The effect of randomization to weight loss on total mortality in older overweight and obese adults: the ADAPT Study.
BACKGROUND
Although weight loss reduces risk for comorbid diseases, many observational studies suggest that weight loss is associated with increased mortality risk, leading to reluctance by clinicians to consider weight reduction as a strategy to maintain health and independence in older adults. However, whether the observed weight loss is intentional is difficult to determine and may not accurately represent the mortality risk associated with intentional weight reduction. Data from the Arthritis, Diet, and Activity Promotion Trial (ADAPT) were used to determine whether randomization to a weight reduction program was associated with total mortality in overweight/obese older adults.


METHODS
ADAPT (n = 318; mean age 69 +/- 6 years, body mass index 34 +/- 5 kg/m2, 72% female) assessed the influence of weight loss (achieved through dietary counseling and lifestyle modification) and/or exercise on function in overweight/obese older adults with knee osteoarthritis. ADAPT ended in December 1999. Participant vital was ascertained status through December 2006 using the National Death and Social Security Indexes.


RESULTS
The mortality rate for those randomized to the 18-month weight loss intervention (n = 159, mean weight loss = -4.8 kg, 15 deaths) was lower than that for those not randomized to the weight loss intervention (n = 159, mean weight loss = -1.4 kg, 30 deaths; hazard rate ratio = 0.5, 95% confidence interval 0.3-1.0). Results were not appreciably changed when analyses were stratified by age, gender, baseline weight status, or magnitude of weight loss.


CONCLUSIONS
In older adults, intentional weight loss was not associated with increased total mortality and may reduce mortality risk. Observational studies of weight loss, especially when intentionality cannot be rigorously established, may be misleading with respect to the effect of weight loss on mortality.
Shea
M Kyla
MK
Sticht Center on Aging, Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA. kshea@wfubmc.edu
Houston
Denise K
DK
Nicklas
Barbara J
BJ
Messier
Stephen P
SP
Davis
Cralen C
CC
Miller
Michael E
ME
Harris
Tamara B
TB
Kitzman
Dalane W
DW
Kennedy
Kimberly
K
Kritchevsky
Stephen B
SB
D000368:Aged; D015992:Body Mass Index; D001835:Body Weight; D016009:Chi-Square Distribution; D004038:Diet, Reducing; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy / Q000401:mortality*; D016016:Proportional Hazards Models; D012307:Risk Factors; D015431:Weight Loss