CANSA Research Highlights – 15 July 2009
CANSA Research Highlights Issue 44 15 July 2009
Studies Affirm value of healthy lifestyle
All that heart-healthy advice about eating the right foods, exercising and losing weight pay off in real life for both men and women, two new studies show.
The reports, both originating at Brigham and Women’s Hospital in Boston and published in the July 22/29 issue of the Journal of the American Medical Association, focused on different aspects of cardiovascular risk in two large groups: the 83,882 women in the second Nurses’ Health Study, and the 20,900 men in the Physicians’ Health Study I. Both arrived at the same conclusion: Do the right things, and you get measurable benefits.
Simultaneous appearance of the two reports was more or less a coincidence, said Dr. Luc Djousse, an associate epidemiologist at Brigham and Women’s at Harvard Medical School, who led the men’s study.
The study in men looked at the relationship between the lifetime risk of heart failure and six lifestyle factors: obesity, exercise, smoking, alcohol intake, consumption of breakfast cereals, and consumption of fruits and vegetables.
“Previous studies have shown benefit from individual lifestyle factors,” Djousse said. “We looked at all of these factors together.”
That look found a straight-line relationship between adherence to healthy lifestyle factors and the risk of heart failure, the progressive loss of ability to pump blood that is often a prelude to death. The lifetime risk of heart failure in the 22-year study was about one in five in men who ignored the advice about all beneficial lifestyle factors and one in 10 for those who adhered to four or more of the factors.
“The one with a huge difference was adiposity,” Djousse said. “The risk of heart failure was 17 percent in men who were overweight or obese, and about 11 percent in those of normal weight.”
Exercise was the next most important. Heart failure occurred in 11 percent of the men who exercised five or more times a week and in 14 percent of those who did not exercise, Djousse said.
Smoking played a surprisingly small role, probably because its incidence was not high among the participants. “These were all physicians, so you would expect a smaller amount of smoking,” Djousse said.
The women’s study looked at the association between high blood pressure — a significant risk factor for heart disease, stroke and other cardiovascular problems — and six lifestyle factors: obesity, exercise, alcohol intake, use of non-narcotic painkillers, adherence to a diet designed to prevent high blood pressure and intake of supplemental folic acid. All six were found to be associated with the risk of developing high blood pressure in the 14-year study, and the association was cumulative.
Women who followed advice on all six factors — just 0.3 percent of those in the group — had an 80 percent lower incidence of high blood pressure than those who followed none of the rules. The incidence was 72 percent lower for the 0.8 percent of the women who followed five lifestyle rules, 58 percent lower for the 1.6 percent of the women following four rules and 53 percent lower for the 3.1 percent of the women who followed three rules. As in the male group, obesity was the most important risk factor.
While the clear message of both studies is that “a healthy lifestyle prevents a number of illnesses,” what is often overlooked is that the choice of a healthy lifestyle is not a purely individual decision, said Dr. Veronique L. Roger, a professor of medicine and epidemiology at the Mayo Clinic, who wrote an accompanying editorial.
“There is a shared responsibility between the individual and the community,” said Roger, who read off a dictionary definition of lifestyle as “a typical way of life of an individual, group or culture.”
“The reality is that society has engineered physical activity out of our lives,” Roger said. “And it is difficult for me to tell someone in Nebraska to follow the Mediterranean diet, which is anchored in the culture of that society.”
Government interventions, such as the decision of New York and other communities, to bar smoking in restaurants and bars, can help more people achieve the healthy lifestyles described in the two reports, she said.
SOURCES: Luc Djousse, M.D., Sc.D, associate epidemiologist, Brigham and Women’s Hospital, and associate professor, medicine, Harvard Medical School, Boston; Veronique L. Roger, M.D., professor, medicine, Mayo Clinic, Rochester, Minn.; July 22/29, 2009, Journal of the American Medical Association
CANSA comment: Up to 40% of cancers can be prevented by living a healthy, balanced lifestyle. This includes:
- Not using any tobacco products
- Eating high fibre and low fat foods
- Drinking lots of fresh clean water
- Getting plenty of exercise
- Watching your weight
Internet may be newest venue for teen tobacco exposure
Even if you make sure your teen isn’t watching TV shows or movies that glamorize smoking, he or she may still be getting positive tobacco messages via the Internet, particularly from popular social networking sites such as MySpace and Xanga.
A new study, published online July 20 in Pediatrics, found that the Internet is the newest place for kids to get exposure to positive messages on tobacco use. Although tobacco content was found on less than 1 percent of the pages that teens view, there were more pro-tobacco pages than anti-tobacco pages.
“We found that only a small proportion of Internet sites visited by adolescents contained tobacco messages. The significance of these messages in social networking and their impact on adolescent tobacco attitudes and use remain unclear,” wrote the study’s authors, from the Julius B. Richmond Center of Excellence at the American Academy of Pediatrics in Elk Grove Village, Ill.
Keeping teens from smoking is critical to ensuring that adult smoking rates go down. Ninety percent of smokers start smoking by their 21st birthday, according to the American Lung Association. About 3,600 kids between 12 and 17 try their first cigarette each day in the United States, and about one-third of those will become regular smokers, the lung association reports.
To assess what type of exposure teens are getting to tobacco messages from the Internet, the researchers randomly selected 346 teenagers with home Internet access. The teens allowed the study authors to track all of their page views for a 30-day period. The researchers then searched those pages for tobacco-related content.
In all, the study volunteers viewed 1.2 million Web pages. Of those, 8,702 (0.72 percent) contained tobacco or smoking content.
Pro-tobacco messages were found on 1,916 pages and anti-tobacco content was included on 1,572 pages. The authors said the tobacco messages were “complex or unclear” on 5,055 pages.
More than half of the tobacco-related page views — 53 percent — came from social networking sites (at the time of the study, MySpace was the predominant social networking site). Often, mentions of smoking or tobacco use were part of user profiles.
Forty-three percent of teens were exposed to pro-tobacco imagery, according to the study. Tobacco products were specifically sold on 50 of the pages, and 242 pages contained links to tobacco products sold on other sites.
“That kids are being exposed to tobacco products in all facets of their lives is not a surprise,” said Erika Sward, director of national advocacy for the lung association. “And I’m not surprised that the tobacco companies are on the cutting edge. They’re always creative in finding new ways to target and prey on kids.”
Sward said the good news was that the study found that not all of the content teens were viewing was pro-tobacco, but the study highlights the need for legislation regarding how tobacco products are promoted online, and that tobacco-control programs should design counter-marketing methods for the Internet.
“This study starts to increase awareness of potential exposure to tobacco messages,” said pediatrician Dr. Deborah Moss, from Children’s Hospital of Pittsburgh, who added that studies have shown tobacco exposure in movies can make teens more likely to smoke, and that Internet exposure may have the same effect.
“One of the things these researchers are concerned about is the social networking sites,” said Moss. “Teens are sensitive to the perception of normalcy in behaviors, and from these sites, they could get a misperception that everyone is smoking.”
Sward said one of the most important ways to make sure your child doesn’t smoke is to not smoke yourself. “The strongest predictor of whether or not kids will smoke is whether their parents smoke,” she said. She also recommended letting them know about your struggles with your tobacco addiction. Let them know the downside of smoking, she suggested.
If you don’t smoke, Moss said you still need to talk with your kids, and it’s important to let them know that you don’t want them to smoke. “Kids of parents who openly express disapproval and have rules against smoking are less likely to smoke,” she said.
Moss also advised parents to keep computers in public places, and to let your teens know that you might periodically review the pages they’ve visited.
SOURCE: Medline Plus
CANSA comment: Smoking and using smokeless tobacco products is not cool. It makes you stink and feel sick. Using tobacco puts so many poisons in your body that you could get nasty diseases. CANSA encourages all young people to be smart and never start this deadly habit in any shape or form. Avoid cigarettes, snus, snuff, hookah pipes and hubbly bubbly. If you don’t die from tobacco, you are likely to be very ill for many years, fighting for your breath.
Coffee and general caffeine intake may affect a woman’s levels of estrogen and other sex hormones, a new study suggests — offering a potential explanation for findings that link caffeine to certain cancers.
For instance, different analyses of the Nurses’ Health Study (NHS) — a large, long-running study of U.S. female nurses — have linked higher caffeine intake to lower risks of breast and ovarian cancers in postmenopausal women, but to a higher risk of ovarian cancer before menopause.
No one knows whether caffeine directly affects the risks of the cancers. But since estrogen and other sex hormones play a role in both diseases, it’s possible that caffeine affects the risks of the cancers via hormonal influences, note investigators Dr.Joanne Kotsopoulos and colleagues at Harvard Medical School.
The team looked at the relationship between coffee and caffeine intake and hormone levels among more than 1,200 women involved in the NHS.
At various points during that study, the women had completed questionnaires on their diets and other lifestyle factors, and provided blood samples. Kotsopoulos and her colleagues used those stored samples to measure the women’s levels of estrogen and other sex-related hormones.
Overall, the researchers found, the more coffee and caffeine a premenopausal woman consumed, the lower her levels of estradiol, a form of estrogen, during the second half of the menstrual cycle.
Meanwhile, higher caffeine intake was related to higher levels of another sex hormone, progesterone, the researchers report in the journal Cancer.
The findings were somewhat different among postmenopausal women. For them, greater coffee and caffeine consumption was linked only to higher levels of sex hormone-binding globulin, or SHBG. Some studies have linked higher levels of SHGB — which decreases the activity of estradiol and testosterone — to a lower risk of breast cancer in postmenopausal women, Kotsopoulos and her colleagues note.
Exactly what the current findings mean is far from clear, according to the researchers.
In theory, lower estrogen levels in premenopausal women would help protect against ovarian cancer — so the findings do not explain the earlier results linking higher caffeine intake to a higher risk of premenopausal ovarian cancer.
Still, the researchers write, the results do suggest that caffeine influences sex hormone levels. They say that more studies are needed to see how those influences may affect hormone-related cancers.
SOURCE: Cancer, June 2009
New evidence supports HPV vaccine
Industry-funded study showed high levels of protection against human papillomavirus.
The human papillomavirus (HPV) vaccine is highly effective at preventing precancerous cervical lesions that can lead to cervical cancer, a new study shows.
The researchers also found that the HPV-16/18 AS04-adjuvanted vaccine also appears to protect against other cancer-causing HPV types closely related to HPV-16/18, most notably HPV-31 and HPV-45.
The study of women aged 15 to 25, who received three vaccine doses over six months, found that it was as much as 98 percent effective against HPV-16/18, and between 37 percent and 54 percent effective against 12 other cancer-causing HPV types.
HPV-16/18 causes about 70 percent of cervical cancer cases, while the remaining 30 percent of cases are caused by other cancer-causing HPV types. The cross-protective effect of the HPV-16/18 vaccine could provide an additional 11 percent to 16 percent protection against cervical cancer.
“Although the importance of continued tests for Pap or HPV in vaccinated and unvaccinated women must be emphasized, HPV vaccination has the potential to substantially reduce the incidence of cervical cancer and precancer, and the numbers of colposcopy referrals and cervical excision procedures,” concluded Dr Jorma Paavonen, of the University of Helsinkiin Finland, and colleagues.
The study, which was funded by GlaxoSmithKline Biologicals, maker of the HPV-16/18 AS04-adjuvanted vaccine Cervarix, appears online July 7 and in an upcoming print issue ofThe Lancet.
In an accompanying editorial, two experts wrote that men must also be included in efforts to halt the spread of HPV.
“Currently, the targets for HPV vaccination are girls and young women aged 11 to 26 years prior to sexual debut,” noted Karin B. Michels, of Harvard Medical School in Boston, and Dr. Harald zur Hausen, of the German Cancer Research Center in Heidelberg.
“While good utilization of the [vaccine] program will reduce cervical cancer incidence in a couple of decades, this subgroup of the population at risk is too small to limit the spread of the virus,” the researchers wrote. “The only efficient way to stop the virus is to also vaccinate the other half of the sexually active population: boys and men.”
SOURCE: The Lancet, 2009
CANSA comment: CANSA welcomes the registration of two new cervical cancer vaccines as an effective way to prevent cervical cancer. In order to be accessible, the vaccines need to be affordable and part of the government immunisation programme for all children before they are sexually active, ideally before the age of 10.
Research reveals clue to breast cancer’s spread
A U.S. research team says it has spotted key signals that help breast cancer cells survive in the bone marrow of patients who’ve undergone treatment.
The finding, reported in the July issue of the journal Cancer Cell, could lead to new treatments to prevent breast cancer’s return, according to the researchers.
“We sought to identify signaling pathways that support the survival of metastasized breast cancer cells and thereby extend the period during which metastasis may emerge after the diagnosis and removal of a breast tumor,” senior study author Dr. Joan Massague, of the cancer biology and genetics programs at Memorial Sloan-Kettering Cancer Center and theHoward Hughes Medical Institute, explained in a journal news release.
The researchers analyzed samples from more than 600 breast tumors and found that a cancer-related enzyme called Src was associated with late-onset bone metastasis. This link was independent of breast cancer subtype and was selective and specific for breast cancer cell survival in bone marrow.
Massague and colleagues then identified Src-regulated signaling molecules that were expressed in bone marrow and promoted survival of breast cancer cells. They also found that Src increased resistance to a key cell death-inducing signal.
The findings provides insights into breast cancer’s spread, “and suggests strategies to hasten the attrition of disseminated breast cancer cells,” the researchers concluded. They also noted that drugs designed to inhibit Src have recently been developed “that may be worthy of consideration” to help fight tumor recurrence.
SOURCE: Cell Press, July 2009
Registration number: 000-524 NPO