By 2030, more than 20% of the U.S. population is expected to be over the age of 65, according to the U.S. Census Bureau. As John A. Batsis, MD, FACP, sees it, “We're in the midst of a geriatric tsunami.” And the wave may carry with it patients with obesity and poor eating habits.
Several generations ago, people experienced a period of normal function, followed by a period of functional impairment before death, he explained. “Current and future generations have a longer period of normal function due to improvements in medical advancements, but they also have a longer period where they're at risk for functional impairment before they pass away,” said Dr. Batsis, a geriatrician at Dartmouth-Hitchcock Medical Center in Lebanon, N.H., and an associate professor of medicine at the Geisel School of Medicine at Dartmouth in Hanover, N.H.
But it may be possible to fight functional impairment with a healthy lifestyle. In a recent study, participants with poor eating habits and obesity (body mass index [BMI] over 30 kg/m2) had a reduction in the proportion of years that they lived without disability, whereas improving physical activity led to more preservation of function, according to results published in 2016 in the Journal of the American Geriatric Society. “This really, in sum, gives us an indication that healthier lifestyles are associated with improvements in maintenance of function,” said Dr. Batsis.
As physicians take care of more and more older adults with obesity, they should keep several considerations in mind when encouraging healthier living, he said in November 2016 at ObesityWeek in New Orleans. During the session, Dennis T. Villareal, MD, FACP, and Denise K. Houston, PhD, added nutritional and lifestyle recommendations.
Geriatric risks of obesity
As with other populations, older adults are living longer but seeing a higher prevalence of obesity, Dr. Batsis said. “NHANES [National Health and Nutrition Examination Survey] data over the past four to five decades demonstrates that both males and females 60 and older have 37% to 39% prevalence, based on BMI,” he said.
However, particularly in older adults, Dr. Batsis noted that there are challenges associated with using BMI as a measure of adiposity. In a study published in 2016 in the International Journal of Obesity, his group examined the diagnostic accuracy of BMI, which demonstrated high specificity but poor sensitivity in both men and women.
“The older you are, the less sensitive BMI was at ascertaining adiposity correctly,” Dr. Batsis said. But abandoning BMI isn't necessarily practical either, he said. “It's easy to use, it's cheap, and it's really hard to change current practice,” he said, although he added that incorporating measurement of waist circumference or other, less cost-effective measures of fat mass (e.g., DEXA scan, bioelectrical impedance) can also be considered.
Despite its shortcomings, BMI can be an important clinical indicator. The longer an individual is classified by BMI as being overweight or obese, the higher the long-term risk of disability, according to results published in 2009 by the American Journal of Epidemiology. “This is important because a person who is overweight or obese solely at the age of 70 to 79 may have a lower risk of disability than an individual who had a longer duration of being classified as overweight or obese,” Dr. Batsis said.
Studies have also shown that patients classified as having class 1 or class 2 obesity may have a higher risk of falling, he said, adding that a 2013 systematic review and meta-analysis published by Epidemiologic Reviews found a 60% higher risk of functional decline among obese participants (mean age of 65 years or more).
In addition, Dr. Batsis noted that patients with midlife obesity have a higher risk of nursing home placement later in life, citing a 2006 study in Obesity. “I can tell you almost every patient of mine fears being placed in a nursing home. … This is important because you're able to take this back to your patients and counsel them accordingly,” he said.
Research suggests that the lowest mortality risk occurs somewhere between a BMI of 25 kg/m2 and about 28 kg/m2, with a definite increase in risk occurring with a BMI exceeding 33 kg/m2, said Dr. Batsis. “When patients come into your office with a BMI of 25 or 26, you want to keep this type of literature in mind. … [but] the data on those between 30 and 33 may be not as clear-cut as we would like them to be,” he said.
Sarcopenia and BMD
Older patients may come into the office and say they'd like to attain their college weight, but that's usually neither practical nor safe, Dr. Batsis said. In fact, nutritional needs for healthy adults actually decline with age, partly because of reduced basal metabolic rates, he said.
Body composition also changes with age, and the goal in older life should be to minimize the losses in muscle mass and muscle function, Dr. Batsis said. “We know that while both muscle mass and muscle strength are integrated in the definition of sarcopenia, muscle strength seems to have a more predictive effect on long-term functional decline than muscle mass,” he said.
With older adults becoming weaker and increasingly obese, sarcopenic obesity presents “a confluence of these two epidemics,” said Dr. Batsis. The estimated prevalence of sarcopenia and obesity in older adults ranges between 15-fold and 18-fold, depending on sex, he said, citing a study his group published in 2013 in the Journal of the American Geriatrics Society. Sarcopenic obesity is associated with physical limitations, and obesity and low muscle strength (but not low muscle mass) are associated with long-term fall risk, Dr. Batsis said. “We know that the sum of the parts is more than the whole,” he said. “So high fat mass and low muscle mass or strength really leads to functional limitations and metabolic abnormalities.”
Lean body mass peaks in the third to fourth decade of life before decreasing thereafter, said Dr. Houston, a registered dietitian and associate professor of geriatrics and gerontology at Wake Forest School of Medicine in Winston-Salem, N.C. “Fat-free mass and bone mineral density [BMD] are two areas that we really need to target if we are considering weight loss in an older person,” she said.
In weight-loss trials, the average amount of body mass lost as lean body mass is about 25%, and this is primarily skeletal muscle mass, Dr. Houston said. But protein may be a key factor in mitigating losses. Adults ages 50 years and older who were randomized to higher protein intakes showed greater retention of lean mass and greater losses of fat mass during weight loss than those consuming less protein, according to a systematic review and meta-analysis published in 2016 by Nutrition Reviews.
Dr. Houston noted that most people are successful at losing weight but not very successful at maintaining weight loss. “So we would hope that if we're losing lean mass when we lose weight, we might regain it when we regain the weight,” she said. This does not appear to be how it works, at least according to a 2011 American Journal of Clinical Nutrition study that followed postmenopausal women up to one year after a weight-loss intervention.
“During the intervention, 33% of the lost weight was comprised of lean mass. Following the intervention, only 20% of the regained weight was lean mass. … So this really illustrates why maintenance of weight loss is going to be very important, especially in the older adult,” Dr. Houston said.
The current recommended dietary allowance for protein is 0.8 g/kg of body weight among all adults. “There has been some suggestion that that probably needs to be higher among older adults,” Dr. Houston said. “Current recommendations that have been proposed are between 1 and 1.5 g/kg of body weight. This is in part because aging is associated with the reduced ability to synthesize muscle protein with lower protein intakes,” she said. “Thus, it's important for older adults to consume high-quality protein, including foods that contain the amino acid leucine to help stimulate maximum muscle protein synthesis.”
In terms of bone health, observational studies show that weight loss results in loss of BMD and increased fracture risk, Dr. Houston said. Fortunately, calcium supplementation appears to suppress bone turnover during weight loss in postmenopausal women, she said. “[One study] showed that calcium supplementation attenuates bone loss during weight loss in postmenopausal women. Those randomized to a high-calcium diet (1,000 mg/day) lost less BMD in the trochanter and in the spine than those randomized to a normal-calcium diet (200 mg/day),” Dr. Houston said.
Protein was previously thought to potentially increase bone loss and increase fracture risk because of its acidity and tendency to enhance urinary calcium losses, she noted. “More recently, studies have shown that dietary protein actually helps with bone loss. … Higher dietary protein during weight loss can attenuate bone loss in the lumbar spine and hip, as well as the radius, among individuals provided adequate calcium (1,200 mg/day),” Dr. Houston said.
Similar to muscle, weight regain does not appear to replace lost bone, she noted. “Even if you maintain your weight loss or you regain your weight loss, there is no regain in BMD across the femoral leg, trochanter, or the spine,” Dr. Houston said. “So once you've lost that BMD, you're unlikely to gain it back with weight regain.” She added that vitamin D should also be recommended in older adults during weight loss. “And this is in part because it helps promote calcium absorption. … During weight loss, probably at least 1,000 IU a day should be recommended,” Dr. Houston said.
Dr. Batsis noted that patients and primary care physicians are not taking full advantage of the Medicare obesity benefit, which was introduced in November 2011. The benefit covers motivational interviewing and face-to-face weight-loss counseling in the primary care setting: up to twenty-two 15-minute visits in the span of a year. “Using Medicare data, we found that … in the first year following its implementation (2012) only 0.35% of those beneficiaries with a BMI over 30 actually availed of the benefit, and this only marginally increased to 0.6% in 2013. Stay tuned—let's hope 2014 data looks a little bit better,” Dr. Batsis said.
During the initial evaluation of an older adult with obesity, clinicians should first assess current health status and comorbidity risk, said Dr. Villareal, a professor of medicine at Baylor College of Medicine and staff physician at Michael E. DeBakey VA Medical Center in Houston. “They should have functional impairments or metabolic complications that can benefit from weight loss,” he said. Next, clinicians should gather personal information in terms of the patient's willingness to lose weight, prior attempts to lose weight, and current lifestyle, Dr. Villareal said. Be sure to consider common conditions in older adults, such as depression, vision loss, and cognitive impairment, he added.
Dr. Villareal discussed three therapeutic tools for treating obesity in older adults: lifestyle interventions, pharmacotherapy, and surgery. The ultimate goal of weight loss in this population, he said, is improving physical function.
“A combination of an energy deficit, diet, increased physical activity, and behavioral therapy causes moderate weight loss, and it offers the lowest risk of treatment-induced complications, as compared to drug therapy or surgery,” Dr. Villareal said, emphasizing the importance of approaches that also minimize the loss of muscle and bone mass (e.g., exercise).
With lifestyle interventions, help patients set a realistic weight-loss goal, recommend an appropriate caloric deficit, and supplement with multivitamins and minerals as necessary, Dr. Villareal said. (See sidebar on page 14 for more nutrition recommendations.) With exercise, “start low and go slow,” gradually increasing intensity, duration, and frequency over time with the goals of increasing flexibility, endurance, and strength while preventing injuries and promoting adherence, he recommended.
“[In] weight-loss interventions in obese older adults, combined diet and exercise resulted in the greatest improvement in physical function and quality of life. Exercise mitigated weight-loss-induced reductions in muscle and bone mass,” Dr. Villareal said. He cited as an example a study he coauthored in 2011, in the New England Journal of Medicine.
Pharmacotherapy for weight loss is not recommended in older patients because there is insufficient evidence to determine efficacy and safety in this population, he said, noting such downsides as polypharmacy and potential side effects.
“However, a thorough review of all medications should be obtained because some medications can in fact promote weight gain, like antipsychotics, for example,” Dr. Villareal said. “Furthermore, weight-loss-induced clinical implications might include changes in medications in order to avoid iatrogenic complications.”
There are also limited efficacy and safety data on bariatric surgery, but that doesn't mean it cannot be considered in select patients with disabling obesity that can be ameliorated with weight loss or who meet criteria for surgery, Dr. Villareal noted. He added that in older patients, bariatric surgery is associated with an “acceptable” complication rate of about 57%, excess weight loss of about 54%, resolution of diabetes in about 55% of patients, and resolution of hypertension in 43% of patients, according to a 2015 systematic review published in Clinical Interventions in Aging. “[This] is comparable to younger adults,” Dr. Villareal said. “So they concluded that patients should not be denied bariatric surgery based on their age alone.”