By Rob Goodier
NEW YORK (Reuters Health) Sep 07 - Asthma patients may not have to shun exercise for fear of exacerbating their symptoms, a new study suggests.
In fact, exercise could improve their symptoms and quality of life, according to research reported September 2 at the European Respiratory Society's annual conference in Vienna, Austria.
With attention to self management, increased physical activity did not worsen asthma control and in most cases was associated with improvement, said Dr. Carol Mancuso and her team at the Hospital for Special Surgery in New York City, in a presentation at the conference.
The researchers randomized 256 patients to two different exercise regimens for a 12-month period. A control group completed a survey measuring energy expenditure, promised to increase physical activity, received a pedometer and an asthma workbook, and then received bimonthly follow-up phone calls. Intervention patients received this protocol plus small gifts and instructions in fostering positive affect and self-affirmation.
"Participants chose the physical activity they wished -- there was no set protocol, "Dr. Mancuso told Reuters Health by email. "The purpose of the study was to foster adoption of lifestyle activities, that is, activities participations (they) could incorporate into their daily routines, and thus have a greater chance of being maintained over a lifetime."
"The ability to choose the physical activity probably played a role in maintaining asthma control," she said.
The main outcome of the study -- the within-patient change in energy expenditure in kilocalories per week -- was reported earlier this year in Archives of Internal Medicine. In fact, both groups of patients showed similar increases in physical activity, so for purposes of the current analysis, the researchers pooled the results from both groups.
At baseline, 38% of the patients reported well-controlled asthma on the Asthma Control Questionnaire. After one year of increased exercise, the number had jumped to 60%.
Patients' scores on the Asthma Quality of Life Questionnaire also increased from an average of 5 at baseline to 5.9 by year's end on the seven-point scale.
On mixed effects modeling, variables linked to quality-of-life improvements included male gender, improvement in asthma symptoms, reduction in medications, less depression, and increased physical activity.
It is not clear how much the patients actually increased their physical activity, but the fact that exercise might improve asthma is impressive, said Dr. Simon Bacon, an exercise science and asthma specialist at Concordia University in Montreal, Quebec, who was not involved in the study.
"There is a dearth of data in the field, especially using non-supervised exercise programs and clinically relevant asthma measures," Dr. Bacon told Reuters Health by email. "However, some caution is needed as there was no control group and the asthma measures used are very subjective, so how much of the effect is purely placebo is unclear to me."
As for a take-home message, Dr. Mancuso said, "My recommendations to physicians and patients are that prudently selected increases in physical activity and exercise are very possible for asthma patients. Both should keep in mind that the alternative of a sedentary lifestyle carries many detrimental risks and that for most patients asthma should not be a reason to incur these risks over a lifetime."
Mediterranean diet: Choose this heart-healthy diet option
The Mediterranean diet is a heart-healthy eating plan combining elements of Mediterranean-style cooking. Here's how to adopt the Mediterranean diet.
By Mayo Clinic staff
If you're looking for a heart-healthy eating plan, the Mediterranean diet might be right for you. The Mediterranean diet incorporates the basics of healthy eating — plus a splash of flavorful olive oil and perhaps a glass of red wine — among other components characterizing the traditional cooking style of countries bordering the Mediterranean Sea.
Most healthy diets include fruits, vegetables, fish and whole grains, and limit unhealthy fats. While these parts of a healthy diet remain tried-and-true, subtle variations or differences in proportions of certain foods may make a difference in your risk of heart disease.
Benefits of the Mediterranean diet
Research has shown that the traditional Mediterranean diet reduces the risk of heart disease. In fact, a recent analysis of more than 1.5 million healthy adults demonstrated that following a Mediterranean diet was associated with a reduced risk of overall and cardiovascular mortality, a reduced incidence of cancer and cancer mortality, and a reduced incidence of Parkinson's and Alzheimer's diseases.
For this reason, most if not all major scientific organizations encourage healthy adults to adapt a style of eating like that of the Mediterranean diet for prevention of major chronic diseases.
Key components of the Mediterranean diet
The Mediterranean diet emphasizes:
- Getting plenty of exercise
- Eating primarily plant-based foods, such as fruits and vegetables, whole grains, legumes and nuts
- Replacing butter with healthy fats such as olive oil and canola oil
- Using herbs and spices instead of salt to flavor foods
- Limiting red meat to no more than a few times a month
- Eating fish and poultry at least twice a week
- Drinking red wine in moderation (optional)
The diet also recognizes the importance of enjoying meals with family and friends.
Fruits, vegetables, nuts and grains
The Mediterranean diet traditionally includes fruits, vegetables, pasta and rice. For example, residents of Greece eat very little red meat and average nine servings a day of antioxidant-rich fruits and vegetables. The Mediterranean diet has been associated with a lower level of oxidized low-density lipoprotein (LDL) cholesterol — the "bad" cholesterol that's more likely to build up deposits in your arteries.
Nuts are another part of a healthy Mediterranean diet. Nuts are high in fat (approximately 80 percent of their calories come from fat), but most of the fat is not saturated. Because nuts are high in calories, they should not be eaten in large amounts — generally no more than a handful a day. For the best nutrition, avoid candied or honey-roasted and heavily salted nuts.
Grains in the Mediterranean region are typically whole grain and usually contain very few unhealthy trans fats, and bread is an important part of the diet there. However, throughout the Mediterranean region, bread is eaten plain or dipped in olive oil — not eaten with butter or margarines, which contain saturated or trans fats.
Healthy fats
The focus of the Mediterranean diet isn't on limiting total fat consumption, but rather to make wise choices about the types of fat you eat. The Mediterranean diet discourages saturated fats and hydrogenated oils (trans fats), both of which contribute to heart disease.
The Mediterranean diet features olive oil as the primary source of fat. Olive oil provides monounsaturated fat — a type of fat that can help reduce LDL cholesterol levels when used in place of saturated or trans fats. "Extra-virgin" and "virgin" olive oils — the least processed forms — also contain the highest levels of the protective plant compounds that provide antioxidant effects.
Monounsaturated fats and polyunsaturated fats, such as canola oil and some nuts, contain the beneficial linolenic acid (a type of omega-3 fatty acid). Omega-3 fatty acids lower triglycerides, decrease blood clotting, are associated with decreased sudden heart attack, improve the health of your blood vessels, and help moderate blood pressure. Fatty fish — such as mackerel, lake trout, herring, sardines, albacore tuna and salmon — are rich sources of omega-3 fatty acids. Fish is eaten on a regular basis in the Mediterranean diet.
Wine
The health effects of alcohol have been debated for many years, and some doctors are reluctant to encourage alcohol consumption because of the health consequences of excessive drinking. However, alcohol — in moderation — has been associated with a reduced risk of heart disease in some research studies.
The Mediterranean diet typically includes a moderate amount of wine. This means no more than 5 ounces (148 milliliters) of wine daily for women (or men over age 65), and no more than 10 ounces (296 milliliters) of wine daily for men under age 65. More than this may increase the risk of health problems, including increased risk of certain types of cancer.
If you're unable to limit your alcohol intake to the amounts defined above, if you have a personal or family history of alcohol abuse, or if you have heart or liver disease, refrain from drinking wine or any other alcohol. Also keep in mind that red wine may trigger migraines in some people.
Putting it all together
The Mediterranean diet is a delicious and healthy way to eat. Many people who switch to this style of eating say they'll never eat any other way. Here are some specific steps to get you started:
- Eat your veggies and fruits — and switch to whole grains. An abundance and variety of plant foods should make up the majority of your meals. They should be minimally processed, and try to purchase them when they're in season. Strive for seven to 10 servings a day of veggies and fruits. Switch to whole-grain bread and cereal, and begin to eat more whole-gain rice and pasta products. Keep baby carrots, apples and bananas on hand for quick, satisfying snacks. Fruit salads are a wonderful way to eat a variety of healthy fruit.
- Go nuts. Keep almonds, cashews, pistachios and walnuts on hand for a quick snack. Choose natural peanut butter, rather than the kind with hydrogenated fat added. Try tahini (blended sesame seeds) as a dip or spread for bread.
- Pass on the butter. Try olive or canola oil as a healthy replacement for butter or margarine. Use it in cooking. After cooking pasta, add a touch of olive oil, some garlic and green onions for flavoring. Dip bread in flavored olive oil or lightly spread it on whole-grain bread for a tasty alternative to butter. Try tahini (blended sesame seeds) as a dip or spread for bread too.
- Spice it up. Herbs and spices make food tasty and are also rich in health-promoting substances. Season your meals with herbs and spices rather than salt.
- Go fish. Eat fish once or twice a week. Fresh or water-packed tuna, salmon, trout, mackerel and herring are healthy choices. Grilled fish tastes good and requires little cleanup. Avoid fried fish, unless it's sauteed in a small amount of canola oil.
- Rein in the red meat. Substitute fish and poultry for red meat. When eaten, make sure it's lean and keep portions small (about the size of a deck of cards). Also avoid sausage, bacon and other high-fat meats.
- Choose low-fat dairy. Limit higher fat dairy products such as whole or 2 percent milk, cheese and ice cream. Switch to skim milk, fat-free yogurt and low-fat cheese.
- Raise a glass to healthy eating. If it's OK with your doctor, have a glass of wine at dinner. If you don't drink alcohol, you don't need to start. Drinking purple grape juice may be an alternative to wine.
By Kate Kelland
LONDON (Reuters) Sep 04 - All girls in Europe should be immunized against the human papillomavirus (HPV) and current vaccine coverage rates are far too low, European Union health officials have announced.
In new advice about tackling the virus, the European Center for Disease Prevention and Control (ECDC) said that while 19 out of 29 countries in the region had introduced HPV vaccine programs, vaccination rates were as low as 17% in some.
Cervical cancer is the second most common cancer in women worldwide, with about 500,000 new cases and 250,000 deaths each year, according to the World Health Organization (WHO).
Virtually all cases are linked to genital infection with HPV, the most common viral infection of the reproductive tract.
British drugmaker GlaxoSmithKline and U.S. rival Merck & Co make the only two HPV vaccines licensed for use in Europe.
Merck's Gardasil targets four strains of HPV - two responsible for cervical cancer and two that cause the less serious condition of genital warts - while GSK's Cervarix shot targets only the two cancer strains.
The ECDC said that in 2010, only Portugal and Britain had vaccination coverage rates above 80% for the target groups of girls aged between about 10 and 14 years.
It urged health authorities to step up their efforts to get more girls vaccinated, saying recent research studies had shown the shots to be safe and effective, as well as cost-effective.
"We public health authorities, frontline healthcare workers and parents alike have a shared responsibility to protect thousands of women from cervical cancer," said Marc Sprenger, the ECDC's director.
"European countries may need to examine why HPV vaccination coverage rates ... are not higher and strengthen their vaccination campaigns accordingly."
A study published last year found that using Cervarix to protect girls against HPV virus is so effective that health authorities who get good coverage rates could start to reduce the need for later cervical screening.
While recent studies have also shown that HPV shots can also help protect boys from various types of cancer - including oral, anal and penile cancers - the ECDC said its recommendations did not as yet seek to include young men in vaccination programs.
"The personal benefit of the vaccine for men in terms of cancer prevention is very low," it said in a statement. "Including boys in the current HPV vaccination programs is unlikely to be cost-effective."
U.S. health authorities advised late last year that all boys should also be routinely vaccinated against HPV.
Lack of Sleep Linked to Breast Cancer Aggressiveness
By Kate Kelland
LONDON (Reuters) Sep 04 - All girls in Europe should be immunized against the human papillomavirus (HPV) and current vaccine coverage rates are far too low, European Union health officials have announced.
In new advice about tackling the virus, the European Center for Disease Prevention and Control (ECDC) said that while 19 out of 29 countries in the region had introduced HPV vaccine programs, vaccination rates were as low as 17% in some.
Cervical cancer is the second most common cancer in women worldwide, with about 500,000 new cases and 250,000 deaths each year, according to the World Health Organization (WHO).
Virtually all cases are linked to genital infection with HPV, the most common viral infection of the reproductive tract.
British drugmaker GlaxoSmithKline and U.S. rival Merck & Co make the only two HPV vaccines licensed for use in Europe.
Merck's Gardasil targets four strains of HPV - two responsible for cervical cancer and two that cause the less serious condition of genital warts - while GSK's Cervarix shot targets only the two cancer strains.
The ECDC said that in 2010, only Portugal and Britain had vaccination coverage rates above 80% for the target groups of girls aged between about 10 and 14 years.
It urged health authorities to step up their efforts to get more girls vaccinated, saying recent research studies had shown the shots to be safe and effective, as well as cost-effective.
"We public health authorities, frontline healthcare workers and parents alike have a shared responsibility to protect thousands of women from cervical cancer," said Marc Sprenger, the ECDC's director.
"European countries may need to examine why HPV vaccination coverage rates ... are not higher and strengthen their vaccination campaigns accordingly."
A study published last year found that using Cervarix to protect girls against HPV virus is so effective that health authorities who get good coverage rates could start to reduce the need for later cervical screening.
While recent studies have also shown that HPV shots can also help protect boys from various types of cancer - including oral, anal and penile cancers - the ECDC said its recommendations did not as yet seek to include young men in vaccination programs.
"The personal benefit of the vaccine for men in terms of cancer prevention is very low," it said in a statement. "Including boys in the current HPV vaccination programs is unlikely to be cost-effective."
U.S. health authorities advised late last year that all boys should also be routinely vaccinated against HPV.
In Postmenopausal Women Only
|
September 7, 2012 — For the first time, lack of sleep has been associated with more aggressive breast cancers, according to findings published in the August issue of Breast Cancer Research and Treatment.
The study was conducted in 101 women with early-stage estrogen-receptor-positive breast cancer who were assessed with the Oncotype DX test, which guides treatment in early-stage breast cancer by predicting the likelihood of recurrence.
The worst scores on the recurrence probability test were found in women who reported having the least sleep at night. Specifically, having fewer than 7 hours of sleep a night during the 2 years before the diagnosis was associated with a greater risk for recurrence.
However, this association between less sleep and breast cancers that are more aggressive and more likely to recur was strong only in postmenopausal women (P = .0011), not in premenopausal women (P = .80).
"This is the first study to suggest that women who routinely sleep fewer hours may develop more aggressive breast cancers than women who sleep longer hours," said lead author Cheryl Thompson, PhD, in a press statement. She and her coauthor, Li Li, MD, PhD, are from Case Western Reserve University in Cleveland, Ohio.
The study findings are limited by the "relatively modest sample size," the authors acknowledge.
Nevertheless, the study adds to the literature on sleep duration and breast cancer. Four previous studies, all of which assessed breast cancer risk and did not specifically look at breast cancer aggressiveness, have had "mixed results," according to the authors. Three of these have suggested that sleep can reduce the risk for breast cancer and 1 found no association at all.
Medscape Medical News asked Simone P. Pinheiro, ScD, from the Center for Drug Evaluation and Research at the US Food and Drug Administration (FDA), for her opinion on this study.
Before joining the FDA, Dr. Pinheiro was the lead author of the large prospective study that "did not find convincing evidence to support an association between habitual duration of sleep and subsequent development of breast cancer" (Cancer Res. 2006;66:5521-5525). However, information on habitual sleep duration was obtained prior to the development of breast cancer in that study, she emphasized.
The study by Drs. Thompson and Li "suggests" a "significant inverse correlation" between sleep duration and breast cancer aggressiveness among women diagnosed with breast cancer, Dr. Pinheiro noted.
These results could also reflect the effect of subclinical...breast cancer on sleep duration.
"These results could also reflect the effect of subclinical (not yet diagnosed) breast cancer on sleep duration," she said in an email. In other words, a woman's nascent breast cancer might have caused sleep disturbance, she explained.
So, is lack of sleep a new risk factor for aggressive breast cancers?
The authors believe it might be. "Our data suggest that lack of sufficient sleep may cause biologically more aggressive tumors," they write. But they note that "further work will need to be done to more thoroughly characterize the biology underlying this epidemiological association."
Less Sleep and Recurrence Scores Defined
All of the study participants are enrolled in a larger 412-patient case–control breast cancer study. As such, they were recruited at diagnosis and asked about lifestyle matters, including average sleep duration in the previous 2 years. Many of the breast cancer patients in the study underwent Oncotype DX testing.
The authors designated 3 levels of nightly sleep: 6 hours or less, 6 to 7 hours, and 7 or more hours.
Using previously published data on the recurrence probability test, they determined that scores below 18 predict a low risk for recurrence, scores of 18 to 30 predict an intermediate risk, and scores of 31 or higher predict a high risk.
Overall, less sleep was found to be correlated with a higher score. Risk for recurrence was intermediate in patients who slept 6 hours or less (mean recurrence score, 27.8) or 6 to 7 hours (mean recurrence score, 18.0) and low for patients who slept 7 or more hours (mean recurrence score, 16.4).
Thus, getting an average of less than 7 hours of sleep a night was associated with an intermediate risk and getting 7 or more hours was associated a with low risk. However, this finding was only statistically significant in the subset of postmenopausal women.
The lack of a strong association in premenopausal women is explainable, say the authors.
"It is well known that there are different mechanisms underlying premenopausal and postmenopausal breast cancers," they explain. "Our data suggest that sleep may affect carcinogenic pathway(s) specifically involved in the development of postmenopausal breast cancer, but not premenopausal cancer."
The positive findings in postmenopausal women remained statistically significant after adjustment for possible confounders, including age, physical activity, smoking status, and body mass index.
"Effective intervention to increase duration of sleep and improve quality of sleep could be an underappreciated avenue for reducing the risk of developing more aggressive breast cancers and recurrence," said Dr. Li in a press statement.
This study adds to the literature on lifestyle factors that can affect breast cancer and its related risk. These studied factors are increasingly diverse and include night-shift work, light in the bedroom, and more obvious variables such as obesity.
The study was supported by National Cancer Institute grants to the Case Western Reserve University School of Medicine. The authors have disclosed no relevant financial relationships.
September 5, 2012 (Montreal, Quebec) — More than 50% of cancer could be prevented if people simply implemented what is already known about cancer prevention, according to a researcher here at the Union for International Cancer Control (UICC) World Cancer Congress 2012.
Graham Colditz, PD, DrPH, from the Washington University School of Medicine in St. Louis, Missouri, reported that a number of interventions, largely involving lifestyle behaviors, but also involving higher-cost interventions in high-income countries, could prevent a large proportion of cancers in 15 to 20 years if widely applied.
Among the "biggest buys" from lifestyle intervention is smoking cessation.
"One third of cancer in high-income countries is caused by smoking," Dr. Colditz said. If smoking rates could be reduced to the current levels in Utah [about 11%], the United States could see a 75% reduction in smoking-related cancers in 10 to 20 years — a target that Dr. Colditz feels is feasible in countries where smoking rates have already declined considerably.
Similarly, it is estimated that being overweight or obese causes approximately 20% of cancer today. If people could maintain a healthy body mass index (BMI), the incidence of cancer could be reduced by approximately 50% in 2 to 20 years. (A healthy BMI for cancer prevention is from 21 to 23 kg/m², as other speakers pointed out.)
Dr. Colditz, among others, estimates that poor diet and lack of exercise are each associated with about 5% of all cancers. Improvement in diet could reduce cancer incidence by 50% and increases in physical activity could reduce cancer incidence by as much as 85% in 5 to 20 years.
Eradicating the main viruses associated with cancer worldwide by implementing widespread infant and childhood immunization programs targeting 3 viruses — human papillomavirus and hepatitis B and C — could lead to a 100% reduction in viral-related cancer incidence in 20 to 40 years, he added. Then there are the "higher tech" interventions that, at least in high-income countries, could prevent a significant proportion of cancer and cancer-related mortality, starting with breast cancer.
"We have shown that tamoxifen reduces the rate of both invasive and noninvasive breast cancer by 50% or more, compared with placebo, at 5 years," Dr. Colditz said.
Similarly, raloxifene has been shown to reduce the risk for invasive breast cancer by about 50% at 5 years, according to the Study of Tamoxifen and Raloxifene (STAR) in postmenopausal women at increased risk for breast cancer. Women in STAR who received raloxifene also had 36% less uterine cancers than control subjects.
"We also observed a 10% to 15% decrease in breast cancer incidence following the results of the Women's Health Initiative that were clearly not due to changes in mammography, but rather to the removal of a late promoter [of breast cancer]," Dr. Colditz explained. The use of hormone replacement therapy in the United States plummeted after the Women's Health Initiative showed that it was associated with an increased risk for breast cancer.
And bilateral oophorectomy in women carrying the BRCA1 or BRCA2 gene, although rare, has been associated with a 50% reduction in breast cancer risk among high-risk women. It has also been estimated that weight loss after menopause (more than 20 lbs [9 kg]) reduces breast cancer risk by 50% in 2 to 20 years.
In addition, Dr. Colditz noted that approximately 20 years of follow-up has shown that aspirin is associated with a 40% reduction in mortality from colon cancer. Screening for colorectal cancer has a similar magnitude of mortality reduction (30% to 40%).
Indeed, a recent study showed that after a median follow-up of 11.9 years, there was a 21% relative risk reduction in the incidence of colorectal cancer and a 26% reduction in mortality in adults screened with flexible sigmoidoscopy, with a repeat screening at 3 or 5 years, compared with those treated with the usual care (N Engl J Med. 2012;366:2345-2357).
Dr. Colditz noted that a concerted and collective effort to promote colon cancer screening in Massachusetts was initiated in 1997. From 1997 to 2010, "we saw almost a doubling of screening with sigmoidoscopy or colonoscopy in age-eligible residents and, during that time, the age-standardized mortality from colon cancer went down by 35%," he said.
They could bring huge benefits to society.
He added that 30 years ago, "epidemiologists were already showing that tobacco, alcohol, and diet — which in their definition was the sum of dietary intake, lack of physical activity, and obesity — accounted for more than half of all cancer. We can't expect these changes in outcome to occur overnight, but they could bring huge benefits to society," he explained.
Session cochair David Hill, AO, PhD, MD (Hon), from the Union for International Cancer Control in Geneva, Switzerland, told Medscape Medical News that it is "absolutely core business" for global bodies in cancer, such as the UICC, to ensure that the knowledge we have about cancer is applied.
The challenge for us is to develop a new form of cancer science called 'implementation science.'
"We have far more knowledge at the moment than we are making use of effectively," Dr. Hill noted. "The challenge for us is to develop a new form of cancer science called 'implementation science.' We've got to work out how to take the benefits of discoveries to the people for population-wide health benefits."
Union for International Cancer Control (UICC) World Cancer Congress 2012. Presented August 29, 2012.
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September 4, 2012 — A new study adds to the growing body of evidence that prenatal exposure to maternal cigarette smoking (PEMCS) may be a factor in the worldwide epidemic of obesity.
Adolescents whose mothers smoked while pregnant had a higher body mass index (BMI), had more total body fat, and reported a higher intake of dietary fat than the children of nonsmoking mothers, lead author Amirreza Haghighi, MD, and colleagues report in an article published online September 3 in the Archives of General Psychiatry.
There was also a correlation between smaller amygdala volume and higher fat intake among patients in the PEMCS group, but not in the control group.
The findings suggest that "PEMCS may increase the risk for obesity by enhancing dietary intake of fat, and that this effect may be mediated in part through subtle changes in brain structures involved in reward processing," the investigators write.
Dr. Haghighi, from the Hospital for Sick Children, University of Toronto, Ontario, Canada, and coauthors studied adolescents aged 13 to 19 years who were recruited from high schools in the Saguenay Lac St. Jean region of Quebec, Canada, as part of the ongoing Saguenay Youth Study. Only adolescents at Tanner stages 4 and 5 were included.
The 180 PEMCS participants were compared with 198 control patients matched for age, school attended, and maternal education to minimize the potential confounding influence of socioeconomic status (SES). Cigarette exposure was defined as "having a mother who smoked more than 1 cigarette per day during the second trimester of pregnancy and being nonexposed was defined as having a mother who did not smoke 1 year before (and throughout) the pregnancy," the authors explain. The mothers of exposed participants smoked an average of 11.1 (standard deviation [SD], 6.8) cigarettes daily throughout their pregnancies.
Dietary fat intake was determined through a 24-hour food recall interview conducted by a trained nutritionist on a Saturday morning. This was complemented by having the participants answer 6 questions about their eating habits, including fruit and vegetable consumption, for the previous 7 days. Brain structures were measured through magnetic resonance imaging of the left and right nucleus accumbens, as well as the left and right amygdala.
Exposed children weighed, on average, 301 g less at birth than the nonexposed children, and were breast-fed for an average of 4.5 weeks less (P < .001 for both comparisons). After adjusting for age, sex, and (when appropriate) height, the exposed children weighed an average of 1.7 kg more in adolescence, but this difference was not significant (P = .10). Their average BMI was 0.7 kg/m2 higher (P = .05).
These differences "remained virtually unchanged after additional adjusting for variables frequently associated with maternal cigarette smoking during pregnancy and implicated on their own in increasing the risk for obesity (ie, lower birth weight, shorter duration [or lack of] breastfeeding, and lower SES)," the authors write. "They also remained virtually unchanged after additional adjusting for maternal BMI, a known risk factor for offspring. Thus, it appears that the association between PEMCS and greater adiposity is independent of these factors and, as such, may be specific to maternal cigarette smoking."
Fat intake was 2.7% higher, as a percentage of energy intake, among the exposed than the nonexposed children (P =.001), a difference that remained significant (P < .001) after adjustment for birth weight, breast-feeding, and family income. Similarly, amygdala volume was 95 mm3 smaller among the exposed children (P < .001), again after adjustment for perinatal and socioeconomic factors, as well as maternal BMI. "In addition, amygdala volume correlated inversely with fat intake (r = −0.15; P = .006), and this correlation was seen in exposed (r = −0.16; P < .04) but not in nonexposed (r = −0.08; P = .29) participants."
The amygdala is part of the reward center in the brain, and lower amygdala volume has been associated with alcohol craving and addiction, the authors write. In animal studies, stimulation of the amygdala appears to decrease the preference for dietary fat.
The current research suggests that the smaller size or lower activity level of the amygdala may stimulate the craving for fat as well as increase the risk for addiction to substances such as alcohol. The reduction in amygdala size associated with PEMCS may help explain the higher fat intake and greater BMI of the PEMCS participants in this study, the authors point out.
These findings support the fetal-programming hypothesis of obesity, they conclude. The data "suggest that PEMCS may contribute in this context by modifying fat intake through neural mechanisms involving the amygdala."
The Saguenay Youth Study is funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Quebec, and the Canadian Foundation for Innovation. The authors have disclosed no relevant financial relationships.
Arch Gen Psychiatry. Published online September 3, 2012. Abstract
September 4, 2012 — A new study adds to the growing body of evidence that prenatal exposure to maternal cigarette smoking (PEMCS) may be a factor in the worldwide epidemic of obesity.
Adolescents whose mothers smoked while pregnant had a higher body mass index (BMI), had more total body fat, and reported a higher intake of dietary fat than the children of nonsmoking mothers, lead author Amirreza Haghighi, MD, and colleagues report in an article published online September 3 in the Archives of General Psychiatry.
There was also a correlation between smaller amygdala volume and higher fat intake among patients in the PEMCS group, but not in the control group.
The findings suggest that "PEMCS may increase the risk for obesity by enhancing dietary intake of fat, and that this effect may be mediated in part through subtle changes in brain structures involved in reward processing," the investigators write.
Dr. Haghighi, from the Hospital for Sick Children, University of Toronto, Ontario, Canada, and coauthors studied adolescents aged 13 to 19 years who were recruited from high schools in the Saguenay Lac St. Jean region of Quebec, Canada, as part of the ongoing Saguenay Youth Study. Only adolescents at Tanner stages 4 and 5 were included.
The 180 PEMCS participants were compared with 198 control patients matched for age, school attended, and maternal education to minimize the potential confounding influence of socioeconomic status (SES). Cigarette exposure was defined as "having a mother who smoked more than 1 cigarette per day during the second trimester of pregnancy and being nonexposed was defined as having a mother who did not smoke 1 year before (and throughout) the pregnancy," the authors explain. The mothers of exposed participants smoked an average of 11.1 (standard deviation [SD], 6.8) cigarettes daily throughout their pregnancies.
Dietary fat intake was determined through a 24-hour food recall interview conducted by a trained nutritionist on a Saturday morning. This was complemented by having the participants answer 6 questions about their eating habits, including fruit and vegetable consumption, for the previous 7 days. Brain structures were measured through magnetic resonance imaging of the left and right nucleus accumbens, as well as the left and right amygdala.
Exposed children weighed, on average, 301 g less at birth than the nonexposed children, and were breast-fed for an average of 4.5 weeks less (P < .001 for both comparisons). After adjusting for age, sex, and (when appropriate) height, the exposed children weighed an average of 1.7 kg more in adolescence, but this difference was not significant (P = .10). Their average BMI was 0.7 kg/m2 higher (P = .05).
These differences "remained virtually unchanged after additional adjusting for variables frequently associated with maternal cigarette smoking during pregnancy and implicated on their own in increasing the risk for obesity (ie, lower birth weight, shorter duration [or lack of] breastfeeding, and lower SES)," the authors write. "They also remained virtually unchanged after additional adjusting for maternal BMI, a known risk factor for offspring. Thus, it appears that the association between PEMCS and greater adiposity is independent of these factors and, as such, may be specific to maternal cigarette smoking."
Fat intake was 2.7% higher, as a percentage of energy intake, among the exposed than the nonexposed children (P =.001), a difference that remained significant (P < .001) after adjustment for birth weight, breast-feeding, and family income. Similarly, amygdala volume was 95 mm3 smaller among the exposed children (P < .001), again after adjustment for perinatal and socioeconomic factors, as well as maternal BMI. "In addition, amygdala volume correlated inversely with fat intake (r = −0.15; P = .006), and this correlation was seen in exposed (r = −0.16; P < .04) but not in nonexposed (r = −0.08; P = .29) participants."
The amygdala is part of the reward center in the brain, and lower amygdala volume has been associated with alcohol craving and addiction, the authors write. In animal studies, stimulation of the amygdala appears to decrease the preference for dietary fat.
The current research suggests that the smaller size or lower activity level of the amygdala may stimulate the craving for fat as well as increase the risk for addiction to substances such as alcohol. The reduction in amygdala size associated with PEMCS may help explain the higher fat intake and greater BMI of the PEMCS participants in this study, the authors point out.
These findings support the fetal-programming hypothesis of obesity, they conclude. The data "suggest that PEMCS may contribute in this context by modifying fat intake through neural mechanisms involving the amygdala."
The Saguenay Youth Study is funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Quebec, and the Canadian Foundation for Innovation. The authors have disclosed no relevant financial relationships.
Arch Gen Psychiatry. Published online September 3, 2012. Abstract
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