. (4-7) According to the National Adult Literacy Survey, 23% of US adults have low literacy skills. (4) Low-income individuals, minorities, the elderly, and those with chronic illness--populations similar to those with high rates of obesity--are disproportionately hindered by literacy barriers.

Despite growing information on the magnitude and consequences of both obesity and low literacy, (2,5,8-10) very little is known about the relation between literacy and weight loss knowledge and attitudes. The purpose of this study was to examine the association between literacy and weight loss knowledge, attitudes, readiness, and experience of obese patients in public hospitals.

Materials and Methods

The study took place in 2002 in two primary care clinics at Louisiana State University Health Science Center-Shreveport. After their physician visit, overweight and obese patients (body mass index [BMI] [greater than or equal to]25 kg/[m.sup.2] or [greater than or equal to]30 kg/[m.sup.2], respectively) were approached for enrollment in the study. Patients with English as a second language were excluded. Height, weight, sociodemographic factors (sex, race, age, insurance, employment status) and obesity-related diagnoses were abstracted from patient charts. A trained research assistant interviewed participants privately, using a structured questionnaire developed by the authors and pilot tested for patient understanding in a low-literate population.

The interview included questions regarding the patient's self-rating of health, understanding of the relation between weight and health, the effect of a 10% weight loss (patients were provided a specific number of pounds), the patient's motivation for weight loss, and previous and current weight loss activities.

In addition, using an instrument previously developed by Macqueen et al, (11) based on Prochaska's stages of change model, patients were asked to categorize themselves by selecting the statement that best represented their readiness for weight loss (see Table 1).

After the interview, literacy was assessed through the use of the Rapid Estimate of Adult Literacy in Medicine (REALM). (12) This individually administered reading recognition test is comprised of 66 health-related words. Raw scores can be categorized into reading grade levels, based on the number of words pronounced correctly. In this study, patient reading levels are reported as 6th grade and below, 7th to 8th grade, and 9th grade and above, which could correspond to low, marginal, and adequate reading ability. The REALM correlates highly with other word recognition tests and the Test of Functional Health Literacy in Adults. (13)

The study protocol was approved by the Louisiana State University Health Science Center-Shreveport Institutional Review Board.

Statistical analysis

[chi square] analysis was used to analyze categoric data. Continuous variables were compared by means of t test or analysis of variance as appropriate. When multiple variables proved to be significantly related to a dependent variable, linear regression was used to obtain adjusted odds ratios. A probability value of less than 0.05 was used for statistical significance.

Results

Of the 215 patients approached, 210 completed the study and 5 refused to participate. An additional 5 answered the questions but refused to take the REALM and were thus excluded from data analysis. Participant demographics are presented in Table 2.

Only one in three patients read on or above a 9th grade level and could be considered to have adequate literacy skills. Patients with lower literacy tended to be older (P < 0.02), male (P < 0.001), black (P < 0.0001), unemployed or retired (P < 0.02), and Medicaid/Medicare recipients (P = 0.0003).

A substantial minority of patients could not read the following words on the REALM reading test: obesity (43%), diabetes (39%), nutrition (28%), or calories (22%). Other commonly used words in weight loss information that some patients could not read were exercise (17%), meals (13%), and fat (7%).

The mean BMI for the study population of overweight and obese patients was 38.9 (range, 26 to 65), with the majority of participants (92%) being obese (BMI [greater than or equal to]30 kg/[m.sup.2]). Almost all (95.6%) patients had obesity-related diseases, including hypertension (83.9%), dyslipidemia (43.9%), type 2 diabetes mellitus (42.4%), coronary artery disease (13.7%), and osteoarthritis (13.2%). Patient BMI levels and rates of obesity-associated diseases did not differ significantly by literacy level.

Thirty-five percent of patients rated their overall health as "good" or "excellent," 42% as "fair," and 23% as "poor" or "very poor." Patients' self-rating of health did not vary by literacy (P = 0.13). Sixty-one percent of patients believed their weight affected their health. Patients with low literacy were less likely to be aware of this relationship. Half of the patients reading at lower than the 6th grade level reported that their weight affected their health, compared with three fourths of those reading at the 9th grade level or above (P < 0.03). The majority of patients indicated a need and desire to lose weight (89% and 88%, respectively), but these sentiments were significantly stronger among those with higher literacy (P < 0.05 for both; see Table 3).

When asked what effect a modest weight loss (equivalent to 10% of current weight) would have, most patients (87%) reported that it would be beneficial to their health. Patients who thought a 10% weight loss would be detrimental or have no effect had significantly lower literacy (P = 0.003).

In addition, most patients (87%) also reported previous attempts at weight loss. Patients reported having lost a median of 22 pounds (range, 0 to 250) for a median of 6 months (range, 2 weeks to 20 years). The quantity and duration of weight loss did not vary by literacy. Patients reported a mean of two weight loss methods (range, 0 to 5, including diet, exercise, fad diets, pills, and other). The 23% of patients who had attempted three or more methods had higher literacy than those who had attempted one or two (P = 0.013). Patients who could not state which weight loss method they had found to be most effective had significantly lower literacy levels than their counterparts (P = 0.004).

Half of patients at all literacy levels answered affirmatively when asked if they were currently trying to lose weight. With regard to stage of readiness to lose weight, 15% of patients reported being in precontemplation, 22% in contemplation, 33% in preparation, 13% in action, and 18% in maintenance. Patients who reported they had not thought about losing weight (precontemplation stage) were more likely to have low literacy than marginal or adequate literacy (P = 0.027).

Discussion

Obesity costs approximately $75 billion annually (in 2003 dollars), with half of that amount spent through Medicaid and Medicare programs. (14) The health impact and economic burden of obesity are likely to worsen if practical strategies to control the epidemic are not developed and implemented.

The good news is that almost all overweight and obese patients interviewed reported wanting and needing to lose weight and having previously attempted weight loss. However, patients with lower literacy were less likely to believe they needed to lose weight or that it would be a health benefit; they were also less likely to be currently considering losing weight. Almost half of overweight and obese patients at the lowest literacy level did not know that their weight affected their health, and approximately one in four had not considered weight loss. These patients may benefit from tailored counseling on health benefits of weight loss.

Though literacy did not affect patients' weight loss attempts, our findings suggest that literacy may affect a patient's weight loss health literacy skills. Patients unable to read the word "calorie" or "obesity" may not be able to understand food labels or obesity-related educational materials. Moreover, dietitians often ask patients to keep a food diary to categorize and measure the food they eat. This constellation of reading, writing, and numeracy health literacy tasks may be impossible for the patient who reads below a 7th grade level. (9)

Our research suggests that the majority of patients in public hospitals may not be able to read, understand, and act on weight loss information. These findings support previous research about public hospital patients' understanding of written health care information. (15) A recent Institute of Medicine report stated that 90 million American adults have difficulty understanding and using health information. (9) The Institute of Medicine points out that patients are increasingly responsible for health care management. The tasks of information gathering, measuring, and monitoring health increasingly rest on patients who may lack the knowledge and skills needed to appropriately manage their disease. (9) The absence of the knowledge and skills needed to manage obesity and accompanying chronic diseases may be particularly pronounced in public hospitals.

Previous research found that literacy-directed educational materials and programs have been successful in enhancing patient understanding and improving health outcomes in high-volume public hospitals. (16) Davis et al (16) found that a video, brochure, and small group coaching tailored to public hospital patients with low literacy increased mammography rates by 30%. A recent study of public patients with diabetes found that those whose physicians confirmed their understanding of information conveyed during the visit were 15 times more likely to have good glycemic control. (7)

Although written materials alone will not solve the problem, simple, to-the-point materials tailored specifically for public hospital patients may improve their understanding of obesity and weight loss instruction. In addition, resident physicians may benefit from in-services to improve communication with patients with limited literacy, which include a teachback technique to confirm patient understanding. (10,17)

This study has several limitations. Participants' prior and current weight loss activity was self-reported. Patient motivation for weight loss was assessed at one point in time and may have been artificially increased by responder effects (the subject matter of the questionnaire, acquiescence bias). Additional research is needed, using objective measures of weight-related activities and longitudinal study designs. Our study, like most current studies of literacy and health relations, uses a cross-sectional study design that does not allow for assessment of the impact of literacy on the course or outcome of patients' current weight loss attempts. A recent Agency for Healthcare Research and Quality report calls for more prospective cohort studies that measure changes in outcomes and literacy over time. (10)

This study, which only included overweight and obese patients, did not answer the question of whether there is an association between obesity and literacy. Future studies may want to examine whether low literate individuals in the public hospital system are at higher risk for obesity or whether literate individuals are more successful at weight loss attempts.

Conclusion

Although it is promising that the majority of obese patients want and believe they need to lose weight, there appears to be a disparity across literacy levels. Weight loss counseling developed for public hospitals may be more effective if it is tailored to the patients' understanding, ability to act on health information, and readiness to change.

Table 1. MacQueen Stages of Change Questionnaire

I'm going to read you some statements. Please tell me which one sounds
  most like you. (Only italicized parts were read.)
Patient's readiness for weight loss based on Prochaska stages of change
  model
  (1) Precontemplation: I have not really thought about it.
  (2) Contemplation: I mean to lose weight but I don't actually get
  around to it.
  (3) Preparation: From time to time I go on a diet/exercise, but then I
  stop after a few days.
  (4) Action: I have been working on losing weight for the past 6
  months.
  (5) Maintenance: I have been working on losing weight for over 6
  months, or I have kept off the weight I lost for over 6 months.

Table 2. Participant characteristics (a)

                                               n             %

Female                                         152           74
Employed                                        63           31
Black                                          155           76
BMI category
  Overweight (25-29.9)                          16            8
  Class 1 (BMI 30-34.9)                         62           30
  Class 2 (BMI 35-39.9)                         51           25
  Class 3 (BMI [greater than or equal to] 40)   76           37
Literacy
  6th Grade or below                            67           32
  7th-8th Grade                                 71           35
  9th Grade                                     67           33
Mean age                                        52 (range, 19-82)
Mean BMI                                        38.9 (range, 26-65)
Mean literacy level                             7th-8th Grade level

(a) BMI, body mass index.

Table 3. Knowledge, attitude, and readiness by literacy level

                                   7th-8th
                        6th Grade  Grade     9th Grade
                        (n = 67)   (n = 71)  (n = 67)      P value

Weight affects health   50.0%      61.4%     72.5%         0.028
Need to lose weight     84.9%      85.7%     97.1%         0.035
Want to lose weight     80.3%      90.0%     94.2%         0.037
Not thinking of losing
  weight                23.1%      11.8%      7.4%         0.027
Previously attempted
  loss                  80.3%      87.1%     94.2%         0.053
Currently attempting
  loss                  48.4%      53.0%     48.4%       Not significant

Acknowledgments

The authors thank Stephanie Brock for her role in data collection, and Stephanie Savory and Anna Bocchini for their help preparing the manuscript.

Accepted August 10, 2004.

References

1. Flegal KM, Carroll MD, Ogden CL, et al. Prevalence and trends in obesity among US adults. JAMA 2002;288:1723-1727.

2. Mokdad AH, Ford ES, Bowman BA, et al. Prevalence of obesity, diabetes, and obesity-related health risk factors. JAMA 2003;289:76-79.

3. Huang J, Marin E, Yu H, et al. The prevalence of overweight, obesity, and associated diseases among outpatients in a public hospital. South Med J 2003;96:558-561.

4. Kirsch I, Jungeblut A, Jenkins L, et al: Adult Literacy in America: A First Look at the Results of the National Adult Literacy Survey. Washington, DC, National Center for Education Statistics, US Department of Education, 1993.

5. US Department of Health and Human Services: Nutrition and Overweight. Healthy People 2010: Understanding and Improving Health. Washington, DC, US Government Printing Office, 2nd ed, 2002.

6. Baker DW, Parker RM, Williams MV, et al. Health literacy and the risk of hospital admission. J Gen Intern Med 1998;13:791-798.

7. Schillinger D, Piette J, Grumbach K, et al. Closing the loop: physician communication with diabetic patients with low health literacy. Arch Intern Med 2003;163:83-90.

8. Gazmararian JA, Baker DW, Williams MV, et al. Health literacy among medicare enrollees in a managed care organization. JAMA 1999;281:545-551.

9. Institute of Medicine, Health literacy: a prescription to end confusion, in Nielsen-Bohlman LT, Panzer AM, Kindig DA (eds). Committee on Health Literacy. Washington, DC, National Academies Press, 2004.

10. Berkman ND, DeWalt DA, Pignone MP, et al. Literacy and health outcomes. Summary, Evidence Report/Technology Assessment: Number 87. AHRQ Publication Number 04-E007-1, January 2004. Agency for Healthcare Research and Quality, Rockville, MD. Available at: http://www.ahrq.gov/clinic/epcsums/litsum.htm. Accessed (DATE)

11. Macqueen CE, Brynes AE, Frost GS. Treating obesity: can the stages of change model help predict outcome measures? J Hum Nutr Diet 1999;12:229-236.

12. Davis TC, Long S, Jackson R, et al. Rapid estimate of adult literacy in medicine: a shortened screening instrument. Fam Med 1993;25:391-395.

13. Parker R, Baker D, Williams M, et al. The test of functional health literacy in adults (TOFHLA): a new instrument for measuring patients' literacy skills. J Gen Intern Med 1995;10:537-545.

14. Finkelstein EA, Fiebelkorn IC, Wang G. State-level estimates of annual medical expenditures attributable to obesity. Obes Res 2004;12:18-24.

15. Williams MV, Parker RM, Baker DW, et al. Inadequate functional health literacy among patients at two public hospitals. JAMA 1995;247:1677-1682.

16. Davis TC, Berkel H, Arnold C, et al. Intervention to increase mammography utilization in a public hospital. J Gen Intern Med 1998;13:230-233.

17. Huang J, Yu H, Marin E, et al. Physicians' weight loss counseling in two public hospital primary care clinics. Acad Med 2004;79:156-161.

RELATED ARTICLE: Key Points

* Patients with low literacy are less likely to understand the health benefits of losing weight, and are less likely to report being ready to lose weight.

* Patients with low literacy may lack understanding of the importance of weight loss or struggle with the literacy skills needed to monitor and measure weight loss.

* Patient education and counseling for weight loss in public hospitals should be tailored for patients with low literacy skills.

Estela M. Kennen, MA, Terry C. Davis, PHD, Jian Huang, MD, Herbert Yu, MD, PHD, Donna Carden, MD, Ricky Bass, MD, and Connie Arnold, PHD

From the Department of Medicine, Louisiana State University Health Sciences Center, Shreveport, LA; and the Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT.

The study protocol was approved by the Louisiana State University Health Sciences Center-Shreveport Institutional Review Board.

Funded in part by an educational grant from the Hoffmann--La Roche Foundation.

Reprint requests to Dr. Terry Davis, LSUHSC-Shreveport, 1501 Kings Highway, Shreveport, LA 71130. Email: [e-mail]