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Changes in Weight Status to Infancy Linked to Risk for Later Obesity

Posted by Darryl Virgiawan on April 9, 2009

Laurie Barclay, MD

April 8, 2009 —- Changes in weight status in infancy are linked to risk for later obesity to an even greater extent than is weight status at birth, according to the results of an ongoing, prospective cohort study reported in the April issue of Pediatrics.

"Rapid weight gain during the first weeks or months of infancy predicts obesity and higher blood pressure later in childhood and adulthood," write Elsie M. Taveras, MD, MPH, from Harvard Medical School and Harvard Pilgrim Health Care in Boston, Massachusetts, and colleagues. "Preventive interventions beginning in infancy may help avoid lifetime complications of excess weight."

The study goal was to evaluate the associations of weight-for-length at birth and at 6 months with obesity at age 3 years among 559 children in Project Viva, a prospective study of pregnant women and their children. Obesity was defined as body mass index (BMI) in the 95th or higher percentile for age and sex.

Weight-for-length z score at birth was adjusted for gestational age, and weight-for-length z score at 6 months was adjusted for weight-for-length z score at birth. Multivariate regression analyses allowed determination of the independent effects of birth weight-for-length z score and, separately, 6-month weight-for-length z score on BMI z score, the sum of subscapular and triceps skinfold thicknesses, and obesity at age 3 years.

At birth, 6 months, and 3 years, mean weights were 3.55, 8.15, and 15.67 kg, respectively, and corresponding lengths were 49.9, 66.9, and 97.4 cm, respectively. Obesity at 3 years of age was present in 48 children (9%).

Each increment in 6-month weight-for-length z score was associated with higher BMI z scores, higher sums of subscapular and triceps skinfold thicknesses, and increased odds of obesity at age 3, after adjusting for confounding variables and birth weight-for-length z score. Among children in the highest quartiles of both birth and 6-month weight-for-length z scores, predicted obesity prevalence was 40% vs 1% for children in the lowest quartiles of both. Birth weight-for-length z scores were linked to higher BMI z scores, but the magnitude of effect was smaller than that of weight-for-length z scores at 6 months.

"More-rapid increases in weight for length in the first 6 months of life were associated with sharply increased risk of obesity at 3 years of age," the study authors write. "Changes in weight status in infancy may influence risk of later obesity more than weight status at birth."

Limitations of this study include inability to determine whether breast-feeding or quality of the infant diet after weaning was an intermediate of the relationship between changes in weight-for-length in infancy and later obesity; inability to examine social and behavioral interactions regarding infant feeding; lack of generalizability to more socioeconomically disadvantaged populations; most measures self-reported; and main outcome of obesity at age 3 rather than later in childhood.

"Additional studies are needed to identify the modifiable determinants of gain in adiposity in the early weeks or months of life that also underlie long-term risks of obesity- related sequelae," the study authors conclude. "The mounting evidence regarding infancy as a critical period in obesity prevention may support efforts of health professionals and public health researchers in formulating policies and interventions to reduce rapid infant weight gain. Given the increasing prevalence of childhood obesity, prevention efforts should assume new urgency in the 21st century."

The National Institutes of Health supported this study in part by grants from the National Institutes of Health. The Physician Faculty Scholars Program of the Robert Wood Johnson Foundation supported Dr. Taveras in part. The authors have disclosed no relevant financial relationships.

Pediatrics. April 2009;123:1177-1183.

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Laurie Barclay, MD is a freelance reviewer and writer for Medscape LLC.

Medscape Medical News 2009. © 2009 Medscape
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