IGF-1 Hormone: Good for the Young but Bad for the Old

IGF-1 Hormone: Good for the Young but Bad for the Old

In 2014, in a study that enrolled 194 people in their 90s, Albert Einstein College of Medicine’s Sofiya Milman, M.D., M.S., and colleagues showed for the first time that having low blood levels of the growth-associated hormone insulin-like growth factor (IGF-1) may benefit older adults. That study in Aging Cell found that women with below-average IGF-1 blood levels lived incrementally longer compared with women with higher IGF-1 levels.

Sofiya Milman

Sofiya Milman, M.D., M.S.

Now, in research published online on August 7 in Aging Cell, Dr. Milman and her team confirmed their earlier findings and added to them in the largest such study to date. Using information from the UK Biobank that followed nearly 450,000 individuals age 37 to 73 for more than 10 years, the researchers found that older adults (both men and women) are at increased risk of death and disease if they have high levels of IGF-1—while younger adults have a much greater risk of death and disease if they have low levels of the hormone.

More specifically, when compared with young adults who had low IGF-1 levels, older adults with low levels of IGF-1 had lower risk of death and occurrence of multiple diseases, including cardiovascular disease, dementia, diabetes, and osteoporosis. On the other hand, having high IGF-1 levels was associated with increased risk for these conditions in people who were older compared with people who were younger. These relationships were remarkably consistent for all age-associated diseases investigated, with the exception of cancer, where having higher levels of IGF-1 was associated with increased risk across all age groups.

The study’s findings should concern older people who take human growth hormone (HGH) in the belief that it can delay aging and rejuvenate them. HGH is not the same as IGF-1, but it promotes the release of IGF-1 within the body. The results of this study clearly show that elevated blood levels of IGF-1 (which may result from taking HGH) are associated with an increase in an older person’s risk of dying and for developing life-threatening diseases.

In addition, the Einstein team’s findings highlight the need for future studies of hormonal effects to include people with a wide range of ages, since the physiologic effect of a hormone can clearly differ depending on a person’s age.

Dr. Milman is an associate professor of medicine and of genetics at Einstein and an attending physician at Montefiore. She also is the director of human longevity studies at Einstein’s Institute for Aging Research.