New York: Smoking is responsible for almost 14 million major medical conditions among American adults yearly, a new study has found.
Chronic obstructive pulmonary disease (COPD) - which includes conditions like chronic bronchitis and emphysema - accounts for more than half of the medical cases attributable to smoking, the researchers found.
"The disease burden of cigarette smoking in the United States remains immense, and updated estimates indicate that COPD may be substantially underreported in health survey data," the researchers wrote in the journal JAMA Internal Medicine.
Data from the US Centers for Disease Control and Prevention's National Health Interview Survey initially suggested that 6.9 million adults in the US suffered from a combined 10.9 million smoking-attributable medical conditions, including COPD, cancers, heart attacks and diabetes, 'LiveScience' reported.
But the actual number of conditions is likely higher because this survey relies on people's self-reports, and COPD is underreported, the researchers said.
To account for this gap, the researchers - led by Brian Rostron, of the US Food and Drug Administration's Center for Tobacco Products - also looked at data from another CDC survey, the National Health and Nutrition Examination Survey.
In this survey programme, participants are not only interviewed, but they also undergo physical exams, including a lung function test called spirometry that is used to diagnose COPD.
Based on that data, Rostron and colleagues estimated that cases of COPD were 70 per cent higher than the number of cases based on self-reported data.
The researchers estimated that 14 million American adults had a smoking-related condition in 2009.
The lack of COPD diagnoses might be the result of current clinical guidelines, the researchers said.
"Individuals with slowly declining respiratory function or individuals who have become accustomed to some degree of chronic airway obstruction may not report these conditions to physicians and consequently would not be screened for or diagnosed with COPD," the authors of the study wrote.