CANSA Research Highlights – 17 April 2009
CANSA Research Highlights Issue 41 17 April 2009
Genes May Boost Harm to Kids From Secondhand Smoke
Variations in several genes can influence children’s lung growth and function, as well as how vulnerable they are to secondhand smoke, say University of Southern Californiaresearchers.
“Many factors can affect lung function and growth, including genetic variation and environmental exposures such as tobacco smoke and air pollutants,” study lead author Carrie Breton said in a USC news release.
“We wanted to determine whether specific gene variations would have measurable and predictable effects on lung function growth and susceptibility to environmental insults,” she said. “We looked at a class of genes known to be involved in antioxidant defense, the glutathione-s transferase (GST) genes. Overall, we found that variation in several of the GST genes was important. This was particularly true for children of mothers who had smoked during pregnancy.”
Breton and colleagues analyzed eight years’ worth of lung function and genotyping data from more than 2,100 children. They identified three specific halotypes (patterns of genetic variation within genes) that had a significant effect on lung function. These halotypes were found in the genes GSTM2, GSTM3 and GSTM4.
The gene variants may not alter lung development, the researchers explained, but they may change the ability of the lungs to defend against damage caused by free radicals, such as those found in smoke.
“The GST genes are important to the detoxification of reactive oxygen species, including carcinogens and environmental exposures, such as cigarette smoke. We speculate that the patterns of genetic variation we investigated may alter this process, thereby reducing the lung’s ability to detoxify harmful agents and causing a cascade of other events that promote inflammation, bronchial constriction, airway hyper-responsiveness and asthma-like symptoms,” Breton said.
The study is in the first April issue of the American Journal of Respiratory and Critical Care Medicine.
“The next step would be to investigate how these genes interact with one another to jointly affect lung development,” Breton said. “Future studies should also investigate the timing and quality of tobacco smoke exposure during pregnancy in combination with variation in these genes to further understand how they jointly affect fetal lung development.”
Source: Medline Plus
CANSA comment: Second-hand smoke is particularly dangerous for children because their bodies are still developing. Smoking when you are with your children can increase their risk of cot death, ‘glue ear’, respiratory illnesses such as asthma and chest infections, and may cause cancer later on in life. If you are a smoker, do not expose your child to your smoke, especially in confined areas indoors and in cars. Read more…
Newly Pregnant Smokers Have a 15-Week Window to Quit
Pregnant women who quit smoking before the 15th week of pregnancy reduce their risk of premature birth and having small babies to that of nonsmoking women, a new study finds.
It’s known that smoking during pregnancy increases the risk of miscarriage, ectopic pregnancy, premature birth, small babies, stillbirth and neonatal death, but no study until now has determined whether stopping smoking in early pregnancy reduces the risks of small babies and premature births, the study authors said.
“Pregnant women who smoke should be encouraged and assisted to become smoke-free early in pregnancy,” said lead researcher Dr. Lesley McCowan, an associate professor of obstetrics and gynecology at the University of Auckland in New Zealand.
Women who don’t quit smoking by 15 weeks are three times more likely to give birth prematurely and twice as likely to have smaller babies, compared to women who stopped smoking, McCowan said.
The findings were published in the BMJ.
For the study, McCowan’s team collected data on 2,504 pregnant women. Eighty percent did not smoke, 10 percent had quit smoking and 10 percent were current smokers.
There was no difference in the rate of spontaneous premature birth between women who did not smoke and those who had stopped by week 15 (4 percent vs. 4 percent). The same was true for having smaller babies (10 percent vs. 10 percent), the researchers found.
However, women who continued to smoke had higher rates of spontaneous preterm birth than woman who quit (10 percent vs. 4 percent) and higher rates of smaller babies (17 percent vs. 10 percent).
The study also found that women who stopped smoking weren’t more stressed than women who continued to smoke, McCowan noted.
“Health professionals who care for pregnant women need to ask about smoking, advise about the importance of stopping, and, where possible, refer for extra support early in pregnancy to assist women to become smoke-free,” she advised.
Dr. Richard Frieder, an associate clinical professor of obstetrics and gynecology at theUniversity of California, Los Angeles David Geffen School of Medicine, said the study authors didn’t explain whether this difference in low birth weight and gestational age at delivery actually translates into a measurable difference in newborn health.
“We assume this to be true, but there was only about a half pound difference in birth weight and six days difference in gestational age. These numbers are not very impressive that one would think a big difference in neonatal health would be achieved. Still, we should assume that a half pound and six days more of gestation is better and that we should strive to help women stop smoking,” he said.
There are other big issues at play when it comes to babies, women and cigarette smoke, Frieder added.
“Babies that live in ‘smoking homes’ have a much higher risk of respiratory ailments, such as asthma and pneumonia and SIDS. In addition, women are more susceptible to the cancer-causing effects of cigarette smoke than men. The tobacco industry specifically targets women, despite this well-known fact,” he said.
Source: Medline Plus
CANSA comment: Exposure to second-hand smoke and smoking while pregnant are both linked to miscarriage, low birth weight and stillborn births. Babies who breathe in second-hand smoke have a higher risk of sudden infant death syndrome (SIDS)
Fruit May up smokers’ cancer risk
Smokers may increase their chances of contracting colon cancer by eating fruit and vegetables, according to a new Europe-wide scientific study.
A high intake of fruit and vegetables appeared to reduce the risk among non-smokers but seemed to have the reverse effect on smokers, findings by the Dutch National Institute for Public Health and the Environment (RIVM) showed.
“People who eat 600gr or more vegetables and fruit a day appear to have a 20% to 25% lower chance of developing colon cancer than people who eat 220% or less,” said the statement. “For smokers, the consumption of vegetables and fruit appears, on the contrary, to increase the chances of colon cancer. Protection against colon cancer through the consumption of vegetables and fruit therefore appears to depend on smoking habits.”
Don’t stop eating greens
RIVM official Hans Verhagen told AFP this did not mean that smokers should stop eating their greens. “On the contrary, the conclusion is to: ‘Please stop smoking’”, he said.
The research project questioned some 500 000 people in 10 European countries about their eating and smoking habits and studied them for 8.5 years. The authors of the final article published in the American Journal for Clinical Nutrition, said the findings meant that substances within fruit and vegetables may even increase the carcinogenic potential of tobacco smoke.
“What is new about this study is that we have for the first time examined the effects of fruit and vegetable consumption while making a distinction between smokers and non-smokers,” said Verhagen.
Colon cancer is the second-most common form of the disease in the Netherlands, after breast cancer, with 11 000 new cases diagnosed every year.
CANSA comment: There is accumulating evidence to support the increased (daily) consumption of fruit and vegetables as a means of protection against a range of cancers, including mouth, pharynx, larynx, esophagus, stomach, lung, pancreas and prostate. Read more…
Colorectal cancer risk appears unaffected by coffee
Coffee is not significantly associated with a decreased risk of colorectal, colon, or rectal cancer, contrary to the results of previous trials that found a possible protective effect of coffee against these cancers, according to the results of a review of studies published in the International Journal of Cancer.
“An inverse association between coffee consumption and the risk of colorectal cancer has been found in several case-control studies,” but the association was not consistent in prospective cohort studies, which are designed differently, Dr. Youjin Je, of Harvard School of Public Health, Boston, and colleagues note.
Case-control studies include patients with a disease or condition who are compared with “controls,” healthy individuals matched up with the study group for factors such as age and sex to avoid bias. Prospective cohort studies are studies in which the participants the have a certain characteristic in common, such as smoking habit or birth order, are identified and then followed forward in time; the final outcome is unknown to the researchers before the trial ends.
The researchers conducted a systematic review of prospective cohort studies to examine the association between coffee consumption and colorectal cancer. They identified 12 studies that included a total of 646,848 participants and 5403 patients with colorectal cancer.
The combined result of the studies, comparing high versus low coffee consumption categories, revealed no significant association between coffee consumption and colorectal cancer risk.
When four studies conducted in the United States were considered, along with five studies conducted in Europe and three Japan, there was no relationship between cancer and coffee consumption and the data from each country were very similar.
Overall, there were no significant differences by sex and cancer site. However, there was a slight inverse association between coffee consumption and colon cancer in women who had a 21 percent reduced risk. This was especially true among Japanese women who had a 38 percent reduced risk.
Studies that analyze the data accounting for the effects of smoking and alcohol use and those with shorter follow-up showed stronger inverse associations between coffee consumption and colorectal cancer.
“Since any effect of coffee intake on colorectal cancer risk could vary by regular or decaffeinated coffee and boiled or filtered coffee, further investigation regarding type- and preparation method-specific analyses is warranted,” Je’s team comments.
SOURCE: International Journal of Cancer, April 2009.
Lifetime exercise may cut breast cancer death risk
Women who participate in recreational exercise and sports over their lifetime may be lowering their risk of death from breast cancer and breast cancer recurrence.
Among 1,231 women with breast cancer who were followed for a minimum of 8.3 years, those who obtained about 4 hours or more of weekly moderate-intensity recreational activity over their lifetime had a 44 percent lower risk of death from breast cancer, report Dr. Christine Friedenreich and colleagues.
Risk for recurrence, progression, or new primary breast cancer was likewise reduced by 34 percent among women reporting similar levels of recreational physical activity, note Friendenreich, of Alberta Health Services-Alberta Cancer Board in Calgary, Canada, and colleagues.
These findings suggest “being physically active before a breast cancer diagnosis can improve survival after breast cancer,” Friendenreich told Reuters Health.
However, occupational activity and physical household work such as gardening, housework, and do-it-yourself home repair did not confer benefits similar to those from lifetime exercise and sports activities, the investigators report in the International Journal of Cancer.
Friendenreich’s team compared the lifetime physical activity reports of 1,231 women, who were 56 years old on average when diagnosed with breast cancer, with their outcomes. Over a minimum of 8.3 years of follow up, 341 women died (223 from breast cancer) and 327 had a recurrence, progressions, or new primary breast cancer diagnoses.
Compared with the least active women (less than 1.4 hours per week of recreational activity), those who engaged in more than 3.9 hours per week of moderate intensity recreational activity had 34 percent decreased risk for the combined outcomes, and 44 percent reduced risk for death from breast cancer.
These effects remained apparent after allowing for other factors potentially associated with survival such as body mass, tumor stage, and age.
Vigorous-intensity recreational activity lowered the risk of breast cancer mortality, but did not appear to reduce the risk of other outcomes.
Friendenreich notes her team continues examinations of “exactly what type and dose of activity is related to improved survival after cancer.” Ultimately they hope this research leads to development of clear exercise guidelines for cancer patients.
Source: Medline Plus
CANSA comment: A healthy, balanced lifestyle includes regular exercise – at least three times a week of over 30 minutes of heart-thumping movement! Read more…
New Technology Allows Better Monitoring of Cancer Cells
A new imaging technology could help improve the tracking of changes in cancer cells, according to researchers from the Stanford University School of Medicine.
The technology uses specially designed dye-containing nanoparticles to simultaneously measure dozens of features in or on a single cell.
Current single-flow technologies are capable of up to 17 simultaneous measurements, but the new method has the potential to do far more, according to a Stanford news release. The new technology enhances the detection of ultra-specific but weak patterns, known as Raman signals, that are emitted by molecules in response to light.
In a study that appears April 15 in the online journal PLoS One, the researchers used the technology to simultaneously monitor changes in two intracellular proteins that play important roles in cancer development.
If further development of the technique is successful, the researchers said, it could improve the ability to diagnose cancers and to separate living, biopsied cancer cells from one another based on characteristics indicating their stage of progression or their level of resistance to chemotherapy drugs.
The ability to separate cancer cells in that way, they said, would speed testing of treatments targeting a tumor’s most resistant cells.
Source: Medline Plus
Sleep May Be Cause, Not Consequence, of Cancer Issues
The pain and depression reported by people with cancer has often led to trouble sleeping — or so people believed. But researchers have found that, in fact, sleep seems to cause those problems rather than be an effect of them.
Their study suggests that interventions such as cognitive behavioral therapy aimed at eliminating the sleep issues could improve and decrease the pain and fatigue felt by people with cancer.
The researchers found that more than a quarter of the 11,445 people receiving cancer treatment at a Memphis clinic had severe to moderate trouble sleeping.
“We believed we would find a bi-directional relationship between insomnia and pain, but instead found that trouble sleeping was more likely a cause, rather than a consequence, of pain in patients with cancer,” the study’s lead author, Edward J. Stepanski, chief operational officer at the Accelerated Community Oncology Research Network in Memphis, said in a news release from the Journal of Clinical Sleep Medicine. The study is in the journal’s April 15 issue.
The study also noted that younger people with cancer and those whose cancer treatment started more recently had greater problems with sleep than others did. The authors noted that more aggressive chemotherapy is given to younger patients, possibly causing toxicity issues.
Alice Victor – Science & Resource Coordinator
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