The research was printed in the March 1 issue of the American Journal of Respiratory and Critical Care Medicine, a journal of the American Thoracic Society.
''Smoking behavior has a known genetic component and smoking is a primary risk factor for chronic bronchitis,'' writes Dr. Jenny Hallberg of the Department of Public Health Sciences at Karolinska Institutet.
Hallberg's team found that heredity accounted for 40 percent of the risk for chronic bronchitis. But its study found that 14 percent of the genetic risk was linked to a genetic predisposition to smoke, whether or not the individual actually smoked tobacco.
The researchers sifted through data from the Screening Across Life Span Twin study in Sweden, which surveyed all known living twins in Sweden born in 1958 or earlier.
The survey included questions on subjects of interest to the study:
- Smoking history.
- A checklist of common diseases.
- Questions designed specifically to discover whether participants had chronic bronchitis.
- Whether the twins shared 100 or 50 percent of their genetic material, which is known as zygosity.
''(This) study on the population-based Swedish Twin Registry, showing a genetic effect for the development of chronic bronchitis that does not differ by sex is the first to our knowledge to quantify heritability of the disease,'' Hallberg said.
Hallberg said that the finding should not be interpreted to mean that smoking has no effect on chronic bronchitis.
''Although there was some genetic interplay, it is safe to say that smoking itself, and not the genes that predispose one to smoking, is a larger risk factor in developing chronic bronchitis ... than genetic predisposition,'' said Hallberg.
CANCER AND WAGES
Women in Canada diagnosed with early breast cancer lose more than a quarter of their usual income in the first 12 months after their diagnosis, says a study published online Feb. 26 in the Journal of the National Cancer Institute.
While many studies have assessed the negative economic effect of breast cancer on the health care system, few studies have examined the impact the disease has on the personal finances of breast cancer patients and their families.
Elizabeth Maunsell of Laval University in Quebec City, Canada, and colleagues surveyed more than 800 women in Quebec who had been diagnosed with early-stage breast cancer. The interviews took place at one, six and 12 months after treatment began.
Maunsell's team asked participants about their working status before they were diagnosed, how much they had missed, and the compensation they had received during their absence from work. Compensation included sick leave payments and disability insurance payments.
Maunsell's team also asked women about their perceptions of their financial situation and whether these perceptions had worsened in the 12 months after diagnosis.
Of the 800 women who completed all three interviews, 459 had paying jobs at the time of diagnosis.
Among the 403 women who missed some work, researchers found that they had lost an average of 27 percent of the wages they would have earned in the 12 months after diagnosis had they not been ill. Ten percent of the women lost more than two-thirds of their income.
The percentage of annual wages lost varied considerably among study participants. The women most likely to suffer the largest loss of wages were those who were less educated, lived farther from the facility where they received treatment, had more serious forms of cancer, had less social support, required chemotherapy, or were self-employed, worked part-time or were recently hired at their current job.
''Overall, these findings point to wage losses from breast cancer in Canada as an important adverse consequence of this disease,'' the authors write. ''These findings should sensitize clinicians to the real extent to which wage losses resulting from breast cancer can substantially and negatively affect the financial situation of working women and their families.''
E-mail Ven Griva at firstname.lastname@example.org or write to P.O. Box 120190, San Diego, CA 92112.