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Aug. 2, 2010 -- The negative impact of obesity on the quality and quantity of life more than doubled in a span of just 15 years, researchers report.
"The burden of obesity includes sickness due to obesity and death due to obesity," says researcher Haomiao Jia, PhD, assistant professor of biostatistics at Columbia University, New York.
Since 1993, this impact has more than doubled, according to his analysis. Physical inactivity strongly contributed to the effect of obesity on quality and quantity of life, Jia tells WebMD.
His report is published in the American Journal of Preventive Medicine.
Researchers have long tracked trends in the prevalence of obesity, Jia writes. While 14.1% of U.S. adults were obese in 1993, 26.7% were obese in 2008 -- nearly a 90% increase. (Although some experts have reported that obesity may be leveling off, other surveys have found increasing rates of obesity in many states in the past year.)
But little is known about the impact of obesity on quality and quantity of life -- what Jia calls the health burden of obesity.
To find out exactly how much obesity shortened life and compromised its quality, Jia and his colleague, Erica Lubetkin, MD, MPH, drew data from the 1993 to 2008 Behavioral Risk Factor Surveillance System, an ongoing state-based survey of U.S. adults. Among other questions, respondents were asked to recount the number of days in the past 30 when their physical or mental health was not good or when activity was limited because of mental or physical conditions.
Each year, the respondent sample size varied, from a low of about 100,000 to a high of more than 400,000, and included adults from across the country. Jia and Lubetkin estimated the effect of obesity on quality and quantity of life, measuring it in what is known as quality-adjusted life years (QALYs) lost. A year in perfect health, for instance, would be equal to 1.0 QALY, a year spent very sick might be 0.5, and death would equal 0 QALYs.
The investigators found a doubling of the obesity-related QALY lost over the span of the study, and this was observed in all gender and race/ethnicity subgroups and across all 50 states and the District of Columbia.
Certain ethnicities were more affected than others. ''Black women have the biggest loss," Jia tells WebMD. Their burden due to obesity was 31% higher than that for black men and about 50% higher than the burden in white women and white men.
Jia found a strong link between physical inactivity among obese people and the impact on quality and length of life.
"No leisure time activity contributed to about 50% of the quality-adjusted life years lost due to obesity," he tells WebMD.