Otago study finds childhood predictors of obesity

CHILDHOOD predictors of becoming overweight or obese as adults in New Zealand include being male, born into a singleparent family, having parents with larger body size and limited or no breastfeeding, new University of Otago research reveals.

International literature has identified childhood determinants of adult weight and obesity. However, less is known about the New Zealand context and the University of Otago research published in the latest issue of the New Zealand Medical Journal provides some answers.

‘‘Childhood predictors of adult adiposity: findings from a longitudinal study’’ is based on findings from 980 participants in the Christchurch Health and Development Study, a longitudinal study of 1265 children born in Christchurch during 1977.

These people have been studied regularly since birth to age 35, using a combination of interviews with parents and participants, standardised testing, teacher reports and official record data.

At ages 30 and 35 about onethird of the people studied were overweight and onefifth were obese.

Being male, born into a singleparent family, having parents with larger body size, limited or no breastfeeding, higher early infant growth, lower levels of cognitive ability and exposure to severe sexual abuse were all predictors of being overweight or obese as adults.

Director of the Christchurch study and one of the researchers for this project, Prof John Horwood, said none of the findings were particularly surprising and were in line with international evidence.

‘‘The findings confirm that risk of obesity is related to a complex mix of factors reflecting biological endowment, socioeconomic disadvantage, early diet and adverse childhood experience,’’ Prof Horwood said.

‘‘Individually, the identified risk factors have a relatively modest impact on adult weight, but jointly they can add up to something that is substantial,’’ he said.

‘‘So, if you have three or more risk factors there is likely to be an associated increased risk of obesity.’’

Most of the factors identified in the present study (such as gender, parental BMI and exposure to childhood sexual abuse) were unable to be changed or modified in the context of obesity prevention, the research paper stated.

The exceptions to this were longer duration of breastfeeding and weight gain in infancy, which had been shown in a number of studies to be associated with lower risk of adult obesity.

This suggested that strategies such as the promotion of breastfeeding, the encouragement of longer duration of breastfeeding, monitoring the use of formula and limiting the early introduction of solid foods could play key roles in any strategy designed to reduce obesity, the researchers said.

The researchers suggest it may be possible to integrate evidencebased early intervention for gaining weight through Plunket, Early Start and Family Start or similar agencies.

Former director of the Christchurch study, Emeritus Prof David Fergusson, current deputy director Associate Prof Joseph Boden, research fellow Dr Geraldine McLeod and Dr Frances Carter, formerly from the department of psychological medicine are coauthors of the Health Research Councilfunded study.