Thursday, April 3rd, 2014
Boys who start smoking before age 11–very young smokers–are far more likely to have sons who battle weight and obesity issues, according to a new British study. The finding puts emphasis on a growing body of research supporting the idea that childhood habits can affect the health of offspring years down the line. More from Reuters:
The scientists said the findings, part of ongoing work in a larger “Children of the 90s” study, could indicate that exposure to tobacco smoke before the start of puberty in men may lead to metabolic changes in the next generation.
“This discovery of transgenerational effects has big implications for research into the current rise in obesity and the evaluation of preventative measures,” said Marcus Pembrey, a professor of genetics at University College London, who led the study and presented its findings at a briefing on Wednesday.
Smoking rates in Britain and some other parts of Europe are on the decline, but worldwide, almost one billion men smoke – about 35 percent of men in developed countries and 50 percent in developing ones, according to the World Health Organization.
While previous studies in animals and in people have found some transgenerational health impacts, the evidence so far is limited. It points, however, to epigenetics – a process where lifestyle and environmental factors can turn certain genes on or off – having an effect on the health of descendants.
Pembrey said his team’s research was prompted in part by signals from earlier Swedish studies that linked how plentiful a paternal ancestor’s food supply was in mid childhood with future death rates in grandchildren.
For the new study, published in the European Journal of Human Genetics, the researchers had access to detailed lifestyle, genetic and other health data from 9,886 fathers.
Of these, 5,376, or 54 percent, were smokers at some time and of those, 166, or 3 percent, said they had started smoking regularly before the age of 11.
Looking at the next generation, the team found that at age 13, 15 and 17, the sons of men who started smoking before 11 had the highest Body Mass Index (BMI) scores compared with the sons of men who had started smoking later or who had never smoked.
“These boys had markedly higher levels of fat mass – ranging from an extra five kilograms (kg) to 10kg between ages 13 and 17,” the study said.
Although it was there, the effect was not seen to the same degree in daughters.
Image: Young man smoking, via Shutterstock
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Friday, March 21st, 2014
Parents who are “authoritarian,” very strict and unyielding when it comes to rules and boundaries, are more likely to have children who struggle with weight issues than parents who are “authoritative,” meaning that rules and boundaries are clear, but more open to discussion and explanation. Time.com has more on a new study, which was conducted by Canadian researchers:
Until now, there hadn’t been a close look at how overall parenting style—how permissively or authoritatively parents interact with their kids on everything from homework to chores and getting along with their siblings—might affect children’s weight. “We looked at the general way that parents can affect their child’s obesity even if they are not trying to control specific health-related behaviors,” says the study’s lead author, Lisa Kakinami, a postdoctoral fellow at McGill University.
She and her colleagues followed a group of more than 37,000 children in Canada aged zero to 11 years, and asked parents about their interactions with their youngsters. The team queried parents about things like how they responded when their child did something they shouldn’t, and how much they praised their kids when they did something positive.
Based on their responses, Kakinami and her colleagues focused on two of the four well-established groups of parenting styles: authoritative, in which parents set rules and boundaries but explain their reasoning and show understanding when the rules are broken; and authoritarian, in which parents set strict rules but aren’t as open to discussing and explaining them to their children. (The others, at the opposite end of the spectrum, are uninvolved, in which parents communicate very little with their children and are virtually absent as authority figures; and permissive, in which parents make few demands and expect little self-control from their kids.)
Kakinami found that children of authoritarian parents were 30% more likely to be obese at 2 to 5 years old, and 37% more likely to be obese if they were 6 to 11 years old compared with children of authoritative parents.
While the study wasn’t designed to tease apart what might be contributing to the higher body mass indices (BMI) in the authoritarian households, pediatricians have some theories. “When a parent says absolutely ‘no,’ that becomes forbidden fruit, and kids may then value that more,” says Dr. Stephen Daniels, chair of pediatrics at the University of Colorado, who was not involved in the study, about certain kid-favorite foods such as sweets, soda and fast food that are high in calories.
Kakinami says there were hints that other factors may be at work as well. Authoritarian parents were less likely than authoritative moms and dads to praise their children or give them positive feedback for good behavior, regardless of whether it was related to their health. “The main difference in authoritative vs. authoritarian styles is the warmth expressed between the parent and child,” she says. “Authoritative parents ranked higher on praise than authoritarian parents.” And when their children misbehaved, authoritarian parents were “most likely to respond emotionally and punish the child but not tell them what they had done wrong.”
Image: Strict parent, via Shutterstock
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Tuesday, March 18th, 2014
A study published last month in the Journal of the American Medical Association, which claimed a 43 percent drop in the number of preschool-aged American kids who have a weight problem, is being questioned as a possible statistical anomaly, and not an indication that the childhood obesity epidemic is on its way out. Reuters reports on the challenge, which is coming from obesity experts from Massachusetts General Hospital and other places:
In fact, based on the researchers’ own data, the obesity rate may have even risen rather than declined.
“You need to have a healthy degree of skepticism about the validity of this finding,” said Dr. Lee Kaplan, director of the weight center at Massachusetts General Hospital in Boston.
No evidence of the kinds of major shifts in the behavior among preschoolers aged 2 to 5 exists which would explain a 43 percent drop in their obesity rates, he said.
The latest study is based a well-respected data set taken from the National Health and Nutrition Examination Survey, or NHANES, which has been conducted annually since the 1960s and involves in-person interviews and physical exams.
The CDC defines obesity in adults as having a body mass index – a ratio of weight to height – above 30, but in children it is defined by where the individual falls on age- and sex-specific growth charts.
The 2011-2012 version of the survey included 9,120 people; 871 of them were 2 to 5 years old.
In some research 871 would be considered a large number. But when the obesity rate is fairly low, having a sample of a few hundred makes it easier for errors to creep in through random chance.
“In small samples like this, you are going to have chance fluctuations,” said epidemiologist Geoffrey Kabat of the Albert Einstein College of Medicine in New York City.
To be sure, the CDC scientists were aware of the statistical limitations of their data, and their paper clearly stated that the findings were imprecise.
The 43 percent headline figure refers to the drop from the 13.9 percent rate in 2003-04 to the 8.4 percent rate in 2011-2012. The change of 5.5 points represents a decline of 40 percent from the original 13.9 percent. (The 43 percent trumpeted by a CDC press release comes from rounding those numbers to 14 and 8, respectively.)
In addition to the small sample size and a lack of supporting evidence from other recent surveys of childhood weight, experts cite a dearth of signs of behavioral changes that would contribute to improving obesity numbers. More from Reuters:
For obesity rates to drop, researchers reckon, young children have to eat differently and become more active. But research shows little sign of such changes among 2-to-5-year olds, casting more doubt on the 43 percent claim.
Such a decline would require changes in exercise, food consumption and sleep patterns, said Mass General’s Kaplan “There is no evidence of that,” he said.
In 2010 [WIC (Women, Infants and Children) program researcher Shannon] Whaley and her colleagues examined the effectiveness of WIC classes and counseling to encourage healthy eating and activities for women and children in the program.
Their findings were discouraging: Television watching and consumption of sweet or salty snacks actually rose, while fruit and vegetable consumption fell – changes that could lead to weight gain. One positive was a rise in physical activity.
Apart from the WIC program, few anti-obesity efforts target preschoolers, Kaplan pointed out. That makes a precipitous decline in obesity in that group highly unlikely.
Image: Brown bag lunch, via Shutterstock
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Monday, March 17th, 2014
A major doctor’s group is urging obstetricians to have serious, often difficult conversations with their patients, telling them that being overweight or obese can have negative impact on both their fertility and their pregnancy health. More from Time.com:
The latest news about the negative effects of our nation’s obesity epidemic on everything from fertility to pregnancy and maternal mortality recently prompted the American College of Obstetricians and Gynecologists (ACOG) to urge doctors to talk with patients about the benefits of slimming down before trying to conceive. It’s part of an ongoing push to make chats about women’s “reproductive lifespan” as routine as an annual pap smear. Just as doctors have historically shied away from telling women that their eggs are getting too old, many haven’t been eager to point out that a woman’s size might come in between her and her dream of becoming a mother.
“For a woman who’s been trying for a year, the last thing she wants to hear is to take another year off to lose weight,” explains Dr. Jeanne Conry, ACOG president and assistant physician in chief at The Permanente Medical Group in Roseville, California. “But if a woman walks into my office who’s been trying to get pregnant and she has a body mass index of 30 or over [more than 180 pounds for a 5’5” woman] and she’s having an irregular period, the first thing we’re going to do is discuss a healthy diet and exercise program.”
Of course, doctors point out that the majority of the estimated 30% of obese women in the U.S. have no problems conceiving. But there’s a growing body of evidence that’s difficult to ignore. Obesity raises a woman’s risk of gestational diabetes, hypertension, premature delivery, miscarriage, and stillbirth. A mother’s chance of having to undergo a caesarian section is 34% if her BMI is over 30, and 47% if her BMI is over 35—compared to 21% for women with a BMI under 30, according to one study. There’s even evidence that babies born to obese women have a greater chance of suffering neural defects than those whose mothers are normal weight, and will be at greater risk of being obese themselves.
In one recent survey of more than 3,300 women, one-third responded they didn’t believe or were unsure whether a woman’s weight affected her chances of conceiving. The doctors’ organization hopes that encouraging ob-gyns to broach the topic will educate women about that connection, considering that about 6% of infertility is due to obesity (another 6% is due to being too thin), according to statistics by the American Society for Reproductive Medicine. (That goes for men, too, since a recent French study showed their excess poundage contributed to low sperm production.) The good news is that 70% of these women will get pregnant naturally after they lose or gain enough weight to get closer to a healthier BMI.
The other goal is to help patients set and achieve weight-loss goals, or even consider weight loss surgery if they’re severely obese. But adding those expectations on top of conceiving can feel daunting to many women, says Julie Friedman, PhD, a psychologist who directs a weight management program comprised of counseling, workshops, and support groups, at Insight Behavioral Health Centers, a chain of outpatient mental health treatment centers based in Chicago. “They’ve struggled with their weight their whole lives and now they’re going through something so stressful, saying ‘Now you’re telling me to lose weight when I’m this stressed out and trying for a baby?’”
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Image: Overweight woman, via Shutterstock
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Monday, March 10th, 2014
Babies who are born by c-section may be at higher risk of being overweight or obese later in their lives, according to a new study published in the journal PLOS One. The New York Times has more:
Researchers pooled data from 15 studies with a combined population of 142,702 for their analysis. The studies classified overweight as a body mass index of 25 or higher and obesity as 30 or higher, and covered various types of vaginal and cesarean deliveries.
Compared with babies delivered vaginally, those delivered by C-section were 26 percent more likely to be overweight and 22 percent more likely to be obese. The type of vaginal or cesarean delivery — natural, forceps or vacuum extraction vaginal births, or pre-labor or in-labor cesarean deliveries — made no difference.
The analysis, published in the February issue of PLOS One, included a large sample from 10 countries, which gives it considerable strength. At the same time, all studies were observational, and the authors write that further study would be required to establish a causal connection between birth method and adult B.M.I.
“Of course if a C-section is needed for clinical reasons, you’ve got no choice,” said one of the authors, Matthew J. Hyde, a research associate at Imperial College London. “But a woman cannot make a reasoned choice unless she’s fully informed not only about the short-term outcomes, but also the long-term outcomes. We want to give you the data you need to make an informed decision.”
Image: C-section tools, via Shutterstock
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