Despite the improvements in healthcare that have led to longer and considerably healthier lifespans, aging is inevitable. Endocrine system disorders that require nuanced treatment are chief among the changes individuals live beyond 70, 80, even 90, according to a panel of experts presenting at symposium on The Aging Patient: Endocrinology for the Ages, at the American Association of Clinical Endocrinologists 26th Annual Scientific and Clinical Congress, held May 3-7 in Austin, Texas.1
Age-related losses in skeletal muscle mass and function, known as sarcopenia, are a major contributor to the loss of independence and deteriorating quality of life in the elderly,1 said John E. Morley, MBBCh, Dammert Professor of Gerontology and director of geriatric medicine at St. Louis University School of Medicine. Visceral obesity brings its own onslaught of harmful factors contributing to muscle decline, including those associated with insulin resistance and increased leptin levels, Dr. Morley said.
“Sedentary individuals over age 70, men with low testosterone levels, and those with diabetes, chronic obstructive pulmonary disease, and multiple hospitalizations are at particular risk for sarcopenia,” Dr. Morley told EndocrineWeb. “All diabetics over age 50 should be screened,” he added.
Metabolic alterations in skeletal muscle in people who have type 2 diabetes (T2D) result in greater declines in muscle mass, muscle strength, and functional capacity.2 In these patients, frailty and sarcopenia are predictors of adverse health outcomes.
Dr. Morley told EndocrineWeb that simple screening for sarcopenia can be done with the SARC-F screen, a tool developed as part of the Rapid Geriatric Assessment at St. Louis University’s Division of Geriatric Medicine. A definitive diagnosis requires further assessment of gait speed, grip strength, and measurement of appendicular muscle mass.3
Early detection of sarcopenia can help identify those who will best respond to resistance exercises that will promote the release of muscle growth factors to encourage muscle regeneration4 as well as nutritional supplementation with a leucine-enriched essential amino acid supplement to regain and maintain muscle.5 Testosterone therapy should be considered for men with definite hypogonadism.6
Resistance exercise can prevent major disability in older adults, as supported by results showing significant decreases in mortality, nursing home admissions, increased ability to perform activities of daily living, and decreases in the use of assistive devices after 12 months of training in patients who underwent surgery for a hip fracture, according to Dr. Morely.1,7
Compared to the average person at age 30, a 75-year-old has 95% of brain weight, 84% of basal metabolism, 70% of kidney filtration rate, and 43% of maximum breathing capacity,1 according to S. Sethu Reddy, MD, MBA, chief of adult diabetes at the Joslin Diabetes Center in Boston, MA.
“Clearly, we are not the people we once were,” Dr. Reddy said. “Humans are destined for a lifespan of 110 years, tops, and drinking from the fountain of youth will not necessarily change our fate.”
However, recent experimental studies indicate that medications targeting aging, such as vitamin E, melatonin, resveratrol, and metformin, can substantially promote health and extend lifespan.1 Pharmacologically targeting aging appears to be more effective in preventing age-related pathology than treatments targeted to particular pathologies, said Dr. Reddy.
The main features of the "westernized" lifestyle, including hypercaloric nutrition and sedentariness, can accelerate aging as this overconsumption has detrimental metabolic consequences, Dr. Reddy noted. Conversely, lifespan-extending maneuvers including caloric restriction may impose beneficial pleiotropic effects on metabolism.1,8
Dr. Reddy presented research showing the beneficial effects of caloric restriction on health and aging,8 but noted that other dietary regimens, such as protein restriction, intermittent fasting, and time-restricted feeding, are currently under investigation and preliminarily have shown some benefit.1
Increasing oxidative stress, a major characteristic of aging, has also been implicated in a variety of age-related pathologies, according to Dr. Reddy. In aging, oxidant production from several sources is increased, whereas antioxidant enzymes, the primary lines of defense, are decreased.1
Repair systems, including the proteasomal degradation of damaged proteins, also decline. Importantly, the adaptive response to oxidative stress declines with aging,1 he said.
Several “blue zones” have been designated as areas with an unusual cluster of centenarians including Sardina, Okinawa, Costa Rica, and Loma Linda, CA. According to 2005 research funded by the National Institute on Aging, factors leading to long life in these areas include:
Adventists, a group known for longevity and health, have demonstrated that 5 simple habits can extend life by as much as 10 years in both men and women:9
Sandeep Dhindsa, MD, an associate professor of medicine and director of endocrinology and metabolism at St. Louis University, highlighted andropause, or late-onset hypogonadism, the age-related decline in testosterone levels, and the impact of testosterone replacement therapy (TRT) on andropausal patients.1
While often characterized by symptoms such as low libido and erectile dysfunction, the most easily recognized clinical signs of androgen deficiency in older men are a decrease in skeletal muscle mass and strength, decreased bone mass, and an increase in central body fat, said Dr. Dhindsa.
“Physicians must be alert to the fact that many of their patients may be suffering from low testosterone levels,” he said. Testosterone levels can be calculated; a normal range for free T is 6.5 – 25 ng/dL. Late-onset hypogonadism is defined by at least 3 sexual symptoms, total T of < 320 ng/dL and free T of < 6.3 ng/dL.
Hypogonadism increases with age and is particularly associated with some of the most common conditions found in clinical practice – diabetes, obesity, and cardiovascular disease, said Dr. Dhindsa. and as the number of men aged 65 years and older increases in the United States, physicians will be increasingly likely to encounter men with the symptoms of hypogonadism.1
Clinicians need to know the symptoms of hypogonadism and the various testosterone replacement treatment options, said Dr. Dhindsa. Testosterone replacement in hypogonadal men has many benefits, including increased skeletal muscle strength, improved bone density, and suppression of adiposity, with no definitive evidence of an increase in cardiovascular events, according to Dr. Dhindsa. Testosterone replacement therapy should be titrated to achieve total serum testosterone concentrations of about 700 ng/dL in men younger than 40 years, and about 400 ng/dL in men over age 70, he said.