Acromegaly is a rare hormonal disorder that develops when the body produces too much growth hormone, leading to gradual changes in appearance and health that can take years to recognize.

Understanding How Common Acromegaly Is

Acromegaly affects a small portion of the population worldwide, making it one of the rarer hormonal conditions that doctors encounter. According to current estimates, fewer than 15 people per 100,000 are living with this condition. Each year, approximately 3 to 5 new cases are diagnosed for every million people in the population^[1]. Some studies suggest these numbers might be underestimates, with actual prevalence possibly reaching up to 70 cases per million, or even higher in certain regions^[7].

The condition can develop at any age after puberty, but doctors most commonly diagnose it during middle age, specifically in the fourth and fifth decades of life^[2]. This means that many people first discover they have acromegaly when they are between 30 and 50 years old^[4]. Because symptoms appear gradually over many years, the true number of people affected may be somewhat higher than reported statistics show, as some cases remain undetected for extended periods.

What Causes This Condition

The overwhelming majority of acromegaly cases, more than 95 percent, result from a benign tumor growing in the pituitary gland, which is a pea-sized gland located at the base of the brain^[7]. These tumors are called pituitary adenomas, and while the word “tumor” can sound frightening, it’s important to understand that these growths are almost always noncancerous^[2]. The tumor causes the pituitary gland to produce excessive amounts of growth hormone, also known as GH, which normally helps regulate the body’s growth and metabolism.

When the pituitary gland releases too much growth hormone, this triggers the liver to produce another hormone called insulin-like growth factor-1, or IGF-1. It is actually IGF-1 that causes most of the physical changes seen in acromegaly, as it directly affects how bones, tissues, and organs grow^[2]. The adenomas responsible for acromegaly typically grow slowly, which explains why symptoms develop gradually and often go unnoticed for years^[6].

In rare instances, tumors in other parts of the body can also produce excess growth hormone, though this accounts for a very small percentage of cases. The condition is not usually inherited from parents, meaning it does not typically run in families^[4].

Who Is at Greater Risk

Acromegaly does not appear to favor one gender over another significantly, and both men and women can develop the condition. The primary risk factor is simply age, as the disorder most commonly manifests during middle adulthood^[2]. Unlike many genetic conditions, acromegaly rarely passes from parent to child, though some people with the disorder may have certain genetic conditions that make them more susceptible to developing tumors in multiple parts of their bodies^[3].

Since the condition develops from a tumor that forms spontaneously in the pituitary gland, there are no clearly identified lifestyle factors, behaviors, or environmental exposures that increase a person’s chances of developing acromegaly. The adenomas appear to arise without warning or known preventable causes, making it difficult to identify specific at-risk groups beyond those in the typical age range for diagnosis.

Recognizing the Symptoms

The symptoms of acromegaly develop so gradually that people often don’t notice them for years. In fact, symptoms may be present for five to ten years or even longer before a person receives a diagnosis^[11]. This slow progression means that both patients and their loved ones may not recognize the changes happening over time. Even healthcare professionals sometimes have difficulty identifying the condition early on^[1].

The most characteristic changes affect the bones and soft tissues. People with acromegaly experience enlargement of their hands and feet, often noticing that their rings no longer fit or that they need progressively larger shoe sizes. The facial features change noticeably, with the brow bone becoming more prominent, the lower jaw jutting forward, and the nose and lips growing larger^[1]. The spaces between teeth may widen as the jaw expands^[4].

Beyond these visible changes, many people experience joint pain and stiffness, which can significantly affect their daily activities. The skin becomes thicker, more coarse, and oilier than before, and some develop skin tags^[4]. Excessive sweating and increased body odor are common complaints. Many patients feel unusually tired or have difficulty sleeping, and some develop sleep apnea, a condition where breathing repeatedly stops and starts during sleep^[4].

Other symptoms include numbness and weakness in the hands, frequent headaches, and a deepening of the voice as the vocal cords and sinuses enlarge. Women may experience irregular menstrual periods, while men may have difficulty achieving or maintaining erections^[4]. If the pituitary tumor grows large enough, it can press against nearby structures, particularly the nerves connected to the eyes, potentially causing vision problems.

Prevention Strategies

Unfortunately, there are no known ways to prevent acromegaly from developing. Because the condition results from spontaneous tumor growth in the pituitary gland, and the exact triggers for these tumors remain unknown, there are no lifestyle modifications, dietary changes, or screening programs that can stop the disease before it starts. The tumors that cause acromegaly appear to form without identifiable external causes or preventable risk factors.

However, once diagnosed, there are important steps people can take to prevent complications. Regular monitoring and appropriate treatment can help prevent the serious health problems associated with excess growth hormone. People with acromegaly benefit from regular health checks to monitor for conditions like diabetes, high blood pressure, and heart disease^[4]. Colonoscopy screenings become particularly important because individuals with acromegaly face an increased risk of developing colon polyps, which can progress to colon cancer if left undetected^[3].

The most effective “prevention” strategy involves early detection and prompt treatment. Because symptoms develop so gradually, people should pay attention to changes in their physical appearance over time. Comparing current photographs with pictures taken several years earlier can sometimes reveal subtle changes that weren’t noticeable day-to-day. Anyone experiencing persistent symptoms such as enlarged hands or feet, facial changes, joint pain, or severe headaches should consult their doctor for evaluation.

How the Body Changes

Understanding what happens inside the body during acromegaly helps explain why symptoms develop the way they do. The process begins with the pituitary tumor producing excessive amounts of growth hormone. This hormone travels through the bloodstream to the liver, where it signals the liver to manufacture large quantities of insulin-like growth factor-1. While growth hormone itself has direct effects on the body, IGF-1 is actually responsible for most of the physical changes seen in acromegaly^[2].

In children, growth hormone causes bones to lengthen, resulting in increased height. However, in adults, the growth plates at the ends of long bones have already fused shut, so height cannot increase. Instead, excess growth hormone and IGF-1 cause bones to thicken rather than lengthen. This explains why the hands, feet, and facial bones become enlarged and misshapen. The jaw grows forward, the brow ridge becomes more prominent, and the bones of the skull thicken^[6].

Soft tissues also respond to the excess hormones by growing larger. Internal organs including the heart, liver, kidneys, and spleen increase in size. The tongue, lips, and nose enlarge, and cartilage throughout the body thickens. The vocal cords and sinuses expand, which accounts for the voice becoming deeper. All these changes happen gradually over years, which is why they often escape notice until they become quite pronounced.

The metabolic effects of excess growth hormone extend beyond physical changes. Growth hormone affects how the body processes sugars and fats, often leading to elevated blood glucose levels. This can progress to type 2 diabetes in many patients. The hormone also influences blood pressure regulation and heart function. High levels of growth hormone and IGF-1 can cause the heart muscle to enlarge and work less efficiently, potentially leading to heart disease^[2].

When the pituitary adenoma grows large enough, it can physically press against surrounding brain tissue. The pituitary gland sits near the optic nerves that carry visual information from the eyes to the brain. A growing tumor can compress these nerves, causing vision problems or visual field defects. The tumor can also interfere with the normal pituitary tissue, potentially affecting the production of other important hormones and leading to various hormonal imbalances beyond just excess growth hormone.