CHICAGO (AP) — Researchers say there's a new way to tell if infants are likely to become obese later on: Check to see if they've passed two key milestones on doctors' growth charts by age 2.
Babies who grew that quickly face double the risk of being obese at age 5, compared with peers who grew more slowly, their study found. Rapid growers were also more likely to be obese at age 10, and infants whose chart numbers climbed that much during their first 6 months faced the greatest risks.
That kind of rapid growth should be a red flag to doctors, and a sign to parents that babies might be overfed or spending too much time in strollers and not enough crawling around, said pediatrician Dr. Elsie Taveras, the study's lead author and an obesity researcher at Harvard Medical School.
Contrary to the idea that chubby babies are the picture of health, the study bolsters evidence that "bigger is not better" in infants, she said.
But skeptics say not so fast. Babies often grow in spurts and flagging the speediest growers could lead to putting infants on diets — a bad idea that could backfire in the long run, said Dr. Michelle Lampl, director of Emory University's Center for the Study of Human Health.
"It reads like a very handy rule and sounds like it would be very useful — and that's my concern," Lampl said. The guide would be easy to use to justify feeding infants less and to unfairly label them as fat. It could also prompt feeding patterns that could lead to obesity later, she said.
Lampl noted that many infants studied crossed at least two key points on growth charts; yet only 12 percent were obese at age 5 and slightly more at age 10. Nationally, about 10 percent of preschool-aged children are obese, versus about 19 percent of those aged 6 to 11.
Lampl and Edward Frongillo, an infant growth specialist at the University of South Carolina, voiced concern in an editorial accompanying the study in the journal Archives of Pediatrics & Adolescent Medicine, released online Monday. They argue that more research is needed to confirm whether the study's recommendation is really a useful way to flag infants for obesity.
"The potential to do more harm than good is actually very high," Frongillo said.
Taveras said the kind of rapid growth noted in the study should be used to raise awareness about potential risks but is not a reason to put babies on a diet.
The study involved 45,000 infants and children younger than age 11 who had routine growth measurements during doctor checkups in the Boston area from 1980 through 2008.
Growth charts help pediatricians plot weight, length in babies and height in older kids in relation to other children their same age and sex. Pediatricians sometimes combine an infant's measures to calculate weight-for-length — the equivalent of body-mass index, or BMI, a height-to-weight ratio used in older children and adults.
The charts are organized into percentiles. For example, infants at the 75th percentile for weight are heavier than 75 percent of their peers.
The study authors used seven major cutoffs on the charts — the 5th, 10th, 25th, 50th, 75th, 90th and 95th percentiles — to calculate growth pace. An infant whose weight-for-length jumped from the 19th percentile at 1 month to the 77th at 6 months crossed three major percentiles — the 25th, 50th and 75th — and would be at risk for obesity later in childhood, the authors said.
Larger infants were most at risk for obesity later on, but even smaller babies whose growth crossed at least two percentiles were at greater risk than those who grew more slowly.
About 40 percent of infants crossed at least two percentiles by age 6 months. An analysis of more than one-third of the study children found that 64 percent grew that rapidly by age 2.
Dr. Joanna Lewis, a pediatrician at Advocate Lutheran General Hospital in Park Ridge, Ill., said she supports the idea that infancy is not too young to start thinking about obesity.
Still, she emphasized that rapid growth in infancy doesn't mean babies are doomed to become obese. "It's not a life sentence," and there are steps parents can take to keep their babies at a healthy weight without restrictive diets, she said.
Lewis said many of her patients are large babies whose parents feed them juice or solid food despite guidelines recommending nothing but breast milk or formula in the first six months.
"The study reinforces what we try to tell parents already: Delay starting solids and don't put juice in a bottle," Lewis said.
Lewis also advises parents that when starting infants on solid food, have the whole family sit down and eat together. Research has shown that obesity is less common in children raised in families that have frequent meals together at home.
<한글 기사>
“영유아 때 성장속도로 비만여부 예측 가능해”
아기의 성장속도 관찰을 통해 이후 비만 여부를 미리 알 수 있다고 미국 하버드 대학 연구팀이 밝혀 주목된다.
하버드 대학 의대 엘시 태버라스 박사팀은 생후 2년까지 성장속도를 나타내는 ‘키ㆍ몸무게 비율’이 또래보다 높을 경우 아동기에 비만이 될 확률이 높다고 ‘소아ㆍ청소년의학 기록’(Archives of Pediatrics & Adolescent Medicine)에 9일 발표했다. 키ㆍ몸무게 비율은 성인의 체질량지수(BMIㆍ체중을 키의 제곱으로 나눈 값)에 준하는 성장지표로, 이 비율이 75분위일 경우 나이ㆍ성별이 동일한 아동 중 성장속도가 상위 25% 안에 든다는 뜻이다.
연구진은 1980년에서 2008년까지 보스턴에 거주하는 11세 미만 아동 및 영유아 4만5000명 대상으로 정기검진을 통해 성장상태를 확인했다. 그 결과 2세 때 키ㆍ몸무게 비율 75분위를 넘는 아동들은 75분위 이하에 있는 아동들에 비해 5세 때 비만이 될 위험이 두 배나 높았다. 이 아동들은 10세 때 비만이 될 위험도 성장속도가 늦은 아동들에 비해 다소 높은 것으로 나타났다.
생후 6개월까지 성장이 급격하게 이루어진 아동 역시 비만 위험이 높았다. 생후 1개월 때 키ㆍ몸무게 비율이 19분위에서 생후 6개월에 77분위까지 치솟은 유아들은 이후 비만이 될 가능성이 유의하게 높았다. 또한 키ㆍ몸무게 비율이 2분위 이하로 평균보다 훨씬 낮은 영유아의 경우 성장속도가 평균인 영유아보다 비만 위험이 더 큰 것으로 나타난 것도 주목할 필요가 있다고 연구팀은 밝혔다.
연구진은 영유아기의 너무 빠른 성장을 주목할 필요가 있다면서 “부모가 너무 많이 먹이고 있다거나 유모차에서 지나치게 많은 시간을 보내고 있다는 사인이 될 수 있다”고 밝혔다. 엘시 박사는 “통통한 아기들이 건강하다는 통념을 재고할 필요가 있다”면서 “큰 것이 좋은 것이란 속설은 아기들에게 적용되지 않으며 영유아기에도 운동부족은 큰 문제를 초래할 수 있다”고 밝혔다.
이에 대해 미 애드버킷 루터 종합병원의 조애나 루이스 박사는 “영유아기부터 비만문제를 주의해야 한다”면서도 이번 연구결과로 아기들의 식이를 지나치게 제한하는 것은 경계해야 한다고 밝혔다. 에모리 대학 미셸 램플 박사도 “이번 연구결과가 자칫 아기들의 성장을 제한해야 한다는 메시지를 줄 위험이 있다”고 우려를 나타냈다. 태버라스 박사는 “성장속도는 잠재위험을 알리는 요인일 뿐 아기에 다이어트를 시키란 뜻은 아니다”라고 밝혔다. (헤럴드 생생뉴스)
