Abstract
Objective
Little is known about the effects of social support on weight loss in Latinos. This study determined whether sex moderated and treatment adherence mediated the association between social support and weight loss.
Methods
Data from 278 Latino males and females with type 2 diabetes in the Intensive Lifestyle Intervention of the Look AHEAD trial were analyzed. Multivariable modeling tested for moderation and parallel multiple mediator modeling simultaneously tested the mediating effects of adherence to physical activity, diet, and session attendance on the relationship between baseline social support and percent weight loss at 1 year.
Results
Social support for physical activity (having family and friends join in physical activity) was related to weight loss. Adherence to physical activity was related to both social support for physical activity and weight loss. Sex did not moderate these relationships. Adherence to physical activity completely mediated the relationship between social support for physical activity and weight loss.
Conclusion
Increasing companionship for physical activity may be an effective intervention strategy to promote behaviors important for weight loss among Latinos.
Keywords: Latino, social support, behavioral adherence, obesity treatment, Look AHEAD trial
Introduction
Type 2 diabetes and diabetes-related complications due to poor glycemic control are significantly more prevalent among Latinos compared to non-Hispanic Whites (1, 2). Weight loss for those who are overweight with type 2 diabetes improves glycemic control (3). However, Latinos tend to lose less weight compared to non-Hispanic Whites in behavioral weight loss trials (4). For example, the Look AHEAD (Action for Health in Diabetes) trial investigated the long-term health effects of weight loss in an ethnically diverse cohort of overweight adults with type 2 diabetes (4). Study results showed that non-Hispanic Whites and males lost a greater percent of baseline body weight than Latinos and females after one year. Among Latinos and females, smaller weight loss appeared to be due to lower treatment adherence. Potential sex differences within Latinos were not examined. Understanding the factors that influence treatment adherence among Latino males and females would help identify strategies to enhance adherence to behaviors important for weight loss.
One factor that may influence adherence is social support (5, 6). Treatment adherence has been suggested to mediate the link between social support and health outcomes (5, 6). Social support, particularly from family and friends, is a significant predictor of adherence for patients with diabetes (7, 8). Not surprisingly, individuals with diabetes who have fewer social relationships are at higher risk of mortality than those with greater social ties (9).
Social support is studied using measures of structural and functional support (10, 11). Structural social support describes the quantitative aspects of social relationships such as the number of individuals in a network or number and types of social contacts. Household composition and marital status are often used to assess structural social support. Living with others has been shown to be positively associated with treatment adherence among patients. Married individuals report higher levels of adherence behaviors (12). Functional social support describes the quality of available resources such as perceived availability of instrumental or emotional support. Instrumental support is assistance with tangible needs such as getting groceries or transportation to appointments. Emotional support refers to communication of caring, understanding, and/or esteem (5, 12).
The role of social support in promoting adherence is influenced by ethnicity. In general, Latinos in the United States report relying on family ties for social support more than non-Hispanic Whites (13). Family support appears to serve as a protective factor against diabetes for Latinos as it predicts diabetes diagnosis in this group but not in non-Hispanic Whites (14). Compared to non-Hispanic Whites, Latinos live in larger and multigenerational family households (15). For Latinos with diabetes, living with family members has been associated with higher levels of dietary adherence. Family support specific to diet and physical activity has also been associated with greater adherence (16). Family members provide instrumental support such as assistance with shopping, attending medical visits, and communicating with doctors (17). Although family is the main source of support for diabetes care, Latinos identify friends as sources of help with physical activity (17). In fact, not having a friend with whom to engage in physical activity has been cited as a primary barrier to physical activity in older adult Latinos (18).
Evidence indicates that the effect of social support on adherence may also differ by gender. In a multiethnic sample of diabetic patients, married men were more compliant with self-care behaviors than married women. Women with diabetes have been found to perceive less general social support and receive less spousal and instrumental social support related to diet than men. Whereas men with diabetes report receiving support from their wives, women receive most support from other women such as adult daughters (19). In a behavioral intervention to improve diabetes management, social support network size was negatively correlated with session attendance and submission of self-monitoring diaries among women only (20). Greater social obligations and demands among women may interfere with treatment participation or adherence. Family responsibilities, in particular, may be a bigger issue for women with children as they are less likely to meet physical activity and dietary guidelines (21).
The evidence above illustrates the important role social support plays in behavioral adherence among individuals with diabetes; however, there is a knowledge gap regarding the relationship of specific types of social support with treatment adherence and weight changes in Latino men and women and whether this relationship depends on sex. The Look AHEAD trial included one of the largest cohorts of overweight Latinos with diabetes, and therefore provides a unique opportunity to study how family and friend support affect treatment adherence and weight loss in Latinos. The purpose of the present study is to test whether 1) structural and functional support predict treatment adherence and weight loss outcomes, 2) sex moderates the association of social support with treatment adherence and weight loss, and 3) treatment adherence mediates the relationship between social support and weight loss.
Methods
Participants
A total of 5,145 adults were enrolled in the Look AHEAD trial across the United States, 677 of which were Latino. To be eligible for the study, individuals were required to be 45–76 years of age, have a diagnosis of type 2 diabetes, and have a body mass index (BMI) ≥25 kg/m2. Participants were randomly assigned to an Intensive Lifestyle Intervention (ILI) or a Diabetes Support and Education. Only data from the 278 Latinos enrolled in the ILI at five clinic sites, which were primary enrollment sites for this group (91%), were included in this study. All participants provided written informed consent, and study procedures were approved by the institutional review boards at each clinic site.
Intervention
The ILI has been described previously and is summarized briefly here (22). The ILI was adapted from the Diabetes Prevention Program. It was designed to achieve an average of ≥7% of initial weight loss, with individual participant weight loss goals set at >10% of initial weight. A total of 42 intervention sessions were offered during the first year. In months 1–6, participants attended group sessions for the first 3 weeks of the month and then met individually with an interventionist the fourth week of the month. In months 7–12, participants attended biweekly group sessions and monthly individual meetings. Participants were prescribed 1,200–−1,800 kcal/day with ≤30% of calories from fat. Structured meal plans and meal replacements were provided. Participants were encouraged to replace two meals and one snack daily during months 1–6 and one meal and one snack during months 7–12 with liquid shakes and meal bars. Participants could be provided with 714 meal replacements during the first year. Participants were prescribed ≥175 minutes/week of moderate intensity physical activity the first 6 months which increased to ≥200 minutes/week for those who met the initial goal. Participants were instructed to keep daily records of their food and beverage intake and physical activity. Submission of self-monitoring records was high (90%).
Measures
Participant characteristics
At baseline, participants provided information on sex, age, education, employment, and household income. Participants also reported on insulin use.
Family structural support
Three measures of baseline structural support were examined. Marital status was categorized as married/living as married or not (separated/widowed/divorced/single). Child status was categorized as living with children <18 years at home or not. Household family size was measured by the number of individuals living at home.
Family/friend functional support
Three measures of baseline functional support were examined. Only instrumental support was examined because data on emotional support were not collected. To allow interpretation of data according to the presence and absence of social support, responses were dichotomized. Support for physical activity was assessed by the question, “In a normal week, how many hours do your spouse, family, and friends spend exercising with you?” Responses were dichotomized to indicate whether or not family and friends participated in physical activity with participants. Support for diet was assessed by the question, “In a normal week, how many hours do your spouse, family, and friends spend shopping for and preparing food for you?” Responses were dichotomized to indicate whether or not participants had family and friends help with food provision. Support for attending medical visits was assessed by asking the question, “When you go to a Look Ahead visit and other doctor or nurse visits, how often does your spouse, family, or friends go with you?” Responses were dichotomized from a 5-point scale into always/usually/half the time or never/rarely to indicate whether or not participants had family and friends accompany them to medical visits.
Treatment adherence
Three measures of adherence were examined. Physical activity adherence was measured by the average minutes per week of physical activity performed during the first year of the intervention as reported by participants in their daily records. Diet adherence was measured by the total number of meal replacements consumed during the first year of the intervention as reported by participants in their daily records. Attendance adherence was measured by the number of sessions attended by participants during the first year of the intervention as recorded by the staff.
Weight loss
Body weight was measured to the nearest 0.1 kilogram by staff at baseline and at 1-year using a digital scale (model BWB-800; Tanita, Willowbrook, IL). Height was measured at the nearest 0.5 centimeter using a wall mounted stadiometer.
Statistical analysis
Means and standard deviations were computed for continuous measures, and frequencies and percent were computed for categorical measures. Sex comparisons were performed on these measures using either t-tests or chi-square tests as appropriate.
Multivariable linear regression analyses were used to test the association of the various measures of baseline structural and functional social support with the three measures of treatment adherence and weight change at 1 year. All models were adjusted for baseline age, education, income, insulin use, weight, sex, and clinic site; sex interactions were also investigated to test for moderation effects.
To test for the potential simultaneous mediation of social support by treatment adherence on 1 year weight change (Figure 1), multiple mediation was assessed by the bootstrapping technique and macro suggested by Preacher and Hayes (23). Bootstrapping is a nonparametric resampling procedure for testing mediation that involves repeated sampling from the data set and estimating the indirect effect in each resampled data set. Parallel mediation was conducted such that all mediators were entered and tested in the regression models simultaneously. Specifically, a 95% bias-corrected confidence interval (CI) was calculated to determine if the proposed mediating variables (weekly minutes of physical activity, total meal replacements consumed, and treatment sessions attended) helped explain the relationship between social support and weight change. In the present study, the 95% CI of the indirect effects of the mediators was obtained with 10,000 bootstrap resamples. A significant indirect effect was determined if the 95% CI did not contain zero. All p-values and CIs were corrected for multiple testing. All analyses were performed using SAS 9.4 (SAS Institute, Cary, NC).
Figure 1.
Multiple Mediation Model
Results
Participant characteristics
Baseline participant characteristics by sex are presented in Table 1. The average age was 57.1 years. The majority of participants were female (72.3%), had a high school education or less (56.1%), and had an annual household income less than $40,000 (63.7%). Mean BMI was 34.6 kg/m2 and weight 89.0 kg. Compared to males, females were younger and more likely to be homemakers.
TABLE 1.
Baseline characteristics by sex
| Overall | Males | Females | p-value* | |
|---|---|---|---|---|
| N (%) | 278 (100.0) | 77 (27.7) | 201 (72.3) | |
| Age (years) [Mean ± SD] | 57.1 ± 5.7 | 58.4 ± 6.1 | 56.6 ± 5.4 | 0.016 |
| Education [N (%)] | 0.118 | |||
| Non high school graduate | 106 (38.6) | 21 (28.0) | 85 (42.5) | |
| High school graduate | 48 (17.5) | 13 (17.3) | 35 (17.5) | |
| Some college | 80 (29.1) | 26 (34.7) | 54 (27.0) | |
| College graduate | 41 (14.9) | 15 (20.0) | 26 (13.0) | |
| Employment [N (%)] | <0.001 | |||
| Full or part-time | 152 (54.7) | 45 (58.4) | 107 (53.2) | |
| Homemaker | 84 (30.2) | 10 (13.0) | 74 (36.8) | |
| Unemployed | 42 (15.1) | 22 (28.6) | 20 (10.0) | |
| Household income [N (%)] | 0.065 | |||
| <$40k | 174 (63.7) | 47 (61.8) | 127 (64.5) | |
| $40k-$59,999 | 55 (20.2) | 11 (14.5) | 44 (22.3) | |
| ≥$60k | 44 (16.1) | 18 (23.7) | 26 (13.2) | |
| BMI (kg/m2) [Mean ± SD] | 34.6 ± 5.3 | 34.0 ± 4.9 | 34.9 ± 5.4 | 0.226 |
| Weight (kg) [Mean ± SD] | 89.0 ± 16.5 | 97.6 ± 15.3 | 85.7 ± 15.8 | <0.001 |
| Insulin use [N (%)] | 42 (15.3) | 15 (19.7) | 27 (13.6) | 0.203 |
p-values are from Chi-Square tests of association for categorical variables, and t-tests for continuous variables, comparing males to females.
Structural and functional social support
Baseline social support by sex is presented in Table 2. More than half of participants were married (64.0%) and almost a quarter had minor-aged children living at home (22.0%). Participants reported an average of 3.3 individuals living in the household. Nearly a third of participants had family and friends join them for physical activity (27.7%). Half of participants had family and friends assist them with grocery shopping and food preparation (50.0%) and about a quarter had family and friends accompany them to medical visits (26.3%). Males and females had similar structural support but differences were found in functional support with more males than females having help with grocery shopping and food preparation and more females than males were accompanied to medical visits.
TABLE 2.
Baseline social support by sex
| Overall | Males | Females | p-value* | |
|---|---|---|---|---|
| Structural Support | ||||
| Married or living as married [N (%)] | 178 (64.0) | 54 (70.1) | 124 (61.7) | 0.189 |
| Have children living at home [N (%)] | 56 (22.0) | 16 (21.9) | 40 (21.0) | 0.991 |
| Household family size [Mean ± SD] | 3.3 ± 2.0 | 3.1 ± 1.3 | 3.3 ± 2.2 | 0.185 |
| Functional Support | ||||
| Family and friends join physical activity [N (%)] | 77 (27.7) | 17 (22.1) | 60 (29.8) | 0.195 |
| Family and friends shop and prepare food [N (%)] | 139 (50.0) | 50 (64.9) | 89 (44.3) | 0.002 |
| Family and friends attend medical visits [N (%)] | 73 (26.3) | 9 (11.7) | 64 (31.8) | <0.001 |
p-values are from Chi-Square tests of association for categorical variables, and t-tests for continuous variables, comparing males to females.
Adherence and weight loss
Treatment adherence and 1 year weight loss by sex are presented in Table 3. Participants on average reported 181.6 minutes per week of physical activity, consumed 350.9 meal replacement products out of 714 provided by the ILI prescription, and attended 34 out of 42 intervention sessions. Males reported significantly more weekly minutes of physical activity than females. Weight loss averaged 8% of initial body weight with no differences by sex.
TABLE 3.
Year 1 weight and adherence outcomes by sex [Mean ± SD]
| Overall | Males | Females | p-value* | |
|---|---|---|---|---|
| BMI (kg/m2) | 31.8 ± 5.4 | 31.4 ± 5.1 | 32.0 ± 5.5 | 0.355 |
| Weight (kg) | 81.9 ± 16.7 | 90.1 ± 16.0 | 78.7 ± 16.0 | <.001 |
| Weight change from baseline (kg) | −7.1 ± 5.7 | −7.6 ± 6.4 | −6.9 ± 5.4 | 0.414 |
| Percent weight change from baseline | −8.1 ± 6.0 | −7.8 ± 6.0 | −8.2 ± 6.1 | 0.667 |
| Weekly minutes of physical activity | 181.6 ± 104.8 | 207.9 ± 118.6 | 171.5 ± 97.5 | 0.017 |
| Total number of meal replacements consumed† | 350.9 ± 167.9 | 375.1 ± 189.2 | 341.6 ± 158.6 | 0.136 |
| Number of treatment sessions attended‡ | 34.9 ± 7.1 | 35.2 ± 7.6 | 34.8 ± 6.9 | 0.724 |
p-values are from t-tests, comparing males to females
714 meal replacements recommended
42 treatment sessions delivered
Multivariable analysis of social support and adherence or weight change
The relationship between structural or functional support and adherence or percent weight change was determined while controlling for covariates. There were no significant main effects of structural support variables on adherence or weight change; however, significant sex interactions were found (data not shown). Sex moderated the effect of marital status, a structural support variable, on consuming meal replacements such that married males used more meal replacements than non-married males but married females used fewer meal replacements than non-married females (p=0.02). Among functional support variables, having social support for physical activity was significantly associated with both adherence and weight change. Specifically, participants who had family and friends join in physical activity at baseline had greater weekly minutes of physical activity during the first year of the intervention (β=57.2, SE=13.7, p<0.01), as well as better attendance at intervention sessions (β= 1.89, SE=0.92, p=0.04). In addition, participants who had support for physical activity achieved greater weight losses (β=−2.10, SE=0.84, p=0.01). Those with no support for physical activity at baseline attended 2 fewer sessions, participated in 56 fewer minutes of physical activity per week, and lost 2.5 percentage points less weight than those with support for physical activity. Neither having family and friends shop/prepare food for you or attend medical visits with you were associated with any of the adherence measures or 1 year weight change. No moderation effects of sex were noted in any of the models involving functional support.
Mediation analysis
We conducted multiple mediation analyses to determine if adherence mediated the association between functional social support and weight loss (Table 4). The relationship between social support and treatment adherence is shown by path a; the relationship between treatment adherence and weight change by path b; and the total effect of social support on weight change by path c. The total effect (c) is the sum of direct (c’) and indirect (ab) effects. The direct effect is the relationship between social support and weight change while controlling for mediators. The indirect effect represents the mediated effect. Parallel mediation was conducted such that all mediators (adherence variables) were tested simultaneously. Mediation analysis showed that weekly minutes of physical activity completely mediated the relationship between social support for physical activity and weight change (c’, p=0.155). No significant indirect effects were found for social support for diet and attendance to medical visits.
TABLE 4.
Multiple mediation testing of adherence measures on the effect of social support on weight change at year 1*
| Potential mediators | Effect of social support on mediator (a) |
Effect of mediator on % weight change (b) |
Effect of social support on % weight change without mediation (c) |
Effect of social support on % weight change with mediation (c’) |
Indirect effect | 95% Bootstrap Confidence Interval |
|---|---|---|---|---|---|---|
| Social Support: Family and friends join physical activity | ||||||
| Weekly minutes of physical activity | 57.2 (13.7) <0.001 |
−0.016 (0.004) <0.001 |
−2.10 (0.84) 0.012 |
−1.06 (0.75) 0.155 |
−0.85 (0.31) | −1.56 – −0.33 |
| Total meal replacements consumed | 36.8 (23.1) 0.113 |
−0.004 (0.002) 0.103 |
−0.17 (0.15) | −0.54 – 0.05 | ||
| Treatment sessions attended | 1.89 (0.92) 0.041 |
−0.209 (0.058) <0.001 |
−0.37 (0.21) | −0.84 –0.001 | ||
| Social Support: Family and friends shop and prepare food | ||||||
| Weekly minutes of physical activity | −17.1 (12.9) 0.185 |
−0.016 (0.004) <0.001 |
0.51 (0.76) 0.791 |
−0.18 (0.67) 0.782 |
0.28 (0.24) | −0.13 – 0.83 |
| Total meal replacements consumed | −30.6 (21.2) 0.149 |
−0.004 (0.002) 0.103 |
0.14 (0.13) | −0.06 – 0.44 | ||
| Treatment sessions attended | −0.31 (0.85) 0.711 |
−0.209 (0.058) <0.001 |
0.06 (0.18) | −0.28 – 0.43 | ||
| Social Support: Family and friends attend medical visits | ||||||
| Weekly minutes of physical activity | 22.4 (14.9) 0.134 |
−0.016 (0.004) <0.001 |
−0.78 (0.91) 0.412 |
−0.62 (0.77) 0.419 |
−0.35 (0.22) | −0.82 – 0.04 |
| Total meal replacements consumed | 17.1 (24.6) 0.488 |
−0.004 (0.002) 0.103 |
−0.08 (0.11) | −0.33 – 0.11 | ||
| Treatment sessions attended | 0.29 (0.98) 0.765 |
−0.209 (0.058) <0.001 |
−0.06 (0.19) | −0.46 – 0.29 | ||
Regression coefficient for all paths based on models adjusting for baseline age, education, income, insulin use, weight, sex, and clinic site. All p-values and CIs are corrected for multiple testing.
Regression coefficient (standard error)
p-value
Discussion
This study examined the effects of structural and functional social support on treatment adherence and weight loss among Latino males and females in the Look AHEAD trial. Our findings suggest that males and females differ in the type of social support received and the effects it has on treatment adherence. However, the relationship between social support and weight loss did not depend on sex. For both males and females, having family and friends join in physical activity predicted weight loss by potentially promoting adherence to physical activity.
Overall, participants received more instrumental support for diet than for physical activity and medical visits from family and friends. Although individuals with diabetes generally cite diet as the greatest challenge of self-care behaviors, they report that family and friends provide the most help in disease management through behaviors such as grocery shopping, food preparation, and shared diet (19). Compared to other adherence behaviors, diet-related support may be more readily offered because eating typically occurs in a social environment, especially in the context of family. We found that less than a third of Latino participants had someone attend medical visits or exercise with them. Previous studies have found that being accompanied to doctor visits and being helped with physical activity are among the types of practical support that Latinos with diabetes report needing (17, 24). Moreover, diabetic Latinos identify family members as primary sources of support for grocery shopping and attending medical appointments (17, 24). Friends, on the other hand, appear to be an important source of help with physical activity as they can provide companionship (17).
Males and females differed in the type of functional support received and not in the type of structural support present. More males than females received assistance with grocery shopping and food preparation. This finding is consistent with studies of diabetic individuals showing that women are primarily responsible for food or meal related tasks and husbands depend on their wives for diet support (19, 25). Additionally, we found that it was more common for females than males to have accompaniment to medical visits, which is in line with reports that Latinas rely on family members such as adult children to help in attendance at medical visits and communication with physicians (17, 24).
Family structure was associated with adherence to diet. Married males consumed more meal replacements than non-married males, but married females used fewer meal replacements than non-married females. In a previous study of diabetic Mexican-Americans, perception of support for diet was stronger for men than women (26). In qualitative studies, Latinas with diabetes reveal experiencing opposition from husbands and family members when changes to traditional or cultural practices were made and subsequently forgoing their personal dietary needs to avoid conflict and the task of preparing different meals for themselves (29, 30). Women who felt their husbands were unsupportive of dietary changes were less likely to control food intake (30). Almost 40% of Latinas in this study were homemakers, suggesting traditional gender roles in meal preparation may have influenced their ability to incorporate meal replacements into their diet (31).
Our results indicate that treatment adherence may mediate the link between social support for physical activity and weight loss. Although supportive social networks had been shown to predict physical activity among older adults in the past (35), our findings suggest that social support, and specifically participating with others in physical activity, increased physical activity thereby enhancing weight loss. While one might assume that participants with support for physical activity at baseline also had higher levels of physical activity at baseline, this was not the case.
This study has limitations to acknowledge. The Look AHEAD trial included one of the largest cohorts of Latinos with diabetes for weight loss; however, our sample size of 278 and 28% males are limitations. Although we studied specific support types associated with adherence behaviors, we did not distinguish between family and friend support and therefore cannot isolate the contribution of each source. Several previous studies have indicated that friends more so than family facilitate physical activity in adults. Social support measures such as friendship network size, contact with friends, and perceived support from friends have been positively associated with physical activity in men and women of various racial/ethnic backgrounds (36–38). Friends may be an especially important support source for physical activity in U.S. Latinos since changes in social networks due to immigration can result in reduced availability of family and greater social isolation (39, 40). Unfortunately, acculturation indictors such as nativity, English language proficiency, and years of U.S. residence were not collected by the Look AHEAD trial which might have provided greater insight into the cultural context of support systems for Latinos with diabetes. Another limitation is the use of self-reported adherence measures for diet and physical activity for our analyses.
Despite the limitations, this study has several strengths worth mentioning. This is one of the first studies to test the mediation effects of treatment adherence in the relationship between social support and intervention outcomes among Latinos with type 2 diabetes (5, 6). Multiple mediation analyses also determined that physical activity adherence uniquely contributes to the relationship between family and friend support for physical activity and weight loss outcome. Examination of structural and functional support for diet, physical activity, and attendance offers a better understanding of the impact of specific types and sources of support on participants’ ability to comply with treatment recommendations. Study findings also highlight the relevance of considering social support differences in men and women and implications of these differences in obesity treatment.
Conclusion
Functional but not structural support predicted weight loss among Latino males and females with type 2 diabetes participating in the Look AHEAD trial. Functional support in the form of engagement in physical activity with family and friends led to greater weight loss potentially by enhancing adherence to physical activity. While more research is needed with a larger sample and greater proportion of males to more definitely describe these mediating relationships, behavioral weight loss interventions may want to consider increasing companionship for physical activity as a strategy to promote behaviors important for weight loss.
Supplementary Material
What is already known about this subject?
Latinos tend to fare worse than non-Hispanic Whites in treatment adherence and weight loss.
Gender differences exist in adherence to diet and physical activity and social support for these behaviors among Latinos.
Social support is associated with adherence and weight loss in non-Hispanic Whites.
What does your study add?
Our findings reveal the following:
Latino males and females differ in the type of social support they receive and the effects it has on treatment adherence.
Specific types of support and adherence behaviors are related to weight loss among Latinos participating in a weight loss trial.
Adherence to physical activity mediates the relationship between social support from friends and family and weight loss.
Acknowledgments
Funding:
This study is supported by the Department of Health and Human Services through the following cooperative agreements from the National Institutes of Health: DK57136, DK57149, DK56990, DK57177, DK57171, DK57151, DK57182, DK57131, DK57002, DK57078, DK57154, DK57178, DK57219, DK57008, DK57135, and DK56992. The following federal agencies have contributed support: National Institute of Diabetes and Digestive and Kidney Diseases; National Heart, Lung, and Blood Institute; National Institute of Nursing Research; National Center on Minority Health and Health Disparities; NIH Office of Research on Women’s Health; and the Centers for Disease Control and Prevention. This research was supported in part by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases. The Indian Health Service (I.H.S.) provided personnel, medical oversight, and use of facilities. The opinions expressed in this paper are those of the authors and do not necessarily reflect the views of the I.H.S. or other funding sources.
Additional support was received from The Johns Hopkins Medical Institutions Bayview General Clinical Research Center (M01RR02719); the Massachusetts General Hospital Mallinckrodt General Clinical Research Center (M01RR01066); the University of Colorado Health Sciences Center General Clinical Research Center (M01RR00051) and Clinical Nutrition Research Unit (P30 DK48520); the University of Tennessee at Memphis General Clinical Research Center (M01RR0021140); the University of Pittsburgh General Clinical Research Center (M01RR000056 44) and NIH grant (DK 046204); the VA Puget Sound Health Care System Medical Research Service, Department of Veterans Affairs; and the Frederic C. Bartter General Clinical Research Center (M01RR01346).
Footnotes
Clinicaltrials.gov number: NCT00017953
The following organizations have committed to make major contributions to Look AHEAD: Federal Express; Health Management Resources; Johnson & Johnson, LifeScan Inc.; Optifast-Novartis Nutrition; Roche Pharmaceuticals; Ross Product Division of Abbott Laboratories; Slim-Fast Foods Company; and Unilever.
Disclosure: The authors declared no conflict of interest.
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