Virtual Medical Centre

Obesity

• What is Obesity?
• Who gets Obesity?
• Predisposing Factors
• Progression
• Probable Outcomes
• How Will Obesity Affect Me?
• Clinical Examination
• How is Obesity Diagnosed?
• How is Obesity treated?
• Obesity References

What is Obesity?

Obesity is defined as being 20% or more over the maximum desirable weight for a man's height or 25% or more in females. It is now considered a chronic health problem of the Western world. Being obese is different from being overweight. Obesity is also defined as having a BMI (body mass index) over 30 kg/m². BMI is calculated by dividing your weight (in kilograms) by your height (in metres) squared. A BMI between 18.5 and 24.9 is generally associated with good health. As the BMI gets higher, more health problems develop.

Calculate your BMI using the calculator below. Then compare your result to the BMIs in Table 1.

Obesity is an important condition which causes significant morbidity and mortality through increased rates of type 2 diabetes mellitus, heart disease, some cancers and arthritis (joint disease) amongst other conditions. In addition, obesity can cause sleep disturbances (such as obstructive sleep apnoea) and lead to reduced fertility rates in females. Morbid obesity refers to very severe obesity which poses significant risks to your health. This occurs when you are greater than 40 kg above your desired weight.

Who gets Obesity?

The number of people who are obese is rising rapidly worldwide, making obesity one of the fastest developing public health problems. The World Health Organisation (WHO) has described the problem of obesity as a "worldwide epidemic".

• Recent studies estimate that more than half of all Australian women (52%) and two-thirds of men (67%) are overweight or obese. That is, almost 60% of the adult population in Australia is overweight or obese. Approximately 20% of the population may be classified as obese or morbidly obese which both pose significant health risks.
• The rates of obesity in Australia has increased dramatically, particularly in the last two decades. The prevalence of obesity has is 2.5 times higher now than it was in 1980.
• Rates of childhood obesity in Australia are at one of the highest amongst developed nations. 25% of Australian children are currently overweight or obese.
• In the 10-year period from 1985 to 1995, the level of combined overweight / obesity in Australian children more than doubled, whilst the level of obesity tripled in all age groups and for both sexes.
• Obesity is a health crisis that is costing the Australian government up to $1.5 billion a year in direct health costs.

Table 2: Obesity prevalence in several countries worldwide

Incidence of obesity according to profession

Recent studies have suggested that lower levels of education and lower levels of occupation are associated with increased rates of obesity. In women these factors have a synergistic (combined to have a greater impact) effect. Overall however, lower level of education is a more important determinant of obesity. One particular study showed that individual job can impact on rates of obesity. Salespersons; personal service workers; plant-machine operators, drivers, labourers and related employees (lower status occupations) have higher BMI and rates of obesity than men and women in managerial, administrative, clerking or professional positions. There is no obvious differences between rates of obesity in employed and unemployed individuals. However in the past it has been thought that unemployment may be associated with higher rates of obesity.

Predisposing Factors

The cause of obesity is complex and depends on both genetic and environmental influences. Most patients suffer from 'simple obesity' (weight gain due to an increased intake of calories) but the following conditions can have obesity as an associated feature:

• Congenital syndromes-e.g. Prader Willi syndrome.
• Hypothyroidism.
• Cushing's syndrome.
• Polycystic ovarian syndrome (PCOS).
• Steroid use.
• Damage to the hypothalamus- part of the brain that plays a role in regulating appetite.

In a general sense, obesity results when the intake of calories exceeds the amount of energy your body burns.Thus the following are considered risk factors:

• Genetics: Various genes may impact on the development of obesity. Research into genetic helps people understand the causes of obesity and possible treatments.
• Food intake: Overeating and consumption of fatty foods plays a role in the development of obesity. The home environment and finances can influence which foods are eaten. Note that many obese patients underestimate their food intake.
• Lack of exercise: This lowers energy expenditure and promotes weight gain. Lifestyle changes over recent decades to more sedentary lifestyles is a key contributing factor to the rise in the rates of obesity.
• Excess alcohol consumption

Progression

Obesity during childhood and adolescence is associated with an increased risk of obesity during adulthood and its associated health problems. Adolescent males with moderate-to-severe obesity seem to be at particular risk. The impacts of childhood and infant obesity are less clear, but generally the greater the degree of obesity and the older the age of the children, the more likely obesity will develop in adulthood. Obesity is associated with risks of early death from diabetes, heart disease and stroke. Gout and bowel cancer increased among men who had obesity as adolescents. Women who had obesity as adolescents have increased rates of arthritis. There are a number of health, social and psychological consequences associated with overweight and obesity. Associated health consequences include:

• Coronary heart disease (CHD)
• Diabetes mellitus
• High blood pressure / hypertension
• High blood cholesterol
• Gallbladder disease
• Osteoarthritis
• Gout
• Certain types of cancer (breast, endometrial, cervical,colon etc.)
• Reproductive hormone abnormalities
• Polycystic ovary syndrome
• Impaired fertility
• Breathlessness
• Sleep apnoea
• Low back pain (due to obesity)
• Premature death.

Generally, the more overweight you are, the more likely you are to have health problems related to the excess weight. Excess fat in the abdominal region (the 'apple' body) is of particular concern as it is associated with greater risks to health than is fat distributed around the body (the 'pear' body). Psychosocial consequences include:

• Social bias
• Discrimination
• Low self-esteem
• Body shape dissatisfaction
• Eating disorders, e.g. binge-eating disorder
• Isolation
• Depression.

Therefore, preventing weight gain is important not only for health and wellbeing, but also for preventing the development of overweight and obesity and therefore the development of associated health and psychosocial problems and diseases.