Obesity Epidemic?
We're hearing a lot about the obesity "epidemic" occurring though out the world. Is there really an epidemic? The short answer is YES. Here are some interesting facts: Today, more than 1.1 billion adults worldwide are overweight, and 312 million of them are obese. When adjusted for ethnic differences the prevalence is even higher - with 1.7 billion people classified as overweight worldwide. In September 2007 the population of the world was estimated to be 6.6 billion people. According to the International Obesity Task Force at least 155 million children worldwide are overweight or obese. After remaining relatively stable in the 1960s and 1970s, the prevalence of obesity among adults in the United States increased by approximately 50 percent per decade throughout the 1980s and 1990s Two thirds of adults in the United States today are obese or overweight Childhood overweight, defined as a body-mass index at or above the 95th percentile for children of the same age and sex, affected approximately 15 percent of children and adolescents in the United States in the period from 1999 through 2002 In the past 20 years, the rates of obesity have tripled in developing countries that have been adopting a Western lifestyle. How are we doing in Canada? The Canadian data shows that the prevalence of obesity has increased substantially from 1978-79 to 2004. In fact the BMI of the entire Canadian adult population has increased during that time! 
Among Canadian provinces BC, Ontario, and Quebec have the lowest prevalence of obesity while Newfoundland and Saskatchewan have the highest. There are some differences between the US and Canada with respect to obesity. Canadian women have lower prevalence of obesity than women in the US, except for those women over the age of 75. The picture for men is more complex with Canadian males between the ages of 25-34 and over 75 being more obese than their American counterparts. So there is an epidemic of obesity. Does it matter? Once again, YES. Obesity is a major risk factor for diabetes and cardiovascular disease. Each year about 18 million people die from CV disease. During the past decade overweight and obesity have joined underweight, malnutrition, and infectious diseases as major health problems threatening the developing world. The trend in the life expectancy of humans during the past thousand years has been characterized by a slow, steady increase - until the last 30 years when this rise in life expectancy has decelerated to the point where life expectancy may start to decline within the first half of this century because of health complications of Obesity! In the developed world, 2 to 7% of total health care costs are attributable to obesity. In the United States alone, the combined direct and indirect costs of obesity were estimated to be $123 billion in 2001. Obesity is not only associated with cardiovascular disease, but obese persons are also at higher risk for cancer, of all types. A study by Calle showed that in a cohort of patients with a BMI of greater than 40, the death rates from all cancers combined were 52 percent higher (for men) and 62 percent higher (for women) than the rates in men and women of normal weight. Peeters et al showed that obesity is associated with a lower life expectancy. Patients with a BMI of 30 or more can expect to have seven fewer years of life than their slimmer brothers and sisters. The effect is independent of sex and smoking. Sturm and Well looked at whether obesity contributed more to morbidity than did poverty or smoking. They found that obesity is more damaging to health than either of these other two risk factors and should be given higher priority in clinical practice and public health campaigns than it currently receives. And as if that evidence isn't damning enough - obesity is associated with erectile dysfunction - for patients with a BMI of greater than 30. Interestingly, the NNT for weight loss to restore erectile function was 3.9 .The NNT for Viagra is 2, however weight loss is a lot healthier overall and much less expensive than Viagra. So, does this increase in the prevalence of Obesity matter? You bet your life it does! Why are we getting fatter? Simply put - Our caloric equation is out of balance! We eat too much and exercise too little! Muller looked at physical activity and diet is children 5-7 years old. Interestingly he found no difference in diet between overweight and normal weight children, but there was a difference between the groups with respect to physical activity (measured by television viewing time and participation in sports activities). As television viewing increased and sports activities decreased, body mass index increased. Television viewing of more than one hour a day was associated with a high consumption of fast foods and sweets, compared with viewing of less than an hour a day. The other significant factor noted in this study was the higher frequency of overweight, inactivity and unhealthy eating habits seen in children from low socio-economic backgrounds. There are likely many reasons for the higher incidence of obesity in lower socioeconomic groups. They include less understanding of the issues and risks of obesity, less access to recreational activities, poorer food choices secondary to financial constraints. It has been noted that in the USA the poor have less access to supermarkets and have to shop more at convenience stores. There are also more fast food restaurants in poor neighborhoods, and in fact black urban neighborhoods have the highest percentage of fast-food restaurants. Schools don't always make it easy for students to follow a healthy diet (although there is now a movement to improve this situation). One US study showed that at school, teens have ready access to high-fat, sugary foods and drinks, and the majority of middle schools (67 percent) and high schools (83 percent) had contracts with a soft-drink company. While high schools are more likely to offer soft drinks, they are less likely to require physical education How does too much fat impact negatively on our bodies? Every physician is familiar with the Metabolic Syndrome. We know that the metabolic Syndrome is associated with obesity and overweight and that persons with the Metabolic Syndrome are at significant risk for developing diabetes and cardiovascular disease. This syndrome is defined by a constellation of markers:
Metabolic Syndrome Definition:
The International Diabetes Federation consensus worldwide definition of the metabolic syndrome According to the new IDF definition, for a person to be defined as having the metabolic syndrome they must have: Central obesity (defined as waist circumference >equal; 94cm for Europid men and >equal; 80cm for Europid women, with ethnicity specific values for other groups) plus any two of the following four factors:
What is the role of fat in the development of the metabolic syndrome? Insulin resistance and hyperinsulinemia seem to be the common factors that predispose to this condition. Fat doesn't just sit on our bodies like stuffing in a pillow. Fat, particularly abdominal fat is metabolically active. This metabolically active intra-abdominal fat releases free fatty acids and adipocytokinins, which in turn appear to be responsible for the development of atherogenic dyslipidemia (characterized by increased triglycerides, low HDL cholesterol increased LDL cholesterol and increased apo B levels). Patients with increased abdominal fat are known to have elevated CRP, plasminogen activated inhibitor 1 and fibrinogen levels. CRP, a marker of inflammation, is felt to contribute to insulin resistance and is a predictor of cardiovascular disease. CRP levels fall with weight loss. Increased plasminogen activated inhibitor 1 and fibrinogen are associated with the prothrombotic state found in the metabolic syndrome. Hypertension is the most prevalent component of the metabolic syndrome, occurring in 50-75% of persons with this condition. Obesity and insulin resistance are associated with hypertension, perhaps because of the hyperinsulinemia induced stimulation of the sympathetic nervous system and vascular tone as well as antinaturesis. Treatment of obesityWhen considering weight loss there are essentially four main approaches for the individual patient. Patients may not need to use all of them, but generally they are most effective when used in combination. They are:
We will consider all of these modalities in upcoming Berries articles. References:
You can search for abstracts of the above references by following this link: PubMed Return to Archives Page ] [ Berries Home Page |
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