Like a silent thief in the night, you are unaware of the presence of osteoporosis, until something breaks suddenly – a window in the case of a burglar; or a bone in your body in the case of osteoporosis.
What is bone?
Although it looks like a rock-solid substance, bone actually consists of living and growing tissue, that is in a constant state of flux. It mainly consists of collagen, which is a protein that provides a soft framework, and calcium phosphate, which is a mineral that adds strength and hardening of the framework. As bone consists of living and growing tissue, old bone is removed and new bone is continuously added to the skeleton. During childhood and adolescence years, more new bone is added than old bone removed. This means bones become heavier, larger and denser. Peak bone mass is reached around the 30-year-old stage, after which bone resorption slowly begins to exceed bone formation.
The bones in your body are composed of two types of tissue: compact bone and trabecular (spongy) bone:
• Compact bone mainly consists of tightly packed tubes of bone tissue which forms cortical bone, the dense outer casing.
• Spongy bone consists of millions of tiny beams and plates that form a lattice-like matrix and is less dense and spongier in consistency than compact bone.
Bones contain a combination of compact and spongy tissue, with compact bone forming the dense outer casing and spongy bone filling the interior. Longer bones, for example those of the arms, legs, and ribs, consist primarily of compact bone. Irregularly shaped bones consist mostly of spongy bone, such as the spinal vertebrae, pelvis, and the ends of the arm and leg bones. When bones begin to lose density, spongy bone weakens faster than compact bone. The spongy bone in the spine will lose density first, followed by the pelvis and the wrists, making the spine more vulnerable to osteoporosis.
What is osteoporosis?
The clue to osteoporosis lies in the name – the bones become porous due to severe bone loss. The characteristics of this disease are low bone mass and deterioration of the structure of bone tissue, caused by bones losing minerals such as calcium. Bone fragility leads to an increased risk of fractures of the hip, spine or wrists. Like termites damaging the wooden structures of your house, osteoporosis does structural damage to the bones, particularly to spongy bone. Not everybody will develop this disease, but those who did not reach optimal peak bone mass during their bone-building years, are at a greater risk.
Calcium is a mineral and the main ingredient of bone, followed by phosphate and smaller amounts of sodium, magnesium and potassium. Bone metabolism is the dynamic process by which bone take in or release calcium, also known as remodeling. Remodeling keeps the skeleton healthy by replacing old bone with new. When remodeling gets out of balance, with more calcium leaving the bones than what is added, it eventually results in osteoporosis. As calcium plays a vital role in other parts of the body, the body raids the bones when calcium levels in the blood drops below a certain threshold. About 1% of the body’s total calcium stores is used to maintain other functions in the body, such as movement in and out of cells; and transmitting signals to nerves and muscles. Both these functions of calcium thus play a crucial role in maintaining heart rate and blood pressure, as well as regulating other organ functions. The remaining 99% of calcium is found in bones and teeth.
Vitamin D (a hormone) plays an important role in the calcium remodeling process, as vitamin D enhances the absorption of calcium from food in the intestines, which means less withdrawal of calcium from bones for other functions in the body. The blood levels of calcium are regulated by Parathyroid hormone, which is secreted by small glands behind the thyroid. Parathyroid hormone is released when calcium levels falls below the levels that are needed by the cells in the body, resulting in more calcium being absorbed from food; less calcium being secreted by the kidneys in urine, and calcium being released from bones.
What causes bone loss and osteoporosis?
Bone loss shows no symptoms, but bones will eventually become too weak to bear normal weight and result in a fracture of the spine, hip or wrist. Declining estrogen levels in woman during menopause leads to rapid bone loss, particularly in spongy bone, for a large percentage of woman. The process accelerates during the first years of menopause and then begins to taper off. Statistics from the USA indicate that about 80% of people with osteoporosis are woman. Women’s bones, in general, are thinner than those of men, while women with a small frame (with thinner bones) are more likely to develop osteoporosis. Aging results in gradual bone loss for both men and woman and is usually not apparent until age 75 or later. Bone loss with aging is due to a number of factors:
• Remodeling in older people means bone is broken down quicker that it is formed, resulting in bone loss, especially in spongy bone.
• Aging results in reduced levels of calcium in the bloodstream, as the intestines absorb less calcium from food, while the kidneys become less efficient in conserving calcium, resulting in more calcium leaving the body. Older people also tend to eat less calcium rich food, which put a further strain on their calcium reserves.
• The aging body also produce less vitamin D, which is vital for calcium uptake and bone health in the body.
A wide range of medical conditions and certain medications have also been linked to bone loss, as indicated in the comprehensive list from Harvard Medical School, attached at the end of this blog.
Preventing bone loss and osteoporosis:
Preventing bone loss starts during the childhood and teenage years, with eating calcium-rich foods, getting enough vitamin D, and exercising regularly, which are investments that pay off with stronger bones as an adult.
Bone health can be maintained or improved through a number of lifestyle factors, such as:
• Eating a diet rich in calcium and vitamin D, and taking supplements if your regular diet is lacking in these elements. The recommended daily intake for woman 19-50 and men 19-70 is 1,000mg calcium and 600IU vitamin D, and for woman 51 and older and men 71 and older it increases to 1,200 mg calcium and 800IU vitamin D. As the body has difficulty to absorb large amounts of calcium at a time, it is best to take calcium in doses of about 500 mg a few times during the day.
• Avoid certain foods that may compromise bone health, such as salty foods, as high levels of sodium can increase the amount of calcium that is excreted in the urine; high levels of caffeine intake (more than four cups of coffee or lots of caffeinated soft drinks) that may increase calcium excretion by the kidneys; as well as soft drinks, as they usually contain phosphate that may interfere with the absorption of calcium from foods.
• Exercise regularly, as staying active not only slows bone loss, but also strengthens the muscles that support the skeleton. Age related loss of muscle mass is known as sarcopenia. It is important to do a combination of strength training (such as weight training) and weight-bearing exercises (where your body is bearing your weight, such as walking, running, etc.). Exercise not only helps to build strong bones, it also increases strength, flexibility and balance.
• Avoid excessive alcohol consumption, as it can interfere with the absorption of calcium and vitamin D, as well as making you more prone to fall.
• Avoid smoking, as smoking can weaken bones in a number of ways, such as reducing the blood supply to the bones (and other body tissues), decreasing the absorption of calcium, affecting the balance of hormones, including estrogen, and the nicotine in cigarettes slows the production of bone producing cells, called osteoblasts.
• Assess your risk by checking calcium and vitamin D levels through blood tests. If for any reason you think you are at risk for osteoporosis, have a bone density test done.
Treating osteoporosis:
Several medications are available for the treatment of osteoporosis and can be prescribed by a medical practitioner to slow down bone loss and slightly increase bone density. Boosting your calcium intake to recommended levels and in particular, regular exercise can benefit bone loss.
Preventing falls is a major issue for people with osteoporosis, as it increases the likelihood of fracturing a bone in the spine, hip or wrist. It is important to keep rooms and floors free of clutter that may cause a fall and to install handrails on stairs, in bathrooms and in other danger areas. Carpets should be secured to the floor or have a skid-proof backing. When walking outdoors, it is recommended to wear rubber-soled and low-heeled shoes and use a cane or walker for added stability.
Keeping the thief circling your house at bay is important. It is just as important to burglar-proof your bones against bone loss and osteoporosis.
Sources:
Osteoporosis. A guide to prevention and treatment. Special Health Report published in 2020 by Harvard Medical School. (www.health.harvard.edu)
How not to get osteoporosis.
Published online and reviewed 18 March 2018. WebMD. (www.webmd.com)
Osteoporosis and related bone diseases. Published online. National Resource Center, National Institutes of Health. (USA). (www.bones.nih.gov)
What is osteoporosis and what causes it? Published online. National Osteoporosis Foundation. (USA). (www.nof.org)
What smoking does to your bones. Published 15 November 2018. UCI Health, UCI Medical Center. Associated with the University of California, Irvine. (www.ucihealth.org)
Medical conditions and medications that can lead to bone loss
MEDICAL CONDITIONS
• Acromegaly • Emphysema • idiopathic scoliosis • Porphyria • Alcoholism • End-stage renal disease • Inflammatory bowel • Post-transplant bone • Amyloidosis • Epilepsy disease disease • Androgen insensitivity • Gastric bypass • Klinefelter’s syndrome • Premature ovarian failure • Ankylosing spondylitis • Gastrointestinal surgery • Leukemia and lymphoma • Primary biliary cirrhosis • Anorexia • Gaucher’s disease • Liver disease • Primary • Athletic amenorrhea • Glycogen storage diseases • Lupus hyperparathyroidism • Bulimia • Heart failure • Malabsorptive disorders • Renal tubular acidosis • Calcium deficiency • Hemochromatosis • Marfan’s syndrome • Rheumatoid arthritis • Celiac disease • Hemophilia • Multiple myeloma • Sarcoidosis • Chronic metabolic acidosis • Homocystinuria • Multiple sclerosis • Sickle cell disease • Cushing’s syndrome • Hypercalciuria • Muscular dystrophy • Systemic mastocytosis • Cystic fibrosis • Hyperprolactinemia • Osteogenesis imperfecta • Thalassemia • Depression • Hyperthyroidism • Pancreatic disease • Thyrotoxicosis • Diabetes (types 1 and 2) • Hypogonadism • Panhypopituitarism • Turner’s syndrome • Ehlers-Danlos syndrome • Hypophosphatasia
MEDICATIONS WITH DEFINITE LINKS TO BONE LOSS
• Anti-androgens • Aromatase inhibitors • Glucocorticoids
MEDICATIONS WITH POSSIBLE LINKS TO BONE LOSS
• Anticonvulsants • Depot • Lithium • Selective serotonin • Barbiturates medroxyprogesterone • Loop diuretics reuptake inhibitors (SSRIs) • Canagliflozin (Invokana) (Depo-Provera) • Methotrexate • Tacrolimus (Hecoria, • Cyclosporine (Neoral, • Gonadotropin-releasing • Proton-pump inhibitors Prograf, others) Sandimmune, others) hormone agonists (PPIs) • Thiazolidinediones (TZDs) • Heparin (long-term • Thyroid hormone (in therapy) excessive doses)