IStock Photo 7997994 © Catherine Lane

Quitting smoking and losing weight are among the most popular New Year’s resolutions. It’s no wonder as both smoking and significant excess weight (obesity) are associated with a variety of illnesses. The 2004 Surgeon General’s report on the health consequences of smoking concluded that “tobacco use remains the leading preventable cause of disease and death in the United States” and that “smoking harms nearly every organ of the body, causing many diseases and reducing the health of smokers in general.” Smoking not only adversely affects the smoker, but those exposed to smoke. Excess weight and obesity “substantially raise the risk of illness from high blood pressure, high cholesterol, type 2 diabetes, heart disease and stroke, gallbladder disease, arthritis, sleep disturbances and problems breathing,” and certain types of cancers.

The odds an adult 15-54 smokes are 1 in 4.81and the odds a smoker 18 or older tried to quit in the past year are 1 in 2.36. From 1998 to 2008, the percentage of US adults who were current cigarette smokers declined from 24.1% to 20.6%, a statistically significant change. The decline in smoking over the past few decades has increased life expectancy. The reasons for the decline include increased awareness of the health risk of smoking, changed attitudes about the social acceptability of smoking, regulations limiting where people can smoke, and the increase in taxes on tobacco products

The history on excess weight is the opposite of smoking. The odds an adult is obese are 1 in 3.91, and while a significant proportion of the population vow to lose weight each year, it is a losing battle. Weight is a measure of health that has been tracked by the Centers for Disease Control (CDC) in the National Health and Nutrition Examination Survey (NHANES) since the 1980s. Relative weight is measured by the body mass index (BMI), which is defined as weight in kilograms (kg) divided by height in meters (m) squared (BMI=kg/m²). As seen in the table below, overweight is defined as a BMI greater than or equal to 25.0 and less than 30.0. Between NHANES III 1988-1994 and NHANES 2005-2006, the percentage of the adult population that is overweight is about the same. However, the percentage of the population that is considered obese (BMI greater than or equal to 30.0) changed from 22.9% to 34.3%, an increase of almost 50%. The trend in the percentage of the adult population that is extremely obese (BMI greater than or equal to 40.0) is even worse, growing from 2.9% of the population to 5.9% by 2005-2006, or, more than doubling.

The potential health risk of obesity has been recognized for some time. In 2000, the US Department of Health and Human Services established goals to reduce the proportion of the population that is obese in its Healthy People 2010 report. Based on the data in the table below, it is likely that these weight targets for the US population will not be met. Life expectancy could decline as a result of the trends in the proportion of obese and extremely obese people in the population. In fact, one recently published simulation analysis projects that the gains in life expectancy from fewer people smoking will be more than offset by the decrease in life expectancy due to the increased number of people significantly overweight in the next decade.

Age adjusted* prevalence of overweight, obesity, and extreme obesity among US adults, age 20 years and over

*Age-adjusted by the direct method to the year 2000 US Bureau of the Census estimates using the age groups 20-39, 40-59, and 60 years and over.

**Crude estimates (not age-adjusted) for 2005-2006 are 32.6% with a BMI greater than or equal to 25.0 but less than 30.0, 34.7% with a BMI greater than or equal to 30.0, and 6% with a BMI greater than or equal to 40.0. Pregnant females were excluded from analyses.

+Calculated by Book of Odds

Source: Prevalence of overweight, obesity and extreme obesity among adults: United States, trends 1976-80 through 2005-2006, E-Stats, CDC. Accessed January 4, 2010: http://www.cdc.gov/nchs/data/hestat/overweight/overweight_adult.htm