Most modifiable risk factors directly impact bone biology and result in a decrease in bone mineral density (BMD), but some of them also increase the risk of fracture independently of their effect on bone itself. These include Kanis, J.A., et al., Alcohol intake as a risk factor for fracture. Osteoporos Int, 2005. 16(7): p. 737-42.
Kanis, J.A., et al., Smoking and fracture risk: a meta-analysis. Osteoporos Int, 2005. 16(2): p. 155-62.
The relationship between alcohol intake and fracture risk is nonlinear. No significant increase in risk is observed for intakes of 2 units or less daily (e.g. 2 glasses of 120 ml of wine). Above this threshold, alcohol intake is associated with an increased risk of 23%, 38% and 68% for any fracture, any osteoporotic fracture, and hip fracture, respectively, compared to people with moderate or no alcohol intake. High intakes of alcohol cause secondary osteoporosis due to direct adverse effects on bone-forming cells, on the hormone that regulates calcium metabolism and poor nutritional status (calcium, protein and vitamin D deficiency) Kanis, J.A., et al., Alcohol intake as a risk factor for fracture. Osteoporos Int, 2005. 16(7): p. 737-42.
Smoking can lead to lower bone density and higher risk of fracture Kanis, J.A., et al., Smoking and fracture risk: a meta-analysis. Osteoporos Int, 2005. 16(2): p. 155-62.
Law, M.R. and A.K. Hackshaw, A meta-analysis of cigarette smoking, bone mineral density and risk of hip fracture: recognition of a major effect. BMJ, 1997. 315(7112): p. 841-6.
Nguyen, T.V., et al., Lifestyle factors and bone density in the elderly: implications for osteoporosis prevention. J Bone Miner Res, 1994. 9(9): p. 1339-46.
Ward, K.D. and R.C. Klesges, A meta-analysis of the effects of cigarette smoking on bone mineral density. Calcif Tissue Int, 2001. 68(5): p. 259-70.
and this risk increases with age Kanis, J.A., et al., Smoking and fracture risk: a meta-analysis. Osteoporos Int, 2005. 16(2): p. 155-62.
. People with a history of cigarette smoking and people who smoke are at increased risk of any fracture, compared to non-smokers. Current smoking was associated with an increased risk of 25% for any fracture compared to non-smokers and 60% for hip fracture, after adjustment for BMD Kanis, J.A., et al., Smoking and fracture risk: a meta-analysis. Osteoporos Int, 2005. 16(2): p. 155-62.
Studies have provided evidence that weight in infancy is a determinant of bone mass in adulthood Cooper, C., et al., Childhood growth, physical activity, and peak bone mass in women. J Bone Miner Res, 1995. 10(6): p. 940-7.
Cooper, C., et al., Growth in infancy and bone mass in later life. Ann Rheum Dis, 1997. 56(1): p. 17-21.
Duppe, H., et al., The relationship between childhood growth, bone mass, and muscle strength in male and female adolescents. Calcif Tissue Int, 1997. 60(5): p. 405-9.
. Generally, leanness (body mass index (BMI) <20 kg/m2) regardless of age, sex and weight loss, is associated with greater bone loss and increased risk of fracture. When compared with a 25 kg/m2 BMI, individuals with a 20 kg/m2 BMI had an almost two-fold increase in the risk ratio for hip fracture De Laet, C., et al., Body mass index as a predictor of fracture risk: a meta-analysis. Osteoporos Int, 2005. 16(11): p. 1330-8.
. Weight loss is also associated with greater bone loss and increased risk of fracture De Laet, C., et al., Body mass index as a predictor of fracture risk: a meta-analysis. Osteoporos Int, 2005. 16(11): p. 1330-8.
Ensrud, K.E., et al., Intentional and unintentional weight loss increase bone loss and hip fracture risk in older women. J Am Geriatr Soc, 2003. 51(12): p. 1740-7.
. However, it is increasingly recognised that obesity is a risk factor for some fractures and for fractures in general after accounting for BMD Johansson, H., et al., A meta-analysis of the association of fracture risk and body mass index in women. J Bone Miner Res, 2014. 29(1): p. 223-33.
When insufficient calcium is absorbed from dietary sources, the body produces more parathyroid hormone (PTH), which boosts bone remodelling, mobilizing osteoclasts in the bone to break down and sacrifice bone calcium to supply the nerves and muscles with the mineral they need. There are indications that protein is also important in that it may act synergistically with vitamin D and calcium. Read more about calcium.
Vitamin D is also essential, since it helps calcium absorption from the intestines into the blood. Vitamin D is made in our skin with exposure to the sun’s ultraviolet rays. In most people casual exposure to the sun for as little as 10-to-15 minutes a day is usually sufficient. However, in elderly people, people who do not go outdoors, and during the winter months in northern latitudes, food or supplemental sources of vitamin D is of importance. At least 800 international units (IU) of vitamin D and 1,000 to 1,200 mg of calcium daily can contribute to protect against osteoporosis Dawson-Hughes, B., et al., Estimates of optimal vitamin D status. Osteoporos Int, 2005. 16(7): p. 713-6.
. Read more about vitamin D.
Osteoporosis can also be compounded by eating disorders such as anorexia nervosa and bulimia – see disorders that affect bone nutrition.
Physical inactivity and a sedentary lifestyle as well as impaired neuromuscular function (e.g., reduced muscle strength, impaired gait and balance) are risk factors for developing fragility fractures Albrand, G., et al., Independent predictors of all osteoporosis-related fractures in healthy postmenopausal women: the OFELY study. Bone, 2003. 32(1): p. 78-85.
Cummings, S.R., et al., Risk factors for hip fracture in white women. Study of Osteoporotic Fractures Research Group. N Engl J Med, 1995. 332(12): p. 767-73.
Dargent-Molina, P., et al., Fall-related factors and risk of hip fracture: the EPIDOS prospective study. Lancet, 1996. 348(9021): p. 145-9.
Nguyen, T.V., P.N. Sambrook, and J.A. Eisman, Bone loss, physical activity, and weight change in elderly women: the Dubbo Osteoporosis Epidemiology Study. J Bone Miner Res, 1998. 13(9): p. 1458-67.
. People with a more sedentary lifestyle are more likely to have a hip fracture than those who are more active. For example, women who sit for more than nine hours a day are 50% more likely to have a hip fracture than those who sit for less than six hours a day Pfeifer, M., et al., Musculoskeletal rehabilitation in osteoporosis: a review. J Bone Miner Res, 2004. 19(8): p. 1208-14.
. Read more about the role of exercise in bone health.
Falls are very common among older people, with one third of people aged 65 years and over falling each year and half of those aged 85 years and over Close, J.C., et al., What is the role of falls? Best Pract Res Clin Rheumatol, 2005. 19(6): p. 913-35.
. Notably, less than 5 % of falls in the elderly result in a fracture, almost 60% of those who fell the previous year will fall again and more than 90% of hip fractures result from falls Tinetti, M.E., Clinical practice. Preventing falls in elderly persons. N Engl J Med, 2003. 348(1): p. 42-9.
Visual impairments, loss of balance, neuromuscular dysfunction, dementia, immobilization, and use of sleeping pills, which are quite common conditions in elderly persons, increase the risk of falling and accordingly increase the risk of fracture. Read more about preventing falls.