What are the results of prospective studies of intentional weight loss (through lifestyle, weight loss medications, or weight loss surgery) in the elderly?
Obesity in older adults is a mounting public health concern given its increasing incidence and association with loss of functional independence and frailty. Hypocaloric diets have been effective in reducing total and visceral fat and improving glucose tolerance, insulin sensitivity, blood pressure, and pulmonary function. Elderly adults with obesity are capable of participating in and adhering to rigorous interventions with diet, exercise, or diet plus exercise. Such studies have found that diet alone and exercise alone both reduce frailty, but the combination of diet and exercise generates the greatest objective functional and subjective benefits.
Intentional weight loss typically results in a loss of lean mass (muscle and bone), which may exacerbate sarcopenia and risk for osteoporosis. This could have adverse effects in elderly adults who are already at risk for osteoporosis. Thus, it has been suggested that exercise training should be added to diet interventions to mitigate the loss of lean mass. Using this approach, the addition of exercise training to diet in older adults with obesity prevented the weight loss–induced increase in bone turnover and attenuated, but did not prevent, the decline in bone mineral density.
Some prospective observational studies have suggested that weight loss in older adults may be associated with increased mortality despite a decrease in comorbidities, such as CVD and type 2 diabetes. However, in randomized controlled weight loss interventions, weight loss did not increase mortality in older adults over a follow-up period of 8 to 12 years. In fact, secondary analyses from one trial suggested that intentional weight loss might reduce the mortality risk in this population. Additional trials of intentional weight loss in older adults are needed to confirm whether it does, indeed, reduce mortality risk and whether the risk-to-benefit profile is similar in older adults who develop obesity earlier versus later in life.
Several weight loss medications can be prescribed with diet and/or exercise in individuals with obesity. However, data are lacking regarding efficacy and safety of antiobesity pharmacotherapy in the geriatric population. Recent clinical trials investigating the antiobesity effects of the combination medication bupropion (antidepressant) and naltrexone (opioid antagonist) as well as lorcaserin (serotonin receptor [5-HT 2C ] activator) included only ∼2% of adults aged ≥ 65 years. Moreover, there were not enough older patients in these studies to determine whether response rates differed between geriatric and younger patients. About 7% of participants in the phentermine/topiramate and liraglutide trials were aged ≥ 65 years, and there were no differences in safety or effectiveness between geriatric and younger patients. Bupropion/naltrexone, lorcaserin, and phentermine/topiramate have warnings and dose adjustments for worsening renal impairment, which is more common in elderly patients and needs to be considered. Orlistat, which prevents some dietary fat from being absorbed, does not appear to have age-related dosing risks.
Weight loss surgery is effective at reducing weight and medical comorbidities in the elderly, though at higher perioperative risk. A recent systematic review of 26 studies of 8,149 patients aged ≥ 60 years revealed a pooled 30-day postoperative mortality rate of 0.01% and overall complication rate of ∼15%. After 1 year, pooled mean excess weight loss was 54%, and the resolution rates of diabetes, hypertension, and lipid disorders were 55%, 43%, and 41%, respectively. These improvements are comparable with those seen in younger patients and appear to be independent of bariatric surgery procedure type. There also does not appear to be an increased mortality in elderly patients who underwent Roux-en-Y gastric bypass compared with nonsurgical elderly controls