Enlarged breast tissue in men linked to heightened risk of death

Men with enlarged breast tissue, not caused by excess weight—a condition formally known as gynaecomastia—may be at heightened risk of an early death before the age of 75, suggests the first study of its kind, published online in the open access journal BMJ Open.

Those with a pre-existing risk factor, such as cancer or circulatory, lung, and gut diseases before diagnosis seem to be most vulnerable, the findings indicate.

Enlarged breast tissue in men is usually caused by a hormone imbalance and affects around a third to around two thirds of men, depending on age. It is distinct from what is often dubbed ‘man boobs’ (pseudogynecomastia), usually associated with overweight/obesity.

The development of gynaecomastia can occur at any age, but has three distinct peaks across the life course, prompted by pronounced changes in sex hormone levels in the neonatal period, during puberty, and at older ages, note the researchers.

To try and find out, the researchers drew on data from Danish national health and population registries: 23,429 men were diagnosed with gynaecomastia between 1 January 1995 and 30 June 2021. Just over 44% were aged between 19 and 40 at diagnosis.

They were each matched by age and date of diagnosis with 5 randomly selected men without the condition (117,145; the reference group), adding up to a total of 140,574.

Among those with gynaecomastia, 1093 (nearly 7%) with the condition of unknown cause and 1501 (21%) of those with a pre-existing risk factor died, compared with 10,532 (9%) deaths among the men without gynaecomastia.

This equates to a 37% higher risk of early death from any cause among those with gynaecomastia than among those without the condition.

But when stratified by group, the risk of death was highest in those with a known pre-existing condition among whom the odds were 75% higher than those with gynaecomastia of unknown cause among whom the odds were 5% higher.

Reference: Enlarged breast tissue in men (gynaecomastia) linked to heightened risk of death; BMJ Open; DOI: 10.1136/bmjopen-2023-076608