Obesity creeps up in US

Obesity continued to creep up in the United States last year and now affects more than one in four US adults, a US government report showed Friday.In 2005, 23.9 percent of adults in the United States were obese, or had a body mass index greater than 30, while in 2007, the percentage had grown to 25.6 percent, data issued by the Centers for Disease Control (CDC) showed.

Body mass index is calculated by dividing a person's weight in kilos by his or her height squared in meters.

In three states -- Alabama, Mississippi and Tennessee -- nearly one in three adults was obese.

Mississippi, which is also the poorest US state, had the highest rate of obesity in the United States, at 32 percent. Colorado had the lowest rate of obesity at 18.7 percent and was the only state in which obesity was running at less than 19 percent.

No state has achieved the official target to bring obesity down to 15 percent of the adult population by 2010, the report showed.

Obesity was highest for non-Hispanic black women, nearly four in 10 of whom were obese.

University graduates were the least likely to be obese -- around 22 percent compared with 29 percent of people who only obtained a high school diploma.

A report issued last year by the Trust for America's Health (TFAH) said the percentage of obsese adults more than doubled in the past 25 years across the United States, growing from 15 percent in 1978-80 to 32 percent in 2003-04.

ADHD children have greater risk of being overweight

Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for being overweight, regardless of whether or not they are currently receiving medications for the condition.The results of prior research has suggested that the impulsivity and poor behavioral regulation that is common in children with ADHD may promote certain eating patterns that increase the risk of obesity, co-authors Molly E. Waring and Dr. Kate L. Lapane, from Brown Medical School in Providence, Rhode Island, note.

To investigate further, the researchers analyzed data from 62,887 children and adolescents included in the 2003-2004 National Survey of Children's Health.

Children with ADHD were identified based the response of the parent to the question: "Has a doctor or health professional ever told you that your child has attention-deficit disorder or attention-deficit/hyperactivity disorder, that is, ADD or ADHD?"

The prevalence of ADD or ADHD was 8.8 percent, the authors report in the journal Pediatrics, and approximately half the affected children were taking medication for the condition.

After accounting for demographic factors as well as depression and anxiety, ADHD patients who were not being treated with medication were 1.5-times more likely to be overweight than children without the disorder. The risk for ADHD among those who were currently receiving medications was only about 0.5-times higher than children without ADHD.

"Future work is needed to better understand the longitudinal and pharmacologic factors that influence the relationship between ADD/ADHD and weight status in children and adolescents," the investigators conclude.

Studies show exercise boon for obesity, diabetes

Walking a bit more each day can help people control their Type 2 diabetes but obese people trying to keep weight off may need to exercise harder than they had thought, according to a studies published on Monday.Simply walking 45 minutes more each day helped people with diabetes use blood sugar better, Michael Trenell of Britain's Newcastle University and colleagues wrote in the journal Diabetes Care.

"People often find the thought of going to the gym quite daunting, but what we've found is that nearly everyone with diabetes is able to become more active through walking," Trenell said.

The Newcastle team paired 10 Type 2 diabetes patients with people without the condition of similar height, weight and age and asked everybody to walk more than 10,000 steps each day.

Magnetic resonance imaging or MRI scans showed that people who walked 45 minutes more each day burned about 20 percent more fat -- increasing the ability of the muscles to store sugar and help control diabetes, the researchers said.

"What is exciting about this study is that it provides an immediate way to help control diabetes without any additional drugs," Trenell said.

Diabetes affects an estimated 246 million adults worldwide and accounts for 6 percent of all global deaths. Type 2 diabetes accounts for about 90 percent of all diabetes cases and is closely linked to obesity and physical inactivity.

Obesity and diabetes both are growing problems as more developing nations adopt a Western lifestyle, something the International Diabetes Federation estimates will propel the number of people with diabetes to 380 million by 2025.

But current exercise guidelines calling for people to get 150 minutes -- 2.5 hours -- each week may not be enough to help the obese keep weight off, John Jakicic of the University of Pittsburgh and colleagues wrote in the Archives of Internal Medicine.

To determine an optimal amount of exercise, the U.S. team enrolled 201 overweight and obese women in a weight loss programme between 1999 and 2003 and assigned them to one of four exercise groups.

After six months, women in all four groups had lost an average of 8 to 10 percent of their weight but many gained it back.

Women assigned to exercise for about an extra hour each day did not gain the weight back, the researchers said. These women were also more likely to stick to healthy diets.

Jakicic recommended that people who want to lose weight and keep it off get at least 4-1/2 hours of exercise a week.

"There is a growing consensus that more exercise may be necessary to enhance long-term weight loss," Jakicic and colleagues wrote.

Obesity not a contraindication to knee replacement

Obese individuals with arthritic knees should not be denied knee replacement surgery, researchers conclude, based on a new study showing that obese patients benefit from the surgery almost as much as their normal-weight peers.Roughly 55,000 knee replacements are performed every year in England to relieve the pain and disability of knee arthritis, according to the British research team that conducted the study. But in some parts of the country the surgery is offered only to people who are not obese, on the grounds that obesity is itself a risk factor for knee arthritis.

Dr. Cyrus Cooper, at the University of Southampton, and associates monitored the progress of 325 patients for around six years after they had had knee replacement surgery. Their progress was compared with that of 363 "control" patients seen in general medical practices, matched for age and sex, who had not had knee replacements.

At the outset, physical function was markedly worse in the knee replacement patient group than in the control group. However, at follow-up, physical function had improved in the knee replacement patients, while that of controls had worsened.

When the researchers restricted their analysis to participants who were obese, the improvements with knee surgery persisted. In obese patients, physical function increased in surgery patients and deteriorated in controls.

"The long term improvement in physical function that we observed in patients who have undergone (knee replacement surgery) is striking when set against the decline that occurred in (the control group)," Cooper and colleagues say. "These benefits extend to patients who are obese."

"There seems no justification for withholding (knee replacement surgery) from patients who are obese," they conclude.

SOURCE: Annals of the Rheumatic Diseases, online July 24, 2008

Childcare before kindergarten may promote obesity

Participation in a childcare program appears to increase the likelihood that a child will be obese when he or she shows up for the first day of kindergarten, researchers report in the journal Pediatrics.Moreover, the report indicates that the type of childcare makes a difference. For instance, children who receive care from a relative, friend, or neighbor, held at least occasionally in the child's own home, were more prone to obesity than those who received care at a daycare center or nursery school.

Latino children, however, seemed to be the exception. While they were found to be at greater risk for obesity than kids of other races, they were less likely to become obese when enrolled in a childcare program rather than spending the week with a parent.

The study, conducted by Dr. Erin J. Maher, from Casey Family Programs in Seattle, and colleagues, involved nearly 16,000 first-time kindergartners who had or had not been enrolled in childcare, defined as spending at least 10 hours per week in care not provided by a parent.

Childcare was subdivided into four types: 1) paid or unpaid care by a relative, friend, or neighbor, held at least occasionally at the child's home; 2) paid care by a non-relative family outside the child's home; 3) Head Start; and 4) care at daycare center, nursery school, preschool, or pre-kindergarten. Children were considered to be obese if their weight was in the 95th or higher percentile for height.

Overall, kids in childcare were more likely to obese than children not in childcare. Of the various childcare types, care by a relative, friend, or neighbor was most strongly linked to obesity. Compared with other racial groups, white children were less likely and Latino children more likely to be obese.

"Our research points to the need to better understand how the specific features of childcare environments may promote or protect against the development of obesity," Dr. Maher's team concludes. "This understanding can then lead to the development of targeted interventions to reach children and families in childcare settings."

SOURCE: Pediatrics, August 2008.

Lack of REM sleep may raise obesity risk in kids

Studies have shown that children and teens who fail to get the proper amount of sleep each night are more prone to obesity, and researchers now think it may be linked to a particular stage of sleep.
They said not spending enough time in rapid eye movement, or REM, sleep -- the type that is normally associated with dreaming -- significantly increased the odds of obesity in children and teens.

"Our results demonstrated that the short sleep-obesity association may be attributed to reduced REM sleep," said Dr. Xianchen Liu of Western Psychiatric Institute and Clinic in Pittsburgh reported on Monday in the Archives of General Psychiatry.

Ultimately, obesity is the byproduct of taking in more calories than the body needs. But Liu and colleagues wanted to see if they could identify any stage of sleep that appeared especially important.

The researchers studied 335 children and adolescents aged 7 to 17 for three consecutive nights. Their sleep was monitored through polysomnography, which measures sleep cycles and stages by recording brain waves, electrical activity of muscles, eye movement, breathing rate, blood pressure, and other variables.

Weight and height were measured to calculate body mass index, a measure of obesity. They found 15 percent were at risk for becoming overweight and 13 were overweight.

When they compared the sleep patterns among these groups, they found children who were overweight slept about 22 minutes less per night than normal-weight children. They also had shorter REM sleep, less eye activity during REM sleep and a longer wait before the first REM period.

After adjusting for other factors, they found one hour less of total sleep doubled the odds of being overweight, and one-hour less of REM sleep tripled the odds.

"Although the precise mechanisms are currently under investigation, the association between short sleep duration and overweight may be attributed to the interaction of behavioral and biological changes as a result of sleep deprivation," Liu and colleagues wrote.

They said sleep loss causes changes in hormone levels that may affect hunger. It also gives a person more time in which to eat, and makes a person sleepy during the day, which may make them less likely to exercise.

Liu said more research is needed to understand changes in the metabolism that occur when children and teens get too little sleep.

They noted that the obesity rate has more than tripled among children aged 6 to 11 years in the past 30 years, and about 17 percent of U.S. adolescents are now overweight or obese.

Given this, the researchers think doctors, schools and families should step in to ensure that children get enough sleep.

Liu suggests parents establish regular bedtime and wake up times at both weekdays and weekends, improve the sleep environment and address any sleep disorders such as sleep apnea that may be keeping children from getting the sleep they need.

Kids Who Sleep Poorly at Risk for Being Overweight

Getting too little sleep or not spending enough time in rapid eye movement (REM) sleep is associated with being overweight among children and teens, a new U.S. study.For three consecutive nights, researchers assessed the sleep patterns of 335 youngsters, aged 7 to 17. They looked at total sleep time, time spent in REM, and time it took to fall asleep. Body-mass index was checked at the start of the study, and 45 participants (13.4 percent) were overweight, while 49 (14.6 percent) were at risk for becoming overweight.

Compared to normal-weight children, those who were overweight slept about 22 minutes less per night and had lower sleep efficiency (percentage of time in bed that a person is asleep), shorter REM sleep, less eye activity during REM sleep, and a longer wait before the first REM period.

After they adjusted for other factors, the researchers concluded that one hour less of total sleep was associated with a twofold increased risk of being overweight. One hour less of REM sleep was associated with a threefold increased risk.

Although the precise mechanisms are currently under investigation, the association between short sleep duration and overweight may be attributed to the interaction of behavioral and biological changes as a result of sleep deprivation, wrote Dr. Xianchen Liu, of the Western Psychiatric Institute and Clinic in Pittsburgh, and colleagues.

They explained that sleep loss causes changes in hormone levels that may affect hunger, and less sleep also means a person has more waking hours in which to eat. Sleep loss also contributes to fatigue the following day, which may lead to less physical activity and fewer calories burned.

Given the fact that the prevalence of overweight among children and adolescents continues to increase and chronic sleep insufficiency becomes more prevalent in modern society, family- and school-based sleep interventions that aim to enhance sleep hygiene and increase sleep duration may have important public health implications for the prevention and intervention of obesity and type 2 diabetes in children, the authors concluded.

"Furthermore, our results demonstrate an important relationship between REM sleep and high BMI and obesity, suggesting that the short sleep-obesity association may be attributed to reduced REM sleep time and decreased activity during REM sleep," they wrote.

The study was published in the August issue of the Archives of General Psychiatry.