Obesity Rates Over Time

Obesity has reached epidemic proportions in the United States. These increased body fat reserves are associated with an increased risk of numerous health problems, including coronary heart disease and heart attacks, diabetes mellitus, stroke, some cancers, and more. Obesity has become so prevalent in the U.S. today that it is difficult to remember that just a couple decades ago, the average American was not overweight, and few were obese. Below is a link to an animated graphic showing the remarkable increase in obesity in U.S. states over time. In the ideal case, the entire map would be colored the aqua color, since there would be data from every state but no obese people.

This is the first frame. See animated version.

As is commonly done, obesity is defined here based on the body-mass index (BMI). The BMI is calculated by dividing one’s weight by one’s height squared. It is traditionally given in SI units (that is, kg/m²), so if U.S. customary units are used, they must be converted. BMIs in the range from 18.5–25 kg/m² is considered normal or healthy. 25–30 kg/m² is overweight, and greater than or equal to 30 kg/m² is obese. (40 kg/m² or greater is often considered morbidly obese, or sometimes 35 kg/m² or greater along with other risk factors is included.) The use of BMI is imperfect (for instance, a very muscular person will have a high weight and therefore BMI), but in practice it is usually simple to differentiate obese from muscular people.

For instance, consider a 1.78-m (5 ft., 10 in.) tall person. The healthy range would be from 58.5–79.0 kg (129–174 lb.). Those weighing more than this would be overweight, and over 94.8 kg (209 lb.) would be obese. For a 1.63-m (5 ft., 4 in.) tall person, the healthy range would be from 47.4–64.0 kg (104–141 lb.). Greater than 76.8 kg (169 lb.) would be obese.

It’s easy to calculate your own BMI. There are plenty of BMI calculators and BMI charts on the Internet. But the fastest way is probably to use Google Calculator: just type your calculation directly into the main search box (see example).

The obesity data are taken from the CDC. I reformulated them into an animated GIF since I didn’t care for the original color scheme and also because that presentation isn’t easily exported to other sites. You are free to use the image (direct linking is fine), though I would appreciate a link back here if you do.

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Minnesota Is Now Smoke-Free

Today, 1 October 2007, a state-wide smoking ban took effect in my state. A major success for public health and especially employees’ health, this law puts major restrictions on indoor smoking in public places with relatively few loopholes. Bars, restaurants, and almost all other indoor locations are included. Private residences, hotel and motel rooms, cigar shops, and casinos and other establishments on Native American lands are exempt. As is well-known, there is an enormous body of scientific data indicating the harm smoking causes to bystanders. Those who work in establishments where smoking is permitted are especially at risk. As attention to public health mounts, smoking bans cover more and more of the United States—at the city, county, and state levels. According to Wikipedia, over half of Americans are covered by some sort of smoking ban.

Wikipedia also featured this interesting map of the United States, showing active and scheduled smoking bans. It uses an innovative “additive color key” to designate the type of ban.

State-wide smoking bans. Credit: Mike Schiraldi.

The gray states have no state-wide smoking bans. The red states, Idaho and Georgia, ban smoking in restaurants; the green ones (North and South Dakota) ban smoking in non-hospitality workplaces (that is, not restaurants or bars); and the yellow states (Nevada, Arkansas, Louisiana, Tennessee, and Florida) ban smoking in both. The lavender state (New Hampshire) bans smoking in bars and restaurants. The white states ban smoking in all three: bars, restaurants, and non-hospitality workplaces.

Energy and Health: Spotlight on the Lancet‘s Series Covering Climate Change and More

As a human and a resident of planet Earth, I care about my home and the environment, and for the other life that shares it with me. But as a physician, I have a special interest in examining the relationship between the health of our planet and that of human health; I have a strong desire to promote public health. And therefore I am indebted to Inel for bringing my attention (via a comment and a subsequent blog entry) to a wonderfully important series of articles in the Lancet covering the many-faceted relationship between energy and health. At the least, I feel that all physicians are obligated to read this series.

The Lancet is one of the world’s premiere medical journals (along with the New England Journal of Medicine, the Journal of the American Medical Association, and the British Medical Journal). In publishing this series, they are taking on a large, complex issue with significant public health implications that previously have not drawn much attention. Strategies to help ameliorate the problem are well–thought out. The series covers so much detail I’d like to devote a series of my own posts to discuss and analyze them.

Editor-in-chief Richard Horton writes the introductory comment, entitled “Righting the Balance: Energy for Health”:

The current debate about the impact of human beings on our planet—especially with respect to climate change—is one of the most important issues of our time. But that debate is presently unbalanced and too narrow. It neglects a far larger set of issues focused on energy—and health.

Energy is a critical, yet hugely neglected, determinant of human health. Health is an important enough aspect of energy policy to deserve a much greater influence on decisions about our future personal, national, and global energy strategies. Society suffers from a disordered global energy metabolism. Energy is as important as any vaccine or medicine. 2 billion people currently lack access to clean energy: they live in energy poverty and insecurity. International institutions, such as the World Bank and WHO, have repeatedly failed to make the connection between energy and health in their country work.

(continued — free registration required)

Dr. Horton gives examples of changes that we need to make at these three levels, such as changing travel habits at the personal level, designing new urban infrastructure at the national level, and controlling greenhouse gases at the global level. This introduction sets the stage for the in-depth analysis to follow.

While physicians should certainly read these, I also encourage others in the allied health professions as well as anyone with an interest in public health to read them as well. They are written in clear language and do not rely on advanced medical terminology or concepts. I will update this post with links to additional posts on the individual articles as I write them.

Source: Horton, R. “Righting the balance: energy for health”. The Lancet 2007;370:921. DOI:10.1016/S0140-6736(07)61258-6. Full text available; free registration required.

Potential Smoking Ban in Europe

Source: Wikipedia, created by Adalbertus.

New Scientist reported today:

The European Union’s health chief is to seek a “comprehensive ban” on smoking in public places across the group’s 27 countries, he announced on Tuesday.…All 27 EU governments, non-governmental organisations, consumers and the tobacco industry will be invited to put forward proposals on smoking bans by 31 May 2007. The Commission is expected to deliver its final recommendations in early 2008

This is all preliminary, but it is very good news. Extensive research has demonstrated the dangers of secondhand smoking (often called passive smoking or exposure to environmental tobacco smoke). Also increasingly apparent is the health detriment to employees of establishments where people smoke, and the improvement in health once smoking is banned.

In the United States, most smoking bans are at the city or county level, though many states have enacted some sort of regulation. No federal-level initiative yet exists. For more information, please see the Wikipedia article “List of Smoking Bans in the United States.”

Pertussis Outbreak at New Trier

Whooping cough infection continues in Chicago suburb

There has been an outbreak of whooping cough, or pertussis, at New Trier High School in Winnetka, Illinois, a suburb of Chicago. As of last Wednesday, twenty-nine students and one staff member had been diagnosed with this respiratory infection; this represents about 6% of all pertussis this year in the state of Illinois. Although infants are vaccinated against pertussis, the immunity wanes over time. Recently, a booster vaccine has become available for adolescents and adults; 95% of freshmen received the vaccine during their high school physicals this year and the only two freshman cases were in students who had not received the vaccine. Several extracurricular events have been cancelled to avoid spreading the disease to other schools, and the Cook County Public Health Department is working with New Trier to provide free vaccination to all students and staff. Those who decline immunization will probably be restricted from such events, and the Health Department has the authority to bar those students from attending school in order to prevent further spread of the disease.

Pertussis is a highly contagious infection of the respiratory tract; it is caused by the bacterium Bordetella pertussis. Attack rates are 80 to 100% among unimmunized household contacts, according to Harrison’s. About a week after infection, patients develop symptoms of the common cold; however, after one or two weeks, the cough becomes more prominent, occurring suddenly and in bursts. The fits may be followed by a sharp inwards breath, called a whoop. After two to four weeks, the coughing becomes less severe, but can continue for a few months. Up to a year later, viral infections may trigger the fits of coughing.

In infants, the disease is especially severe, and can lead to death. The development of a vaccine against pertussis has dramatically reduced the rates of infection and death. It was combined with immunizations against diphtheria and tetanus; the combination vaccine is termed “DTP.” The occurrence of some side effects led researchers to formulate a new vaccine that uses only components of Bordetella pertussis instead of whole cells, this “acellular” version is called “DTaP” and is now the version used in the United States; DTP is still used in many countries, especially developing ones. DTaP is given as a series at ages 2, 4, and 6 months, with repeat injections at 15–18 months and 4–6 years. However, this immunity fades over time, and adolescents and adults may be infected, though the disease is usually not as severe. However, it can still cause lengthy sickness and such people can easily transmit the disease to others. Infants less than a year old, still developing immunity, are at the highest risk.

Pertussis is usually milder in adolescents and adults. However, its effects can persist for months and complications may occasionally result—and of course, while infected, they can pass the disease on to others, including infants. Recently (around a year and a half ago), vaccines have been tested and licensed that can be used in those ages 10–64. It is administered as part of a combination called “TDaP.” Many countries, including the United States, recommend their routine use. Studies over the next years and decades will measure the magnitude of the effect; we may hope that the rates of pertussis will decline (after reaching a low point in 1976, cases of pertussis in the United States have started to rise, now about seven or eight times the 1976 level).

Further reading

• “Whooping cough” at MayoClinic.com
• “Whooping cough hits Chicago suburb” at CNN. 27 Nov 2006.
• “Pertussis hits New Trier” at the Chicago Tribune. 30 Nov 2006.
• “New Trier will offer vaccine to curb pertussis” at the Chicago Tribune. 2 Dec 2006.

World Aids Day

Today, 1 December 2006, is World AIDS Day. The first case was documented twenty-five years ago, in 1981. Since then, 25 million people have died and 40 million people today are infected with HIV (the virus that causes AIDS). Worldwide, 11,000 people contract HIV every day. In the United States alone, over 1.1 million people are infected with HIV, and almost a quarter of them don’t know it. AIDS affects people of all races, genders, and sexualities. While sub-Saharan Africa is affected the most, AIDS is now a worldwide pandemic. At the very least, please take this day to educate yourself and others on HIV/AIDS and what you can do to protect yourself and others. HIV is preventable, but ignorance and prejudice hamper efforts to control the disease.

HIV (the human immunodeficiency virus) is the virus that causes AIDS. It is transmitted via bodily fluids such as blood, pre-ejaculate and semen, vaginal fluids, and breast milk. The most common ways that HIV is spread are through sexual intercourse, by sharing needles used to inject drugs, and from mother to child (during pregnancy, birth, or breast feeding).

Video Games as an Anti-Obesity Tool?

The prevalence of obesity has been increasing at a tremendous rate in industrialized countries. In the United States, where the problem is most pronounced, three-fifths of adults are overweight, and almost a quarter are obese (source, CDC):

In 2005, among the total U.S. adult population surveyed, 60.5% were overweight, 23.9% were obese, and 3.0% were extremely obese. Obesity prevalence was 24.2% among men and 23.5% among women and ranged from 17.7% among adults aged 18–29 years to 29.5% among adults aged 50–59 years…. Among racial/ethnic populations, the greatest obesity prevalence was 33.9% for non-Hispanic blacks. Overall, age-adjusted obesity rates were 15.6%, 19.8%, and 23.7% for the 1995, 2000, and 2005 surveys, respectively.

Children are affected as well. Also according to the CDC,

The most recent data indicate that in the United States about 16% of children ages 6–19 years are overweight. Since the 1970s, overweight has doubled among young children aged 2–5 years and tripled among school-aged children aged 6–19 years.