Overweight and its more serious form, obesity, refer to the condition in which excess fat has accumulated in the body. This is caused by consuming more calories than the body needs. The problem is largely due to our ‘obesogenic’ environment. Overweight and obesity are important risk factors for a range of diseases and disorders. Obesity is an important risk factor for cardiovascular disease, type 2 diabetes mellitus, certain cancers and osteoarthritis. Other conditions associated with obesity are infertility among women, mental problems such as depression and low self-esteem and sleep apnoea. Due to the growing problem of obesity, an increase in obesity-related morbidity and mortality is expected in the future.
Considerable variations in overweight prevalence among adults
The proportion of adults who are obese in the EU-25 ranges from less than 10% in Italy to more than 20% in Cyprus, Czech Republic, England, Germany, Hungary, Scotland (UK) and Slovakia. The proportion of adults who are overweight (including those who are obese) ranges from 36% of French women to more than 75% of German men. In all countries the prevalence of overweight is higher among men than among women, but obesity is generally higher among women than in men. There is clear evidence of increasing trends in overweight and obesity in the EU.
Childhood obesity is accelerating in many EU-countries
Childhood obesity is an epidemic in some EU-countries. Some southern European countries report overweight (including obesity) levels exceeding 30% among children aged 7-11. Rates of increase vary, with England and Poland showing the steepest increases. The epidemic of childhood obesity and overweight is accelerating in the EU.
An inverse association between obesity and socio-ecomic status
In many EU-countries there is a clear inverse association between obesity and socio-economic status. Especially in women, the prevalence of obesity is higher among low educated than among high educated people.
Some interventions have proven to be effective
Some prevention strategies linked to behaviour, diet and exercise have proven to be effective to a certain extent. However, maintenance of interventions is necessary to sustain weight loss. Surgery may help people with severe obesity.
Environmental interventions attempt to affect behavioural changes by modifying the external surroundings. The aim of such interventions is to prevent weight gain, without exclusive reliance on an individual’s knowledge or motivation. Many environmental factors have been cited as contributing to obesity. Still, there have been few controlled studies showing that changes in these factors will prevent weight gain.
11 April 2008
Overweight
Definition and scope
Overweight and obesity can be measured in different ways
Overweight and obesity refer to the condition in which excess fat has accumulated in the body. This condition is a risk factor for a range of diseases and disorders. The extent of overweight is determined in various ways.
The most common method of determining weight status is Body Mass Index (BMI). This measure relates an individual’s weight to his or her height. According to the WHO classification, individuals with a BMI between 25 and 30 are defined as overweight and those with a BMI equal to or over 30 as obese (see Table 1).
Abdominal skinfold measures, Waist-to-Hip ratio (WHR) and waist circumference are considered to be markers of central obesity or intra-abdominal fat. Waist circumference in combination with BMI has shown to be the best descriptor of obesity and predictor of health risks. A waist size greater than 102 cm for men and 88 cm for women increases the risk for most weight-related illnesses.
Other methods for measuring body fat include using electronic impulses, water tank submersion, scanning techniques such as computed tomography (CT) or magnetic resonance imaging (MRI) and special scales. These newer techniques, although providing more precise measures of body fat, are costly and impractical for use in large epidemiological studies or in population surveys (WHO, 2000d; Kuller, 1999).
In this EUphact, overweight and obesity are described in terms of BMI.
Table 1: Classification of Overweight and Obesity by BMI (WHO, 2000).
Prevalence of overweight and obesity varies widely within the EU
The proportion of adults who are obese in the EU-25 ranges from less than 10% in Italian women to more than 25% in Czech women. The proportion of adults who are overweight ranges from 23.3% of French women to 53% of German men (see Prevalence of overweight and obesity in European countries). In all EU-countries the prevalence of overweight is higher among men than among women. In most countries obesity is more frequently present among women than among men. No gradient in the prevalence of overweight can be distinguished.
Prevalence rates of overweight and obesity in populations are often obtained in samples with different age distributions and in different time periods. Precisely comparable prevalence rates are rare, and international comparisons should be interpreted with caution.
Number of overweight people has increased in the EU
The percentage of people with overweight or obesity has increased in the EU, as well as in the rest of the world. The WHO talks of the "global epidemic of obesity" (WHO, 2003b). Trend data suggest an increase in obesity rates in almost all countries. Even in those countries with relatively low rates of obesity, such as France and Denmark, there is clear evidence of an increase. In France, obesity in women rose from 8% to 13% while in men it rose from 8.4% to 11.8% between 1997 and 2006 (self reported data). In the Netherlands obesity among men rose from 4.9% to 8.5%, while for women it went from 6.2% to 9.3% from the late 1970s to the mid-1990s (measured data). In the UK (England), the annual health survey has recorded dramatic increases in measured obesity from 13% to 22.7% in men and 16% to 23.8% in women, in just 10 years, until 2004. This compares with an obesity prevalence of 6-7% in 1980 (IOTF, 2005b).
Childhood obesity is turning into an epidemic
Childhood obesity is already an epidemic in some European countries and on the rise in others (WHO, 2003b). In 2004 it was estimated that 14 million school-age children in the EU were overweight, including three million obese children. These estimates were made using the IOTF standard definition for international data comparisons (IOTF, 2004). Recently, two papers on overweight and obesity prevalence in European children have been published, involving at least 10 countries (Lobstein & Frelut, 2003; Lissau et al., 2004). The findings of these studies and differences in data collection used are described in Papers on childhood overweight.
Childhood obesity epidemic is worsening
Most publications on childhood obesity agree that the epidemic of childhood obesity and overweight is accelerating. An analysis of survey data conducted throughout Europe since the mid-1970s, reveals a rapid shift in the trend during the mid-1990s (IOTF, 2006). The number of children affected by overweight and obesity is now rising at more than 400,000 a year and already affects almost one in four across the entire EU. The new prevalence of 24% in 2002 is five points higher than had been expected based on original trends in the 1980s and is already higher than the predicted peak for 2010 (IOTF, 2006).
There is a clear socio-economic gradient in most EU-countries
In many EU-countries there is a clear socio-economic gradient in obesity (Rahkonen et al., 1998; Stam-Moraga et al., 1999; Hulshof et al., 2003; Molarius et al., 2000; Eurothine, 2007). Especially in women, a strong inverse association between obesity and socio-economic status, mostly assessed by educational level, has been reported in many EU countries. This means that obesity among women with lower education levels is more prevalent than among highly educated women.For the WHO-MONICA study, 26 mostly European populations were monitored over a 10-year period (Molarius et al., 2000). Lower education was associated with higher BMI in about half of the male and in almost all of the female populations, and the differences in relative body weight between educational levels increased over the study period (for both, men and women). For women in the MONICA project, the results of the final measures were similar to those in the initial survey (1979-1989). For men, the proportion of population having a significant inverse association increased from 23% in the initial survey to 50% in the final survey. Poland is the only EU country in which a significant positive association was found in one of its regions
Obesity is a key risk factor for a number of diseases
Although obesity could be considered a disease in its own right, it is also a key risk factor for a number of chronic diseases that constitute the principal causes of death in the EU. Obesity, especially central obesity, is an important risk factor for cardiovascular disease (CVD), type 2 diabetes mellitus and certain cancers. Overweight and obesity contribute significantly to osteoarthritis, a major cause of disability in adults.
Other conditions associated with obesity are infertility among women, mental problems such as depression and low self-esteem and sleep apnoea.
Obesity and type 2 diabetes mellitus: a close relationship
One of the consequences of weight gain is insulin resistance, which can result in type 2 diabetes mellitus. Obesity, in particular abdominal obesity, is the most important risk factor for the onset of diabetes. Compared with the lowest BMI category, risks for developing type 2 diabetes mellitus are increased more than tenfold among women with BMIs higher than 29 kg/m2 and among men with BMIs higher than 31 kg/m2 (Carey et al., 1997; Visscher & Seidell, 2001). Being moderately overweight is also closely related to the onset of type 2 diabetes mellitus. About 64% of type 2 diabetes in North-American men and 74% in North American women could be avoided if there were no BMIs above 25 kg/m2 (WHO, 2000; Visscher & Seidell, 2001). See also the EUphocus Diabetes prevention and care.
Overweight is related to several cancers
Overweight, in particular obesity is related to the incidence of some cancers. The strongest evidence is for cancer of the endometrium. A BMI exceeding 30 kg/m2 is associated with a one and a half to three times higher risk of developing endometrial cancer than a BMI between 20 and 25 kg/m2 (WCRF, 1997; Visscher & Seidell, 2001). The WCRF classifies the relationship between high BMI and breast and kidney cancer as “probable”, with approximately 1.8-fold higher risk for those with a BMI exceeding 27 kg/m2 compared with those having a BMI below 17 kg/m2. Furthermore, there is evidence of a possible relationship between high BMI and colon cancer. This relationship is more consistent for men than for women. Gallbladder cancer is possibly associated with high BMI, particularly for women.
A possible mechanism for the relationship between high body weight and cancer is based on the metabolic abnormalities (metabolic syndrome) that result from high BMI levels (Visscher & Seidell, 2001).
Effects of overweight on cardiovascular health
The effects of obesity on cardiovascular disease are manifold. Hypertension is probably one of the most common ones. Blood pressure increases with the increase of BMI, and people who are obese have been found to have a much higher prevalence of hypertension (AIHW, 2004).
An overview of relative risks for diseases associated with obesity is presented in Estimated increased risk for the obese of developing associated diseases. The data are extracted from The National Audit Office (NAO) in England (NAO, 2001). A more extensive overview of relative risks for the different BMI levels is given in the report ‘Our food, our health - Healthy diet and safe food in the Netherlands’ (Kreijl et al., 2006). Based on international literature, risks have been estimated for different age classes, both sexes and different levels of overweight. From this overview it becomes clear that morbidity is elevated in overweight people and that it is higher in obese people than in overweight people. This is particularly true of type 2 diabetes, but also holds for cardiovascular diseases, gallbladder diseases, conditions which impaired mobility (such as osteoarthritis), and various forms of cancer.
Indirect costs of obesity are far greater than direct costs
The direct costs of obesity are now estimated to be around 1% - 5% of total health care costs in Europe, compared to 7% (or US$ 70 billion) in the United States (Colditz, 1999; Seidell, 1995). Indirect costs, which are far greater than direct costs, include work days lost, physician visits, disability pensions and premature mortality.
Narbro calculated that approximately 10% of the total costs of the productivity losses due to sick leave and work disability may be attributable to obesity-related diseases (Narbro et al., 1996). Due to the increase in prevalence and costly consequences, obesity is now being recognised not only as a risk factor in the clinical setting but also as an important threat to public health. The public health impact of obesity should be measured by its combined effect on disability and mortality. Intangible costs such as impaired quality of life are also enormous.
19 March 2007
Overweight
Causes and risk factors
An imbalance between energy consumption and energy expenditure
Weight gain, overweight and obesity are caused by consuming more calories than the body needs, usually by eating a diet high in fat and calories, living a sedentary lifestyle or both. The environments most people in the EU live in are increasingly obesity-favourable (“obesogenic”). There is often no need to be physically active and the availability of energy-rich food is overwhelming.
It is impossible to establish a direct causal link between environmental/cultural factors and the rise in obesity levels, but there are obvious associations between changing environments and increasing waistlines (Royal College of Physicians, 2004).
Evidence of factors that promote or protect against overweight
Based on a comprehensive review of evidence for the dietary causes of obesity, Swinburg and colleagues pointed out a number of factors that might promote or protect against overweight or weight gain (Swinburn et al., 2004). The evidence was classified as: convincing, probable, possible and insufficient. The results of the review are presented in Evidence of factors that might promote or protect against overweight or weight gain.
Major shifts in eating and physical activity patterns
The way in which work and leisure time are spent has changed, resulting in a major shift in eating and physical activity patterns:
Jobs are more sedentary;
Labour saving devices (lifts, remote controls) have reduced daily activity levels;
Screen based entertainment (TV, computer) has increased;
Less time is spent preparing meals and more processed food is consumed;
Eating out and snacking and grazing are more common;
Alcohol intake has increased, especially among young people.
Food advertised to children often less healthy than recommended
Food marketing and advertising reflect heavy investment and great sophistication, and permeate all levels of society. Research in the UK reveals that ninety per cent of food advertising screened during children’s broadcasts is for foods high in fat, salt and/or sugar (Royal College of Physicians, 2004). A review of the effects of food promotion to children concluded:
Food advertising to children is extensive;
The diet being advertised is less healthy than the recommended diet for children;
Children enjoy and engage with food promotion;
Food promotion is affecting preference, purchase behaviour and consumption;
The effect is independent of other factors and operates at both brand and food category level.
Overweight is not only related to food intake and physical activity
The imbalance between calories consumed and calories burned can also be caused by other obesity-related factors. For instance, metabolism, hormones that affect the way calories are processed, and other organ systems in the body can all affect appetite or the way in which the body stores the extra energy.
As with many conditions, obesity is a result of combined influences of genetic and environmental factors. Some genetic abnormalities that predispose to obesity have been identified, but these are absent in most people with obesity.
19 March 2007
Overweight
Interventions
It is difficult to prevent and treat overweight and obesity
Most population-based prevention programs that have been scientifically assessed have not demonstrated any favourable effects on the prevalence of obesity. However, there are examples of successful programs for both adults and children.
According to the Swedish systematic review of interventions (Asp et al., 2002), scientific assessments of treatment methods for obesity show that:
Changes in dietary habits through counselling can lead to weight reduction in the range of 3 to 10 kg during the first year (or 10% of body weight in children). The long-term effects are uncertain.
Regular exercise contributes to weight reduction.
Behavioural therapy in conjunction with changes in diet and exercise can have further effects on weight if supportive interventions continue for a longer period.
Treatment based on the ‘Weight Watcher’ approach often results in a permanent weight loss of 10% or more of their original weight.
VLCD for 6 to 12 weeks yields a greater weight reduction than conventional low energy diets. In studies of VLCD for 1 to 2 years (often periodic), a retained weight loss of a few kilograms more than in treatment using a balanced diet alone was noted.
Pharmacological treatment using orlistat (Xenical®) or sibutramine (Reductil®) yields an average weight loss of 2 to 5 kg beyond what would be attained through diet and exercise alone. In clinical trials, one fourth to one fifth of those who started pharmacological treatment lost at least 10% in weight compared to half as many of those treated with placebo.
The scientific evidence for a wide range of alternative medicine methods is too weak to draw any conclusions concerning the possible effects these methods have on obesity.
Usually weight loss is not permanent. Within a few years most who had initially succeeded in losing weight had returned to their original weight. Therefore, it is particularly important to develop and assess long-term treatments that aim at permanent weight loss.
Surgical treatment is an option in severely obese patients. On average, it reduces weight by more than 25% (e.g., from 125 to 90 kg) up to 5 years after surgery. After 10 years, a weight loss of approximately 16% remains, on average slightly over 20 kg. This has substantial health and quality of life benefits for the patient. The intervention, however, carries risks of complications.
Environmental interventions need to be developed
Although many environmental factors have been cited as contributing to obesity, there have been few controlled studies showing that changes in these factors will prevent weight gain. Environmental interventions attempt to modify the external surroundings with a goal of affecting behavioural changes, such as improvement in diet, increased physical activity, and or decreased sedentary behaviours. The aim of such interventions is to prevent weight gain, without exclusive reliance on an individual’s knowledge or motivation.
Examples of environmental interventions include:
Providing safe walking or cycling routes in the context of a “walk/cycle to school” campaign;
Offering smaller portion sizes, at lower prices, in restaurants, cafeterias and/or vending machines;
Providing access to bicycle racks, lockers, showers, and other incentives to encourage cycling to work or school and physical activity during the workday;
Making stairways more accessible and attractive, through lighting, signals and open access, while discouraging the use of elevators.
An integrated approach is recommended
In 2005, the Heart and Stroke Foundation of Canada made an inventory of interventions related to obesity (HSF, 2005). They concluded that public health approach to disease prevention should not focus solely on risk behaviour education and behavioural skill development. It should also incorporate environmental and policy measures, plus an understanding of the barriers preventing behaviour change. Efforts to develop the next generation of preventive interventions must focus on building relationships with communities and develop interventions that derive from the communities’ assessments of their needs and priorities (HSF, 2005).
Several authoritative bodies have published a range of opportunities for intervention related to obesity. A short review is presented in Opportunities for interventions.
Prevalence of obesity (BMI 30+), both sexes, for selected Isare health regions, in 1999
Obesity
Remarks
Data were gathered by the correspondents of the ISARE project in each of the participating countries by contacts with the national statistical offices.
The ISARE project (health indicators in the regions of Europe) aims at gathering useful information on health indicators in the regions of the European Union.
The ISARE project firstly defined "health regions" within European Member States and then tested the feasibility of gathering data at those regional levels. The list of data to be collected was defined taking into account the ECHI list and information on the availability of these data at the regional level. The report of the ISARE-1 and ISARE-2 projects are available on the ISARE website. The ISARE-3 project continues the work of the ISARE-1 and -2 and includes data of new Member States (EU-25).
Some of the data are coming from Health examination surveys, others from Health interview surveys. For the latter, an underestimation is a common phenomenon. The age range usually includes the population of 15 and over, but sometimes it is 20 and over or 20-64. Because of these variations, a proper assesment of differences is difficult to make, especially between countries.
Good evidence of an association between overweight and obesity and CVD incidence among young to middle-aged men and women but not among older people.
Moderate evidence of an association between the duration of obesity and CVD mortality among adults, which may mediate the protective effect of overweight in older age.
Moderate evidence of an association between obesity and CVD mortality among adults.
Moderate evidence of an association between abdominal obesity and risk of CVD, particularly among older men.
Coronary heart disease
Good evidence of an association between overweight and obesity and increased risk of CHD in adults.
Moderate evidence of an association between abdominal obesity and risk of CHD in older men and younger women.
Little evidence of an association between childhood and adolescent obesity and risk of CHD (particularly among girls), unless the children become obese adults.
Heart failure
Moderate evidence of an association between overweight and obesity and risk of heart failure.
Stroke
Moderate evidence of an association between overweight and obesity and increased risk of ischaemic stroke among adults
Moderate evidence of an association between abdominal adiposity and risk of stroke in men and women.
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. Obesity: impact on cardiovascular disease. Armonk, NY: Futura Publishing Co., Inc, 1999</p>
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An EU project. The first phase, ISARE I (1999-2001) defined the most appropriate sub-national level (\'health region\') for the exchange of health indicators within the European Union and enabled the assessment of the extent of data availability at those levels. The second phase, ISARE II (2002-2004), made it possible to test the feasibility of collecting regional data in each European country. www.isare.org
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A group of diseases characterised by pathological changes in the circulatory system of the body, i.e. the heart muscle and the blood vessels. It includes hypertension (elevated blood pressure), coronary heart disease (CHD) including heart attack, cerebrovascular disease (CVS) including stroke, peripheral vascular diseasese (PVD), rheumatic heart disease, congenital heart disease, and cardiomyopathies.
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