Skeleton bone size and sturdiness vary between the sexes. Bone structure differences start as early as childhood. In the majority of populations, men have larger and stronger bone and joint surfaces, and more bone at muscle attachment sites.
However, women have stronger pelvises because of their distinct ability to carry a child and experience childbirth. Women are also more vulnerable to certain bone diseases, like osteoarthritis, osteoporosis, and inflammatory arthritis. Read on to find out about bone structure differences and bone disease risk for men and women.
One of the most significant differences between male and female skeletons is body size and bone size. These differences become evident at birth and continue throughout childhood.
Further and more significant bone structure differences will emerge when puberty starts. Puberty is the period of physical changes through which a child’s body matures into an adult body that is capable of reproduction.
Bone growth patterns in puberty in boys are different than in girls. Boys have two or more years of growth before puberty and a growth spurt that will last about four years, whereas girls have a growth spurt period of three years.
During childhood and adolescence, bone formation is higher than bone resorption. Bone resorption is a process where osteoclasts—bone cells that absorb bone tissue during growth and healing—break down bone tissue and release minerals, resulting in calcium transfer from your bones into the bloodstream.
By the early 20s, both genders achieve peak bone mass—that is the greatest amount of bone a person can attain. Bones contain the total bone mineral accrued over childhood and adolescence.
A 2014 article in the journal Endocrine Reviews reported on a mathematical model with experimental variables to predict influences of peak bone mass, menopause, and age-related bone loss on the development of osteoporosis, a condition that causes bones to become weak, brittle, and more prone to fractures (bone breaks).
It was determined a 10% increase in peak bone mass would delay osteoporosis by 13 years. This analysis indicates peak bone mass achieved in adolescence is the single most important factor for preventing osteoporosis later in life.
Peak bone mass differences in boys and girls are mostly determined by genetics. But they can also be influenced by modifiable factors like regular exercise and diet, including regular consumption of dairy products, which are a natural source of calcium and vitamin D—two nutrients vital to bone health.
Most of the gains to bone mass made in adolescence are increases to bone length and size, rather than bone mineral. This is the reason fractures are more common in the teenage years. During this time, bone mass lags behind in bone length, leaving the bone temporarily weak.
But in the general, and as is the case with young men, boys have a higher risk for fractures compared to girls. That risk has a lot to do with bone growth patterns and gender differences in physical activity (i.e. sports) and risk-taking.
Another consideration of bone growth in boys is testosterone—the major sex hormone in males—that helps to improve bone size. On the other hand, estrogen—the major sex hormone in females—reduces bone growth while regulating levels of bone mineral.
Differences in testosterone and estrogen offer rationale as to why boys develop larger bones and have higher peak bone mass than do girls. And this fundamental difference is also why adult women have a higher risk of fractures due to hormones rather than sports injuries or risk-taking.
Differences that exist in bone structure between men and women are often prominent. For example, women are shorter, and gender height differences are common around the world. Globally, women are about 4 1/2 inches shorter than men.
In addition to the height difference, men also have bigger heads and longer arms and legs than women, and this is relative to body size. Other skeletal differences in males versus females are in the skull and in the long bones, specifically the femur and the tibia. Differences also exist in the elbows, shoulders, fingers, and thigh bones.
Women also have wider pelvises and torsos in comparison to men. In fact, researchers can determine whether a skeleton is male or female by measuring hip bones alone.
The pelvis is shaped and sized so that it has the potential for childbirth. It is wider and longer and held together by ligaments that loosen up during pregnancy to allow the pelvis to widen or else the pelvis would be too narrow for pregnancy and childbirth. Additionally, women’s torsos are wider so that their bodies can accommodate their organs during pregnancy.
After reaching peak bone mass, both men and women will start to lose bone tissue as they age. In women, age-related bone loss starts in their early to mid-30s. This process is heightened by rapid decreases in estrogen as women enter menopause.
Gradual bone loss is not unusual with aging, but women tend to be younger when they start to lose bone. In addition, they lose bone at a faster rate. Researchers also think specific bone loss markers and changes to the periosteum—the fibrous membrane covering the surface of bone—might explain the amount of bone loss that occurs between sexes.
The rate for bone loss in men is much lower throughout their lives and is influenced by estradiol levels. Estradiol is a form of estrogen crucial to male sexuality.
Another factor in bone health for women as they get older is pregnancy. This is because pregnancy increases the need for calcium—for building the fetus’s skeleton and during breastfeeding.
During pregnancy, some women will experience changes in their bone density, which suggests bone mass can deteriorate during pregnancy. These changes may affect the fetus with potential long-term consequences in musculoskeletal development and reduced bone mass later in life.
To offset the negative effects of calcium loss for the mother and growing fetus, doctors will prescribe calcium and vitamin supplements to pregnant mothers.
Bone Disease Risk
Bone diseases that come with aging—osteopenia, osteoporosis, and osteoarthritis are more common in women, especially early on. Additionally, inflammatory arthritis affects more women than men. And while inflammatory arthritis can affect anyone of any age, the majority of women with these conditions are between ages 30 to 50.
Osteopenia and Osteoporosis
Osteopenia is a condition that occurs when you start to lose bone mass and bones start to weaken. The cause of this condition is the loss of calcium, which can be common as people age. But for some people, this process occurs much quicker and puts them at risk for osteoporosis.
Osteoporosis causes bones to thin and weaken over time, making them vulnerable to fractures. Much like osteopenia, osteoporosis affects both men and women. However, the number of women who develop osteopenia, osteoporosis, or both conditions outnumber men in both prevalence and fractures associated with low bone density.
According to a 2017 review of studies in the Journal of Clinical Medicine Research, osteoporosis in women age 50 and older is four times more common and osteopenia is two times more common in women compared to men their age.
Estrogen deficiency also plays a part in osteoporosis development in women and at younger ages than men. After age 50, women—because of bone loss—will have more fractures than men, but before age 50, men have higher incidences of fractures due to sports activities and risk factors than do women.
According to the National Osteoporosis Foundation, 1 in 4 men will break a bone due to osteoporosis, and each year 80,000 men will break a hip. Men who break a hip are more likely to die due to problems that occur after the break, like infections.
Osteoarthritis (OA) is more common in older women than older men, but researchers don’t really know why. Additionally, women tend to have more severe OA compared to men.
Researchers speculate women are more often affected because of hormones and biomechanics. In terms of hormones, reduced estrogen and testosterone are believed to play a part in the development of OA in women. The risk of OA actually shoots up right after menopause—the time in a woman’s life when her periods stop.
Because testosterone is produced in the ovaries, menopause means lower testosterone levels. Testosterone generally helps builds up muscles and strengthens them, so they are better able to support the bones and joints. The reduced levels further increase a women’s risk for OA.
OA’s connection to biomechanics has to with the unique function of women’s joints. Wider hips, more flexible joints, hypermobility, and the effects of childbirth all play a part in the development of OA and the increased risk for the condition.
Inflammatory arthritis conditions—like ankylosing spondylitis, psoriatic arthritis, and rheumatoid arthritis (RA)—affect multiple joints and develop because a person’s immune system is overactive and malfunctioning.
Inflammatory arthritis conditions are considered autoimmune diseases and are known for causing chronic, ongoing inflammation that can lead to joint and tissue damage in the people affected.
Women tend to get inflammatory arthritis more often than men do. Researchers think this is related to sex hormones and women’s responses to infections, vaccinations, and environmental triggers—like stress, responsibilities, and how they respond to external events.
High estrogen levels in women can force the immune system to malfunction and attack itself through a misdirected response called autoimmunity. Researchers also know that estrogen heightens B cells—cells known for causing dysfunction in the immune system.
Further, estrogen can increase the production of certain inflammatory proteins that under general circumstances and at moderate levels would fight off bacteria, viruses, and other harmful substances.
Genetics might be able to explain some of the differences in risk for inflammatory arthritis between men and women. A study reported in 2012 in the journal Nature Genetics suggests X chromosomes play a part in the development of autoimmune diseases and because women have two, their risk for these types of conditions is twice as great in comparison to men.
A Word From Verywell
It is possible to delay bone loss and reduce your risk for bone disease regardless of gender. Eat a healthy and well-balanced diet that is rich in calcium and vitamin D. Stay active with weight-bearing exercise that is appropriate for your age and ability. Don’t smoke and drink alcohol in moderation.
Talk to your doctor about medications or health conditions that may affect your bone health. Your doctor might recommend vitamin D and calcium supplements. If necessary, they can prescribe bone-strengthening medications, especially if you have bone loss and risk factors for a specific bone condition.