Aaron I. Vinik, M.D., Ph.D., FCP, MACP, FACE
Member, American Association of Clinical Endocrinologists (AACE)
The many advances we’ve made in modern medicine have dramatically increased the average lifespan in the United States over the past century, but healthful longevity with an excellent quality of life is the goal.
Considering the rapidly growing elderly population, examining the endocrine system’s far-reaching effects in longevity and healthy aging deserve greater attention and understanding.
Defined as age-related low muscle function (walking speed or grip strength) in the presence of low muscle mass (muscle wasting), the prevalence of sarcopenia varies widely, with estimates suggesting it is present in up to 13 percent of people ages 60-70, and up to 50 percent in those 80 years of age and older. It is one of the root causes of a host of health issues that plague the elderly, including physical frailty, hip fractures, and other injuries.
While there are common, non-endocrine causes of sarcopenia, such as inactivity, weight loss without exercise, reduced blood flow, and genetic factors, the muscles are supported by the endocrine system.
Another area that should be examined is how the aging process affects the thyroid function. Aging is associated with decreased secretion of thyroid-stimulating hormone, which is produced by the pituitary gland in the brain, and directs the thyroid to make and release essential thyroid hormones T3 and T4 into the blood, where they travel to and are used by multiple target organs and systems. T3 and T4 secretions also are impaired as we age.
As a result of these changes, there is an increased prevalence of thyroid disease in the elderly, particularly what is known as sub-clinical thyroid disease, a disease that is not severe enough to present definite or readily observable symptoms.
It is widely known that testosterone concentrations decline with age. It is important to determine in older men if a low testosterone level is simply caused by aging or if it is due to hypogonadism, a disease in which the body is unable to produce normal amounts of testosterone because of a problem with the testicles or the pituitary gland, which controls the testicles.
There are many other endocrine system changes that occur with aging that significantly impact how we age and, thus, deserve greater attention; bone disease, growth hormone therapy, and type 2 diabetes, as well as the interaction of nutrition and metabolism, just to name a few.
As we become more focused on these changes and gain critical insight into the complex association between aging and the endocrine system, the valuable information produced by these efforts will help us enhance function in our aging population and lead to not only longer lives, but better quality ones as well.