Abstract
Introduction: Excessive body weight, as reflected by a body mass index [BMI (kg/m2) > 25] is consistently and independently associated, not only with post‐menopausal breast cancer incidence, but mortality as well, with weight gain during adulthood being most strongly associated with risk. In addition, there is consensus that an increased BMI at the time of diagnosis is a poor prognostic indicator, and accumulating evidence that weight gain post‐diagnosis is associated with poorer overall and disease‐free survival. Thus, to reduce the burden of breast cancer, efforts are needed to promote weight control and to target those most at risk, i.e., women who already have breast cancer (for tertiary prevention of progressive/ recurrent disease and co‐morbidity) and their 1st degree relatives (as a means of primary prevention).
Previous studies also suggest that the cancer diagnosis catalyzes a “teachable moment” that may provide an opportune time for health promotion. The DAMES trial (Daughters And MothErS against breast cancer) is currently in the field and will explore whether the momentum of the teachable moment created by the cancer diagnosis, as well as the mother‐daughter bond, can be harnessed and used to promote weight loss in overweight women with breast cancer and their overweight adult daughters, and to discern whether team‐based vs. independently‐delivered interventions offer more promise.
Methods: 68 women diagnosed with loco‐regional breast cancer within 5‐years and their adult daughters (body mass index [BMI] 25+) were randomized to: 1) a tailored diet‐exercise intervention emphasizing the mother‐daughter team (TEAM); 2) a tailored diet‐exercise intervention delivered to mothers and daughters independently (INDEPENDENT); or 3) an attention control arm that received standardized diet‐exercise materials in the public domain (CONTROL); the unit of randomization was the motherdaughter dyad and the distribution of dyads was as follows: 25 dyads in the TEAM; 25 dyads in the INDEPENDENT, and 18 dyads in the CONTROL arms. All interventions consisted of mailed print materials (personalized workbook, plus 6 mailings over the course of the 1‐year study period. TEAM & INDEPENDENT participants also received pedometers, portion control tableware, diet/exercise logs, and iPoDs during the intervention (the control arm received iPoDs upon completion of the study). In addition to monitoring accrual, retention and adverse events, effect sizes (variation) regarding changes in weight status and lifestyle behaviors were assessed at baseline, 6‐and 12‐month follow‐up. Survey data (e.g., dietary intake of energy, saturated fat, fruits and vegetables and nutrient density via 2‐day dietary recalls, level of physical activity via the Godin Leisure Time Physical Activity Questionnaire [with supporting accelerometry], social support, in general and specific to changing diet and exercise via the Duke Social Support Index and the Sallis et al. Social Support Index for Diet and Exercise, Stage of Readiness and Self‐Efficacy for diet and exercise change, perceived risk of recurrence [for mothers] and primary risk of breast cancer [for daughters], health‐related quality of life via the SF‐36, and strength of the mother‐daughter bond via the Interpersonal Closeness Score) were captured at each time point via computer‐assisted telephone interviews, and anthropometric measures (weight, height, waist circumference and blood pressure) were assessed inperson by study staff.
Results: While this study is still in the field, at present the full sample has been accrued and randomized; characteristics of the study sample are as follows: Race/Ethnicity (73%White, 18%African American, 7% Hispanic and 2% Asian); Mean Years of Age (Mothers: 61/Daughters: 36), and Mean Distance Separating Dyad Members: 75 miles).
It is noteworthy that although this study was able to achieve its accrual target, a substantial number of breast cancer cases (N=2336) were contacted in order fulfill enrollment. While only a 26% response rate was achieved for the initial screener which accompanied the letter of invitation, the leading reasons for women reporting that they could not participate was because they either did not have an adult‐aged daughter, or did not have a daughter who was overweight.
At the time of this abstract submission, data collection is almost complete for the 6‐month time point. At this time, attrition is minimal (3%) and only two serious adverse events have been reported (none of which is attributable to the intervention). Preliminary findings from 57 dyads suggest that both the TEAM and INDEPENDENT interventions were associated with significant changes from baseline with decreases in mean dyadic weight (sd) over time being −6.44 (7.49) kg and −6.90 (8.91) kg, respectively as compared to the control −1.61 (6.0) kg (p‐values <.05). No significant differences were noted between the experimental interventions, though change scores were −3.2 vs. ‐3.0 kg (Mothers) and −2.9 vs. −3.5 kg (Daughters) for TEAM vs. INDEPENDENT interventions, respectively. BMI and waist circumference measurements mirror these findings. In addition, baseline to 6‐month increases in the level of moderate‐to‐vigorous physical activity were as follows: CONTROL: Mothers (29 min/week)/Daughters (19 min/week); TEAM: Mothers (53 min/week)/Daughters (55 min/week) and INDEPENDENT: Mothers (33 min/week)/Daughters (87 min/week)(overall p=.19/Team vs. Control p= .08 and Independent vs. Control p=.07).
Conclusions: The mother‐daughter weight loss interventions appear feasible as indicated by full enrollment, excellent acceptance, low attrition, and the absence of serious attributable adverse events. Thus far, the lessons learned from this study are as follows: 1) Substantial numbers of women with breast cancer are not eligible on the basis that they don't have a daughter, or one who is interested and eligible; 2) Preliminary data suggest that both interventions perform better than the control; however, data appear somewhat stronger (though not significantly) for mothers assigned to the TEAM intervention, whereas daughters appear to perform better with the INDEPENDENT intervention; and 3) More complete data will be available in the upcoming months to provide some clues as to the effects of the interventions over the longer term (1‐year), and will include dietary data, as well as analyses that explore potential moderation by the mother‐daughter bond. These additional data will be important in determining the future of family‐based lifestyle interventions aimed at the prevalent problem of breast cancer, and for developing future interventions that harness the momentum of the teachable moment and that optimize existing relationships and family dynamics to promote healthful lifestyle change.
Citation Information: Cancer Prev Res 2010;3(1 Suppl):CN09-03.
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