Trans Health – the effect of hormones on your bones

Bone health is important for everyone, regardless of age or gender identity. From a young age we build the foundations of what our bone health will be like later in our lives. Preventing diseases like osteoporosis is a key part of bone health in our early years. Weight bearing exercise and adequate nutrients are important factors that help increase the strength of our bone.

However, there are things that can impede our ability to build and maintain healthy bones. Low bone density can put you at risk of stress fractures when you are young and exercising. Reduced vitamin D and low calcium levels are the more well known factors, but did you know that hormones can affect your bone health too?

We know that in cisgender women (women who’s personal and gender identity corresponds with their birth sex), their hormonal changes throughout their life affect their body’s ability to strengthen their bones. For instance, if there is a late start to puberty, the bone density of that girl is likely to be lower due to the delayed release of oestrogen in the body. In a similar way, when cisgender women fall pregnant, they have a change in their usual hormonal cycle, so they can develop transient osteopaenia (low bone density during their pregnancy). This can also happen if that mother breastfeeds, as breastfeeding suppresses the release of oestrogen. And finally, at menopause, there is another hormonal fluctuation which can increase the risk of osteoporosis developing. 

But what about in transgender women? It really depends on what part of your transitioning journey you are in and what choices you have made regarding hormone therapy and surgical interventions. In some research studies, risk factors for osteoporosis were present in transgender women prior to gonadectomy surgery (surgical removal of the sexual organs) and prior to hormonal therapy. These factors were reduced vitamin D, reduced muscle mass and strength, and reduced physical activity. Other studies have explored the effect of hormone therapy and found that oestrogen therapy in transgender women actually protects their bones from becoming weaker. Finally, studies have found that a transgender woman who undergoes gonadectomy surgery and takes hormone replacement therapy will also preserve her bone health. However, should hormone replacement therapy not be taken, the risk of low bone density and osteoporosis increases.

In cisgender men (men who’s personal and gender identity corresponds with their birth sex), there is generally a lower rate of osteoporosis as they do not have periods, do not go through menopause, and they release different hormonal levels more consistently than cisgender women. In transgender men, there has been no detrimental effect on bone mineral density when taking testosterone. However, should an oophorectomy (surgical removal of the ovaries) be performed prior to the age of 45 and no hormone replacement therapy given, the risk of osteoporosis increases.

If you are unsure of who to speak to, at Performance Medicine, we have Dr Kathy Yu – a sports doctor who is incredibly knowledgeable and would love to help you.

Regardless of your gender, phase of transition or age, we should all do what we can to maintain healthy and happy bones. Eat plenty of calcium, exercise, get enough sunlight (with sunscreen and hats depending on the season) and stay strong! And if you aren’t sure if your hormones are doing what they should for your bones, chat to your doctor.

Catherine Etty-Leal