1. Examining Weight Loss Outcomes for Black and White Participants
Melanie Warziski Turk, PhD, RN
Obesity Researchers Journal Club
University of Pittsburgh
November 18, 2008

2. Introduction Minorities disproportionately affected
non-Hispanic Blacks = 45%
non-Hispanic Whites = 30.6%
Women:
54% Black compared to 30.2% White
(Ogden et al., 2006)
Medical conditions linked to overweight and obesity

3. How effective are behavioral weight loss interventions?
Review of several lifestyle interventions and the weight loss (WL) outcomes for black and white participants

4. Trials to Prevent Hypertension
Hypertension Prevention Trial (HPT)
Assessed effects of WL, ↓ sodium,
↑ potassium on blood pressure (B/P)
(Arch Intern Med. 1990; 150:153-62)
Trials of Hypertension Prevention (TOHP)
Examined the efficacy of WL, ↓ sodium, stress management, dietary supplements on lowering or preventing an increase in diastolic B/P (JAMA. 1992; 267: )

5. Trials to Prevent Hypertension (2)
HPT (36 mo)
Women
White (n=43): -1.2 ± 7.2 kg
Black (n=28): +2.6 ± 4.7 kg
Men
White (n=155): -1.5 ± 5.3 kg
Black (n=10): -0.7 ± 3.3 kg
TOHP (18 mo)
Women
White (n=48): -2.5 ± 6.3 kg
Black (n=33): -0.2 ± 4.1 kg
Men
White (n=204): -4.9 ± 6.3 kg
Black (n=18): -3.5 ± 3.5 kg
(Kumanyika, Obarzanek, Stevens et al., 1991)

6. Trials of Hypertension Prevention, Phase II- TOHP II
Additional 18 mo
Variety of options to stay involved
No differ. in WL at 36 mo, p > .02
Women
White (n=131): +0.8 kg (-0.3 to 1.9)
Black (n=62): +0.5 kg (-1.1 to 2.0)
Men
White (n=295): -0.9 kg (-1.6 to -0.3)
Black (n=34): 1.2 kg (-0.4 to 2.8)
(Stevens, Obarzanek, Cook et al., 2001)

7. Behavioral Weight Control Program for Individuals with NIDDM
12 mo behavioral intervention:
Low-calorie diet throughout
Very-low-calorie diet (12-wk periods)
Black: -7.1 kg vs. White: kg, p < .02
Magnitude of regain greater for black ps in second 6 mo
Black: 5.45 kg vs. White = 1.7 kg, p < .02
Major limitation: B: n=16 and W: n=59
(Wing & Anglin, 1996)

8. Trial of Nonpharmacologic Interventions in the Elderly (TONE)
Evaluate efficacy of 3 interventions:
Weight loss (WL)
Sodium reduction (Na)
WL + Na
Both WL groups at 6 mo:
Black (n=74):
-3.2 ± 0.4 kg
White (n=220):
-5.6 ± 0.3 kg
p = .004
Both WL groups at 36 mo:
Black (n=74):
-3.3 ± 0.5 kg
White (n=220):
-4.2 ± 0.4 kg
p = .12
(Kumanyika, Espeland, Bahnson et al., 2002)

9. Diabetes Prevention Trial (DPP)
Intensive Lifestyle vs. Metformin vs. Usual Care
7% WL goal min/week
Met individual case manager
49% achieved WL goal at end of core
57% White vs. 35% Black, p < .0001
37% achieved WL goal at the final visit with no differences in weight loss success, p = .11
(Diabetes Prevention Program Research Group, 2004)

10. Additional DPP Data
Secondary analysis of weight loss by gender and racial group for each arm
Lifestyle Intervention
Women
White (n=261): -4.5% ± 7.6%
Black (n=102): -2.0% ± 6.2%
Men
White (n=135): -5.8% ± 7.1%
Black (n=31): -5.1% ± 3.7%
(West, Prewitt, Bursac et al., 2008)

11. Additional DPP Data (2) Metformin Women White (n=251): -1.9% ± 6.7%
Black (n=106): -1.8% ± 6.4%
Men
White (n=166): -1.5% ± 5.6%
Black (n=37): -1.0% ± 4.5%
(West, Prewitt, Bursac et al., 2008)

12. Additional DPP Data (3) Placebo Women White (n=269): -0.9% ± 7.2%
Black (n=104): + 1.5% ± 5.3%
Men
White (n=124): -0.6% ± 5.0%
Black (n=39): +0.7% ± 5.2%
(West, Prewitt, Bursac et al., 2008)

13. (West et al., 2008)

14. Lifestyle Intervention in Post-Menopausal Women
6-mo intervention of reduced-calorie diet and walking
kcal deficit
3 days/week for min
White (n=57): -6.6 ± 4.2%
Black (n=19): -4.3 ± 4.3%
p < .05
(Nicklas, Dennis, Berman et al., 2003)

15. Weight Maintenance after a Behavioral Intervention- PREFER II
PREFER trial:
Randomly assigned
Standard or lacto-ovo-vegetarian diet
Standard behavioral therapy: 12-mo intervention then 6-mo maintenance
(Burke, Hudson et al., 2007; Burke, Warziski et al., 2008)
PREFER II:
Ancillary study at 18 mo after PREFER
Explore differences between black and white ps in weight maintenance

16. PREFER II (2) % Weight ∆ White Black (n=81) (n=26) M(SD) M(SD) p-value
Multiple linear regression:
Ethnicity: b = .86, SE = 1.45, p = .55

17. Treatment of Obesity in Underserved Rural Settings
6-mo lifestyle WL intervention (Phase I)
Reduced calories and increased physical activity
Weekly group meetings
Followed by 12-mo an extended care or control condition (Phase II)
In-person groups
Telephone counseling
Control: educational mailings
(Rickel, Gibbons, Milsom, et al., 2007)

18. Treatment of Obesity in Underserved Rural Settings (2)
Phase I
White (n=181): ± 4.9 kg
Black (n=43): -6.5 ± 4.7 kg
Phase II
p < .001
Black:
Extended care:
+1.7 ± 6.3 kg
Control:
+1.9 ± 4.2 kg
ps > .15
White:
Extended care:
+1.1 ± 6.2 kg, p > .10
Control:
-3.9 ± 6.9 kg, p < .01
(Rickel, Gibbons, Milsom, et al., 2007)

19. Weight Loss Maintenance Trial
30-mo multi-center RCT of strategies for maintaining WL
20-wk, non-randomized WL phase
Minimum of 4 kg lost:
Monthly personal contact
Unlimited access to interactive technology
Self-directed control
(Svetkey, Stevens, Brantley et al., 2008)

20. Weight Loss Maintenance Trial- WL Phase
African American
Men (n=196):
-5.4 ± 7.7 kg
(-5.1 ± 7.2%)
Women (n=540):
-4.1 ± 2.9 kg
(-4.4 ± 3.1%)
Non-African American
Men (n=355):
-8.5 ± 12.9 kg
(-8.1 ± 11.8%)
Women (n=594):
-5.8 ± 6.1 kg
(-6.5 ± 6.9%)
(Hollis, Gullion, Stevens et al., 2008)

21. (Hollis et al., 2008)

22. Weight Loss Maintenance Trial- Weight Maintenance Phase*
Interactive
Group n
African American
Men
Women
Non-African American
Men
Women
*Mean weight change (with standard error) at 30 mo. adjusted for age, site, gender,
race by gender interaction, study entry weight, and weight change during the WL phase.
2/24/2019
(Svetkey, Stevens, Brantley et al., 2008)

23. Weight Loss Maintenance Trial- Ancillary Study from Phase I
During 20-week WL phase
Comparison of all African Am. (AA) intervention groups to mixed race
Same AA interventionists
To control for potential interventionist effects
Avg. proportion of AA in mixed intervention groups: 56%
(Ard, Kumanyika, Stevens et al., 2008)

24. Weight Loss Maintenance Trial- Ancillary Results from Phase I
Ps from all-AA groups (n=271):
-4.2 ± 4.6 kg
61.2% achieved ≥ 4kg WL goal
Ps from mixed-race groups (n=106):
-4.2 ± 8.6 kg
55.7% achieved ≥ 4kg WL goal
No difference in outcomes, ps > .33.
(Ard, Kumanyika, Stevens et al., 2008)

25. Theoretical pathways for race & ethnicity as influences on weight management
Smoking
Alcohol
Genes
Gestation
Energy Metabolism
Race
Ethnicity
Energy
Balance
BMI
Food Intake
Sedentariness
Self-dieting
Activity/Exercise
Culture
SES
Context
Weight Management Programs
2/24/2019
(Kumanyika, S., Obesity Treatment in Minorities in Handbook of Obesity Treatment, 2004)

26. Guidelines for Adapting Weight Loss Programs for Effectiveness in Diverse Populations
1. Setting or treatment location
Physically accessible
Free of factors creating a lg. social distance
Promotes active involvement
2. Staff
Self-aware, competent
3. Educational and counseling approaches
Knowledge base
Daily routines
Financial resources
Cultural preferences
(NHLBI, 1998)

27. Guidelines for Adapting Weight Loss Programs for Effectiveness in Diverse Populations (2)
4. Weight management advice
Facilitate integration with other aspects of health care
5. Program modification
Expect and allow for based on feedback
(NHLBI, 1998)

28. Summary Black participants experienced smaller, shorter term WL
Weight regain was also smaller for black persons compared to white
Black women most pronounced difference in outcome
Weight regain after a behavioral intervention is commonplace

29. Future Research
Larger trials incorporating and testing culturally appropriate methods
Systematic studies of long-term WL patterns among black persons
Intensified multidisciplinary research to identify factors for black women
Well-designed analyses controlling for SES in order to avoid confounding
Evaluation of explicit strategies to promote WLM for all ethnicities

30. Acknowledgement Funding sources for PREFER and PREFER II
NIH 5R01 DK58631
NIH F31 NR

31. Thank you.