According to reports from the National Health and Nutrition Examination Survey (NHANES), the prevalence of obesity in women 60 to 79 years is 42.3% (95% confidence interval [CI]: 38.3%–46.3%), compared with a prevalence of 31.9% (95% CI: 28.6%–35.5%) in women aged 20 to 39;1
as such, obesity among older women represents a serious public health problem. Obesity in this age group is strongly associated with diabetes, hypertension, dyslipidemia, and osteoarthritis,2
although the relation between obesity and all-cause mortality in this age group is inconsistent.3
Independent of weight status, age is correlated with greater prevalence and severity of many obesity-related health conditions and metabolic risk factors.7
Additionally, obesity has been associated with significant impairment in health-related quality of life in older individuals.8
However, excess weight in older persons (65 years and older) may also offer protective benefits with respect to bone loss, osteoporosis, and hip fracture.9
Further, some have noted the “obesity paradox,” whereby obesity has been found to be protective against mortality due to certain causes such as heart failure or cardiovascular disease.11
For middle-aged and young adults who are obese, the benefits of behavioral weight-loss treatment clearly outweigh potential risks. Reviews of randomized trials demonstrate that lifestyle interventions, typically delivered in weekly group sessions over the course of 4 to 6 months, produce average weight losses of 8.5 kg posttreatment (approximately 5%–10% of initial body weight).13
Reductions of this magnitude can have beneficial effects on a variety of weight-related health conditions and risk factors.16
However, several longitudinal observational studies have demonstrated that weight loss in older adults is related to increased mortality, disability, functional limitation, institutionalization, loss of lean muscle mass and bone mineral density, increased risk of hip fracture, and loss of mobility.19
These studies, however, have not controlled for a number of potential confounds, such as intentionality of weight loss, obesity status prior to weight loss, occult disease or pathology, and smoking status.
A small number of clinical trials have been conducted to examine the effects of weight-loss treatment among older, obese adults,21
but a recent meta-analysis suggested that high-quality evidence regarding the efficacy of weight-loss interventions among older adults is lacking and that additional studies are needed.23
This meta-analysis also indicated that although obese, older adults are able to achieve significant weight losses, changes in blood pressure, lipid profile, glycemic control, exercise capacity, and quality of life, as a consequence of weight-loss treatment, did not reach statistical significance. Moreover, data on these health outcomes were very limited, and there was substantial heterogeneity across studies.23
Adverse outcomes were not examined in this meta-analysis, though results from the Diabetes Prevention Program indicated that rates of musculoskeletal adverse events were slightly higher among the lifestyle intervention group as compared with the placebo (although authors reported no significant differences by treatment assignment).24
Older participants were more likely to report adverse events as compared with younger participants.24
In a recent randomized controlled clinical trial examining the effectiveness of diet, exercise, or a combination, among adults 65 years of age or older, Villareal et al22
reported that participants in the diet-only arm experienced reductions in lean body mass and bone mineral density, while participants in the exercise arm reported a greater degree of musculoskeletal injuries. This study also reported significant improvements in a variety of weight-related health outcomes.22
However, authors did not report whether these risks and benefits of weight-loss treatment differed by age.
At present, it remains unclear whether the benefits of intentional weight loss in older, obese adults outweigh potential risks of weight-loss treatment, and whether improvements in health or risks associated with treatment are similar across age cohorts. Few studies have examined the effects of behavioral weight-loss treatment in older adults.10
Intentional weight loss in older, obese adults could ameliorate weight-related diseases and conditions, such as joint pain, psychological symptoms, and quality of life,10
but could simultaneously present risks with regards to musculoskeletal injury, and bone and muscle loss.
The current study investigated both the health benefits (ie, weight loss, improvements in metabolic risk factors) and adverse consequences of weight-loss treatment in older adults (65–74 years) and examined whether these effects were comparable to those experienced by middle-aged adults (50–59 years). The primary aims of the present study were to determine: (1) if older, obese women experience significant benefits (ie, weight loss) from a lifestyle intervention for weight loss; (2) if behavioral weight-loss treatment is associated with negative outcomes (ie, musculoskeletal injury) for older, obese women; and (3) if weight loss and adverse event outcomes are equivalent in older and middle-aged participants. We hypothesized that positive and adverse outcomes would be similar across age groups. A secondary aim of this study was to describe and compare the responses of older and middle-aged participants with regards to changes in metabolic risk factors, including systolic blood pressure, LDL cholesterol, Hemoglobin A1c, and C-reactive protein.