Obesity is usually caused by the underlying pathology of accumulation of excess body fat and excess weight gain. It impairs health to a great extent especially by raising the risk of other chronic illnesses such as heart disease and diabetes. Obesity is defined as a Body mass index (BMI) exceeding 30 kg/m2.
Obesity is one of the most prevalent disorders of developed countries, and its incidence is increasing rapidly. In England for example obesity rose between 13.2% to 23.6% in men and 16.4% to 23.8% in women between 1993 and 2004. In the United States the numbers rose from 23% in 1990 to 31% in 2000. In both countries present figures are nearly one third of the total population.
Obesity and disease
Central obesity (abdominal obesity) as well as obesity in general is associated with physiological changes that may cause the development of diseases like high blood pressure, heart disease, high blood cholesterol and type 2 diabetes.
Obesity also raises the risk of fatty liver disease, gall bladder disease, osteoarthritis and certain cancers. Increased body weight raises the risk of musculoskeletal disorders like osteoarthritis, gouty arthritis and fractures associated with obesity.
It is estimated that the cost of treating obesity related diseases contributes 2–7% of total national health care costs in developed countries.
Obesity and bone health in children
There have been studies that show that obese children are more likely to incur fractures that involve the growth plate of their bones compared to children who are not obese. This may cause permanent stunting of growth and deformities.
Obesity and bone health in adults and the elderly
The incidence and prevalence of obesity among the elderly is higher than in younger adults. The trends are prominent in developed nations like United States and also in other nations. With age the natural risk of brittle bones and easily fractured bones due to conditions like osteoporosis is common. Osteoporosis may be major contributing factor to fractures among the obese and overweight elderly individuals.
Risk of fractures is also high among the elderly with a low body mass index. There are several factors that may contribute to increased risk of fractures among the low body weight elderly. This includes low bone mineral density (BMD), less soft tissue that may protect bone from impact of the injury and increased fall risk resulting from muscle weakness. They are more at risk of hip fractures.
The interest in the association between overweight and obese elderly individuals still gains precedence over low weight individuals because of the rising prevalence of obesity. Less than 1% elderly individuals may have a low BMI related fracture whereas obese elderly form nearly three quarters of all obese individuals in developed nations.
Elderly obese individuals are also at risk of osteoporosis and fracture of the spine or vertebra. This has been demonstrated in several studies. BMI and total body weight are the most common body size measurements evaluated in association with fracture risk. Other measures include fat mass, hip girth, and waist to hip ratio etc.
From the National Health and Nutrition Examination Survey I it was estimated that majority of men over 65 years who experience hip fracture were overweight or obese and among women 46% of hip fractures occurred in those who were overweight or obese.
Evaluation of the NHANES III data shows that approximately one-third of overweight and obese Americans aged over 45 have low bone mass and are thus at risk of osteoporotic fractures. Among these prevalence of osteoporosis and low bone mass is higher in whites and Mexican Americans than in African Americans.