Published: June 3, 2004
Updated: Nov. 3, 2004
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By Duke Medicine News and Communications
DURHAM, N.C. -- A new analysis of data on smoking and health finds that smokers who quit before the age of 35 have a reasonable chance to regain their health over time and to live as long and as well as people who have never smoked. The Duke University Medical Center researchers who performed the analysis said that smokers who quit can dodge the debilitating effects of smoking-related diseases and maintain a high quality of life into middle-age and beyond.
The Duke researchers suggest that smoking cessation efforts should emphasize the impact of smoking on quality of life, in addition to its relationship to early mortality. They said smokers might be more inclined to quit if they understand that not only might their life be shortened, but that the quality of their final years might be significantly lowered.
"Any time smokers quit, they're bettering their health; however, for many smokers it takes a negative health event to stop. For these people and for smokers who quit later in life, it is much more difficult to get back on track," said Donald Taylor Jr., Ph.D., Duke University Medical Center and Center for Health Policy, Law and Management at the Terry Sanford Institute of Public Policy, Duke University. "The message is that it's better to quit now than later. The result is a longer, healthier life."
The researchers published their findings in the June 2004 issue of the journal Health Services Research. The study was funded by the National Institute on Aging.
The Duke study focused on the effects of smoking on quality of life or years of healthy life (YHL) in middle-aged and older Americans. For the purposes of the study, quality of life was described as the degree to which people perceive themselves able to function physically, emotionally and socially.
The Duke researchers analyzed data on smoking and health taken as part of the Health and Retirement Study (HRS) and its companion study, The Asset and Health Dynamics Among the Oldest Old (AHEAD). Both of these studies collected data from 1993 to 2000 on how retirement impacts the health and wealth of both men and women. The studies were funded by the National Institute on Aging. In the HRS study, 12,652 men and women aged 50 to 60 were interviewed about their health behaviors, disease and disability, and medical care usage. The AHEAD study, which collected similar data, focused on 8,124 men and women aged 70 years and older.
In both studies, participants were asked every two years to rate their health as excellent, very good, good, fair or poor. The HRS group members also were asked if they were current or former smokers. Current smokers were asked if they would describe themselves as heavy (one pack or more per day) or light (less than one pack per day) smokers. Former smokers were asked if they had quit within three years, between three to 15 years or for 15 years or more. The AHEAD study limited the questioning to whether study participants were current or former smokers.
"Former smokers felt healthier and on average lived longer than smokers," said Truls Ostbye, M.D., Ph.D., professor in Duke's department of community and family medicine and lead author of the paper. "Smoking had a clear relationship with both years of life remaining and years of healthy life remaining. It's not a surprising result, but by examining these large data sets that included long periods of follow up, we can confirm what other smaller studies suggested."
Importantly, former smokers, both male and female, who reported having quit for 15 years or more had no statistically significant difference in years of remaining life or years of healthy life when compared to those who reported never having smoked at all, the study found.
In contrast, the researchers found that a 50- to 54-year-old male heavy smoker would lose approximately two years of healthy life and also reduce their years of life remaining by two years. A heavy smoking 50- to 54-year-old woman loses approximately 1.66 years of healthy life and 1.44 years of life remaining on average. Smoking takes a heavier toll on men because their estimated life expectancy is shorter than women.
Overall in terms of years of healthy life, an estimated 3.1 million years of healthy life were lost per year among U.S. men aged 50 to 84, while 1.6 million years of healthy life were lost per year to U.S. women in the same age group, the researchers said.
"It's hard to quantify what makes life worth living, but health has an important role in perceived high quality of life," said Ostbye. "Heart disease, stroke and cancer, all of which have a relationship with smoking, are debilitating diseases. They can limit mobility and steal independence. The consequences of these diseases are severe and to many people this reduced quality of life is worse than a shortened lifespan."