Poorer heavy kids may suffer more heart woes

Study suggests children in affluent areas may be fat, but not unhealthy

Overweight children from lower- and middle-income neighborhoods may fall short of their thinner peers in one measure of cardiovascular fitness — but the same may not be true of those from more affluent areas, a new study suggests.

Researchers found that among 480 children and teenagers who underwent treadmill exercise tests, those with a high body mass index tended to have a slower heart rate recovery after their workout — but only if they were from lower- or middle-income neighborhoods.

Extra pounds did not generally seem to affect heart rate recovery among kids from the highest-income areas, the study found.

Heart rate recovery refers to the amount of time it takes a person's heart rate to return to its resting rate after a bout of exercise. It is one measure of cardiovascular fitness.

It's not certain why a high BMI would affect kids' heart rate recovery differently based on income, but there are a couple potential explanations, according to lead researcher Dr. Tajinder P. Singh, of Children's Hospital Boston.

One has to do with how BMI is calculated, he told Reuters Health in an e-mail.

BMI is a measure of weight in relation to height, but it does not differentiate between weight from body fat and weight from muscle. It's possible, Singh said, that children and teens from more advantaged families were more likely than their peers to have a high BMI because of muscle mass.

Another potential explanation, Singh speculated, is that kids from affluent neighborhoods have healthier lifestyles — better diets, more opportunities for exercise — so that even if they are overweight, they may be in good health.

Whatever the reasons for the findings, Singh said they suggest that lower- to middle-income children stand to gain the most from losing excess weight.

The findings, published in the Archives of Pediatrics & Adolescent Medicine, are based on the records of 480 children who underwent exercise testing at Children's Hospital Boston because of symptoms such as breathlessness and heart palpitations during physical activity. The tests were done to rule out heart disease, and all of the children had normal results.

Singh's team divided the children into three groups based on the socioeconomics of their neighborhoods. In the most affluent neighborhoods, the median household income was just over $100,000, and two-thirds of residents older than 25 had a college degree. In the least advantaged neighborhoods, the median income was $40,000, and 19 percent of residents older than 25 had a college degree.

Of all 480 children and teens, 70 percent had a normal BMI while the rest had a high BMI — with 17 percent falling into the "overweight" BMI category and 13 percent into the obese category.

Heart rate recovery was measured one minute after the children completed their exercise tests. Overall, Singh's team found that in the lower- and middle-income groups, overweight kids were slower to return to their pre-exercise heart rate than their normal-BMI counterparts.

On the other hand, normal-weight kids had similar heart rate recovery results regardless of socioeconomics.

One implication of the findings, Singh said, is that "children who have normal weight are likely to have good cardiovascular health irrespective of their socioeconomic position."

Another, he added, is that while weight loss is important for all kids who are overweight or obese, it may be "most immediately beneficial" for those from lower- to middle-income families.

Studies in adults have linked slower heart rate recovery to a higher risk of heart disease. But there are no studies on whether slower recovery in children predicts an increased risk of heart problems later in life.

 

Morbidly obese 'may have missing genes'

A small number of extremely overweight people may be missing the same chunk of genetic material, claim UK researchers.

The findings, published in the journal Nature, could offer clues to whether obesity can be "inherited" in some cases.

Imperial College London scientists found dozens of people - all severely obese - who lacked approximately the same 30 genes.

The gene "deletion" could not be found in people of normal weight.

While much of the "obesity epidemic" currently affecting most Western countries has been attributed to a move towards high-calorie foods and more sedentary lifestyles, scientists have found evidence that genes may play a significant role in influencing weight gain in some people.

The latest study focused on the "morbidly obese", who have a Body Mass Index (BMI) of more than 40, and who are at the highest risk of health problems.

There are an estimated 700,000 of these people in the UK.

'Learning difficulties'

The first clue came by looking at a group of teenagers and adults with learning difficulties, who are known to be at higher risk of obesity, although the reasons for this are not entirely clear.

They researchers found 31 people who had nearly identical "deletions" in their genetic code, all of whom had a BMI of over 30, meaning they were obese.

Then a wider scan of the genetic makeup of a mixture of more than 16,000 obese and normal weight people revealed 19 more examples of the missing genes.

All of the people involved were classed as "morbidly obese", with a BMI of over 40, and at the highest risk of health problems related to their weight.

Most of them had been normal weight as toddlers, but then became overweight during later childhood.

None of the people studied with normal weight had the missing code.

The precise function of the missing genes is unclear, as is the precise nature of the relationship between learning difficulties and obesity - none of the people with the deletions in the wider study had learning problems.

Weight-loss surgery

Professor Philippe Froguel, from Imperial College, said: "It is becoming increasingly clear that for some morbidly obese people, their weight gain has an underlying genetic cause.

"If we can identify these individuals through genetic testing, we can then offer them appropriate support and medical interventions, such as the option of weight loss surgery, to improve their long-term health."

Dr Robin Walters, also from Imperial, said that while this particular set of deletions was rare - affecting some seven in 1,000 morbidly obese people - there were likely to be other variations yet to be found.

"The combined effect of several variations of this type could explain much of the genetic risk for severe obesity, which is known to run in families."

Dr Sadaf Farooqi, from Cambridge University, who collaborated with this research, and was involved in similar research published in December which pointed to another gene flaw which could be linked to obesity.

She said it was likely that a "patchwork" of different genetic variations would eventually emerge to explain more cases of obesity - perhaps by affecting appetite, or the rate at which the body burns fat.

She said: "There is still an important public health message about diet and exercise, but simply blaming people for their obesity is no longer appropriate."

Overweight elderly 'live longer'

Moderately overweight elderly people may live longer than those of normal weight, an Australian study suggests.

But being very overweight or being underweight shortened lives.

The report, which was published in the Journal of the American Geriatric Society, said dieting may not be beneficial in this age group.

But the study of 9,200 over-70s also found that regardless of weight, sedentary lifestyles shortened lives, particularly for women.

The study by the University of Western Australia set out to find out what level of body mass index (BMI) was associated with the lowest risk of death in the elderly.

For younger people, there is a well established health risk from being overweight or obese.

Overweight best

The team tracked the number of deaths over 10 years among volunteers who were aged 70 - 75 at the start of the study.

It found that those with a BMI which classed them as overweight not only had the lowest overall risk of dying, they also had the lowest risk of dying from specific diseases: cardiovascular disease, cancer and chronic respiratory disease.

The overall death rate among the obese group was similar to that among those of normal weight.

But those who were very obese had a greater risk of dying during the 10 year period.

Lead researcher, Professor Leon Flicker said: "Concerns have been raised about encouraging apparently overweight older people to lose weight.

"Our study suggests that those people who survive to age 70 in reasonable health have a different set of risks and benefits associated with the amount of body fat to younger people."

The conclusion of this study, that being overweight may be less harmful for elderly people, corroborates the findings of previous research.

Staying still

Sedentary lifestyles shortened lives across all weight groups, doubling the risk of mortality for women over the period studied, and increasing it by 25% for men.

Physical exercise "really matters", said Professor Flicker.

As well as helping to build muscle mass, it has broader health benefits for elderly people, he said.

The authors believe BMI may give a poor reflection of fatty mass in elderly people.

"It may be time to review the BMI classification for older adults," says Professor Flicker.

Professor Kay-Tee Khaw from Cambridge University agreed, noting that optimal weight appears to be higher in older age groups.

"This is important since under-nutrition is an important problem in older people.

"Waist circumference, which assesses abdominal obesity, appears to be a better indicator of health consequences of obesity" she said.